3com 2000 TR Manual De Usuario

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How TR-in-FE Works
2-3
How TR-in-FE Works
Figure 2-1 shows a diagram of a basic TR-in-FE sys-
tem. The illustration depicts three Switch 2000 TRs 
interfacing with a Switch 3000 through the Token 
Ring-in-Fast Ethernet Module. In this example, the 
Switch 3000 acts as an 800 Mbps point of aggrega-
tion for this system with multiple FDX Fast Ethernet 
pipes feeding it.
Traffic that enters a port on the Token Ring switch 
and that is not destined for another port on the same 
switch is directed at the TR-in-FE Module. Subse-
quently, the module puts a Fast Ethernet wrapper 
(see “Tunneling” section below) on the native Token 
Ring frame, and forwards the modified packet as a 
Fast Ethernet frame to the Switch 3000. 
The Switch 3000 handles the frame as it would any 
other FE frame and forwards it to the appropriate 
port. If the destination address is another TR end sta-
tion located on another switch, the destination 
TR-in-FE Module strips the frame of the Fast Ethernet 
information and sends the native TR frame to the 
appropriate destination port. If the destination is a 
Fast Ethernet attached server, the Fast Ethernet NIC 
with a TR-in-FE driver interprets the frame before pro-
viding it to upper level applications. The fact that the 
application communicates using TR-in-FE is transpar-
ent to the user.
Figure 2-1   A Simple Token Ring-in-Fast Ethernet 
Configuration
Figure 2-2 illustrates another example of Token 
Ring-in-Fast Ethernet, but one on a scale more exem-
plary of what a real user configuration looks like as 
part of an integrated system.
Fast Ethernet
 Server
Fiber
Copper
SuperStack II 
Switch 3000 TX
SuperStack II 
Switch 2000 TR