877 VPN randomly drops for a second - ideas?

Unanswered Question
May 10th, 2008


I have a Cisco 877 VPN running over an ADSL line. I have put in many of these without issue. I have this new remote office where we have installed a new ADSL line and a Cisco 877 which is again setup as a VPN to a Cisco ASA.

The VPN is up and running but maybe once an hour is might blip and the VPN and I believe the ADSL line will go down as I can't access the router from the outside.

The ADSL provider says the line is fine (I have my doubts it's the router), but I use the same router and IOS version on other lines.

Are there any commands I can use to help me or any other suggestions?


IOS = c870-advipservicesk9-mz.124-15.T5.bin

877#sh dsl interface


Alcatel 20190 chipset information


Modem Status: Showtime (DMTDSL_SHOWTIME)

DSL Mode: ITU G.992.1 (G.DMT) Annex A

ITU STD NUM: 0x03 0x2

Vendor ID: 'STMI' 'TSTC'

Vendor Specific: 0x0000 0x0000

Vendor Country: 0x0F 0xB5

Chip ID: C196 (0)

DFE BOM: DFE3.0 Annex A (1)

Capacity Used: 99% 87%

Noise Margin: 3.0 dB 11.0 dB

Output Power: 20.0 dBm 12.5 dBm

Attenuation: 41.0 dB 22.0 dB

Defect Status: None None

Last Fail Code: None

Watchdog Counter: 0x33

Watchdog Resets: 0

Selftest Result: 0x00

Subfunction: 0x00

Interrupts: 12420 (0 spurious)

PHY Access Err: 0

Activations: 8

LED Status: ON

LED On Time: 100

LED Off Time: 100

Init FW: init_AMR-3.0.014_no_bist.bin

Operation FW: AMR-3.0.014.bin

FW Source: embedded

FW Version: 3.0.14

Interleave Fast Interleave Fast

Speed (kbps): 6336 0 832 0

Cells: 1516428 0 24379932 0

Reed-Solomon EC: 3898 0 467 532

CRC Errors: 1988 0 502 506

Header Errors: 907 0 475 522

Total BER: 65535E-255 0E-0

Leakage Average BER: 65535E-255 0E-0


Bitswap: enabled enabled

Bitswap success: 0 0

Bitswap failure: 0 0

LOM Monitoring : Disabled

This router plugs into a Nortel switch which only has 1 PC in it at the moment.

I have this problem too.
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hmhrcook1 Tue, 05/13/2008 - 08:49

I have the same problem on adsl or vdsl and 850s or 870s. I am having a hard time catching the issue while it is happening to troubleshoot. I would also like some guidance on how to single out the true issue.

Giuseppe Larosa Tue, 05/13/2008 - 11:32


enable logging on the local buffer (logging buffer) and then check the log buffer with sh log command.

If your guess is right you should see messages like line protocol down on interface ATM0 and other related messages.

To help you correlate the events you could configure NTP protocol on your remote router and the service debug timestamps datetime ms and service log timepstamps datetime ms commands in order to have timestamps with date and time.

By looking at your show command you can see there have been some CRC errors and Reed-Solomon error corrections (EC). 1988 errors over so many cells are not too much.

total BER is 0.

may be there some events related to IPSec by looking at the log buffer you can find new information

hope to help



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