Cabletron Systems 9A100 manual Ip Routing, Administrative Weight and Parallel Routes

Switch Administration IPRouting

Enter show PNNIMetric to view the newly created metric pair:

SmartSwitch # show pnnimetrics
Metrics(ALL)	:
Metrics Metrics Tag Direction Index	GCAC CLP Admin Wt Service Categories

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

1	0x9	Incoming	0x10	CLP0+1	200	CBR
2	0x9	Outgoing	0x10	CLP0+1	200	CBR
3	0x111113	Outgoing	0x1	CLP0+1	5040	UBR
4	0x111113	Outgoing	0x2	CLP0+1	5040	ABR
5	0x111113	Outgoing	0x4	CLP0	5040	NRTVBR
6	0x111113	Outgoing	0x18	CLP0	5040	CBR RTVBR
7	0x111114	Outgoing	0x1	CLP0+1	5040	UBR
8	0x111114	Outgoing	0x2	CLP0+1	5040	ABR
9	0x111114	Outgoing	0x4	CLP0	5040	NRTVBR
10	0x111114	Outgoing	0x18	CLP0	5040	CBR RTVBR

SmartSwitch #

The newly created metric pair appears at the top of the list.

Once the metric is created, we can specify its metric tag number within the definition of a route:

SmartSwitch # add atmroute
PortNumber(A1)	: b2
AtmAddress()	: 39:00:00:00:00:00:00:00:00:00:55:77:88
PrefixLength(104)	:
Index(0)	:
Type(Internal)	:
Scope(0)	:
MetricsTag(0)	: 9	< The index tag of our metric pair
SmartSwitch #

Administrative Weight and Parallel Routes

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

The ability to control the PNNI routing service in this fashion allows for parallel routes into an IISP domain to be weighted such that one route is designated as the default, while the other becomes the backup route. This default/backup routing topology is typically used where a link to a particular domain requires a high degree of reliability. If the default route becomes congested or reaches its bandwidth limit, the routing service can initiate load sharing by routing additional calls through the backup route.

4.3IP ROUTING

The SmartSwitch 9A100 switch provides limited IP routing. IP routing allows switches that are not connected directly to Ethernet to communicate with an Ethernet-based network management system (NMS). The connection is made by adding IP routes on the non-connected switches that specify a client on a connected switch as their gateway to the Ethernet.

SmartSwitch 9A100 User Guide 4-7