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Serial interface problem

I have connected a 4000 series router and a 2500 series routers serially using a back-to-back serial cable.The problem is that the line protocol never comes up.I am attaching the outputs here.Please help.

-----------------------------------------------------

2500 series router outputs

2500#show interfaces serial 1

Serial1 is down, line protocol is down

Hardware is HD64570

Internet address is 10.0.0.1/8

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input never, output never, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/0/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 1158 kilobits/sec

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

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 collisions, 39 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=down DSR=down DTR=up RTS=up CTS=up

2500#debug serial interface

Serial network interface debugging is on

2500(config)#int s 1

2500(config-if)#shut

2500(config-if)#no shut

2500(config-if)#

%LINK-3-UPDOWN: Interface Serial1, changed state to down

%LINK-3-UPDOWN: Interface Serial1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to up

2500#

Serial1: attempting to restart

HD(1): Deasserting DTR and RTS

HD(1): Reset from 0x3087208

HD(1): Asserting DTR

HD(1): Deasserting LTST

HD(1): Asserting DTR and RTS

HD(0): New serial state = 0x0600

HD(0): Cable is unplugged.

HD(1): got an interrupt state = 0x815A

HD(1): New serial state = 0x015A

HD(1): DCD is down.

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to down

-----------------------------------------------------

4000 series router outputs.

4000#show interfaces serial 1

Serial1 is up, line protocol is down

Hardware is HD64570

Internet address is 10.0.0.2 255.0.0.0

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255

Encapsulation HDLC, loopback not set, keepalive set (10 sec)

Last input never, output 0:00:00, output hang never

Last clearing of "show interface" counters never

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

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 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

88 packets output, 3188 bytes, 0 underruns

0 output errors, 0 collisions, 27 interface resets, 0 restarts

0 output buffer failures, 0 output buffers swapped out

54 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

4000#debug serial interface

4000#

Serial1: HDLC myseq 12, mineseen 0, yourseen 0, line down

Serial1: attempting to restart

HD(1): Reset from 0x2F080

HD(1): New serial modem register = 0x019F

HD(1): DTR is up.

Serial1: HDLC myseq 13, mineseen 0, yourseen 0, line down

Serial1: HDLC myseq 14, mineseen 0, yourseen 0, line down

HD(1): New serial modem register = 0x019D

HD(1): DTR is up.

HD(1): New serial modem register = 0x0198

HD(1): DTR is down.

HD(1): New serial modem register = 0x019D

HD(1): DTR is up.

HD(1): New serial modem register = 0x019F

HD(1): DTR is up.

Serial1: HDLC myseq 15, mineseen 0, yourseen 0, line down

1 REPLY
New Member

Re: Serial interface problem

What does your config look like?

Here's mine (same setup):

4000

!

interface Serial1

ip address 192.168.1.1 255.255.255.252

clockrate 1300000

!

2500

!

interface Serial0

ip address 192.168.1.2 255.255.255.252

no ip mroute-cache

no fair-queue

!

Output of show controller? Maybe you don't hav "clockrate" set.

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