1-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.1 Copyright  2001, Cisco Systems, Inc.
Lab 8.3.4.1: Troubleshooting Frame Relay 1

Frame Relay
Atlas 550
192.168.192.0/24
1/2
2/1
S0/0 S0/0
DLCI 17 DLCI 18
.2
.4
Fa0/0 192.168.200.1/24 Fa0/0 192.168.232.1/24
London Singapore
Objective

Apply the troubleshooting method to a simple Frame Relay network problem.

Scenario

A new Frame Relay connection was installed between London and Singapore
over the weekend. On Monday, both network operators at London and
Singapore call to let you know they are unable to reach each other with this
new Frame Relay connection. You check connectivity between the London
router and the Singapore router and find you cannot ping or telnet between
the sites. It is your responsibility to get London and Singapore communicating. Step 3

Gather the facts about the situation at hand. The commands listed below are
useful for gathering factual information about each router.

• show interfaces
• show frame-relay lmi
• show frame-relay pvc
• show frame-relay map

Gather information about the London router first. Console into the London
router and issue a show interfaces serial 0/0 command. The
highlighted information in the sample output below is useful for troubleshooting
and should be the same as the information in your output.

London#show interfaces serial 0/0
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 192.168.192.2/24
MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, loopback not set
Keepalive set (10 sec)
LMI enq sent 152, LMI stat recvd 152, LMI upd recvd 0, DTE LMI up
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 0 LMI type is ANSI Annex D frame relay DTE
Broadcast queue 0/64, broadcasts sent/dropped 33/0, interface broadcasts 20

London#show frame-relay lmi

LMI Statistics for interface Serial0/0 (Frame Relay DTE) LMI TYPE = ANSI
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 16 Num Status msgs Rcvd 16
Num Update Status Rcvd 0 Num Status Timeouts 0Notice that the router and Frame Relay switch are exchanging LMIs, “Num
Status Enq. Sent” and “Num Status msgs Rcvd.” When this is the case the
DLCI and LMI type are most likely configured correctly.

Issue a show frame-relay pvc command on the London router. The
highlighted information in the sample output below is useful for troubleshooting
and should be the same as the information in your output. (Remember to ignore
information about other DLCIs.)

London#show frame-relay pvc

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

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


CISCO, status defined, active
Serial0/0 (up): ip 192.168.192.4 dlci 17(0x11,0x410), static,
broadcast,
CISCO, status defined, activeThe DLCI has been successful mapped to the remote IP address via a “static”
frame-relay map statement. “CISCO” identifies the Frame Relay
encapsulation used with frame-relay map statement, which is the default
Frame Relay encapsulation on Cisco routers.

Listed below is a summary of pertinent factual information gathered about the
London router.

• The WAN interface serial 0/0 interfaces and line protocol are up; the
encapsulation is Frame-Relay; the LMI is up; and the LMI type is ANSI.
• LMIs are being sent and received so the router and Frame Relay switch are
exchanging LMIs.
• The PVC for DLCI 17 is active indicating the PVC between the router and
switch is configured correctly.
• The Frame Relay map is configured correctly.

So far there does not appear to be any configuration problems on the London
router. Now, gather information about the Singapore router.

Console into the Singapore router and issue a show interfaces serial
0/0 command.

2. What pertinent factual information about the interface did you gather and is
there any indication of a possible problem? (Hint: The information should

to handle/forward frames that your router sends with that DLCI number, but
it is not aware/informed that your destination router is ready to receive them.
The destination router may be down, non-existent, or having Layer 1
problems. Also, if it is INACTIVE there might be an LMI type mismatch
between the local router and the Frame Relay switch.

Issue a show frame-relay map command.

5. What pertinent factual information about the frame-relay map did you
gather and is there any indication of a possible problem? (Hint: The status
should be “deleted”.) Step 4

6. Examine the facts you have just gathered. Based on your observations,
what are the possible causes of the problem? (Hint: If the DLCI status is