Tài liệu Troubleshooting Frame Relay 3 pdf

1-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. Lab 8.3.4.3: Troubleshooting Frame Relay 3 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 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. Adtran Atlas 550 Note If using the Adtran Atlas 550 as your Frame Relay switch, you will see information about DLCIs (such as DLCI 16) that is not shown in sample outputs of this lab. These DLCIs are configured on the Atlas 550, but are not being used for this specific lab. You would not normally see these extra DLCIs, so any information pertaining to them should be disregarded for this lab. Step 1 Cable the lab as shown in the diagram. Load the configuration file called Lab8-3-4-3-LondonBrokenConfig.txt into the London router. Load the file called Lab8-3-4-3- SingaporeBrokenConfig.txt into the Singapore router. Step 2 2-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. Use ping and telnet to check connectivity between London and Singapore. All ping and telnet attempts from either site to the other should fail. From each router, ping its directly connected LAN interface. This ping should be successful. 1. Define the problem you are experiencing. Step 3 Gather the facts about the situation. The commands listed below are useful for gathering factual information about each router. • show interface • show frame-relay lmi • show frame-relay pvc • show frame-relay map • debug frame-relay lmi Gather information about the London router first. Console into the London router and issue a show interface 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 interface serial 0/0 Serial0/0 is up, line protocol is down 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 69, LMI stat recvd 0, LMI upd recvd 0, DTE LMI down LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0 LMI DLCI 1023 LMI type is CISCO frame relay DTE Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0 Last input 00:15:53, output 00:00:05, output hang never Last clearing of "show interface" counters 00:11:37 Input queue: 0/75/0 (size/max/drops); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/32 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 9 input errors, 0 CRC, 9 frame, 0 overrun, 0 ignored, 0 abort 69 packets output, 897 bytes, 0 underruns 0 output errors, 0 collisions, 22 interface resets 0 output buffer failures, 0 output buffers swapped out 3-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up 2. Examine the output and list the pertinent facts about the interface. Issue a show frame-relay lmi command on the London router. The highlighted information in the sample output below is useful for troubleshooting and should be similar to the information in your output. London#show frame-relay lmi LMI Statistics for interface Serial0/0 (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 188 Num Status msgs Rcvd 0 Num Update Status Rcvd 0 Num Status Timeouts 187 Checking the status of the LMI is always a good place to start with Frame Relay. 3. Examine the output. Do you notice anything unusual? 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 0 1 0 0 Switched 0 0 0 0 Unused 0 0 0 0 DLCI = 17, DLCI USAGE = LOCAL, PVC STATUS = INACTIVE, INTERFACE = Serial0/0 input pkts 0 output pkts 0 in bytes 0 out bytes 0 dropped pkts 0 in FECN pkts 0 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 4-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. in DE pkts 0 out DE pkts 0 out bcast pkts 0 out bcast bytes 0 pvc create time 00:47:06, last time pvc status changed 00:47:06 4. Notice the PVC for DLCI 17 is INACTIVE. Would this be unexpected? Issue a show frame-relay map command on the London router. There should not be any output. Since no LMI messages are being received and the PVC is inactive, no mapping is taking place. Before any mapping between the local DLCI and the remote IP address can happen, LMIs must be exchanged between the routers and the Frame Relay switches, and the PVC must be active. Listed below is a summary of pertinent factual information gathered about the London router. • The WAN interface serial 0/0 interface 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. Issue a debug frame-relay lmi command on the London router. Since LMIs were not being received, debugging the LMI process gives you a closer look and will verify LMIs are not being received. Note: Your sequence numbers may differ. London#debug frame-relay lmi Frame Relay LMI debugging is on Displaying all Frame Relay LMI data London# 00:18:57: Serial0/0(out): StEnq, myseq 96, yourseen 0, DTE down 00:18:57: datagramstart = 0x1A01ED4, datagramsize = 13 00:18:57: FR encap = 0xFCF10309 00:18:57: 00 75 01 01 00 03 02 60 00 00:18:57: 00:19:07: Serial0/0(out): StEnq, myseq 97, yourseen 0, DTE down 00:19:07: datagramstart = 0x1A01ED4, datagramsize = 13 00:19:07: FR encap = 0xFCF10309 00:19:07: 00 75 01 01 00 03 02 61 00 00:19:07: 00:19:17: Serial0/0(out): StEnq, myseq 98, yourseen 0, DTE down 00:19:17: datagramstart = 0x1A01ED4, datagramsize = 13 00:19:17: FR encap = 0xFCF10309 00:19:17: 00 75 01 01 00 03 02 62 00 00:19:17: 5-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. The "Serial0/0(out):" and "myseq" greater than "0" indicate LMIs are