FR Connectivity- LMI Receiving

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May 2nd, 2008
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Hi,


I have one Frame Relay link which I need to turn up. Currently my Serial1/0 is up/up but my sub-interface 1/0.1 is down/down, although I am receiving LMI on my interface. Does receiving LMI mean that I have layer 1 & 2 connectivity between my router and telco's FR switch? Let me know my assumption is wrong/right.

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mheusing Sat, 05/03/2008 - 07:12
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Hi,


receiving FR LMI messages means connectivity between your router and the FR switch of the provider.

To get further information you can debug the LMI messages (debug frame-relay lmi). You might have to wait for a minute or so, but finally you should see a message regarding the configured DLCI. It should look similar to


: Serial1(in): Status, myseq 3

: RT IE 1, length 1, type 0

: KA IE 3, length 2, yourseq 4 , myseq 3

: PVC IE 0x7 , length 0x3 , dlci 100, status 0x0


The information to check:

1) which DLCI number is reported? Does it match your configuration?

2) what is the status? If the DLCI is active it should show 0x2

Any other status should be reported to the service provider for further trouble shooting inside the SP network.

Possible status states are


0x0-Added/inactive means that the switch has this DLCI programmed but for some reason (such as the other end of this PVC is down), it is not usable.


0x2-Added/active means the Frame Relay switch has the DLCI and everything is operational. You can start sending it traffic with this DLCI in the header.


0x3-0x3 is a combination of an active status (0x2) and the RNR (or r-bit) that is set (0x1). This means that the switch - or a particular queue on the switch - for this PVC is backed up, and you stop transmitting in case frames are spilled.


0x4-Deleted means that the Frame Relay switch doesn't have this DLCI programmed for the router. But it was programmed at some point in the past. This could also be caused by the DLCIs being reversed on the router, or by the PVC being deleted by the telco in the Frame Relay cloud. Configuring a DLCI (that the switch doesn't have) will show up as a 0x4.


0x8-New/inactive


0x0a-New/active



For details on how to troubleshoot frame relay please also have a look at "Comprehensive Guide to Configuring and Troubleshooting Frame Relay"

http://www.cisco.com/en/US/tech/tk713/tk237/technologies_tech_note09186a008014f8a7.shtml


Hope this helps! Please use the rating system.


Regards, Martin

yagnesh_tel Tue, 05/06/2008 - 12:31
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Martin,

Your information as well as provided link really help to resolve issue.

Thanks.

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