Unanswered Question
Apr 16th, 2008

I am trying to migrate a P2P serial interface from a 3640 router to a 3845 router but noticed that interface is down.

The config is shown below.

interface Serial0/1----2811 router


ip address x.x.x.1

encapsulation ppp

interface Serial0/1/1--------3845


ip address x.x.x.2

encapsulation ppp

. What could be the problem.

Under the sh int s0/1 on the the 3640 hardware shows serial while on the 3845 it shows syncronous.

I have this problem too.
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Richard Burts Wed, 04/16/2008 - 08:34


Is it possible that the T1 card on the 3845 needs some controller commands (or service module)? If clocking was not right, or the timeslots were not right, or framing or line code were not right then it might produce these symptoms.



OLOFINLUADARE Thu, 04/17/2008 - 03:55

I actually configure a side as the DCE with clockrate of 64000.

What do you think should be added?

Rick Morris Wed, 04/16/2008 - 12:14

can you provide a sh ip int br

Also a sho interface serial0/1/1

and a sh ver



OLOFINLUADARE Thu, 04/17/2008 - 03:48

3640 router

BACKUP_C/R#sh ver

Cisco Internetwork Operating System Software

IOS (tm) 3600 Software (C3640-I-M), Version 11.2(23)P, RELEASE SOFTWARE (fc1)

Copyright (c) 1986-2000 by cisco Systems, Inc.

Compiled Tue 11-Jul-00 23:22 by torowe

Image text-base: 0x600088E0, data-base: 0x604A2000

ROM: System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (f


BACKUP_C/R uptime is 1 week, 4 days, 19 hours, 15 minutes

System restarted by power-on

System image file is "flash:c3640-i-mz.112-23.P", booted via flash

cisco 3640 (R4700) processor (revision 0x00) with 24576K/8192K bytes of memory.

Processor board ID 22105692

R4700 processor, Implementation 33, Revision 1.0

Bridging software.

X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.

4 Ethernet/IEEE 802.3 interface(s)

4 Serial network interface(s)

8 Low-speed serial(sync/async) network interface(s)

DRAM configuration is 64 bits wide with parity disabled.

125K bytes of non-volatile configuration memory.

8192K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

BACKUP_C/R#sh int s0/1

Serial0/1 is up, line protocol is up

Hardware is QUICC Serial


Internet address is X.X.X.X/30

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 79/255

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

LCP Open


Last input 00:00:02, 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: 47948

Queueing strategy: weighted fair

Output queue: 0/1000/64/47902 (size/max total/threshold/drops)

Conversations 0/88/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

5 minute input rate 97000 bits/sec, 72 packets/sec

5 minute output rate 479000 bits/sec, 77 packets/sec

30818315 packets input, 2305457320 bytes, 0 no buffer

Received 552689 broadcasts, 0 runts, 0 giants, 0 throttles

333 input errors, 0 CRC, 2 frame, 2 overrun, 329 ignored, 0 abort

32584561 packets output, 3465915925 bytes, 329 underruns

329 output errors, 0 collisions, 2255 interface resets

0 output buffer failures, 0 output buffers swapped out

154 carrier transitions

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

3845 router

#sh ver

Cisco IOS Software, 3800 Software (C3845-IPBASE-M), Version 12.3(11)T3, RELEASE


Technical Support:

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Wed 26-Jan-05 01:59 by pwade

ROM: System Bootstrap, Version 12.3(11r)T1, RELEASE SOFTWARE (fc1)

PlatinumHabibCore uptime is 1 week, 4 days, 19 hours, 9 minutes

System returned to ROM by power-on

System image file is "flash:c3845-ipbase-mz.123-11.T3.bin"

Cisco 3845 (revision 1.0) with 224256K/37888K bytes of memory.

Processor board ID FHK0908F1AZ

16 FastEthernet interfaces

2 Gigabit Ethernet interfaces

1 Serial(sync/async) interface

24 Low-speed serial(sync/async) interfaces

DRAM configuration is 64 bits wide with parity enabled.

479K bytes of NVRAM.

62592K bytes of ATA System CompactFlash (Read/Write)

Configuration register is 0x2102

Rick Morris Thu, 04/17/2008 - 04:58

Which side is down?

Are you interconnecting these two routers together?

Is it across a WAN link or in the same office?

It shows that the 3640 is up/up.

Can you explain the topology a little. This will help understand the output above too. Also the 3845 sho interface is not there, can you post that?

s.marino Thu, 04/17/2008 - 05:28

I agree with Rick, we need more info such as a topology diagram, a complete sh int s0/1 from each router and sh controllers. I don't see the clockrate set 64000, also the sh int s0/1 output shows input and output errors.


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