being sent, but "yourseen 0" indicates LMIs are not being received. Note too that there are no "Serial0/0(in):" messages which also indicate there are no LMI messages being received. "DTE down" also means there is a problem communicating LMIs between the local router and the Frame Relay switch. Turn the debugging off. Examine the Singapore router to see if you can learn any new information. Issue a show interface serial 0/0 command. Your output should be similar to the sample output below. Singapore#show interface serial 0/0 Serial0/0 is up, line protocol is up Hardware is PowerQUICC Serial Internet address is 192.168.192.4/24 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 227, LMI stat recvd 227, 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 0/0, interface broadcasts 29 Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters 00:38:03 Input queue: 0/75/0 (size/max/drops); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/32 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 228 packets input, 3572 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 228 packets output, 3192 bytes, 0 underruns 0 output errors, 0 collisions, 1 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up 5. Compare this output with the output from the London router. What are the differences? So far the Singapore router seems to be successfully sending and receiving LMIs with its Frame Relay switch. Issue a show frame-relay lmi command to verify this. Your output should appear similar to the sample output shown below. 6-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. Singapore#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 326 Num Status msgs Rcvd 326 Num Update Status Rcvd 0 Num Status Timeouts 0 Examine the output. Notice LMI inquiries have been sent and messages received and there are no timeouts. There are no indications of a problem. Check the status of the PVC to London. Issue a show frame-relay pvc command. Your output should appear similar to the sample output shown below. (Remember to ignore information about other DLCIs.) Singapore#show frame-relay pvc PVC Statistics for interface Serial0/0 (Frame Relay DTE) Active Inactive Deleted Static Local 0 2 0 0 Switched 0 0 0 0 Unused 0 0 0 0 <output omitted> DLCI = 18, DLCI USAGE = LOCAL, PVC STATUS = INACTIVE, INTERFACE = Serial0/0 input pkts 0 output pkts 0 in bytes 0 out bytes 0 dropped pkts 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 pvc create time 01:04:26, last time pvc status changed 01:04:26 Note that DLCI 18 PVC status is INACTIVE, which should be expected since London is not exchanging LMIs with its Frame Relay switch. As was addressed previously, when the PVC status is inactive status, it is a good idea to look at the local router; however, in this case, the status is inactive on both routers and LMIs are not being exchanged on the London router while it is being exchanged on the Singapore router. Issue a show frame-relay map command. There should not be any output (except for maybe DLCI 16, which should be ignored). Even though LMI messages are being sent and received, the PVC is inactive so no mapping is taking place. Before any mapping between the local DLCI and the remote IP address can happen, LMIs must be exchanged between the routers and the Frame Relay switches, and the PVC must be active. 7-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. Issue a show running-config command to check the mapping statement and other interface information. Your output should appear similar to the sample output below. interface Serial0/0 ip address 192.168.192.4 255.255.255.0 no ip directed-broadcast encapsulation frame-relay no ip mroute-cache cdp enable frame-relay interface-dlci 18 frame-relay lmi-type ansi As was discovered earlier, the encapsulation is frame-relay and the frame-relay type is ANSI and a frame-relay interface-dlci statement was used. If the Singapore router was configured with a frame-relay map statement instead of the frame-relay interface-dlci statement, this would have caused a static mapping to London's remote IP address and the mapping would have been displayed. However, the PVC status would be inactive. Step 4 Examine the facts about both routers you have just gathered. • The London router Serial 0/0 line is up, but the protocol is down. • The Singapore router Serial 0/0 line is up and the protocol is up. • Both routers’ Serial 0/0 encapsulations are Frame-Relay. • DLCI 17 PVC status on the London router is inactive. • DLCI 18 PVC status on the Singapore router is inactive. • LMI status inquires have been sent, but no messages received on the London router. • LMI status inquires have been sent and messages received on the Singapore router. • DTE LMI is down on the London router. • DTE LMI is up on the Singapore router. • Frame-relay interface-dlci commands were used on both routers and are correct. • LMI type is CISCO on the London router. • LMI type is ANSI on the Singapore router. Based upon the information gathered, it would appear the Singapore router configuration is fine while the London router may require attention—the line protocol is down; LMI status inquiries and messages have not been sent and received; and the DTE LMI is down. Even though the LMI type is ANSI on the Singapore router and CISCO on the London router, this is not necessarily a problem as the LMI type is only between 8-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. the local router and its Frame Relay switch. The LMI at opposite ends of the same PVC can be different. However, all indications point to an LMI problem on the London router as LMIs must be sent and received between the router and Frame Relay switch before the PVC status becomes active. LMIs are being successfully exchanged between the Singapore router and its Frame Relay switch, but the PVC status is inactive. 