Table of Contents

PNNI Migration Examples

This appendix provides examples of how to migrate a flat network topology to a Private Network-Network Interface (PNNI) hierarchical network topology, and includes the following sections:

Adding a Higher Level of PNNI Hierarchy

Figure A-1 shows an example network with two PNNI peer groups connected by an Interim Inter-Switch Signalling Protocol (IISP) interface.

You can convert the network to a single hierarchical PNNI routing domain by configuring a second level of hierarchy in each peer group and converting the IISP interface to a PNNI interface, as shown in Figure A-2.

The initial configuration for each ATM switch router is shown in the sections that follow. The commands used to migrate the network to a two-level PNNI hierarchical network (shown in Figure A-2) are also provided.

Switch T1 Initial Configuration

The initial configuration for switch NewYork BldB.T1 follows:

Switch T2 Initial Configuration

The initial configuration for switch NewYork BldB.T2 follows:

To display the reachability information, use the show atm route command.

Switch T3 Initial Configuration

The initial configuration for switch NewYork BldB.T3 follows:

To display the reachability information, use the show atm route command. To display the interface type, use the show atm interface command:

Note   In the example, the interface type of interface atm 0/0/2 on NewYork.BldB.T3 is determined using Integrated Local Management Interface (ILMI) autoconfiguration. Because the other side of the link on SanFran.BldA.T4 is configured as IISP, the interface type is determined to be IISP. When using ILMI autoconfiguration on one side of the link and manually configuring the other side as IISP, be careful to specify the configured side as either the user or network side, depending on whether it has the larger value of atmfMySystemIdentifier.

Switch T4 Initial Configuration

The initial configuration for switch SanFran.BldA.T4 follows:

To display the reachability information, use the show atm route command. To display the interface type, side, and version, use the show atm interface command:

Switch T5 Initial Configuration

The initial configuration for switch SanFran.BldA.T5 follows:

Configuring Second Level of PNNI Hierarchy on Switches T3 and T4

The following example shows how to configure and display the second level of PNNI hierarchy on switches NewYork.BldB.T3 and SanFran.BldA.T4 (see Figure A-2):

Note   In this example, the configuration of the second level of PNNI hierarchy on switch NewYork.BldB.T3 or switch SanFran.BldA.T4 has no effect on new or existing connections.

Use the following commands to confirm the creation of the PNNI hierarchy:

Configuring the Link Between Switch T3 and Switch T4 for PNNI

The following example shows how to configure the link between switch NewYorkBldB.T3 and SanFran.BldA.T4 for PNNI.

Note   In this example, only one side of the IISP interface is configured to change the link from IISP to PNNI because the other side of the link is using ILMI autoconfiguration for the interface type. You can use either the atm auto-configuration or atm nni command to change the link from IISP to PNNI.

Note   When you change the link from IISP to PNNI, all existing connections across the interface are cleared. The ability to route new connections across the link is restored within a few seconds, when the PNNI uplinks and induced horizontal link come up.

Verifying Connectivity to All ATM Addresses and Deleting an Old Static Route on Switches T4 and T3

The following example shows how to verify connectivity to all ATM addresses before deleting an old static route on switch T4:

The following example shows how to delete the old static route from switch T4:

The following example verifies that the old static route on switch T4 has been deleted:

The following example shows how to delete the old static route from switch T3:

To verify the deletion of the old static route on switch T3, use the show atm route command.

Adding a New Lowest Level of PNNI Hierarchy

Figure A-3 shows an example network configured with only one level of PNNI hierarchy at level 56.

You can convert the network into a two-level hierarchical PNNI network by bringing each lowest level node down to level 72 and splitting the network into two peer groups. At the same time, you can add a second level of hierarchy at level 56. The resulting network topology is shown in Figure A-4.

Note   This example assumes that all addresses have already been assigned according to a hierarchical ATM address plan. All the ATM switch routers share the same 56-bit prefix. The ATM switch routers in Building A in San Francisco share the same 72-bit prefix. The ATM switch routers in Building B in New York share a different 72-bit prefix. As a result, no renumbering is necessary to migrate the network from a single level of PNNI hierarchy to two levels of PNNI hierarchy.

Note   If no renumbering is necessary and all ATM switch routers are peer group leader/logical group node (PGL/LGN)-capable (Cisco IOS Release 11.3T, WA4, or later releases), existing connections are not affected by the migration process. The existing connections remain active while you modify the PNNI configuration.

You can implement the migration process one ATM switch router at a time. As each ATM switch router is moved down to level 72, the ability to establish new connections across that ATM switch router is lost temporarily and then automatically restored. You can pause for long periods of time during the migration process without any harmful effects.

The initial configuration for each ATM switch router is shown in the sections that follow. The commands used to migrate the network to the two-level PNNI hierarchical network (shown in Figure A-4) are also provided.

Switch T1 Initial Configuration

The initial configuration for switch NewYork BldB.T1 follows:

The following example shows the output from the show atm route command for the switch:

Switch T2 Initial Configuration

The initial configuration for switch NewYork BldB.T2 follows:

Switch T3 Initial Configuration

The initial configuration for switch NewYork BldB.T3 follows:

Switch T4 Initial Configuration

The initial configuration for switch SanFran.BldA.T4 follows: