Network traffic is transmitted across a network, such as the Internet, from a sending system (e.g., a computer system) to a receiving system (e.g., a computer system) via a network interface card (NIC). The NIC is a piece of hardware found in a typical computer system that includes functionality to send and receive network traffic. Typically, network traffic is transmitted in the form of packets, where each packet includes a header and a payload. The header contains information regarding the source address, destination address, size, transport protocol used to transmit the packet, and various other identification information associated with the packet. The payload contains the actual data to be transmitted from the network to the receiving system.
Each of the packets sent between the sending system and receiving system is typically associated with a connection. The connection ensures that packets from a given process on the sending system reach the appropriate process on the receiving system. Packets received by the receiving system (via a NIC associated with the receiving system) are analyzed by a classifier to determine the connection associated with the packet.
With the rising popularity of offering critical services (e.g., web services, applications, identity services, mail services, etc.) on the Internet, attacks on the receiving system that offer such critical services have become relatively common. A common attack is a denial of service (DOS) attack where a sending system bombards a receiving system (i.e., host) with a large number of packets causing excessive amounts of endpoint, and possibly transit, network bandwidth (or resources) to be consumed. Such attacks are commonly referred to as packet flooding attacks. Recently, the use of source IP address spoofing during DOS attacks and the advent of distributed attack methods and tools have provided a continuing challenge in the area of DOS attack prevention.
The Internet is entirely composed of limited resources. Such limited resources as network bandwidth, processor resources, and storage capacities are all common targets for DOS attacks designed to consume enough of a host's available resources to cause some level of service disruption. One reaction to DOS attacks is to overprovision a system to handle excess loads that may be generated by the attack. However, a limit exists to the amount of limited resources that can be allocated to a system, both in terms of availability and cost. Accordingly, most of the service providers with any level of critical services on the Internet deploy various kinds of resource consumption monitors to assist in identifying when packet destinations (i.e., containers or services) are consuming excessive resources, such as network bandwidth and CPU resources, and/or subject to a DOS attack.
Attacks initiated on a single container or service, which is located on a single computer system with multiple containers and services, has the effect of disrupting all containers or services on the computer system. Consider an example where an Internet Service Provider (ISP) (e.g., Earthlink, AOL, Yahoo, etc.) hosts multiple websites on the same physical computer system by establishing several containers, which are virtual application environments. If only one of the websites hosted on the same computer system is under a DOS attack, then the entire computer system grinds to a halt and all other containers on the same computer system suffer. Customers running multiple services on the same machine are faced with the same problem. For example, if a customer runs a http and a https based service on the same computer system and a DOS attack is initiated against just one service, all services on that computer system grinds to a halt.