Our recent work on the regioselective synthesis of a number of heterocycles (4) prompted us to search for a simple and effi- cient reagent for this heterocyclization. We have recently achieved a facile entry to this ring system 6 (5) with the use of a well-known brominating agent, pyridine hydrobromide per- bromide, which we report here.
Voice VLAN. 1  Voice VLAN allows you to enhance VoIP service by configuring ports to carry IP voice traffic from IP phones on a specific VLAN. VoIP traffic has a preconfigured OUI prefix in the source MAC address. 2  You can configure VLANs on which voice IP traffic is forwarded.
VLANs are data link layer (OSI layer 2) constructs, analogous to IP subnets, which are network layer (OSI layer 3) constructs. In an environment employing VLANs, a one-to-one relationship often exists between VLANs and IP subnets, although it is possible to have multiple subnets on one VLAN.nder IEEE 802.1Q, the maximum number of VLANs on a given Ethernet network is 4,094 (the 4,096 provided for by the 12-bit VID field minus reserved values 0x000 and 0xFFF). This does not impose the same limit on the number of IP subnets in such a network, since a single VLAN can contain multiple IP subnets.