Chapter 9: Managing the Address Forwarding Table

Overview

The Address Forwarding Table (AFT) is a mapping table of MAC addresses with their associated port locations.The AFT is used by the Avaya Multiservice switch to correctly forward (bridge) frames destined for a particular MAC address to the correct physical port. The AFT performs several major functions, learning new MAC addresses, aging out old MAC addresses, and providing a management interface to display, add, modify, and remove AFT entries (MAC addresses). AFT's are maintained throughout the system, on media modules and the supervisor module.

There is one AFT created for each VLAN. The entire Avaya Multiservice Switch can store up to 24,000 MAC addresses and 1000 VLANs.

Note: Although the Avaya Multiservice Switch can support 1000 VLANs, (in Fabric mode 2 with all 80-series modules), restrictions apply for the size of the Hash tables, the size of the Address Forwarding Tables and the number of VLANs. This information is detailed in the following pages in this chapter.

• New address Learning - When a MAC address of a packet is unknown, it must be learned by the AFT
• Address Aging - On a periodic basis (which you can set) the addresses in the AFT are aged out, MAC addresses not received for a period of time (e.g. 5 minutes) are removed from the AFT along with their port associations.
• Static Address Management - Static MAC address entries are saved in memory upon module reset. These static address always exists in the AFT, and are not aged out or overwritten.Static entries are those manually configured. Each VLAN and its AFT has 18 AFT entries automatically entered by the switch that are reserved for internal use.
• Address Management - The user has the ability to display entries, add entries to the AFT, remove entries from the AFT, and change entries within the AFT. This is accomplished through the Web Agent interface or CLI commands. A user can also make an entry or entries static, which saves the entries upon module reset.

For more information about the CLI commands that are mentioned in this chapter, see Command Reference Guide for the Avaya P580 and P882 Multiservice Switches, Software Version 6.2