[c-nsp] STM-1 loop prevention

[Andrew Gallo]

 On 10/6/2010 7:58 AM, RAZAFINDRATSIFA Rivo Tahina wrote:
> Hi all,
>
> I'm using a 7200-G2 with the the following:
>
> Software: IOS Version c7200p-adventerprisek9-mz.124-15.T6.bin
>
> 3 Packet over SONET interfaces
> NAME: "module 1", DESCR: "POS Port Adapter (SM)"
> PID: PA-POS-OC3SMI=    , VID: N/A, SN: 25403598
> (Interface POS1/0
> Hardware is Packet over Sonet)
>
>
> I'm running BGP with this box.
> During test performed by the provider, they did physical loopback on
> interfaces, that causes the box to crash, is there an option the
> interface down when loop is detected?
>
> Regards.
> _______________________________________________

I believe the command you want is 'down-when-looped':






down-when-looped

To configure an interface to inform the system it is down when loopback
is detected, use the down-when-looped interface configuration command.

down-when-looped
Syntax Description

This command has no arguments or keywords.
Defaults

Disabled
Command Modes

Interface configuration
Command History
Release
   
Modification

10.0
   

This command was introduced.

Usage Guidelines

This command is valid for HDLC or PPP encapsulation on serial and HSSI
interfaces.

There is not a no form of this command.

Backup Interfaces

When an interface has a backup interface configured, it is often
desirable that the backup interface be enabled when the primary
interface is either down or in loopback. By default, the backup is only
enabled if the primary interface is down. By using the down-when-looped
command, the backup interface will also be enabled if the primary
interface is in loopback.

Testing an Interface with the Loopback Command

If testing an interface with the loopback command, or by placing the DCE
into loopback, down-when-looped should not be configured; otherwise,
packets will not be transmitted out the interface that is being tested.
Examples

The following example configures interface serial 0 for HDLC
encapsulation. It is then configured to let the system know that it is
down when in loopback mode.

Router(config)# interface serial0

Router(config-if)#  encapsulation hdlc

Router(config-if)#  down-when-looped