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US20120158861A1 - Sip-based custodian routing in content-centric networks - Google Patents
Sip-based custodian routing in content-centric networks Download PDF
Marc E. Mosko
Simon Barber
Cisco Technology Inc
Palo Alto Research Center Inc
2010-12-16 Application filed by Palo Alto Research Center Inc filed Critical Palo Alto Research Center Inc
2010-12-17 Assigned to PALO ALTO RESEARCH CENTER INCORPORATED reassignment PALO ALTO RESEARCH CENTER INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BARBER, SIMON, MOSKO, MARC E.
2016-12-02 Assigned to SAMSUNG ELECTRONICS CO., LTD, PALO ALTO RESEARCH CENTER INCORPORATED reassignment SAMSUNG ELECTRONICS CO., LTD ASSIGNMENT (IN PART) Assignors: PALO ALTO RESEARCH CENTER INCORPORATED
2017-02-14 Assigned to CISCO SYSTEMS, INC. reassignment CISCO SYSTEMS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PALO ALTO RESEARCH CENTER INCORPORATED
2017-02-14 Assigned to CISCO TECHNOLOGY, INC. reassignment CISCO TECHNOLOGY, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CISCO SYSTEMS, INC.
H04L65/10—Signalling, control or architecture
H04L65/1066—Session control
H04L65/1069—Setup
H04L65/1096—Features, e.g. call-forwarding or call hold
H04L29/00—Arrangements, apparatus, circuits or systems, not covered by a single one of groups H04L1/00 - H04L27/00
H04L29/12—Arrangements, apparatus, circuits or systems, not covered by a single one of groups H04L1/00 - H04L27/00 characterised by the data terminal
H04L29/12009—Arrangements for addressing and naming in data networks
H04L29/1233—Mapping of addresses of the same type; Address translation
H04L29/12339—Internet Protocol [IP] address translation
H04L29/1249—NAT-Traversal
H04L29/12528—NAT-Traversal using address mapping retrieval, e.g. Simple Traversal of UDP through NATs [STUN]
H04L29/12594—Arrangements for managing names, e.g. use of aliases or nicknames
H04L61/00—Network arrangements or network protocols for addressing or naming
H04L61/25—Network arrangements or network protocols for addressing or naming mapping of addresses of the same type; address translation
H04L61/2503—Internet protocol [IP] address translation
H04L61/256—Network address translation [NAT] traversal
H04L61/2575—Network address translation [NAT] traversal using address mapping retrieval, e.g. simple traversal of user datagram protocol through NAT [STUN]
H04L61/30—Arrangements for managing names, e.g. use of aliases or nicknames
One embodiment of the present invention provides a system for facilitating establishment of connections between a local endpoint and a remote endpoint. During operation, the system sends, from the local endpoint, a single connection-request message to a proxy server, which forks the single connection-request message to a number of remote endpoints. The system receives one or more response messages from the remote endpoints. A respective response message carries address information associated with the remote endpoint. Upon receiving the response message, the system sends an acknowledgment corresponding to the received response message to the corresponding remote endpoint via the proxy server, and establishes a connection between the local endpoint and at least one remote endpoint.
The subject matter of this application is related to the subject matter of the following applications:
U.S. patent application Ser. No. 12/123,344 (Attorney Docket No. PARC-20080361-US-NP), entitled "VOICE OVER CONTENT-CENTRIC NETWORKS," by inventors Paul J. Stewart, Van L. Jacobson, Michael F. Plass, and Diana K. Smetters, filed 19 May 2008;
U.S. patent application Ser. No. 12/332,560 (Attorney Docket No. PARC-20080625-US-NP), entitled "METHOD AND APPARATUS FOR FACILITATING COMMUNICATION IN A CONTENT-CENTRIC NETWORK," by inventor Van L. Jacobson, filed 11 Dec. 2008;
U.S. patent application Ser. No. 12/565,005 (Attorney Docket No. PARC-20090115Q-US-NP), entitled "SYSTEM FOR FORWARDING A PACKET WITH A HIERARCHICALLY STRUCTURED VARIABLE-LENGTH IDENTIFIER," by inventors Van L. Jacobson and James D. Thornton, filed 23 Sep. 2009;
U.S. patent application Ser. No. 12/638,478 (Attorney Docket No. PARC-20090115-US-NP), entitled "SYSTEM FOR FORWARDING PACKETS WITH HIERARCHICALLY STRUCTURED VARIABLE-LENGTH IDENTIFIERS USING AN EXACT-MATCH LOOKUP ENGINE," by inventors Van L. Jacobson and James D. Thornton, filed 15 Dec. 2009;
U.S. patent application Ser. No. 12/640,968 (Attorney Docket No. PARC-20090115Q1-US-NP), entitled "METHOD AND SYSTEM FOR FACILITATING FORWARDING A PACKET IN A CONTENT-CENTRIC NETWORK," by inventors Van L. Jacobson and James D. Thornton, filed 17 Dec. 2009;
U.S. patent application Ser. No. 12/970,740 (Attorney Docket No. PARC-20100498-US-NP), entitled "CUSTODIAN-BASED ROUTING IN CONTENT-CENTRIC NETWORKS," by inventors Van L. Jacobson and Marc E. Mosko, filed 16 Dec. 2010;
U.S. patent application Ser. No. 12/970,776 (Attorney Docket No. PARC-20100499-US-NP), entitled "ENERGY-EFFICIENT CACHING WITH CUSTODIAN-BASED ROUTING IN CONTENT-CENTRIC NETWORKS," by inventor Van L. Jacobson, filed 16 Dec. 2010; and
U.S. patent application Ser. No. 12/970,802 (Attorney Docket No. PARC-20100500-US-NP), entitled "ENERGY-EFFICIENT CONTENT RETRIEVAL IN CONTENT-CENTRIC NETWORKS," by inventor Van L. Jacobson, filed 16 Dec. 2010;
the disclosures of which are incorporated by reference in their entirety herein.
The present disclosure relates generally to routing in content-centric networks. More specifically, the present disclosure relates to an apparatus and a method for facilitating session initiation protocol (SIP)-based custodian routing in a content-centric network with firewalls.
RELATED ART
The proliferation of the Internet and e-commerce continues to fuel revolutionary changes in the network industry. Today, a significant number of information exchanges, from online movie viewing to daily news delivery, retail sales, and instant messaging, are conducted online. An increasing number of Internet applications are also becoming mobile. However, the current Internet operates on a largely location-based addressing scheme. That is, a consumer of data can only receive the data by explicitly requesting the data from an address (e.g., IP address) closely associated with a physical object or location. This restrictive addressing scheme is becoming progressively inadequate for meeting the ever-changing network demands.
The current architecture of the Internet revolves around a conversation model, which was created in the 1970s for the ARPAnet to allow geographically distributed users to use a few big, immobile computers. This architecture was designed under the influence of the telephone network, where a telephone number is essentially a program that configures the switches along a path from the source to the destination. Not surprisingly, the designers of the ARPAnet never expected it to evolve into today'subiquitous, relentlessly growing Internet. People now expect a lot more from the Internet than the ARPAnet was designed to provide. Ideally, an Internet user should have access to any content, anywhere, at any time—a task that is difficult to perform with the current location/device-binding TCP/IP (transmission control protocol/Internet protocol) networks.
Content-centric networks (CCNs), also referred to as "content-based networks," bring a new approach to data transport in a network. Instead of having network traffic viewed at the application level as end-to-end conversations over which content travels, content is requested or returned based on the name given to it, and the network is responsible for routing data, or "content," from the provider to the consumer.
One embodiment of the present invention provides a system for facilitating establishment of a connection between a local endpoint and a remote endpoint. During operation, the system sends, from the local endpoint, a single connection-request message to a proxy server, which forks the single connection-request message to a number of remote endpoints. The system receives one or more response messages from the remote endpoints. A respective response message carries address information associated with the remote endpoint. Upon receiving the response messages, the system sends an acknowledgment corresponding to the received response message to a remote endpoint associated with the received response message via the proxy server, and establishes at least one connection between the local endpoint and the multiple remote endpoints.
In one variation on this embodiment, the local endpoint, the remote endpoints, or both are respectively behind a network address translation (NAT) firewall.
In a further variation, the system further determines the type of NAT firewall behind which the local endpoint resides, and in response to the local endpoint not being behind any NAT or behind a cone type NAT, the system sends a single connection-request message to the proxy server. The connection-request message carries address and port information associated with the external side of the NAT through which the local endpoint can be reached, or if no NAT is detect then the local endpoint.
In one variation on this embodiment, the proxy server is a session initiation protocol (SIP) proxy server, and the connection-request message is a SIP INVITE message without SDP payload.
In a further variation, the response message is a SIP provisional response or a 200/OK message which carries a session description protocol (SDP) offer.
In a further variation, the SDP offer includes a list of addresses corresponding to the remote endpoint associated with the response message. The list of addresses includes a NAT external address and may also include a local address and port, and/or an external relay address.
In a further variation, the acknowledgement is a SIP PRACK or ACK message, and the SIP PRACK or ACK message carries a session description protocol (SDP) answer.
In a further variation, the SDP answer includes a list of addresses corresponding to the local endpoint. The list of addresses includes at least one of: a local address and port, a NAT external address and port, and an external relay address.
In one variation on this embodiment, the system further determines whether one or more remote endpoints are in an energy-saving sleep mode. In response to the one or more remote endpoints being in the energy-saving sleep mode, the system wakes up at least one of the remote endpoints using an out-of-band signal.
In a further variation, the out-of-band signal includes a telephone call, a text message, or both.
In one variation on this embodiment, the local endpoint and the remote endpoint are coupled to a content-centric network (CCN).
FIG. 1 presents a diagram illustrating the exemplary system architecture for custodian routing in accordance with an embodiment of the present invention.
FIG. 2 presents a diagram illustrating whether NAT traversals are possible when establishing endpoint-to-endpoint connections for all combination of NATs.
FIG. 3 presents a diagram illustrating an exemplary scenario where a proxy attempts to setup point-to-multipoint (forked) connections.
FIG. 4 presents a diagram illustrating whether multiple NAT traversals are possible when establishing point-to-multipoint (forked) connections for all combination of NATs.
FIG. 5 presents a block diagram illustrating the architecture of a device capable of implementing a SIP-based rendezvous in accordance with an embodiment of the present invention.
FIG. 6 presents a time-space diagram illustrating the process of a SIP-based rendezvous in accordance with an embodiment of the present invention.
FIG. 7 presents an exemplary computer system for facilitating SIP-based rendezvous in accordance with an embodiment of the present invention.
In the figures, like reference numerals refer to the same figure elements.
The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
The data structures and code described in this detailed description are typically stored on a computer-readable storage medium, which may be any device or medium that can store code and/or data for use by a computer system. The computer-readable storage medium includes, but is not limited to, volatile memory, non-volatile memory, magnetic and optical storage devices such as disk drives, magnetic tape, CDs (compact discs), DVDs (digital versatile discs or digital video discs), or other media capable of storing computer-readable media now known or later developed.
Embodiments of the present invention provide session initiation protocol (SIP)-based rendezvous that facilitate custodian routing in content-centric networks (CCNs) with firewalls. In embodiments of the present invention, a custodian for content periodically registers with a SIP proxy, which maintains information for a number of endpoints associated with the custodian. When a content requester attempts to establish a connection with at least one communication endpoint of the custodian, it sends a SIP INVITE that contains no session description protocol (SDP) payload to the SIP proxy, which then replicates the payload-less SIP INVITE and sends one INVITE to each endpoint associated with the custodian. When an endpoint of the custodian responds to the INVITE, it sends a SIP 200/OK message including a SDP payload to the content requester via a SIP proxy server, making this message a SDP offer. By responding to the SDP offer with an SDP answer (in a SIP ACK message), the content requester sends its own connection information to an endpoint on the custodian. Consequently, multiple SIP sessions can be established between the content requester and the custodian across various types of network address translation (NAT) firewalls, including certain types of symmetric NAT firewalls.
Although the present disclosure is presented using examples based on the CCN, embodiments of the present invention are not limited to the CCN.
The term "custodian" refers to a device that stores the content of interest. A custodian can be any type of device that is capable of storing data in volatile or non-volatile storage. A custodian can be a mobile computing device, such as a laptop computer, a tablet or slate computer, a smartphone, or a personal digital assistant (PDA), or a stationary computing device, such as a desktop computer or a home media server.
The term "communication endpoint" refers to a communication interface located on a computing device, through which a remote device can communicate with the computing device. A "communication endpoint" can be any type of communication interface, including, but not limited to: a WiFi™ (trademark of the Wi-Fi Alliance) interface, a 3G cellular interface, and a Bluetooth™ (trademark of the Bluetooth Special Interest Group of Kirkland, Wash.) interface.
Content-Centric Network
In a content-centric network (CCN), communication is driven by the consumers of data. In a CCN, there are two packet types, interest packet and data packet. An interest packet (also called a "query") is a request for some content. An interest packet encodes a special form of query that expresses what content is desired and what content is not desired. A data packet (also called a "content packet") is a unit of content. Data packets are self-identifying by carrying within them their full name. A consumer asks for content by broadcasting its interest over all available connectivity. Any node hearing the interest and having data that satisfies it can respond with a data packet. Data is transmitted only in response to an interest and consumes that interest. Both interest and data identify the content being exchanged by the content name (or CCN name). In one embodiment, data can "satisfy" an interest if the CCN name in the interest packet is a prefix of the CCN name in the data packet.
CCN names are opaque, binary objects composed of an explicitly specified number of components. In addition, CCN names are persistent and content-specific. That is, if one changes the content of a file or data object, the content is effectively associated with a new name. This persistency can be achieved with an explicit versioning mechanism where, for example, the new content can be "version 4" of a given name. The persistency can also be achieved implicitly. For example, contents can be associated with not only their human-established names but also with authentication metadata (e.g., a digital signature by the publisher of the content). As a result, the complete content name changes when the data associated with a given name changes.
Functionally, a CCN can retain associations among various names and the content which they represent. The names are hierarchically structured, have variable length, and in many situations can be understood by a user. For example, "/abcd/bob/papers/ccn/news" could be the name of an article, i.e., the "news" article from the "ccn" collection of papers for a user named "Bob" at the organization named "ABCD." In a CCN, from an application's perspective, there is no need for a content consumer to determine how to find the "ABCD" organization, or to find which host there holds Bob's CCN publications. In one embodiment, to request a piece of content, a device in the CCN registers with the network that it is interested in that content by its name, and the content, if available in the local network, is routed back to it. The routing infrastructure takes care of intelligently propagating the interest to the prospective publishers, and then carrying any available content back along the path which the interest traversed.
CCNs have additional properties which make them especially appealing. All content can be cryptographically authenticated, meaning that some subset of nodes on the network (e.g., a legitimate querier of the content) can verify the authenticity of a piece of content. CCNs also allow data to be accessed by name, independent of publisher. At the same time, one can tailor a specialized request for data by a certain publisher. For example, one can ask for "foo.txt," or "foo.txt signed by Bob." Any form of self-verifying name can be used as a contract between producer and consumer. It is also possible to use hybrid self-verifying names, where the former components of the name are for organization and efficient routing, and the latter components of the name are self-verifying. Finally, CCNs allow the separation of content and trust, enabling different data consumers to use different mechanisms for establishing trust in the same piece of content. Although content might have been signed by a single publisher, it can be trusted for different reasons. For example, one user might trust a given piece of content because of a direct personal connection with its signer, whereas another user might trust the same content because of the content signer's participation in a Public Key Infrastructure (PM) which that user has chosen to trust.
Custodian-Based Routing
To enable content sharing among various user devices within a social network group, custodian-based routing can be implemented over a CCN-based content delivery network (CDN) that includes various user devices. In a CDN implementing custodian-based routing, content is associated with devices storing it, called custodians. A request for a particular piece of content can always be routed to its custodian, regardless of the physical location of the custodian.
To ensure that the requesting party of a piece of content can correctly connect to the custodian of that content, the CCN-based CDN maintains three different types of mapping, including content-prefix-to-custodian mapping, custodian-to-communication-endpoint mapping, and communication-endpoint-to-physical-address mapping. Each time a device interacts with another device, they exchange the three mappings with each other to make sure that the routing information is distributed across the CDN. Alternatively, the communication-endpoint-to-physical-address mapping information can be stored at a third-party service, such as a public session initiation protocol (SIP) server which provides rendezvous service between the requesting party and the custodian.
Details about custodian-based routing can be found in U.S. patent application Ser. No. TBD (Attorney Docket No. PARC-20100498-US-NP), entitled "CUSTODIAN-BASED ROUTING IN CONTENT-CENTRIC NETWORKS," by inventors James D. Thornton, Van L. Jacobson, and Marc Mosko, filed TBD, the disclosure of which is incorporated by reference in its entirety herein.
NAT Traversal
FIG. 1 presents a diagram illustrating the exemplary system architecture for custodian routing in accordance with an embodiment of the present invention. System 100 includes a number of devices, such as a laptop computer 102, a media server 104, a desktop computer 106, a smartphone 108, and a proxy server 110. Laptop computer 102, media server 104, desktop computer 106, and smartphone 108 are coupled to both a CCN 120 and a conventional network 130, such as an IP-based network. Proxy server 110 is coupled to conventional network 130. In one embodiment, proxy server 110 is a SIP proxy server. Note that CCN 120 can also be overlaid on top of conventional network 130.
During operation, laptop computer 102 requests a piece of content, and after performing content-prefix-to-custodian mapping, laptop computer 102 determines that smartphone 108 is the custodian of such content, and identifies that smartphone 108 has two logical endpoints. Note that a logical endpoint is a high-level representation of a physical communication endpoint, and is possibly combined with a rendezvous mechanism. In one embodiment, a custodian publishes a logical-endpoint entry for each way in which the custodian may be contacted. For example, the two logical endpoints of smartphone 108 may include a WiFi endpoint and a 3G cellular endpoint, and smartphone 108 may publish the entries as: "cell_sip," "wifi_sip," and "wifi_homenet." These entries tell other parties, such as laptop computer 102, how to connect to smartphone 108. For example, "cell_sip" and "wifi_sip" mean that its cellular and WiFi interfaces can be reached by establishing a point-to-point tunnel negotiated via SIP, and "wifi_homenet" means that the WiFi interface can also be connected to directly if smartphone 108 is on the home (trusted) WiFi network.
In one embodiment the content-prefix-to-custodian mapping and custodian-to-logical-endpoint mapping are exchanged/distributed among all devices coupled to CCN 112 whenever these devices communicate with each other. Subsequently, the identified logical endpoints are mapped to their network endpoint identifiers (NEIs), which are network addressees, such as IP sockets (IP addresses and ports). Note that the logical-endpoint-to-NEI mapping is dynamic, because a logical endpoint's NEI can change frequently. For example, the NEI of the WiFi interface of smartphone 108 changes whenever smartphone 108 is coupled to a different WiFi hotspot. In addition, the logical-endpoint-to-NEI mapping often involves issues arising from the presence of network address translation (NAT) firewalls. More specifically, in the case where a custodian includes multiple logical endpoints, trying to establish connections with the multiple endpoints can be challenging in the presence of NAT firewalls.
