Cisco Cisco IOS Software Release 12.2 Release Notes
14
Frame Relay PVCs/Soft PVCs on an IDSL Interface
OL-3177-01B
Limitations and Restrictions
DSL Interface Limitations
In DSLAMs, each DSL interface can support multiple permanent virtual circuits (PVCs), but we
recommend that you use one routed MPLS VC if a dynamic routing protocol (such as RIP) is used
between the customer equipment and the provider equipment.
recommend that you use one routed MPLS VC if a dynamic routing protocol (such as RIP) is used
between the customer equipment and the provider equipment.
MPLS VPN Mapping Not Supported on the Eight-Port IDSL ITU-C Line Card
Routed termination of IDSL connections has not been supported since Cisco IOS Release 12.2(1b)DA.
Frame Relay PVCs/Soft PVCs on an IDSL Interface
The number of Frame Relay PVCs/Soft PVCs on an IDSL interface is restricted to 1 if you use the
default row in a frame-relay connection traffic table (FR-CTT).
default row in a frame-relay connection traffic table (FR-CTT).
When upgrading to Release 12.2(12)DA2 from earlier releases, you must first create a new row in the
FR-CTT with the desired CIR value and use the resultant row number during PVC/Soft PVC creation.
If you do not create a new row, the second FR PVC/Soft PVC command is not parsed and installed on
the IDSL interface.
FR-CTT with the desired CIR value and use the resultant row number during PVC/Soft PVC creation.
If you do not create a new row, the second FR PVC/Soft PVC command is not parsed and installed on
the IDSL interface.
Use of a Ring Topology in a DSLAM Subtend Environment to Achieve ATM
Trunk Redundancy
Trunk Redundancy
Ring topology is achieved when a node in the subtend tree is attached to the ATM access to provide a
physically redundant loop. Thus, when the primary ATM access or one of the ATM trunks in the subtend
tree fails, the soft permanent virtual circuits (SPVCs) can be dynamically rerouted through the use of
Private Network-Network Interface (PNNI) (
physically redundant loop. Thus, when the primary ATM access or one of the ATM trunks in the subtend
tree fails, the soft permanent virtual circuits (SPVCs) can be dynamically rerouted through the use of
Private Network-Network Interface (PNNI) (
Figure 1
SPVCs Prior to Failure
This redundancy requires the use of SPVCs. If you use permanent virtual circuits (PVCs) or permanent
virtual paths (PVPs), redundancy cannot be provided. The use of the SPVCs allows traffic to be rerouted
around the failed access point, because SPVCs leverage this feature of PNNI. When the failure occurs,
the SPVCs are disconnected and dynamically reconnected across the new path (
virtual paths (PVPs), redundancy cannot be provided. The use of the SPVCs allows traffic to be rerouted
around the failed access point, because SPVCs leverage this feature of PNNI. When the failure occurs,
the SPVCs are disconnected and dynamically reconnected across the new path (
).
DSLAM
CPE
DSLAM
CPE
DSLAM
CPE
ATM
Active
Inactive
Inactive
54056