STM-1 CPOS card on the NE40/NE80 routers support the following link-protocols:
But some times when using the command "link-protocol" in the interface view of the Serial Interface created on the STM-1 CPOS card you only get the options of PPP and HDLC and the FR is Missing.
The above problem can easily be recreated with the following VRP version:
VRP (R) software, Version 5.30, RELEASE 0213
There are two ways to resolve this problem:
1. You delete the Serial Interface in the STM-1 CPOS card and then Recreate it. This will solve the problem but will cause service disruption as on the CPOS card to delete an interface you have to shut down the whole Cpos Controller.
2. The other way is to issue the following command in the interface view:
[Router-Serial8/0/0/3:0]undo ppp mp
The above command will resolve the problem without any disruption of service on other Serial interfaces of the CPOS Card.
The above phenomenon happens when one bundels the serial interface into a MPPP group. The following commands are used for bundeling in the interface view:
bundle mp-group x/x/x
Now if you delete the mp-group interface with the command:
undo mp-group x/x/x
Then all the member serial interfaces of the above mp-group will stop supporting fr link-protocol.
If you Check the configuration of the serial interface it will show no configuration as shown below:
hdlc Enable HDLC encapsulation
ppp Enable PPP encapsulation
It can clearly be seen that no option for fr is available.
Solution 2 of the above problem is recomended as it will not lead to disruption of service on other serial interfaces of the STM-1 CPOS