Device routing in the presence of NAT requires a NAT traversal process, such that an endpoint may find the current network address of another endpoint, thus enabling establishment of connection between the two endpoints. There are six different endpoints scenarios, including one in which an endpoint is not behind a NAT and scenarios where an endpoint is behind one of the five types of NATs. The five types of NAT include: full-cone NAT, address-restricted cone (AC) NAT, port-restricted cone (PC) NAT, predictable symmetric (PS) NAT, and randomized symmetric (RS) NAT.
Cone NATs are NATs that always map any particular internal address and port combination to the same external address and port combination, as long as the NAT binding is kept alive. Therefore, multiple connections can be made from the same internal address and port to different remote addresses and ports, and all the connections will appear to come from the same NAT external address and port. Depending on the filtering ability, cone NATs are also categorized as FC NAT, AC NAT, and PC NAT.
If an endpoint is behind a FC NAT, once the NAT binding is created, any remote external address and port can send data to the NAT external address and port and the data will be forwarded to the internal host address and port. There is no filtering here, and as soon as the NAT binding is created, anyone on the Internet can use it to send data to that particular internal host address and port. FC NAT is the least restrictive kind of NAT, and is the easiest to traverse, but opens up the highest security risk.
An AC NAT adds some address filtering. If an endpoint is behind an AC NAT, only remote external addresses that have a NAT binding open to them can send data back to the internal address, yet those remote external hosts can do so from any port number—not just the port the binding was opened to. AC NAT implements a simple address filter to prevent anyone on the Internet using the NAT binding by limiting the IP addresses that can send data to the internal host through the NAT to those external hosts that has previously received data from the internal host. AC NAT provides better security than an FC NAT, but is still relatively easy to traverse.
A PC NAT adds further port filtering. In the situation where a PC NAT is implemented, when a NAT binding is set up from an internal address and port to a remote external address and port, only that exact remote address and port can send data back to the internal address and port through the PC NAT.
A Symmetric NAT is different from a Cone NAT. Symmetric NATs map each connection, defined by a 4 tuple (local internal address, local internal port, remote address, remote port), to a different NAT external address and port. Symmetric NATs are substantially harder to traverse, and in some cases it is impractical to traverse a symmetric NAT. Symmetric NATs can be divided into 2 classes, including the predictable symmetric (PS) NAT and the randomized symmetric (RS) NAT. Note that a large NAT box may have a number of external addresses, although normally the number is normally relatively small.
A PS NAT refers to a symmetric NAT that allocates its external address/port combinations in a predictable fashion. For example, consecutive connections through the PS NAT may be mapped to sequential external port numbers. Both the loading of the NAT box and the internal algorithm for allocating NAT bindings affect the predictability. The predictability can be discovered by performing a number of test connections to a test server (more than one server address is required), and looking for patterns in the external addresses used by the NAT box.
An RS NAT refers to a NAT box that hands out apparently random address and port combinations. An RS NAT box may maintain an unordered list of unused mappings, and returns mappings to the start or end of the list as they time out, which will over time randomize the list. Consequently, a subsequent connection is mapped to an apparently random address/port combination. Lightly loaded symmetric NATs, such as those used in homes or small businesses are often predictable. Heavily loaded symmetric NATs, such as those used by service providers or large corporations, are frequently not predictable because many ports are in use and the pattern of available ports becomes quickly randomized regardless of allocation algorithm in use.
NAT traversal is required to establish an endpoint-to-endpoint connection in the presence of NAT. A common method used for NAT traversal is based on the interactive connectivity establishment (ICE) protocol. ICE involves the local host sending an offer with a list of possible connection addresses (including ports) for the local host to a remote host via a third party. This list of the possible connection addresses and ports includes an address and port for each of the host's local interfaces (usually only one), as well as the external address and port for any NAT box the host is behind. The NAT external address and port is usually determined by sending packets out to a well-known server on the external network, which replies with the address it observed from which the requests are sent. The session traversal utilities for NAT (STUN) protocol can be used for this purpose. By sending out several such requests to at least two servers, a client can determine what type of NAT it is behind, and predict an address it will be reachable by almost all NAT cases, except the RS NAT. Optionally, a third type of address is included, which is the address of an external relay server. The relay server allows the endpoint to be reached in cases where the NAT is not traversable. The traversal using relay NAT (TURN) protocol can be used to setup and discover an external relay address. Upon receiving the list of possible connection addresses and ports for the local host, the remote host responds with a list of its own possible connection addresses and ports, which are generated in the same way. As soon as each host obtains the list of the possible connection addresses and hosts for the other host, each tries to establish all possible connections between each other. The various combinations are prioritized to test links that are likely to be faster or more efficient first (likely in the order of local interfaces, NAT box external interfaces, and the relay server). This process stops when the 2-way communication is established.
When setting up an endpoint-to-endpoint connection across NAT boxes, a third party, such as a SIP proxy server on a public network, is required to relay setup messages between the endpoints. Note that, as explained earlier, not all NAT situations are traversable. FIG. 2 presents a diagram illustrating whether NAT traversals are possible when establishing endpoint-to-endpoint connections for all combination of NATs. As one can see from FIG. 2, if one of the endpoint is behind an RS NAT, and the other endpoint is behind a PC NAT, a PS NAT, or a RS NAT, NAT traversal becomes impossible and an external relay server will be needed in order for the two endpoints to communicate.
Point-to-Multipoint Connection Across NAT
In addition to setting up an endpoint-to-endpoint connection across NATs, the third party can also set up multiple connections from one local endpoint to multiple remote endpoints. For example, a SIP proxy server can fork a single SIP INVITE message to multiple SIP endpoints that are registered with the SIP proxy. Such a process can happen when the multiple endpoints are all registered with the same address of record (AOR) on the SIP proxy, or when the original INVITE is addressed to a group name that was expanded to a list of multiple addresses. The presence of NAT boxes in front of the endpoints can impose further challenges for setting up point-to-multipoint connections.
FIG. 3 presents a diagram illustrating an exemplary scenario where a proxy attempts to setup point-to-multipoint connections. In FIG. 3, a local device 302 includes an interface 304 behind a NAT box 306. A remote device 308 includes a number of interfaces 310-312 behind NAT boxes 314 and 316, respectively. Also included in FIG. 3 is a proxy server 318. From FIG. 3, one can see that local device 302 can communicate with remote device 308 via connections from interface 304 to interfaces 310 and 312. Because all interfaces are behind NAT firewalls, proxy server 318 is needed to relay the setup messages. During operation, interface 304 sends out a connection-request message 320, such as a SIP INVITE, to proxy server 318. Proxy server 318 makes multiple copies of connection-request message 320, including connection-request messages 322 and 324, and subsequently sends out connection-request messages 322 and 324 to interfaces 310 and 312, respectively.
The forking of the connection-request message at the proxy can further complicate the NAT traversal process. In a conventional system, the local address binding is sent out in the connection-request message, which only includes one address and port combination, thus limiting the ability for establishing multiple connections. This is not a problem if the NAT is a Cone NAT because a Cone NAT allows multiple connections to be made from this one address and port. However, if the Nat is a symmetric NAT, the multiple connections may fail because only a single connection can be made using a single NAT external address and port mapping. Consequently, the first responder to the forked invite may successfully connect, but subsequent ones will fail.
FIG. 4 presents a diagram illustrating whether multiple NAT traversals are possible when establishing point-to-multipoint connections for all combination of NATs. Compared with FIG. 2, one can see that in FIG. 4, two additional situations where NAT traversal becomes impossible. When the local host (the one sending out the connection-request message) is behind a PS NAT, NAT traversal for point-to-multipoint connections can fail if the remote hosts (or endpoints) are behind a PC NAT or a PS NAT. In other words, the system may fail to establish multiple connections successfully. More specifically, when a proxy forks the connection-request, in these two NAT situations, only the first forked connection can traverse the NAT, whereas all subsequent forked connections cannot traverse.
In the situation where the local endpoint is behind a PS NAT and the remote endpoints are behind a PC NAT, the local endpoint sends out a single external and port combination, and the NAT binding for the local endpoint is made when negotiating with the first responder to the connection request. A subsequent connection will come from a different address and port. Any subsequent responders have opened their port restricted cone filter to the first connection's address and port, thus preventing traffic from passing. Similarly, if the remote endpoints are behind a PS NAT, after NAT binding is made for the local endpoint, subsequent responders have opened their predicted symmetric NAT filter to only the first connection's address and port, thus preventing traffic from passing.
SIP-Based Rendezvous
