Beta Draft Confidential
Configuring PNNI Routing
Resilient UNI and APS Resilient UNI Over PNNI
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000 1/19/0521-25
Resilient UNI and APS Resilient UNI Over PNNI
This section describes PNNI resilient UNI and APS resilient UNI support for ATM
PVC circuits. This feature enables you to use the resilient UNI or APS resilient UNI
features to configure fault-tolerant ATM PVCs across a PNNI or combined
VNN/PNNI routing domain.
About Resilient UNI and APS Resilient UNI Over PNNI
A fault-tolerant ATM PVC configuration enables ATM UNI DCE and ATM DTE
logical ports to serve as a backup for any number of active UNI ports. You manually
activate the backup port if a primary port fails or if you need to take a primary port
offline. This function is sometimes referred to as resilient UNI.
To automate resilient UNI/fault-tolerant ATM PVC functions, you can configure the
CBX 3500, CBX 500, or GX 550 physical port on which the ATM UNI logical port
resides for APS. APS resilient UNI allows you to protect optical interfaces by
provisioning a backup (protection) port that automatically takes over for the primary
(working) port when a physical layer fault or module failure occurs.
You configure both resilient UNI and APS resilient UNI by associating a Service
Name Binding with the working and protection logical port pair. The Service Name
Binding is advertised to all switches in the network and contains address information
indicating whether the primary (working) or backup (protection) port is currently
active. If the primary (working) port fails and a manual or automatic switchover
occurs, the Service Name Binding is re-advertised throughout the network to indicate
that the backup (protection) port has been activated. When a switch receives this
information, it reroutes circuits from the primary (working) port to the specified
backup (protection) port.
The PNNI routing protocol advertises and recognizes Service Name Bindings using a
specially-formatted ATM address. This extends resilient UNI and APS resilient UNI
support to PVCs using paths that are entirely or partially within the PNNI routing
domain.
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