Specifications

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Cisco MGX 8800/8900 Series Software Configuration Guide
Release 5.1, Part Number OL-6482-01, Rev. A0, January 25, 2005
Chapter 8 Managing PNNI Nodes and PNNI Routing
Managing PNNI Routes
Preferred routes can be configured to be directed or non-directed. A directed route only attempts a
connection on the preferred route. If the connection cannot route over the preferred route, that
connection will go into a failed state. A non-directed route first attempts to route over the preferred route.
If the preferred route is not available, the connection will be attempted over other routes.
Keep the following in mind when planning preferred routes:
All nodes in the preferred route must exist in the network node table.
A preferred route can be confined to the same peer group as the source node, or it can go outside the
local peer group.
A preferred route can include non-Cisco nodes.
A node can appear only once in a preferred route.
Any preferred routes you defined using Release 3 software will be lost during an upgrade to Release
4. Once you have upgraded to Release 4, you must be manually re-enter your preferred routes. Prior
to an upgrade, use the dspprefs command view all the configured preferred routes. Write down any
preferred routes you want to re-enter once you have upgraded to Release 4.
The preferred route feature is not compatible with point-to-multipoint SPVC configuration.
Connections mastered on an RPM cannot be associated with a preferred route.
Note As of Release 4 and beyond, Cisco MGX switches with PXM45/A, PXM45/B, or PXM1E controllers
support up to 5000 preferred routes per switch. When used with PXM45/C controllers, MGX 8850
(PXM45) and MGX 8950 switches, and the MGX 8880 Media Gateway, support up to 10000 preferred
routes.
A preferred route consists of a sequential list of up to 20 nodes, including the local node that hosts the
starting point of the preferred route. The destination node can be up to 19 network elements (NEs), or
19 NNI links, away from the local node.
Maintaining the Network Node Table
To support preferred routes, the network administrator manually creates a node table that contains
information about all the nodes in the network. All the nodes that will be in a preferred route must appear
in the network node table, and each node in a preferred route must have its own entry in the network
table.
Cisco recommends that you keep the same network node table on every node in your network for the
purpose of convenience when configuring preferred routes. Once you create the node table on one node,
you can to FTP that table to all the other nodes in the network. If you change any information in one of
the node tables, you need to update all of the node tables in the network to ensure synchronicity.
Before you can create a preferred route, all the nodes that will be in the preferred route must be in the
network node table. Enter the dspnwnodes command to ensure that all the nodes in your planned
preferred route are in the network node table, as shown in the following example:
U1.8.PXM.a > dspnwnodes
Node Identifier PXM Pref rte Node name
-------------------------------------------------- ----- -------- ---------
56:160:47.009181000000003071f80406.003071f80406.01 pxm1 No Fargo
56:160:47.009181000000003071f80422.003071f80422.01 pxm45 No Denver
56:160:47.339181000000003071f80433.003071f80433.01 pxm1E Yes Chicago
If one or more nodes in your preferred route does not appear in the network node table, use the following
procedure to add the missing nodes to the table.