For custodian-based routing in a CCN network, the point-to-multipoint NAT traversal problem arises when a device trying to establish multiple connections to a custodian with multiple logical endpoints via a rendezvous mechanism. Among possible rendezvous methods, SIP-based rendezvous has a number of advantages. One advantage is that many firewall vendors actively support peer-to-peer SIP and will automatically hole-punch UDP ports based on Session Description Protocol (SDP) content in SIP exchanges. Therefore, this disclosure uses SIP as an example for achieving the point-to-multipoint NAT traversal. In one embodiment, the mapping between a logical endpoint and its NEI is achieved using a public SIP proxy. In the example shown in FIG. 1, smartphone 108 can periodically register with SIP proxy 110 its current NEIs for all of its logical endpoints, with one register entry corresponding to a logical endpoint. Each register entry indicates where to register and the NEI of the corresponding logical endpoint. Note that, instead of registering with a public SIP proxy, it is also possible to distribute the logical-endpoint-to-NEI mapping information to all devices coupled to CNN 112. However, because the logical-endpoint-to-NEI mapping information changes frequently, and because such mapping is required to achieve content communication within CCN 112, it is unlikely to be useful to distribute such mapping. Nevertheless, there could be situations in which the distribution of the logical-endpoint-to-NEI mapping information can serve as a backup to the public SIP server, especially in cases where a device has a stable IP address or can be a directly reachable SIP endpoint.
In order to allow a remote device to establish a connection to smartphone 108, smart phone 108 needs to register a SIP identity with SIP proxy 110. The SIP identity can be a SIP-compliant identity for a device derived from the device's public key information. Such identity can be computable by any other devices with knowledge of the public key information. In one embodiment, smartphone 108 maintains one or more SIP register records. These register records specify the NEI of SIP proxy 110 at which smartphone 108 maintains the logical-endpoint-to-NEI mapping information.
After checking the SIP register record, laptop computer 102 identifies SIP proxy 110 as a possible proxy for communication with smartphone 108. In one embodiment, laptop computer 102 obtains the logical-endpoint-to-NEI mapping information for smartphone 108 from the register records. The register record for smartphone 108 also indicates whether multiple endpoints exist. For example, the SIP register record for smartphone 108 indicates that smartphone 108 has two logical endpoints reachable via SIP, the WiFi endpoint and the 3G cellular endpoint. Depending on the types of NAT being implemented, laptop computer 102 may attempt to connect to the multiple endpoints of smartphone 108 sequentially or parallelly. If laptop computer 102 detects itself being behind a symmetric NAT firewall, it may decide to use a sequential NAT strategy by trying to connect to the multiple endpoints of smartphone 108 sequentially; otherwise, it can use a parallel NAT strategy. However, in some cases, laptop computer may want to simultaneously establish connections to all endpoints in order to choose one that performs the best, even if PS NATs are implemented. To do so, special cares are needed in order to achieve the point-to-multipoint NAT traversal across the symmetric NATs. In some cases smartphone 108 may specify which endpoint has a higher preference level in the custodian-to-logical-endpoint mapping entry. Accordingly, laptop computer 102 will attempt to connect to the logical endpoint with the higher preference level first.
To start the rendezvous procedure, laptop computer 102 sends a connection request, such as a SIP INVITE, to the proxy server 110. The SIP INVITE is destined to the SIP identity of smartphone 108. In order to facilitate the point-to-multipoint NAT traversal, this SIP INVITE is not a conventional SIP INVITE, in a sense that it does not include any SDP payload. When SIP proxy 110 receives the INVITE and identifies that there are multiple logical endpoints registered for this SIP identity, SIP proxy 110 forks the INVITE (i.e., makes multiple copies) and forwards the forked INVITE to all registered logical endpoints. Note that because SIP proxy 110 is responsible for forking the single INVITE message to multiple endpoints, it needs to be a stateful SIP proxy.
In response to receiving the INVITE, smartphone 108 can respond to SIP proxy 110 with one or more 200/OK messages (as defined by Internet Engineering Task Force (IETF) RFC 3261, available at the IETF website at http://tools.ietf.org/html/rfc3261), each corresponding to a logical endpoint of smartphone 108. A 200/OK message contains an SDP offer specific to the corresponding logical endpoint. In one embodiment, the SDP offer includes a list of possible connection addresses (including ports) for each interface of smartphone 108. The list includes local address and port, as well as the external address and port for any NAT box an interface is behind. In a further embodiment, the list also includes the address of an external relay server.
SIP proxy 110 then relays the 200/OK messages to laptop computer 102, which in turn responds to each 200/OK message with an ACK message. The ACK message includes the SDP answer specific to laptop computer 102. In one embodiment, the SDP answer includes a list of possible connection addresses (including ports) for laptop computer 102. Note that, if the NAT strategy is sequential, laptop computer 102 will pace the ACK messages. When a logical endpoint of smartphone 108, such as its 3G cellular endpoint, receives an ACK message, it will launch a link adapter, and an interactive connectivity establishment (ICE) NAT negotiation begins between the 3G cellular endpoint and laptop computer 102. Details about ICE can be found in IETF RFC 5245, which is available at the IETF website (http://tools.ietf.org/html/rfc5245). Other NAT traversal techniques, such as session traversal utilities for NAT (STUN) and traversal using relay NAT (TURN) can also be used, depending on the type of NAT firewall. When the link adapter determines that the ICE negotiation is complete, the link adapter will send a message to indicate that the connection is ready for use.
By delaying identifying and sending the inviter's address and port and by allowing the SDP offer to be included in the 200/OK message sent from each invitee, embodiments of the present invention make it possible to establish point-to-multipoint connections across almost all types of NAT firewalls, with the exception of the RS NAT (which is impossible to traverse without an external relay server). Note that, if the NAT is a Cone NAT, then it is possible for the INVITE from laptop computer 102 to include the SDP offer, because the INVITE multiple connections can be established between the single address and port and the multiple endpoints of smartphone 108.
In cases where a custodian device has a SIP-friendly firewall, meaning that the device is able to keep a SIP endpoint hole punched in the firewall, a public SIP proxy is no longer needed for rendezvous. Instead, the custodian device can function as a directly reachable SIP endpoint, or as a private SIP proxy. In addition, no SIP proxy is needed if the custodian device has a public IP address.
FIG. 5 presents a block diagram illustrating the architecture of a device capable of implementing a SIP-based rendezvous in accordance with an embodiment of the present invention. Device 500 includes a connectivity agent 502, a number of SIP agents, such as SIP agents 504-506, a session initiator 508, and a number of connection controllers, such as connection controllers 510-512.
During operation, connectivity agent 502 receives an unsatisfied CCN interest from a CCN process, such as a CCN daemon (CCND), and determines how to connect to remote systems that may be able to satisfy the interest. Based on the content-prefix-to-custodian mapping, connectivity agent 502 determines which physical device (custodian) to connect to in order to satisfy the interest. Connectivity agent 502 provides SIP agents 504-506 the NEI of a public SIP proxy to use, along with the SIP identity of device 500. SIP agents 504-506, in turn contact the public SIP proxy and maintain SIP registrations for each logical endpoint (network interface). For example, SIP agent 504 maintains the SIP registration for a WiFi interface, whereas SIP agent 506 maintains the SIP registration for a 3G cellular interface. Note that the local address for an interface may change, and the corresponding SIP agent monitors the local interface address and keeps the SIP proxy registration up to date. The SIP agent needs to keep a communication path open with the SIP proxy. In one embodiment, the SIP agent uses feedback from the SIP proxy, such as in Via headers, to keep a proper registration.
When connectivity agent 502 determines that a session needs to be initiated with a remote device (in order to obtain a piece of content from the remote device), it passes the SIP identity of the remote device to session initiator 508, which in turn instructs a particular SIP agent to send a payload-less INVITE to the remote SIP identity via the SIP proxy. Note that the INVITE is not an SDP offer, because it does not include an SDP payload. If a SIP agent, such as SIP agent 504, receives an INVITE from a remote SIP identity, it will generate a 200/OK message that includes an SDP offer with a list of interface-specific NEIs, which can include a local address and port, a server reflective address and port, and a relay address. If a SIP agent receives a 200/OK message containing an SDP offer, it will construct an ACK with an SDP answer listing interface-specific NEIs, thus completing the SIP setup message exchange.
Connection controllers 510-512 are responsible for maintaining a link between a given pair of local and remote NEIs. When a SIP agent receives an ACK, it passes the 200/OK and ACK information to session initiator 508, which creates a connection controller for the specific interface. By using a NAT traversal library, such as ICE, a connection controller can connect to a remote device even in the presence of NAT firewalls.
FIG. 6 presents a time-space diagram illustrating the process of a SIP-based rendezvous in accordance with an embodiment of the present invention. Prior to allow any connection attempt, remote endpoints 606 and 608 need to register with a SIP proxy 604 (operation 610 and 612). In order to establish connections to remote endpoints 606 and 608, local endpoint 602 sends a payload-less INVITE message destined to a SIP identity corresponding to remote endpoints 606 and 608 to SIP proxy 604 (operation 614). Note that the payload-less INVITE does not include an SDP payload and, thus, is not an offer. SIP proxy 604 forks the single INVITE by forwarding an INVITE to endpoint 606 and an INVITE to endpoint 608 (operations 616 and 618). Upon receiving the INVITE message, each endpoint responds with a 200/OK message to SIP proxy 604 (operations 620 and 622). Each 200/OK message includes an SDP offer with a list of endpoint-specific NEIs, which may include the local address and port of the endpoint, the NAT external address and port, and an optional relay address. In a further embodiment, instead of a 200/OK message, a remote endpoint may send out the SDP offer in a SIP provisional response message. SIP proxy 604 relays the 200/OK messages back to local endpoint 602 (operations 624 and 626).
Upon receiving the 200/OK messages that include the SDP offers from remote endpoints 606 and 608, local endpoint 602 sends an ACK message to SIP proxy 604 for each 200/OK (operations 628 and 630). If the SDP offer is included in a SIP provisional response message, then local endpoint 602 sends a provisional response acknowledgement (PRACK) to SIP proxy 404. The ACK message includes an SDP answer, which may include the local address and port, the NAT external address and port, and an optional relay address for local endpoint 602. SIP proxy 604 forwards the ACK messages back to remote endpoints 606 and 608 (operations 632 and 634), thus completing the exchange of the SIP setup messages. Note that, if the local NAT strategy is sequential, local device 602 may pace sending the ACK messages. Once a pair of endpoints obtains possible connection addresses and ports from each other, they can launch a link adapter to start the ICE negotiation (operations 636 and 638). Once the ICE negotiation process is completed, the connection is ready for use (operations 640 and 642).
