Cabletron Systems 04-0053-01 manual Physical Connections Between Peer Groups

PNNI Routing Multi-level PNNI Topology

Connectivity is now established between the two peer groups. For example, if LANE services are running on a switch within peer group A, LANE clients can exist in group B. The clients in group B will traverse the link between the two groups, find the LANE server in group A, and join the ELAN. Figure 3-2shows a logical representation of the topology created in the example.

	Logical Group Nodes
	for Peer Groups A and B
Parent Group of	Logical link
Group A and B SWA3	SWB3
Level 72

	Physical Link
SWA1	SWB3	SWB1
SWA3
SWA2		SWB2
Peer Group A		Peer Group B
Level 80		Level 80
Peer Group Leader	Peer Group Leader

N/A Horizontal Link to/from LGN in show pnnilink command

Outside Uplink in show pnnilink command

Figure 3-2 Logical representation of connectivity between groups A and B

3.2.2Physical Connections Between Peer Groups

Keep in mind that the two PGL switches (switches SWA3 and SWB3) do not have to be directly connected to each other for the two peer groups to maintain connectivity. PGLs can find each other through any physical link that connects the two groups. For example, if a second physical link is made between two other switches in groups A and B (for instance, between SWA1 and SWB2), and if the physical link between the PGLs is removed, the PGLs will reestablish their connectivity across the second physical link.

Adding Higher-level Peer Groups

Adapting the process in the example above, more sophisticated PNNI topologies can be created. For example, to establish connectivity with other parent groups at level 72, do the following:

1.Make a physical connection between any two switches represented in the separate parent groups.

SmartSwitch ATM User Guide 3-7