AC206-DS05-405-R datasheet(22/70 Pages) BOARDCOM

22 / 70 page

AC206

Preliminary Data Sheet

07/08/02

B roa dcom

Page 10 Addressing Algorithm, Routing, Learning and Aging

Document

AC206-DS05-405-R

LEARNING PROCESS

The address learning process is composed of the SA packets and the addressing algorithm described above. The bridge

checks each incoming packets integrity and buffers availability. If a packet is error-free and the buffer is available, the SA/port

number pair of the packet is written into the address lookup table. The following figure describes the general operations of

address learning and recognition.

Figure 3: Address Learning and Recognition

AGING TIME

The switch automatically examines the status of address lookup table. The round robin speed and checking timer are

dependent on the aging time. The switch aging time is set at 300s. When the aging timer is started after power on, the switch

guaranties that free spaces can be released from occupied address entries.

FORWARDING SCHEME

The store-and-forward algorithm is used. The incoming packet has to be completely stored in the buffer and verified error-

free before forwarding operations take place.

Xor Hashing Function

DA or SA

[9:0]

Address

Entry Point

AAA-1

AAA

AAA+1

Address Lookup Table

AC206-DS05-405-R データシート(PDF) 22 Page - Broadcom Corporation.