Note that sometimes a remote device, especially a mobile device, may be in power saving mode and therefore does not keep a cellular data connection or a WIFi connection open. As a result, the device is not reachable via SIP. In such cases, a local device may use other means, such as a text message or a phone call, to wake up the remote mobile device. Such out-of-band signaling is a bootstrap to cause the remote mobile device to bring up a data connection to begin SIP-based rendezvous. Note that the out-of-band signal is not used for rendezvous, but for initiating SIP registration and exchanges, so SIP-based rendezvous can proceed. Depending on the capabilities of the SIP proxy, devices can register a telephone number or other contacts with the SIP proxy to indicate an out-of-band wakeup method.
Also note that, because delaying the sending of the local address and port combination may result in a slower session-setup process, in cases where NAT can be easily traversed, such as when the local endpoint is behind a Cone NAT, the system can use a conventional NAT traversal method which can result in a faster session-set up process. In one embodiment, a local endpoint first determines what types of NAT it is behind. If it determines that it is behind a Cone NAT, then normal NAT traversal is performed. In the SIP case, the local endpoint can send out a conventional SIP INVITE that includes an SDP offer containing its connection address/port combination to the SIP proxy. On the other hand, if it determines that it is behind a predictable symmetric NAT, it will delay sending its own address and port combination by sending out a payload-less SIP INVITE.
Computer and Communication System
FIG. 7 presents an exemplary computer system for facilitating SIP-based rendezvous in accordance with an embodiment of the present invention. In FIG. 7, a computer and communication system 700 includes a processor 702, a memory 704, and a storage device 706. Storage device 706 stores programs to be executed by processor 702. Specifically, storage device 706 stores a SIP-based rendezvous application 708, as well as other applications, such as applications 710 and 712. During operation, SIP-based rendezvous application 708 is loaded from storage device 706 into memory 704 and then executed by processor 702. While executing the program, processor 702 performs the aforementioned functions. Computer and communication system 700 is coupled to an optional display 714, keyboard 716, and pointing device 718.
Note that although this disclosure describe a rendezvous process using SIP to achieve point-to-multipoint NAT traversal, other types of message exchange are also possible for achieving the same purpose, as long as the inviter of the connect does not send out its address and port combination in the initial connection request.
The methods and processes described in the detailed description section can be embodied as code and/or data, which can be stored in a computer-readable storage medium as described above. When a computer system reads and executes the code and/or data stored on the computer-readable storage medium, the computer system performs the methods and processes embodied as data structures and code and stored within the computer-readable storage medium.
Furthermore, the methods and processes described below can be included in hardware modules. For example, the hardware modules can include, but are not limited to, application-specific integrated circuit (ASIC) chips, field-programmable gate arrays (FPGAs), and other programmable-logic devices now known or later developed. When the hardware modules are activated, the hardware modules perform the methods and processes included within the hardware modules.
The foregoing descriptions of embodiments of the present invention have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present invention to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art. Additionally, the above disclosure is not intended to limit the present invention. The scope of the present invention is defined by the appended claims.
1. A computer-executable method for facilitating establishment of a connection between a local endpoint and a remote endpoint, the method comprising:
sending, from the local endpoint, a single connection-request message to a proxy server, which forks the single connection-request message to a number of remote endpoints;
receiving one or more response messages from the remote endpoints, wherein a respective response message carries address information associated with the remote endpoint;
upon receiving the response message, sending an acknowledgment corresponding to the received response message to the corresponding remote endpoint via the proxy server; and
establishing a connection between the local endpoint and at least one remote endpoint;
wherein the proxy server is a session initiation protocol (SIP) proxy server, and wherein the connection-request message is a payload-less SIP INVITE message.
2. The method of claim 1, wherein the response message is a SIP provisional response or a 200/OK message which carries a session description protocol (SDP) offer.
3. The method of claim 2, wherein the SDP offer includes a list of addresses corresponding to the remote endpoint associated with the response message, and wherein the list of addresses includes a network address translation (NAT) external address and port and may optionally include a local address and port and/or an external relay address.
4. The method of claim 1, wherein the acknowledgement is a SIP PRACK or ACK message, and wherein the SIP PRACK or ACK message carries a session description protocol (SDP) answer.
5. The method of claim 4, wherein the SDP answer includes a list of addresses corresponding to the local endpoint, and wherein the list of addresses includes a NAT external address and port and may optionally include a local address and port and/or an external relay address.
6. The method of claim 1, wherein the local endpoint and the remote endpoint are coupled to a content-centric network (CCN).
7. A computer device capable of establishing a connection between a local endpoint belonging to the computer device and a remote endpoint, the computer device comprising:
a connection-request sending mechanism configured to send a single connection-request message to a proxy server, which forks the single connection-request message to a number of remote endpoints;
a receiving mechanism configured to receive one or more response messages from the remote endpoints, wherein a respective response message carries address information associated with the remote endpoint
an acknowledgment sending mechanism configured to, upon receiving the response messages, send an acknowledgment corresponding to a received response message to the remote endpoint associated with the received response message via the proxy server; and
a connection mechanism configured to establish a connection between the local endpoint and at least one remote endpoint;
8. The computer device of claim 7, wherein the response message is a SIP provisional response or a 200/OK message which carries a session description protocol (SDP) offer.
9. The computer device of claim 8, wherein the SDP offer includes a list of addresses corresponding to the remote endpoint associated with the response message, and wherein the list of addresses includes a NAT external address and port and may optionally include a local address and port and/or an external relay address.
10. The computer device of claim 7, wherein the acknowledgement is a SIP PRACK or ACK message, and wherein the SIP PRACK or ACK message carries a session description protocol (SDP) answer.
11. The computer device of claim 10, wherein the SDP answer includes a list of addresses corresponding to the local endpoint, and wherein the list of addresses includes a NAT external address and port and may optionally include a local address and port and/or an external relay address.
12. The computer device of claim 7, wherein the local endpoint and the remote endpoint are coupled to a content-centric network (CCN).
13. A computer-readable storage medium storing instructions which when executed by a computer cause the computer to perform a method for facilitating establishment of a connection between a local endpoint and a remote endpoint, the method comprising:
14. The computer-readable storage medium of claim 13, wherein the response message is a SIP provisional response or a 200/OK message which carries a session description protocol (SDP) offer.
15. The computer-readable storage medium of claim 14, wherein the SDP offer includes a list of addresses corresponding to the remote endpoint associated with the response message, and wherein the list of addresses includes a network address translation (NAT) external address and port and may optionally include a local address and port and/or an external relay address.
16. The computer-readable storage medium of claim 13, wherein the acknowledgement is a SIP PRACK or ACK message, and wherein the SIP PRACK or ACK message carries a session description protocol (SDP) answer.
17. The computer-readable storage medium of claim 16, wherein the SDP answer includes a list of addresses corresponding to the local endpoint, and wherein the list of addresses includes a NAT external address and port and may optionally include a local address and port and/or an external relay address.
18. The computer-readable storage medium of claim 13, wherein the local endpoint and the remote endpoint are coupled to a content-centric network (CCN).
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text:
Match Day Arrangements for the FA Vase Quarter Final versus Leighton Town
Thu 15 Feb 2018 Thu 15 Feb 2018 Mark Edgeley Mark Edgeley
The club can confirm that our forthcoming FA Vase Quarter Final tie against Leighton Town next Saturday 24 February is NOT all ticket.
However, following discussions with Leighton Town it has been decided that to aid with the expected demand, we will have match day tickets available to purchase this Saturday at the Runcorn Town match being played at Wincham Park.
This will ease the expected congestion at the turnstile(s) on the day
However, supporters will still be able to "pay on the gate" if they have been unable to purchase a ticket beforehand.
Tickets are priced £6 for adults, £3 concessions and £1 for children under 16 and will be on sale in the social club at Wincham Park before our game against Runcorn Town this Saturday.
Coach Travel Arrangements for the FA Vase Quarter Final versus Leighton Town.
The club are pleased to announce that 2 coaches have been organised for our forthcoming FA Vase quarter final to be played next Saturday 24 February against Leighton Town.
These will leave Northwich town centre from the Memorial Court at 10 am with a further pick up outside the Kingsmead Shopping parade at around 10:15 am.
The cost is £15 for adults and £5 for children 11 or under.
Such has been the demand for this game there are only limited spaces left so in order to book your seat(s) please contact the club either by text 07975679624 or via email at Secretary@1874northwich.com
In order to help the process to be as smooth as possible on match day, we would ask those supporters who have booked on a coach, to please pay for the seat at our home game on Saturday against Runcorn Town. The money will be collected in the bar, before and after the game.
Categories 1874 News, Away Travel Post navigation
Volunteers required.
1874 Board appointments

