Cisco Catalyst 8540 MSR Configuration Manual page 882

Adding a New Lowest Level of PNNI Hierarchy
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
SanFran.BldA.T5
Uplinks
Induced horizontal links
Logical group nodes (LGNs)
Peer group leaders (PGLs)
This example assumes that all addresses have already been assigned according to a hierarchical ATM
Note
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.
If no renumbering is necessary and all ATM switch routers are peer group leader/logical group node
Note
(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
provided.
ATM Switch Router Software Configuration Guide
A-8
Two-Level PNNI Hierarchical Network
SanFran
T5
T4
*
SanFran.BldA.T4
*
NewYork
*
T3 NewYork.BldB.T3
T2
NewYork.BldB.T2
T1
NewYork.BldB.T1
Appendix
Figure A-4.
Level 56
Level 72
Figure A-4) are also
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