i think u should do this now Special Serial Line Tests In addition to the basic diagnostic capabilities available on routers, a variety of supplemental tools and techniques can be used to determine the conditions of cables, switching equipment, modems, hosts, and remote internetworking hardware. For more information, consult the documentation for your CSU, DSU, serial analyzer, or other equipment. CSU and DSU Loopback Tests If the output of the show interfaces serial exec command indicates that the serial line is up but the line protocol is down, use the CSU/DSU loopback tests to determine the source of the problem. Perform the local loop test first, and then the remote test. Figure 15-9 illustrates the basic topology of the CSU/DSU local and remote loopback tests. Figure 15-9: CSU/DSU Local and Remote Loopback Tests ---------------------------------------------------------------------------- ---- Note These tests are generic in nature and assume attachment of the internetworking system to a CSU or DSU. However, the tests are essentially the same for attachment to a multiplexer with built-in CSU/DSU functionality. Because there is no concept of a loopback in X.25 or Frame Relay packet-switched network (PSN) environments, loopback tests do not apply to X.25 and Frame Relay networks. ---------------------------------------------------------------------------- ---- CSU and DSU Local Loopback Tests for HDLC or PPP Links Following is a general procedure for performing loopback tests in conjunction with built-in system diagnostic capabilities: Step 1 Place the CSU/DSU in local loop mode (refer to your vendor documentation). In local loop mode, the use of the line clock (from the T1 service) is terminated, and the DSU is forced to use the local clock. Step 2 Use the show interfaces serial exec command to determine whether the line status changes from "line protocol is down" to "line protocol is up (looped)," or if it remains down. Step 3 If the line protocol comes up when the CSU or DSU is in local loopback mode, this suggests that the problem is occurring on the remote end of the serial connection. If the status line does not change state, there is a possible problem in the router, connecting cable, or CSU/DSU. Step 4 If the problem appears to be local, use the debug serial interface privileged exec command. Step 5 Take the CSU/DSU out of local loop mode. When the line protocol is down, the debug serial interface command output will indicate that keepalive counters are not incrementing. Step 6 Place the CSU/DSU in local loop mode again. This should cause the keepalive packets to begin to increment. Specifically, the values for mineseen and yourseen keepalives will increment every 10 seconds. This information will appear in the debug serial interface output. If the keepalives do not increment, there may be a timing problem on the interface card or on the network. For information on correcting timing problems, refer to the section "Troubleshooting Clocking Problems," earlier in this chapter. Step 7 Check the local router and CSU/DSU hardware, and any attached cables. Make certain the cables are within the recommended lengths (no more than 50 feet [15.24 meters], or 25 feet [7.62 meters] for a T1 link). Make certain the cables are attached to the proper ports. Swap faulty equipment as necessary. Figure 15-10 shows the output from the debug serial interface command for an HDLC serial connection, with missed keepalives causing the line to go down and the interface to reset. Figure 15-10: debug serial interface Command Output CSU and DSU Remote Loopback Tests for HDLC or PPP Links If you determine that the local hardware is functioning properly but you still encounter problems when attempting to establish connections over the serial link, try using the remote loopback test to isolate the problem cause. ---------------------------------------------------------------------------- ---- Note This remote loopback test assumes that HDLC encapsulation is being used and that the preceding local loop test was performed immediately before this test. ---------------------------------------------------------------------------- ---- The following are the steps required to perform loopback testing: Step 1 Put the remote CSU or DSU into remote loopback mode (refer to the vendor documentation). Step 2 Using the show interfaces serial exec command, determine whether the line protocol remains up with the status line indicating "Serial x is up, line protocol is up (looped)," or if it goes down with the status line indicating "line protocol is down." Step 3 If the line protocol remains up (looped), the problem is probably at the remote end of the serial connection (between the remote CSU/DSU and the remote router). Perform both local and remote tests at the remote end to isolate the problem source. Step 4 If the line status changes to "line protocol is down" when remote