Dell PowerConnect 5548 User Guide - Page 477

Protocol Groups Protocol groups are based on protocol-based VLANs. Protocol-based VLANs Untagged frames received on a VLAN-aware switch can be classified by methods others than source port, such as data-link-layer protocol identification. This classification method is referred to as protocol-based VLANs. Protocol-based VLANs are useful for isolating Layer 2 traffic of various Layer 3 protocols. If, for example, a switch serves IP stations and IPX stations that communicate with a single VLAN-unaware server, without using protocol-based VLANs, all the Layer 2 Broadcast traffic would reach all the stations. With protocol-based VLANs, the switch can forward incoming traffic from the server to stations in a specific VLAN only. Protocol-based VLANs are only available on General ports. Classification rules are set on a per-port basis, and may be sensitive to the frame's encapsulation. The default encapsulation assumed is Ethernet. On each port, a user can define associations between groups of data-link layer protocols and ports. For each group/port combination, the user may set the VLAN to which frames incoming on that port will be classified if they belong to any of the protocols in the group. Several protocol-groups may be associated to a single port, and a protocol group may be assigned to multiple ports, if so desired. It is not guaranteed that the VLAN to which the frame is classified exists in the system, or is active on that port. Restrictions The following frames (packet) types are supported: Ethernet, RFC 1042, and LLC Other. There may be dependencies between protocols and encapsulations, and specifying one protocol may automatically add additional protocols to the protocol-group, such as specifying IP implies ARP and vice-versa. Dell PowerConnect 55xx Systems User Guide 477