Troubleshooting Frame Relay (Layer 2)

Troubleshooting frame relay (layer2)

The basic command that we need to consider on every troubleshooting is "sh ip int brief". Consider status of Line and Protocol. Line means layer 1. and Protocol means layer 2.

For frame-relay.
If line is down, protocol is down.  =  physical layer issue
If line is up, protocol is down       =  layer 2 problem such as encapsulation, lmi type mismatch

These followings VC status helps you understand more about layer 2 frame-relay. So we can know exactly where the problem is.

VC information

ACTIVE       =  normal operation

INACTIVE   =  locally up but not end-to-end

DELETED     = Conflict in DLCI configured locally and Frame relay switch

STATIC        = LMI keepalive is disabled.

Example1
//the interface of the other end is shutdown. No comminication of LMI
R1 interface : encapsulation frame-relay
R1# show frame-relay pvc


PVC Statistics for interface Serial1/0 (Frame Relay DTE)

              Active     Inactive      Deleted       Static
  Local          0            1            0            0
  Switched       0            0            0            0
  Unused         0            0            0            0

DLCI = 101, DLCI USAGE = LOCAL, PVC STATUS = INACTIVE, INTERFACE = Serial1/0

  input pkts 0             output pkts 0            in bytes 0
  out bytes 0              dropped pkts 0           in pkts dropped 0
  out pkts dropped 0                out bytes dropped 0
  in FECN pkts 0           in BECN pkts 0           out FECN pkts 0
  out BECN pkts 0          in DE pkts 0             out DE pkts 0
  out bcast pkts 0         out bcast bytes 0
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
  pvc create time 00:00:07, last time pvc status changed 00:00:07
R1#

Example2

//interface dlci was configured incorrect. The PVC on frame-relay switch ad R1 does not match.

R1#sh frame-relay pvc

PVC Statistics for interface Serial1/0 (Frame Relay DTE)

              Active     Inactive      Deleted       Static
  Local          0            0            2            0
  Switched       0            0            0            0
  Unused         0            0            0            0

DLCI = 101, DLCI USAGE = LOCAL, PVC STATUS = DELETED, INTERFACE = Serial1/0

  input pkts 0             output pkts 0            in bytes 0
  out bytes 0              dropped pkts 0           in pkts dropped 0
  out pkts dropped 0                out bytes dropped 0
  in FECN pkts 0           in BECN pkts 0           out FECN pkts 0
  out BECN pkts 0          in DE pkts 0             out DE pkts 0
  out bcast pkts 0         out bcast bytes 0
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
  pvc create time 00:03:10, last time pvc status changed 00:00:06


Example3
interface sub-command
no keepalive 
// Line and protocol will be forced to up. And PVC status is static.


R1#sh frame-relay pvc

PVC Statistics for interface Serial1/0 (Frame Relay DTE)

              Active     Inactive      Deleted       Static
  Local          2            0            0            0
  Switched       0            0            0            0
  Unused         0            0            0            0

DLCI = 101, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial1/0

  input pkts 0             output pkts 0            in bytes 0
  out bytes 0              dropped pkts 0           in pkts dropped 0
  out pkts dropped 0                out bytes dropped 0
  in FECN pkts 0           in BECN pkts 0           out FECN pkts 0
  out BECN pkts 0          in DE pkts 0             out DE pkts 0
  out bcast pkts 0         out bcast bytes 0
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
  pvc create time 00:07:05, last time pvc status changed 00:00:15