loopback mode is activated, make certain that ones density is being properly maintained. The CSU/DSU must be configured to use the same framing and coding schemes used by the leased-line or other carrier service (for example, ESF and B8ZS). Step 5 If problems persist, contact your WAN network manager or the WAN service organization -----Original Message----- From: Andrew Larkins [mailto:[EMAIL PROTECTED]] Sent: Wednesday, July 18, 2001 5:15 PM To: [EMAIL PROTECTED] Subject: FW: WAN link funnies - UP UP but no comms- on same subnet!!! [7:12800] -----Original Message----- From: Andrew Larkins Sent: 18 July 2001 14:59 To: Robert Nelson-Cox; Andrew Larkins Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! [7:1 2785] Both are DTE: Show controllers are below: Remote site:sho controller s 1/0 CD2430 Slot 1, Port 0, Controller 0, Channel 0, Revision 15 Channel mode is synchronous serial idb 0x60F54F00, buffer size 1524, X.21 DTE cable Global registers rpilr 0x2, rir 0x2, risr 0x0, rfoc 0x0, rdr 0x2 tpilr 0x1, tir 0x2, tisr 0x60, tftc 0x0, tdr 0x7 mpilr 0x3, mir 0x2, misr 0xE0 bercnt 0xFF, stk 0x0 Per-channel registers for channel 0 Option registers 0x02 0x00 0x42 0xE7 0xE0 0x00 0x00 Command and status registers cmr 0xC0, ccr 0x00, csr 0xCC, msvr-rts 0xF1, msvr-dtr 0xF1 Clock option registers rcor 0x86, rbpr 0x01, tcor 0xC8, tbpr 0x01 Interrupt registers ier 0x89, livr 0x00, licr 0x00 DMA buffer status 0x08 DMA receive registers arbaddr 0x1955DC4, arbcnt 1548, arbsts 0x1 brbaddr 0x1953044, brbcnt 1548, brbsts 0x1 rcbaddr 0x19529FC DMA transmit registers atbaddr 0x19D2CB4, atbcnt 56, atbsts 0x62 btbaddr 0x19CEAF4, btbcnt 56, btbsts 0x62 tcbaddr 0x19D2CEC Special character registers schr1 0x00, schr2 0x00, schr3 0x00, schr4 0x00 scrl 0x0, scrh 0x0, lnxt 0xF1 Driver context information Context structure 0x60F5A404, Register table 0x3C800400 Serial Interface Control 5:1 Register (0x3C800802) is 0x0 Adaptor Flags 0x0 Serial Modem Control Register (0x3C800804) is 0x18 Receive static buffer 0x60F5B288 Receive particle buffers 0x60F5AC00, 0x60F5AA40 Transmit DMA buffers 0x0, 0x0, 0x0, 0x0 Transmit packet with particles 0x0, first word is 0x0 Interrupt rates (per second) transmit 0, receive 0, modem 0 True fast-switched packets 22 Semi fast-switched packets 0 Transmitter hang count 0 Residual indication count 7 Bus error count 0 Aborted short frames count 40580 CRC short frames count 321675 Error counters CTS deassertion failures 0 Nested interrupt errors transmit 0, receive 0, modem 0 Other side: sho controll s 3/0 CD2430 Slot 3, Port 0, Controller 0, Channel 0, Revision 15 Channel mode is synchronous serial idb 0x60F52854, buffer size 1524, X.21 DTE cable Global registers rpilr 0x2, rir 0x1, risr 0x0, rfoc 0x0, rdr 0x40 tpilr 0x1, tir 0x1, tisr 0x60, tftc 0x0, tdr 0x0 mpilr 0x3, mir 0x0, misr 0x0 bercnt 0xFF, stk 0x0 Per-channel registers for channel 0 Option registers 0x02 0x00 0x42 0xE7 0xE0 0x00 0x00 Command and status registers cmr 0xC0, ccr 0x00, csr 0xAC, msvr-rts 0xF1, msvr-dtr 0xF1 Clock option registers rcor 0x86, rbpr 0x01, tcor 0xC8, tbpr 0x01 Interrupt registers ier 0x89, livr 0x00, licr 0x00 DMA buffer status 0x23 DMA receive registers arbaddr 0x319AAE4, arbcnt 1548, arbsts 0x1 brbaddr 0x3199764, brbcnt 1548, brbsts 0x1 rcbaddr 0x319AB45 DMA transmit registers atbaddr 0x31AE0B4, atbcnt 56, atbsts 0x62 btbaddr 0x3000994, btbcnt 24, btbsts 0x62 tcbaddr 0x30009AC Special character registers schr1 0x00, schr2 0x00, schr3 0x00, schr4 0x00 scrl 0x0, scrh 0x0, lnxt 0xF1 Driver context information Context structure 0x60F57D58, Register table 0x3D800400 Serial Interface Control 5:1 Register (0x3D800802) is 0x0 Adaptor Flags 0x0 Serial Modem Control Register (0x3D800804) is 0x18 Receive static buffer 0x60EDEE28 Receive particle buffers 0x60F58240, 0x60F58180 Transmit DMA buffers 0x0, 0x0, 0x0, 0x0 Transmit packet with particles 0x0, first word is 0x0 Interrupt rates (per second) transmit 0, receive 138, modem 0 True fast-switched packets 4167 Semi fast-switched packets 1 Transmitter hang count 0 Residual indication count 0 Bus error count 0 Aborted short frames count 0 CRC short frames count 1 Error counters CTS deassertion failures 0 Nested interrupt errors transmit 0, receive 0, modem -----Original Message----- From: Robert Nelson-Cox [mailto:[EMAIL PROTECTED]] Sent: 18 July 2001 14:31 To: [EMAIL PROTECTED] Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! [7:1 2785] Are both cables DTE? Can you give me a show controller for these two interfaces? Rob./ >From: Andrew Larkins >To: Robert Nelson-Cox , Cisco Mail List > >Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! [7:1 >2785] >Date: Wed, 18 Jul 2001 14:27:24 +0200 > >Lease line > >-----Original Message----- >From: Robert Nelson-Cox [mailto:[EMAIL PROTECTED]] >Sent: 18 July 2001 14:23 >To: [EMAIL PROTECTED] >Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! >[7:12785] > > >Is this