Cisco 877 ADSL router line problems and interpreting debugs

Dear Experts,

This 877 router stops passing traffic approx once every 24 hours.  It appears to be some kind of line fault, but I guess I can't be certain.  The interfaces all appear "up", and even the VPN tunnel is "up" but idle, with no SAs of course.

I am trying to report faults to the carrier, but so far they think the line is OK, if a little slow.

With some debugs turned on, we get a lot of these:

atmsar_fastsend(ATM0): QUEUE_PER_VC enqueue fails!, vcd = 1

and then a few of these:

ATM0: AAL5 rx errors (status = 0C010000)

then the traffic stops passing.  A reload of the router then solves the issue.  Below are some of the "show" outputs.  Significantly (or a coincidence?) the router wouldn't connect at all until the firmware was upgraded (see output).

Protocol [ip]: atm
ATM Interface: 0
% Enter a Valid ATM Interface
ATM Interface: atm 0
VPI value [0]:
VCI value [1]: 38
Loopback - End(0), Segment(1) [0]:
Repeat Count [5]: 100
Timeout [2]:
Type escape sequence to abort.
Sending 100, 53-byte end-to-end OAM echoes, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 32/41/693 ms


ATM0
Alcatel 20190 chipset information
                ATU-R (DS)                      ATU-C (US)
Modem Status:    Showtime (DMTDSL_SHOWTIME)
DSL Mode:        ITU G.992.1 (G.DMT) Annex A
ITU STD NUM:     0x01                            0x1
Vendor ID:       'STMI'                          'TSTC'
Vendor Specific: 0x0000                          0x0400
Vendor Country:  0x0F                            0xB5
Chip ID:         C196 (0)
DFE BOM:         DFE3.0 Annex A (1)
Capacity Used:   98%                             68%
Noise Margin:    12.0 dB                         16.0 dB
Output Power:    16.0 dBm                        12.5 dBm
Attenuation:     55.5 dB                         25.5 dB
Defect Status:   None                            None
Last Fail Code:  None
Watchdog Counter: 0x37
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction:     0x00
Interrupts:      8282 (0 spurious)
PHY Access Err:  0
Activations:     1
LED Status:      ON
LED On Time:     100
LED Off Time:    100
Init FW:         init_AMR_4.0.018.bin
Operation FW:    AMR-E-4.0.018.bin
FW Source:       external
FW Version:      4.0.18

                 Interleave             Fast    Interleave              Fast
Speed (kbps):          1056                0           448                 0
Cells:               160046                0      10870644                 0
Reed-Solomon EC:       2432                0             0                 0
CRC Errors:              23                0             0                 0
Header Errors:           14                0             0                 0
Total BER:                2639E-10               0E-0
Leakage Average BER:      2661E-10               0E-0
                        ATU-R (DS)      ATU-C (US)
Bitswap:               enabled            enabled
Bitswap success:          0                   0
Bitswap failure:          0                   0

LOM Monitoring : Disabled


DMT Bits Per Bin
000: 0 0 0 0 0 0 2 4 5 6 7 8 8 9 8 9
010: 9 8 8 8 8 7 8 7 7 5 5 4 2 0 0 0
020: 0 0 7 8 9 8 9 7 8 8 7 7 7 7 6 7
030: 7 7 6 7 6 7 6 6 6 5 5 4 2 4 5 2
040: 0 3 4 3 3 0 2 3 0 3 0 2 0 2 0 2
050: 0 3 2 3 2 2 2 0 2 0 2 0 0 0 0 0
060: 2 2 0 0 0 3 0 4 2 3 0 3 2 2 3 3
070: 4 0 4 3 4 3 4 2 4 3 4 4 3 4 3 4
080: 3 4 3 4 3 3 3 3 2 0 2 0 2 0 2 0
090: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0A0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0B0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0C0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0D0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0E0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0F0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

DSL: Training log buffer capability is not enabled

I have heard of some people enabling LOM monitoring - should I look into this?  What would you recommend for the next step?  I think the carrier wants to focus on the ADSL to wall socket cable and the microfilter.  These have been changed once already.  



LVL 1
support_ferretAsked:
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Brain2000Connect With a Mentor Commented:
Instead of rebooting it, what happens if you go to the ATM interface and type "shut", then "no shut"?  Does it work again?

Can you post the full config, and the IOS version you are using.  You may have to upgrade the IOS again if nothing works.  Some of the IOS versions just downright don't work right.
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Justin MaloneSystem AdministratorCommented:
Is that really the correct VPI/VCI information? it looks a bit off.
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support_ferretAuthor Commented:
thank you for your comments!  After complaining to the carrier three times, the line became "reliable" for a record 2 days...

However, the line is down completely this morning and the ATM 0 reports it cannot train to the DSLAM.  Now looking at the dsl interface status, it says the line has not yet been activated.

I will get details on here shortly.
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Brain2000Commented:
Sounds like there's two problems.  One is a bad line.  Two is a Cisco that isn't retraining after too many errors.  Let us know how the line goes.
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support_ferretAuthor Commented:
Thank you for your help - the router has stayed passing traffic for 2 days now.  There are many line errors in the logs, but the router is now more resilient.  We managed to obtain the latest IOS v15 and applied that.  Interestingly, the VPN tunnel failed after the upgrade as it suddenly became intolerant of the far-end PIX presenting itself using hostname instead of IP address. This was resolved and we even got an extra 512kbps download out of the upgrade!
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