Dell N3200-ON EMC Networking N-Series Switches CLI Reference Guide version 6.7 - Page 872

Protocol Based VLANs The main purpose of Protocol-based VLANs (PBVLANs) is to selectively process packets based on their upper-layer protocol by setting up protocolbased filters. Packets are bridged through user-specified ports based on their protocol. In PBVLANs, the VLAN classification of a packet is based on its protocol (IP, IPX, NetBIOS, and so on). PBVLANs help optimize network traffic because protocol-specific broadcast messages are sent only to end stations using that protocol. End stations do not receive unnecessary traffic, and bandwidth is used more efficiently. It is a flexible method that provides a logical grouping of users. An IP subnet or an IPX network, for example, can each be assigned its own VLAN. Additionally, protocol-based classification allows an administrator to assign nonrouting protocols, such as NetBIOS or DECnet, to larger VLANs than routing protocols like IPX or IP. This maximizes the efficiency gains that are possible with VLANs. In port-based VLAN classification, the Port VLAN Identifier (PVID) is associated with the physical ports. The VLAN ID (VID) for an untagged packet is equal to the PVID of the port. In port-and protocol-based VLAN classifications, multiple VIDs are associated with each of the physical ports. Each VID is also associated with a protocol. The ingress rules used to classify incoming packets include the use of the packet's protocol, in addition to the PVID, to determine the VLAN to which the packet belongs. This approach requires one VID on each port for each protocol for which the filter is desired. IP Subnet Based VLANs This feature allows an untagged packet to be placed in a configured VLAN based upon its IP address. MAC-Based VLANs This feature allows an untagged packet to be placed in a configured VLAN based upon its MAC address. Layer 2 Switching Commands 872