across a leased circuit, or x-over cable? > >If leased circuit, then you A and B end may not be joined. > >Rob./ > > > >From: "Andrew Larkins" > >Reply-To: "Andrew Larkins" > >To: [EMAIL PROTECTED] > >Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! > >[7:12785] > >Date: Wed, 18 Jul 2001 08:01:08 -0400 > > > >The interface resets are from when we moved the config to other ports to > >rule out physical issues > > > >First side > >Serial3/0 is up, line protocol is up > > Hardware is CD2430 in sync mode > > Description: xxxxxxxx > > Internet address is 10.99.253.17/30 > > MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec, rely 255/255, load 1/255 > > Encapsulation HDLC, loopback not set, keepalive set (10 sec) > > Last input 00:00:00, output 00:00:00, output hang never > > Last clearing of "show interface" counters never > > Input queue: 0/75/0 (size/max/drops); Total output drops: 0 > > Queueing strategy: priority-list 1 > > Output queue (queue priority: size/max/drops): > > high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0 > > 5 minute input rate 25000 bits/sec, 60 packets/sec > > 5 minute output rate 0 bits/sec, 0 packets/sec > > 1073220 packets input, 61641174 bytes, 0 no buffer > > Received 1911 broadcasts, 0 runts, 0 giants, 0 throttles > > 2 input errors, 0 CRC, 0 frame, 2 overrun, 0 ignored, 0 abort > > 9220 packets output, 906798 bytes, 0 underruns > > 0 output errors, 0 collisions, 4 interface resets > > 0 output buffer failures, 0 output buffers swapped out > > 0 carrier transitions > > DCD=up DSR=up DTR=up RTS=up CTS=up > > > >Remote side: > >Serial1/0 is up, line protocol is up > > Hardware is CD2430 in sync mode > > Description: xxxxxxx > > Internet address is 10.99.253.18/30 > > MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec, rely 255/255, load 1/255 > > Encapsulation HDLC, loopback not set, keepalive set (10 sec) > > Last input 00:00:02, output 00:00:02, output hang never > > Last clearing of "show interface" counters 00:00:02 > > Input queue: 0/75/0 (size/max/drops); Total output drops: 0 > > Queueing strategy: priority-list 1 > > Output queue (queue priority: size/max/drops): > > high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0 > > 5 minute input rate 0 bits/sec, 0 packets/sec > > 5 minute output rate 0 bits/sec, 0 packets/sec > > 1 packets input, 56 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 > > 1 packets output, 56 bytes, 0 underruns > > 0 output errors, 0 collisions, 0 interface resets > > 0 output buffer failures, 0 output buffers swapped out > > 0 carrier transitions > > DCD=up DSR=up DTR=up RTS=up CTS=up > > > >-----Original Message----- > >From: Farhan Ahmed [mailto:[EMAIL PROTECTED]] > >Sent: 18 July 2001 13:24 > >To: 'Andrew Larkins' > >Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! > >[7:1 2780] > > > > > >send me the sh int > > > >-----Original Message----- > >From: Andrew Larkins [mailto:[EMAIL PROTECTED]] > >Sent: Wednesday, July 18, 2001 3:17 PM > >To: [EMAIL PROTECTED] > >Subject: RE: WAN link funnies - UP UP but no comms- on same subnet!!! > >[7:12780] > > > > > >the very weird thing here is at RTS DTS etc are all up.... both devices >are > >on a /30 subnet no problems here. I do not need any routing because these > >are directly connected networks. NO crc errors on link flap/ interface > >resets!! > > > >Very confused > > > >-----Original Message----- > >From: Phil Barker [mailto:[EMAIL PROTECTED]] > >Sent: 18 July 2001 12:45 > >To: [EMAIL PROTECTED] > >Subject: Re: WAN link funnies - UP UP but no comms- on same subnet!!! > >[7:12778] > > > > > >Andrew, > > From what you say your remote end is working fine > >both in Tx and Rx and your Tx is working fine since > >remote end sees your cdp. Your Rx appears to be the > >problem. Have you tried swapping out your local Serial > >cable ? What about 'sh int serial xxx' to check your > >pins ? DCD RTS etc. > > > >regards, > > > >Phil. > > --- Andrew Larkins > >wrote: > HI all, > > > > > > Strange problem here. > > > > > > The serial interface are UP UP on both sides, but we > > > are not able to ping > > > each other - even though directly connected. A > > > "debug ip ICMP" on the > > > remote site shows the ping coming through and > > > replying, but the reply never > > > gets back. > > > Also the remote site saw my router using CDP, but I > > > do not see him. > > > > > > Any ideas?? > > > > > > I believe this is Telco related, but the line shows > > > clean from the interface > > > stats > > > > > > Andrew > >[EMAIL PROTECTED] > > > >____________________________________________________________ > >Do You Yahoo!? > >Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk > >or your free @yahoo.ie address at http://mail.yahoo.ie >_________________________________________________________________________ >Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. 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