Automatic Broadcast Control (Abc); How Abc Operates - HP J3245A Installation And Configuration Manual

Advanced Concepts

Automatic Broadcast Control (ABC)

Automatic Broadcast Control (ABC)
ABC helps to conserve bandwidth and processing power for IP and/or IPX
traffic within a broadcast domain without adding the levels of cost and latency
normally associated with routers. ABC achieves this by using the switch to
reduce IP ARP and RIP broadcast traffic and IPX NSQ, RIP, and SAP broadcast
traffic normally found on a network. Also, when enabled, ABC allows you to
set the global broadcast limit (Bcast Limit parameter) for all ports on the
switch (or, if VLANs are configured, for all ports in the specified VLAN).

How ABC Operates

Reducing ARP Broadcast Traffic. When enabled on the switch or a VLAN,
ABC does the following to reduce ARP (Address Resolution Protocol) broad-
cast traffic:
1.
2.
For example, assume that host A has traffic for host D.
Figure 7-17. Example of a Network Using ABC
7-30
Learning which port various hosts reside on by reading the address
information in broadcast ARP (Address Resolution Protocol) packets and
unicast ARP response packets
Proxy responding to subsequent ARP broadcast requests for those hosts
from other devices instead of forwarding such requests out all ports and
requiring each host to respond
Switch
Hub Hub
Host A Host B Host C
Server #1
Server #2
Host D