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ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter6 Configuring ATM Network Interfaces
Configuring NNI Interfaces
Configuring a 12-Bit VPI NNI Interface (Catalyst 8540 MSR)
The Catalyst 8540 MSR ATM switch router can accommodate up to six interfaces per modu le for
maxvpi-bits greater than the standard 8-bit configuration. If you try to configure more than the maximum
number of allowed interfaces with 12-bit virtual path identifiers (VPIs), follow these precautions:
When you must remove an interface (for example, hot-swapping a port adapter) that is configured
for a maxvpi-bit, the number of interfaces (with maxvpi-bit value greater than 8) on the module is
decremented. This allows you to then configure other interfaces on the same module for maxvpi-bits
greater than eight bits.
If a port adapter with interfaces configured with a maxvpi-bits value of eight is reinserted into a
module location that previously held a port adapter with maxvpi-bits greater than eight bits, the VCs
with VPIs greater than255 remain in “No HW RESOURCES” state. An interface can be
reconfigured to maxvpi-bits greater than eight, by changing the value to less than or equal to eight
bits on a different interface. The VCs can be restored from “No HW RESOURCES” state by toggling
the interface state using the shutdown and no shutdown commands.
When you need a 12-bit VPI range greater than 255, change the maximum VPI bits con figuration.
Perform the following steps, beginning in global configuration mode:
Note 12-bit VPI support is only available on ATM NNI interfaces.
Example
The following example shows that if you are unable to configure a port with a maximum 12-bit VPI value
greater than 8, you receive a message prompting you to reconfigure the port:
Switch(config)# interface atm 0/0/0
Switch(config-if)# no atm auto-configuration
Switch(config-if)# atm nni
Switch(config-if)# atm maxvpi-bits 12
This port can not be configured for vpi bits greater than 8, unless one
of the following ports is reconfigured for 8 bits vpi
interface a11/0/0
interface a11/0/1
interface a11/0/2
interface a11/0/3
interface a12/0/0
interface a12/0/1
Command Purpose
Step1 Switch(config)# interface atm card/subcard/port
Switch(config-if)#
Selects the interface to be configured.
Step2 Switch(config-if)# no atm auto-configuration Disables autoconfiguration on the interface.
Step3 Switch(config-if)# atm nni Configures the ATM NNI interface.
Step4 Switch(config-if)# atm maxvpi-bits max-vpi-bits Modifies the maximum VPI bits configuration.