Discarding Local Traffic - Cabletron Systems SmartSTACK ETHERNET ELS10-27 User Manual

Introduction
This allows for complete error checking, and limits the amount of time
between a device request access to the network, and permission to
transmit. In addition, full store and forward switching ensures data
integrity; preventing network error conditions from being generated
throughout the network.
Discarding Local Traffic
The SmartSTACK Ethernet ELS10-27 checks all incoming packets for the
destination address against the Bridge Address Table. If a packetÕs
destination address is not on the same network segment as the
originating packet, the SmartSTACK Ethernet ELS10-27 forwards the
packet to the network segment associated with that destination address,
if known. However, if the packetÕs source and destination addresses are
on the same network segment, known as local trafÞc, the packet is
automatically discarded (i.e., ignored by the SmartSTACK Ethernet
ELS10-27).
For example, a Þle transmitted from Workstation A, to Workstation C, in
Figure 1-3, does not need to leave LAN 1. The SmartSTACK Ethernet
ELS10-27 connected to LANs 1 and 2 sees all trafÞc from LAN 1,
including LAN 1 local trafÞc.
ELS10-27
LAN 1
LAN 2
A B C
Figure 1-3. Typical Switching Application
By forwarding only packets addressed to devices on other network
segments, the SmartSTACK Ethernet ELS10-27 reduces unnecessary
trafÞc and thereby enhances the overall performance of the network.
Note: If the packet address is not found in the Bridge Address Table, it will be
forwarded (flooded) to all network segments.
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