Alcatel Carrier Internetworking Solutions Omni Switch/Router - Manual (Page 540)

Dissimilar LAN Switching Capabilities
Page 18-44
Switching Between Similar LANs across a Native Backbone
Switched traffic between similar LANs across a non-trunked or native backbone will have
translations performed at each egress point. In the figure below, for traffic originating from
Station A destined to Station B, point 1 represents the ingress (input) port of Switch 1. Like-
wise, point 2 represents the egress (output) port of Switch 1, point 3 represents the ingress
(input) port of Switch 2 and the point 4 represents the egress (output) port of Switch 2.
Translations will occur at each egress port. For traffic from Station A to Station B, output
translations will occur at points 2 and 4. For traffic from Station B to Station A, output transla-
tions will occur at points 3, and 1.
Similar LANs Across a Native Backbone
In the above example, the backbone could be of any media type other than Ethernet. If all
three media types were Ethernet, then no translations would occur, because the traffic is
being switched from like media to like media.
Ethernet Ethernet
FDDI Native Backbone
Switch 1 Switch 2
3
4
1
2
Station A Station B