Cabletron Systems 04-0053-01 manual Managing Parallel Pnni Links, SmartSwitch # show pnniinterface

PNNI Routing Managing Parallel PNNI Links

3.3MANAGING PARALLEL PNNI LINKS

ATM SmartSwitches can be connected by more than one physical link. PNNI treats these connections as parallel physical links. By default, parallel links are considered to have equal capabilities with regard to call set ups.

For example, if a second link is added between switch SWA3 and switch SWB3 (from the example above), this parallel link can be seen using the show pnnilink command.

SWA3	# show pnnilink
Num(ALL)						:
Num	Port	Node		Remote Node		Hello State		Link Type
	Number	Index		IP Addr
===========================================================================
1	7A1		1	206.61.237.20		2WayInside		Lowest Level Horizontal		Link
2	7A3		1	206.61.237.19		2WayInside		Lowest Level Horizontal		Link
3	7B1		1	206.61.237.23		CommonOut		Outside and Uplink
4	7B2	1	206.61.237.23		CommonOut		Outside and Uplink		— Second physical link to B3
5	--		2	N/A		2WayInside		Horizontal Link to/from		LGN
6	--	2	N/A		2WayInside		Horizontal Link to/from LGN			— Second logical link to B3

SWA3 #

You can adjust the advertised capabilities of each link (on a per-port, per-service class basis) by changing the link’s administrative weights. Use the show pnniinterface command to view the current administrative weights. For example:

SmartSwitch # show pnniinterface
PortNumber(ALL)			:
Port	Admin Wt	Admin Wt	Admin Wt	Admin	Wt	Admin Wt	Aggregation
Number	CBR	RTVBR	NRTVBR	ABR		UBR	Token

================================================================================

CPU	5040	5040	5040	5040	5040	0
CPU.1	5040	5040	5040	5040	5040	0
7A1	5040	5040	5040	5040	5040	0
7A2	5040	5040	5040	5040	5040	0
7A3	5040	5040	5040	5040	5040	0
7A4	5040	5040	5040	5040	5040	0
7B1	5040	5040	5040	5040	5040	1
7B2	5040	5040	5040	5040	5040	0
7B3	5040	5040	5040	5040	5040	0

SmartSwitch #

A link’s administrative weight defines its desirability to the PNNI routing service when setting up a call of a particular class of service. The lower the numerical value of the administrative weight, the more desirable the route. For example, a route with administrative weight 200 for a particular class of service is considered a better route than one with the default weight of 5040 for that service. As a result, the administrative weight provides a quantitative way to control which routes are favored for call set up with regard to service class.

The ability to control the PNNI routing service in this fashion allows for parallel routes to be weighted such that one link is designated as the favored for a particular service class, while a parallel link can be designated as the favored route for a different service class.

SmartSwitch ATM User Guide 3-9