Frame-Relay / LMI question

CompUBug

If there's a problem with LMI, such as when you run the command "show frame-relay lmi" and you find an error, where should you begin to seek the solution?

alliasneo

Hi Compubug,

The LMI messages need to be incrementing between sending and recieving:

R3#sh frame lmi
LMI Statistics for interface Serial2/0 (Frame Relay DTE) LMI TYPE = CISCO
Invalid Unnumbered info 0 Invalid Prot Disc 0
Invalid dummy Call Ref 0 Invalid Msg Type 0
Invalid Status Message 0 Invalid Lock Shift 0
Invalid Information ID 0 Invalid Report IE Len 0
Invalid Report Request 0 Invalid Keep IE Len 0
Num Status Enq. Sent 7 Num Status msgs Rcvd 6
Num Update Status Rcvd 0 Num Status Timeouts 16


These should always be around about the same number. These are sent between our DTE devices and recieved by the ISP's DCE frame switches. If these numbers are looking a little strange:

R3#sh frame lmi
LMI Statistics for interface Serial2/0 (Frame Relay DTE) LMI TYPE = CISCO
Invalid Unnumbered info 0 Invalid Prot Disc 0
Invalid dummy Call Ref 0 Invalid Msg Type 0
Invalid Status Message 0 Invalid Lock Shift 0
Invalid Information ID 0 Invalid Report IE Len 0
Invalid Report Request 0 Invalid Keep IE Len 0
Num Status Enq. Sent 27 Num Status msgs Rcvd 6
Num Update Status Rcvd 0 Num Status Timeouts 25

you know that you have an LMI keepalive problem and the messages are not getting through.

LMI messges are sent every 10 seconds. so the sent/received should increment in this interval. If your time-outs are also increasing this is a good indication something is wrong.

If you run a sh interface for the frame connection you will probably see:

R3#sh int s2/0
Serial2/0 is up, line protocol is down (disabled)

Which would suggest an LMI mismatch. You can also check #sh frame map and this will probably display the DLCI's as being inactive.
You can also run a

#debug frame lmi



Serial2/0(in): Status, myseq 1, pak size 21
nRT IE 1, length 1, type 0
nKA IE 3, length 2, myseq 27, yourseen 55, DTE down
nPVC IE 0x7 , length 0x6 , dlci 301, status 0x0 , bw 0

Serial2/0(in): Status, myseq 1, pak size 21
nRT IE 1, length 1, type 0
nKA IE 3, length 2, myseq 28, yourseen 55, DTE down
nPVC IE 0x7 , length 0x6 , dlci 301, status 0x0 , bw 0

Serial2/0(in): Status, myseq 1, pak size 21
nRT IE 1, length 1, type 0
nKA IE 3, length 2, myseq 29, yourseen 55, DTE down
nPVC IE 0x7 , length 0x6 , dlci 301, status 0x0 , bw 0




If myseq increments but yourseen stays the same you can tell the messages arn't getting through.