EXP Computer S200 manual Supported, Topologies, Improper LT

LLC2 Local Termination

Supported	Local Termination is supported only on Token Ring topologies configured for
Topologies	Source Route Bridging. And there are two important guidelines to remember when
	you are planning your Local Termination strategy:
	• When you turn on Local Termination in your network, the MAC address/SAP
	value you assign is always locally terminated.
	• You must have a PathBuilder S200 series switch running Local Termination
	positioned at both ends of your network to provide spoofing from one edge
	point to another.
Improper LT
	For example, Figure 51 shows a Token Ring network improperly configured for
Configuration	Local Termination.
	LLC2

SNA FEP

1

2

CC

3

Non-3Com Bridges

CC

Figure 51. Example of Improper LT Configuration

The cluster controller (CC) using non-PathBuilder S200 series switch bridge 3 in Figure 51 is source route bridged to the FEP. The local PathBuilder S200 series switch, bridge 1, at the FEP use location tries to locally terminate the session since all frames bearing the MAC address of the FEP are to be spoofed. However, the non- PathBuilder S200 series switch bridged cluster controller will never come up unless Local Termination is disabled entirely. The cluster controller on PathBuilder S200 series switch bridge 2 will come up because it runs Local Termination. PathBuilder S200 series switch bridge 2 is unable to spoof traffic unless it originates from its own Token Ring. For spoofing to work, you must use PathBuilder S200 series switches with Local Termination enabled at the network’s edge points.

102 Bridging