redpajama_set_name: RedPajamaCommonCrawl


For testing objects quick and easy within a workshop and under increased safety conditions, the RTC is the right solution. The RTC is a single workshop test cabinet that can be combined with a seperated HPU control system to perform complete pressure tests.
The use of two systems has the advantage that you can position the test cabinet in another part of you workshop then the control system. As a result, the operator can control the test cabinet at a distance from the cabinet. The cabinet itself has several safety precautions. The mechanical cover is fully made of an impact resistant window that is automatically locked when the unit is under pressure. And an extra alarm light can be installed that warns the operator when it is safe to open the cabinet.
Next to safety, the RTC test cabinet offers you a quick and easy way of testing objects, because of its spacious stainless steel test compartment in which test objects are quickly filled and serial tested by setting the pressure in advance. The system has a Resato high pressure pump that automatically stops when the set pressure is reached. This will save energy and reduce the noise level in the workshop.


One of the great gifts that a person can give to another person is commitment.
Love is never cheap. There is always a price that it is willing to bear for another. When God loved us, He let go of His one and only Son, and let Him be born for us. Jesus, too, because of His love for us, let go of His life and willingly suffered and died on the cross. "No greater love can a man have than this, than to die for a friend. You are my friends, Jesus said." In a similar vein, Jesus said that if we loved Him we would feed His sheep. We would pick up our cross and follow Him in living our life for God and serving others.
For four-weeks beginning on Sunday, January 18th we will focus on the topic of committing and dedicating ourselves for ministry using our time, talent and treasures through sermons and special Bible Studies. In other words, we will focus on becoming "consecrated stewards" of God's gifts. We invite you to be a part of this worship and conversation about God's love for us and our response to His great sacrifice.
On February 8th we will celebrate Consecration Sunday and serve breakfast all morning.


2017 has been a phenomenal year for Bitcoin, Rising from around $1,000 at the start of the year to a new all time high of $7,000 just 11 months later, seeing total increases of more than 700%!!!
And the price seems to be having a snowball effect. In the week leading up to the new all time high of $7,000 the price increased by over 20% in just 7 days.
On top of this news it has been confirmed that Coinbase, one of the largest Bitcoin merchants in the world, has gained more than 100,000 users in a 24 hour period. This is likely in light of the recent news that hit global media regarding CME adding Bitcoin 'futures markets' to their list of instruments.
Back In May, Coinbase reported that they had 7.4 million users. This figure had increased by almost 60% on 1st November and was at 11.8 million… fast forward just 24 hours and Coinbase now has 11.9 million users on 2nd November at the time of writing this.
There is speculation that this incredible spike in the Bitcoin price may be anticipation of the potential Bitcoin 2X fork due to occur. Users may be stocking up in the hope of free coins if a split does occur. However, it could also be due to the fact that Bitcoin is receiving global media attention for all the right reasons.
Coinbase was first developed in 2012 and is gaining more and more momentum, very much like the Bitcoin price. And we can't see either number slowing down. Coinbase seems to be where a lot of the new users go to get started and purchase their first Bitcoins/Ether/Litecoin. The website is very user friendly and offers competitive prices, it also has a very handy app available on IOS and Android.


Byaheng Victory is a collaboration between Victory Liner and Travel Factor. Are you interested in exploring Alaminos and Bolinao, Pangasinan? This is your chance to explore the famous Hundred Islands Park and visit some of Bolinao's special tourist spots specially the Patar White Beach!
You can participate in Byaheng Victory's Pangasinan Beach Weekend! This summer, they offer two schedules: March 23-24 and May 11-12. Reserve a slot now and enjoy a fun beach weekend!


In this summers issue of Remix magazine, boys will be boys! Fun fabrics and blazers under cut with street apparel creates a perfect canvas for rockabilly comb-overs and slicked up man-buns done by our very own Gabrielle Houghton.
Models DJ and Andrey from Red 11.