6. Based on your observations, what is the possible cause of the problems on the London router? Step 5 Create an action plan to solve this problem. You could check with the Frame Relay provider to confirm the LMI type on the switch; you could try a different LMI type; or you could use the frame-relay qos-autosense command to let the router receive LMI type information from the Frame Relay switch. The Frame Relay provider has not gotten back to you yet so you either must try an LMI type of ANSI or Q933a, or use the auto sensing command. You decide to try an LMI type of ANSI first. Step 6 Implement the action plan. Change the LMI type on the Serial 0/0 interface of the London router to ANSI. London(config-if)#frame-relay lmi-type ansi It is a good idea to shutdown, and no shutdown the interface after changing the LMI type. Observe the results of your implementation. You may need to wait a minute or two for the connection to come up. First, ping and/or telnet from either the London or Singapore site to the other. Both should now be successful. Verify the results of your change on both the London and Singapore routers using the same commands you used to gather information to make sure that 9-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. the change not only corrected the problem, but that it didn’t cause any new problems. • show interface • show frame-relay lmi • show frame-relay pvc • show frame-relay map The outputs below are only from the commands that were showing problematic output. These commands will now show that the change has worked. Issue a show interface serial 0/0 command on the London router. Your output should appear similar to the sample output shown below. Note that the line protocol and DTE LMI are now up and LMI inquiries and messages are being sent and received. London#show interface 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 868, LMI stat recvd 314, 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 104/0, interface broadcasts 39 <output omitted> Issue a show frame-relay lmi command on the London router. Your output should appear similar to the sample output below. Note the LMI type is ANSI and LMI inquiries and messages are being sent and received. 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 897 Num Status msgs Rcvd 343 Num Update Status Rcvd 0 Num Status Timeouts 565 Issue a show frame-relay pvc command on the Singapore and London routers. Your output should appear similar to the sample outputs below. (Remember to ignore information about other DLCIs.) Both PVCs should now be active. Singapore#show frame-relay pvc PVC Statistics for interface Serial0/0 (Frame Relay DTE) Active Inactive Deleted Static Local 1 0 0 0 Switched 0 0 0 0 10-10 Semester 8 Internetwork Troubleshooting v1.0 - Lab 8.3.4.3 Copyright  2001, Cisco Systems, Inc. Unused 0 1 0 0 <output omitted> DLCI = 18, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0 input pkts 203 output pkts 188 in bytes 22572 out bytes 21339 dropped pkts 3 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 72 out bcast bytes 14212 pvc create time 02:22:00, last time pvc status changed 00:28:57 London#show frame-relay pvc PVC Statistics for interface Serial0/0 (Frame Relay DTE) Active Inactive Deleted Static Local 1 0 0 0 Switched 0 0 0 0 Unused 0 1 0 0 <output omitted> DLCI = 17, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0 input pkts 246 output pkts 255 in bytes 23808 out bytes 26563 dropped pkts 2 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 89 out bcast bytes 16624 pvc create time 02:19:54, last time pvc status changed 00:32:06 Issue a show frame-relay map command on the Singapore and London routers. Your output should appear similar to the sample outputs below. (Remember to ignore information about other DLCIs.) Note a map is now present on both routers established dynamically—indicating a frame-relay interface-dlci command was used to map the PVC. Singapore#show frame-relay map Serial0/0 (up): ip 192.168.192.2 dlci 18(0x12,0x420), dynamic, broadcast,, status defined, active London#show frame-relay map Serial0/0 (up): ip 192.168.192.4 dlci 17(0x11,0x410), dynamic, broadcast,, status defined, active 7. Did your solution fix the problem? If not, undo your changes and repeat the process. Step 7 8. Document the results. . 8 Internetwork Troubleshooting v1.0 - Lab 8 .3. 4 .3 Copyright  2001, Cisco Systems, Inc. Lab 8 .3. 4 .3: Troubleshooting Frame Relay 3 Frame Relay Atlas 550. each router. • show interface • show frame- relay lmi • show frame- relay pvc • show frame- relay map • debug frame- relay lmi Gather information about the