3Com 2500 manual MAC Address Group VLANS, Application-Oriented VLANS, Protocol-Sensitive VLANS

2-2 CHAPTER 2: VLANS ON THE LANPLEX® SYSTEM

the data contained in the frames. Port groups are useful when traffic patterns are known to be directly associated with particular ports. They can benefit the user by restricting traffic based on a set of simple rules.

MAC Address Group VLANS

VLANs allow a switch to make filtering decisions based on grouping MAC addresses together. These MAC address groups can be configured so that stations in the group can only communicate with each other or with specific network resources. This solution is good for security. It allows the VLAN association to move with the station. However, MAC-address-grouped VLANs may require complex configuration in comparison to other types of VLANs.

Port group and MAC address group VLANs are supported using the packet filtering capabilities in the LANplex system. For information on port group and MAC address group filtering, refer to your LANplex Operation Guide and LANplex Administration Console User Guide.

Application-Oriented VLANS

Using the LANplex filtering capability, application-specific traffic such as telnet traffic or FTP traffic can be filtered based on higher-layer information. You create this application-oriented VLAN by configuring packet filters that specify data and offsets of the data within received packets. For example, to use a filter on a particular port for all telnet traffic, create a a filter that discards all TCP traffic received on the telnet port.

IP multicast routing and autocast VLANs are additional VLAN features in the LANplex that can be used to group IP multicast traffic for specific applications. For more information on how the LANplex system manages IP Multicast traffic, see Chapter 8.

Protocol-Sensitive VLANS

When the LANplex system receives data that has a broadcast, multicast, or unknown destination address, it forwards the data to all ports. This process is referred to as bridge flooding.

Protocol-sensitive VLANs group one or more switch ports together for a specified network layer 3 protocol, such as IP or AppleTalk. These VLANs make flooding decisions based on the network layer protocol of the frame. In addition, for IP VLANs, you can also make flooding decisions based on