Looking for a new home in Upriver Drive Addition? It is a great time to buy real estate in Upriver Drive Addition and our site is a great place to begin your search. You can check out Upriver Drive Addition schools, market statistics, the latest listings and more. Whether you are a first-time home buyer or you are already familiar with the home buying process, you can be assured that you have the best tools and the perfect agent available to help with your Upriver Drive Addition home search.
There are currently 1 Res/Site Blts for sale in Upriver Drive Addition. The average price for Upriver Drive Addition properties is $189,900which is 47% lower than all Res/Site Blts within a 20 mile radius. The highest priced property in Upriver Drive Addition is $189,900 while the lowest priced Res/Site Blt is listed at $189,900. Most of the properties available in Upriver Drive Addition are Res/Site Blts . Compared to last month, the average price of real estate in the area has gone up 100%.


text:
Love Jihad Law to Prohibit Unlawful Conversion
March 1, 2021 February 22, 2021 by The Legal State
Introduction to Unlawful Conversion
Key Provisions of the ordinance(Love Jihad Law):
Rules for Valid Conversion:
Punishments under Love Jihad Law:
Why is this ordinance being criticized?
This article is written by Shubhangi Rajora, a 3rd-year BA-LLB student at The Maharaja Sayajirao University Baroda. All the aspects of Love jihad and Unlawful Conversion has been discussed in this article.
The Ordinance titled, Uttar Pradesh Prohibition of Unlawful Conversion of Religion Ordinance(Love Jihad Law), 2020 (Uttar Pradesh Vidhi Virudh Dharma Samparivartan Pratishedh Adhyadhesh in Hindi) was cleared by the State Cabinet. This controversial Uttar Pradesh ordinance on Unlawful Conversion came into force after State Governor Anandiben Patel signed off on it.
Also Read: Religious Practices: The Test of Essentiality Crawling In
The Ordinance invites penalties of up to 10 years in prison if found to be effected for marriage or through misrepresentation, force, undue influence, coercion, allurement or other allegedly fraudulent means and also makes religious conversion a cognisable and non-bailable offence. "There were more than 100 incidents reported in which forceful religious conversion was being done. Also, it was reported religious conversions were going on in the state using deceitful means. So to make a law on this becomes an important matter of policy now," UP Cabinet Minister Siddharth Nath Singh told ANI.
Through this ordinance, Forcible religious conversion is considered a non-bailable offense, and a provision of punishment of up to 10 years has been made under this offense.
In this ordinance, the following actions will be considered as a crime:
If the religious conversion is done by misrepresentation, by deception, by greed, forcibly, by marriage, or by any other type of pressure.
If the forceful conversion is done with a minor, a woman or person belonging to the Scheduled Caste or Scheduled Tribe Communities.
If the mass conversion is done.
The ordinance says any marriage done with the sole purpose of "unlawful conversion or vice versa" by a man of one religion with a woman of another religion, "either by converting himself/herself before or after marriage, or by converting the woman before or after shall be declared void".[1]
Also Check Out: Sarla Mudgal and Ors. Vs. Union of India
Under Section 8(1) person who wants to convert has to give a declaration to the District Magistrate or Additional District Magistrate, 60 days in advance.
Under Section 8(2) Religious convertor has to give one month's advance notice to the District Magistrate or any officer who is not below the rank of Additional District Magistrate; who'll be appointed by the District Magistrate for the purpose of such ceremony.
Under Section 8(3) when DM receives information either by the person who want to convert or by a Religious Converter as per clause (1) and clause (2) of Sec 8; shall conduct a Police Enquiry to clear the intention.
Under Section 9(1) and (3) once a person gets converted, he/she has to send a declaration to the DM within 60 days of his/her conversion stating his present address, date of conversion, spouse or parent's name, the current and past religion, etc.
Under Section (4), once the declaration is given to the DM under Section 9(1) and (3); he/she has to appear before the DM within 21 days for the purpose of identification.
If any of the clauses as mentioned; from Section 9(1) to (4) is breached, then such conversion will become void and illegal.[2]
Read: Lily Thomas vs. Union of India and Others
If Section 8 (1) is violated, where a person who wishes to convert himself/herself fails to declare his intentions sixty days prior in advance; then he would be imprisoned for the term not less than six months and may extend to three years and fine which shall not be less than 10,000/-
If Section 8(2) is violated, where the religious converter fails to give a one month notice; then such person's imprisonment shall not be less than One year and which may be extended to Five Years and fine would not be less than Rs 20,000/-.
If the person unlawfully converted is a minor, a woman, a Scheduled Caste or Schedule Tribe person, then the punishment with imprisonment shall not be less than Two Years, extendable to Ten Years and fine shall not be less than 25,000/-.
If there has been a mass conversion then the punishment with imprisonment shall not be less than Three Years, extendable to Ten Years and fine shall not be less than 50,000/-.
If it is an institution or organization then, the person or persons in charge will be punished with imprisonment not less than One Year, extendable to Five Years and fine shall not be less than 15,000/-.
If a person has been convicted has also been convicted in past under the same law then he/she shall be liable for the twice of the punishment.[3]
Read: The Doctrine of Severability and Doctrine of Eclipse- Explanation, Differences
The provisions which are mentioned in the Ordinance gives State supervising powers over a citizen's choice of life-partner or religion are in conflict with the fundamental rights to individual autonomy, privacy, human dignity and personal liberty guaranteed under Article 21 of the Indian Constitution. Before the promulgation of the Ordinance, the Allahabad High Court had also pronounced an important verdict which states that "Right to live with a person of his/her choice irrespective of religion professed by them, is intrinsic to right to life and personal liberty."
This verdict clearly explains how the Ordinance leads to an unreasonable intrusion into the domain of a personal autonomy.[4] Subhasini Ali, president of the All India Democratic Women's Association, said the ordinance encroached upon women's right to choose a life partner. "It is born out of same mindset that frowns on intercaste marriages to maintain the purity of caste and to control women. Because this concerns other religions, the government has been able to come up with this draconian law. There have been numerous judicial pronouncements on forcible conversions, so there is no need bring a special law for it. The need is to make the Special Marriages Act more accessible to people".[5]
Minerva Mills Ltd. and Ors. vs Union of India and Ors.
This Ordinance is said to be opposed to an individual's right to privacy, this law also infringes the fundamental right to choice and the right to change of faith. It is also in conflict with the fundamental rights to individual autonomy, human dignity, privacy, and personal liberty guaranteed under Article 21 Right to life and Personal Liberty of the Constitution.
At present when changes should be made to improve the Special Marriage Act; the only law that allows inter-faith marriages without the need to convert, this Ordinance is instead squashing the wrong and dangerous path towards the communalisation and criminalization of love and marriage. This move will further encourage prejudice in the Indian mainstream thinking.
Also, Check Defamation and freedom of the press
[1] https://www.thehindu.com/news/national/other-states/up-governor-gives-assent-to-ordinance-on-unlawful-convesion/article33198888.ece
[2] https://lexforti.com/legal-news/anti-conversin-prohibition-unlawful-ordinance/
[4] https://www.livelaw.in/columns/up-ordinance-criminalizing-converson-for-marriage-is-an-assault-on-personal-liberty-166575
[5] https://www.theweek.in/news/india/2020/11/28/political-leaders-activists-oppose-up-govt-ordinance-to-end-unlawful-conersions.html(Love Jihad Law)
Categories All Blogs, All Legal Updates, Blogs, Latest Updates Tags Love Jihad, religious conversion, Unlawful Conversion
Custodial Torture
Independence of the Judiciary


text:
Die Schuppenheiden (Cassiope) sind die einzige Pflanzengattung der Unterfamilie Cassiopoideae innerhalb der Familie der Heidekrautgewächse (Ericaceae).

Beschreibung
Die Cassiope-Arten wachsen als "erikoide", immergrüne Sträucher oder Zwergsträucher. Die verzweigten Äste sind niederliegend oder aufsteigend. Die eng zusammenstehenden Laubblätter sind an den Zweigen kreuzgegenständig und meist in vier deutlichen Reihen angeordnet; dadurch wirken die Zweige vierkantig. Die ungestielten Laubblätter sind schuppenförmig, ledrig und oft zugespitzt. Die flache oder nach außen eingerollten Blattspreiten besitzen einen glatten oder gefransten bis bewimperten Blattrand und keine erkennbare Blattnervatur.

Die kleinen Haare (Trichome) sind nur in dieser Gattung innerhalb der Ericaceae bündelig-verzweigt. Als einzige Gattung innerhalb der Ericaceae besitzt sie einen bisporischen Embryosack vom Polygonum-Typ.

Die Blüten stehen einzeln in den Blattachseln an mehr oder weniger langen Blütenstielen; manchmal entspringt ein zweiblütiger Blütenstand auch am Ende des Zweiges. Es sind vier bis sechs Tragblätter vorhanden. Die hängenden Blüten sind zwittrig, radiärsymmetrisch und (selten vier-) meist fünfzählig. Die fünf freien Kelchblätter sind schuppenförmig; sie umgeben auch noch die Frucht. Die fünf weißen bis rosafarbenen Kronblätter sind glockenförmig verwachsen, mit fünf zurückgebogenen Kronlappen. Am Grund der Blüte finden sich Honigdrüsen. Die zehn Staubblätter überragen die Kronblätter nicht. Die aufrechten Staubfäden sind abgeflacht. Die eiförmigen Staubbeutel besitzen zwei lange zurückgebogene Hörner (Anhängsel). Die fünf Fruchtblätter sind zu einem oberständigen Fruchtknoten verwachsen mit vielen Samenanlagen.

Die fünf Fächer der Kapselfrucht sind jeweils an ihrer Spitze zweispaltig. Sie öffnet sich bei Reife mit fünf Zähnen und entlässt eine Vielzahl von Samen. Die winzigen Samen besitzen keine Flügel.

