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Beta Draft Confidential
1-4
1/19/05
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
Overview
Fault-tolerant PVCs
Fault-tolerant PVCs
describes an optional logical port feature called fault-tolerant PVC
(sometimes referred to as resilient UNI/NNI). A fault-tolerant PVC configuration
enables a UNI data communications equipment (DCE) or data terminal equipment
(DTE) logical port to serve as a backup for any number of active UNI ports. If a
primary port fails or if you need to take a primary port offline for maintenance, you
activate the backup port.
Using this feature, a logical port is given a service name. When you configure a PVC,
select this service name as the logical port endpoint. If you activate the backup port,
all PVCs on the failed primary port are automatically rerouted.
If you use resilient UNI features in conjunction with the Automatic Protection
Switching (APS) functions available on the CBX 3500, CBX 500 and GX 550 optical
modules, you can configure a PVC to automatically revert to the backup port if the
primary port fails.
RLMI
describes the Frame Relay Resilient Link Management Interface (RLMI)
feature and how to configure RLMI on ATM Network Interworking for Frame Relay
NNI logical ports on ATM IWU and ATM CS cards.
RLMI provides resiliency by monitoring Link Management Interface (LMI) link
status. RLMI enables a pair of Frame Relay UNI, NNI, or ATM Network Interworking
for Frame Relay NNI logical ports configured on a B-STDX 9000, CBX 3500, or
CBX 500 switch to serve as preferred and backup ports. If the primary port fails, a
switchover to the backup port occurs.
SVCs
The CBX 3500, CBX 500, and GX 550 offer switched virtual circuit (SVC) features.
With SVCs, connections are not predefined as they are for PVCs. Instead, end stations
use a signaling protocol to indicate to the ATM network the endpoint to which it
routes the SVC request. To support SVC services, each user endpoint is assigned a
unique address that identifies the endpoint and enables the network to route the SVC
request.
Note – You should not configure SVCs on a logical port that is also designated as a
backup port.
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