Multicast Addressing
Class D IP addresses are assigned to a group of network devices that comprise a multicast group. The four most significant four bits of a Class D address are set to "1110". The following 28 bits is referred to as the 'multicast group ID'. Some Class D address groups are registered with the Internet Assigned Numbers Authority (IANA) for special purposes. For example, the block of multicast addresses ranging from 224.0.0.1 to 224.0.0.225 is reserved for use by routing protocols and some other
Asymmetric VLANs
Many network managers may not need an elaborate VLAN setup but still want to provide the added security of VLANs to the network. Asymmetric VLANs allow a manager to quickly and automatically set up a VLANs for single Switch or multiple Switch installations. The feature is enabled Switch wide and creates a unique VLAN for every client port. For cascaded Switch groups, a unique VLAN is created for each client port in the cascaded group. The VLANs created for the client ports each contain the client port, plus the uplink port as members. This creates a VLAN environment where each client port can freely link to the uplink port, but can not link to any other client port on the Switch or in the cascade group. See the section on configuring Asymmetric VLANs in Chapter 6 for an illustration of VLAN assignment using this feature.
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