Vorkommen
Die nur auf der Nordhalbkugel vorkommende Gattung Cassiope hat eine hauptsächlich zirkumboreale Verbreitung. Ihr Gesamtverbreitungsgebiet reicht südwärts bis China, das Himalaya-Gebiet, Japan, Russland und das westliche Nordamerika. In China kommen elf Arten vor; davon sind sechs dort endemisch.

Systematik
Die Gattung Cassiope wurde 1834 von David Don im Edinburgh New Philos. Journal, 17, Seite 157 veröffentlicht. Typusart ist Cassiope tetragona . Cassiope ist die einzige Gattung der einzigen Tribus Cassiopeae  der Unterfamilie Cassiopoideae  innerhalb der Familie der Heidekrautgewächse (Ericaceae).

Arten
Es gibt etwa 12 bis 17 Cassiope-Arten:
 Cassiope abbreviata : Sie kommt in Sichuan in Höhenlagen zwischen 3800 und 4000 Metern vor.
 Cassiope argyrotricha : Sie kommt im nordwestlichen Yunnan in Höhenlagen zwischen 3000 und 4400 Metern vor.
 Cassiope fastigiata : Sie kommt in Indien, Bhutan, Nepal, Yunnan und Xizang vor.
 Cassiope fujianensis : Sie kommt in Fujian vor.
 Bärlappähnliche Schuppenheide (Cassiope lycopodioides ): Sie kommt in Japan, im fernöstlichen asiatischen Russland, in Alaska und in British Columbia vor.
 Cassiope membranifolia : Sie kommt im nordwestlichen Yunnan vor.
 Mertens-Schuppenheide (Cassiope mertensiana ): Sie kommt in Alaska, im westlichen Kanada und in den westlichen Vereinigten Staaten vor.
 Cassiope myosuroides : Sie kommt in Myanmar und im nordwestlichen Yunnan in Höhenlagen zwischen 4000 und 4500 Metern vor.
 Cassiope nana : Sie kommt im nordwestlichen Yunnan in Höhenlagen zwischen 2000 und 3800 Metern vor.
 Cassiope palpebrata : Sie kommt in Myanmar und im nordwestlichen Yunnan in Höhenlagen zwischen 3000 und 4300 Metern vor.
 Cassiope pectinata : Sie kommt in Myanmar, im südwestlichen Sichuan, im östlichen Xizang und im nordwestlichen Yunnan in Höhenlagen zwischen 3600 und 4100 Metern vor.
 Cassiope selaginoides : Sie kommt in Bhutan, Nepal, Xizang, Sichuan und Yunnan vor.
 Vierkantige Schuppenheide (Cassiope tetragona ): Sie kommt in Alaska, Kanada, in Montana, Washington, in Island, Norwegen, Finnland, auf Spitzbergen, Jan Mayen und in Russland vor.
 Cassiope wardii : Sie kommt im südöstlichen Xizang in Höhenlagen zwischen 3900 und 4200 Metern vor.

Nicht mehr zur Gattung gehören:
 Moosheide (Cassiope hypnoides)  ⇒ Harrimanella hypnoides
 Cassiope stelleriana  ⇒ Harrimanella stelleriana

Nutzung
Einige Arten werden selten als Zierpflanzen genutzt.

Quellen
 Fang Ruizheng & Peter F. Stevens: Cassiope in der Flora of China, Volume 14, S. 456: Online.
 Cassiopoideae in Ericaceae-Homepage von Kathleen A. Kron.
 Kathleen A. Kron, Walter S. Judd, P. F. Stevens, D. M. Crayn, A. A. Anderberg, P. A. Gadek, C. J. Quinn, & J. L. Luteyn: A phylogenetic classification of the Ericaceae: Molecular and morphological evidence., Bot. Rev., 68, 2002, S. 335–423.

Einzelnachweise

Weblinks

Heidekrautgewächse

redpajama_set_name: RedPajamaWikipedia


There is no doubt that V.R. is huge upgrade for gaming.The feel it gives is spectacular.
The question is , what is the best game to be played with V.R.?
I actually never did play with a V. R., though I would love to play a horror game to scare the pants out of me.
Astrobot is the best VR game. Spectacular and easily the best showcase for the Tech which has everyone grinning from ear to ear.
Outside of that behemoth you have great technical showcase in the game Statik. VR is essential as its impossible to mirror the experience on a flat screen.


Forget to listen when I have something to say.
To let me know that you care.
Have any questions? Please don't hesitate to contact us!
Sunshine Children's Home and Rehab Center is a 54-bed licensed nursing facility that specializes in the care and treatment of medically complex children who require post acute, rehabilitative care.


What a wonderful, amazing adventure!
I spent a whole week with my beautiful sister Kim in the Sierra Nevada Mountains of California.
Each time I see her it's as if a new part of my heart opens and blossoms. We leap into each other's presence (no matter the time apart!) as if we'd just had tea together yesterday. We finish each other's sentences. We find we like (and dislike) so many of the same (random) things. We nearly laugh ourselves into fits and almost jabber ourselves hoarse.
We had sooooo much fun this last week together; excitedly sharing news of our lives, comparing our fondest dreams, conjuring collaborative projects, giggling like kids, & always up to some sort of mischief or other.
at the beautiful Intermountain Nursery! It's a gorgeous nursery, operated by very dear people who have dedicated their lives to plant ecology and restoration projects.
The class was a pure delight!
and she is the most encouraging of teachers.
We spent another whole day roaming the gorgeous green, spring Sierras, dabbling in the roaring creeks, picnicking and napping, exploring and rejoicing!
at the very height of spring!
as we sat around her on the path to the majestic gush of Yosemite Falls.
We had such an amazing day that we decided to gift each other a week long nature sketchbook journaling class in October at Yosemite with Janet Takahashi. We're going to stay in the historic tent camps! We're both incredibly excited!
The water! The green! The cool! The trees! The flowers!
I will hold all those memories so dear as we enter our scorching Sonoran summer.
I feel Kim and I are two magical fairy sisters (like these delightful felted ones from chopoli) who have so much joy and love to share!
It is my great good fortune to have darling Albert to hold-down-the-fort, keep the critters and the gardens afloat, and send me off with such a happy heart to be with my sister. I am so lucky that the Creative Cottage tribe sent me off with such love. I was so blessed that Kim's husband Bro was such a wonderful naturalist guide and bemused encourager of all of our crazy fun.
It was such a beautiful time shared and it will long live in my heart as one the most glorious weeks of my life!
Thanks to Kim & Bro, to dearest Albert, and to all my amazing friends who sent me on my way with such a heart full of love to share!
Happy Summer & Happy Birthday Dear Sister Kim!
P. S. Please check out my June class schedule by clicking on the Cottage Classes tab and have a gander at our new Art Gifters Anonymous, Random Acts of Art, project by clicking on the Art Gifters tab.
Thanks to Pinterest for images mixed with many of my own photos.
© Copyright, Kaitlin Meadows. All Rights Reserved, 2017.
in these dark and perilous times.
and adds joy to our tortured world.
has a color to add.
Each of us has a bit of light to bring.
by the evil armies of hate, bigotry, exclusion, or fear.
Try to control us at your peril!
Try to silence us at your peril!
cocoon when we need to.
and the stories of our foremothers in us.
are beating strong & steady in us.
Underestimate us at your peril!
or what you think of us.
the dancers in the temple of joy.
and we are every speck of light.
You cannot destroy the divine feminine.
Tamper with us at your peril!
Step Into The Circle Of Color and Light!
Images from Pinterest with great thanks to all artists who so generously share their work.


A pavilion which spans over 4,000 m2 comprising an interactive network which connects the first three floors and allows visitors to interact with their surroundings: this is the image with which Brazil wanted to present itself at Expo Milano 2015. "Feeding the world with solutions" is the theme picked by this South American country, which is today a world leader in the "network" agricultural production industry connecting farmers, distributors and retailers.
This project by Studio Arthur Casas, in partnership with Atelier Marko Brajovic, winner of the public tender held by the Institudo de Arquitetos do Brasil (IAB), places the utmost focus on the environment. It is not just the setting that was built using sustainable and eco-friendly materials, but the installation process and commissioning of the facility were also low environmental impact, just like the dismantling will be when the event is over.
The facility comprises two bodies: one is in the open air, planted with trees and vegetable patches, which visitors can observe from the top thanks to a trail which is accessed along a suspended net walkway. The other body is covered and instead houses a theatre, some workshops and service amenities including a bar and restaurant area situated on the top floor of the facility.
Poliform Contract contributed towards furnishing the two areas set aside for visitor refreshments and relaxation, devising Corian tables and hide chairs for the restaurant, as well as chairs and tables with a metal and Corian top for the bar area. These customised creations in conjunction with Studio Arthur Casas demonstrate once again the ability of Poliform's Contract division to offer sophisticated furnishings designed not just for private homes but also for public and recreational areas.