Debugging PPPoe

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Oct 17th, 2008
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How can I dig down a bit deeper and debug why a pppoe connection is dropping?


My log is below and this happens intermitently on my cisco 1801 - it doesn't happen on the free Eircom router which means it's not a physical line issue as the error suggests


Any ideas anybody?


Thanks


Colin


*Oct 13 10:05:39.962: %LINK-3-UPDOWN: Interface ATM0, changed state to down *Oct 13 10:05:40.962: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to down *Oct 13 10:06:25.218:

%DIALER-6-UNBIND: Interface Vi1 unbound from profile Di0 *Oct 13

10:06:25.230: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to down *Oct 13 10:06:26.218: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to down *Oct 13 10:06:46.462:

%LINK-3-UPDOWN: Interface ATM0, changed state to up *Oct 13

10:06:47.462: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to up *Oct 13 10:08:52.558: %DIALER-6-BIND: Interface Vi1 bound to profile Di0 *Oct 13 10:08:52.562: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to up *Oct 13 10:08:56.074:

%LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to up


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cmgowcity Fri, 10/17/2008 - 05:41
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Thanks for the reply


I have been through this and everything is ok. I should have said that the connection works and the site-to-site I created works great. But the connection drops occasionally, about twice a day with no pattern. What I need to do is drill down a bit further into the log I posted above and debug whay is actually happening when the atm inferface goes down.


Thanks


Colin

Giuseppe Larosa Fri, 10/17/2008 - 05:46
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Hello Colin,


try to collect every day the output of


sh dsl interface



on 30 minutes interval


look for errors, may be there are bursts of erros that make the ADSL link to be dropped


Hope to help

Giuseppe



cmgowcity Fri, 10/17/2008 - 05:51
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thanks, there is a lot of info here, what should I be looking for, your help is much appreciated


Dublin1801W#sh dsl int

ATM0

Alcatel 20190 chipset information

ATU-R (DS) ATU-C (US)

Modem Status: Showtime (DMTDSL_SHOWTIME)

DSL Mode: ITU G.992.5 (ADSL2+) Annex A

ITU STD NUM: 0x03 0x2

Chip Vendor ID: 'STMI' 'BDCM'

Chip Vendor Specific: 0x0000 0x6198

Chip Vendor Country: 0x0F 0xB5

Modem Vendor ID: 'CSCO' ' '

Modem Vendor Specific: 0x0000 0x0000

Modem Vendor Country: 0xB5 0x00

Serial Number Near: FCZ1231900JCISCO73916708

Serial Number Far: Chip ID: C196 (0)

DFE BOM: DFE3.0 Annex A (1)

Capacity Used: 100% 100%

Noise Margin: 6.0 dB 10.5 dB

Output Power: 20.0 dBm 12.0 dBm

Attenuation: 27.0 dB 11.0 dB

Defect Status: None None

Last Fail Code: None

Watchdog Counter: 0x53

Watchdog Resets: 0

Selftest Result: 0x00

Subfunction: 0x00

Interrupts: 4380111 (0 spurious)

PHY Access Err: 0

Activations: 42

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


DS Channel1 DS Channel0 US Channel1 US Channel0

Speed (kbps): 0 11853 0 1021

Cells: 0 5856966 0 24296518

Reed-Solomon EC: 0 4195 0 0

CRC Errors: 0 371 0 0

Header Errors: 0 379 0 0

Total BER: 0E-0 1922E-9

Leakage Average BER: 0E-0 1171E-9

Interleave Delay: 0 16 0 8

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 0 7 9 A A B C C D D

010: E E E E E E E E E E D D C B B A

020: 0 7 8 8 A A B C C D D E E E F F

030: F F F F F F F F F F F F E F F F

040: F F F F F F F F F F F F F F F F

050: 2 F F F F F F F F F F F F F F F

060: F F E B C E F F F F F F F F F E

070: E E E D D C B 7 8 B C D D E E E

080: E E E E E E D B D C A 5 9 B C D

090: D D D D E E E E E E E E E D D 9

0A0: D E E E E E E E E E E E E E E D

0B0: B B A 4 2 C D D D D E D D D D D

0C0: D D C C A 9 7 0 7 A A A B B B B

0D0: B B B C C B B B A 9 7 1 5 A A B

0E0: B A B C C C C C C C C C B A 8 6

0F0: 9 B B B C B B B 9 B B B B B A A

100: A 8 5 5 7 9 A A A A A A A A 9 9

110: 9 9 9 9 8 7 4 5 7 8 8 8 8 8 8 8

120: 8 8 8 8 8 7 7 7 7 7 3 5 7 7 8 8

130: 8 8 8 8 8 8 8 8 8 8 8 8 8 7 3 7

140: 8 8 8 8 8 7 8 8 8 8 8 8 8 7 7 7

150: 6 6 1 6 6 7 7 6 6 6 6 5 5 5 5 5

160: 5 5 4 4 0 0 0 1 2 2 4 3 4 2 2 3

170: 3 2 2 2 2 2 2 2 0 0 0 1 2 2 2 1

180: 2 2 2 2 2 2 2 2 2 1 1 0 0 0 0 0

190: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1A0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1B0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1C0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1D0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1E0: 0 0 0 0 0 0 0 0 0 1 0 1 1 0 0 0

1F0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0


DSL: Training log buffer capability is not enabled


Colin

cyberglobe Sat, 10/18/2008 - 12:24
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If the DMT Bits per BIN is the Signal strength of your DSL connection there seems to be some problem around the 0B3-0B4,0C6-0C8, and 0D9-0DB where the signal strength plummets. Could be possible there may be either bridge taps or a problem with your copper wiring.

Giuseppe Larosa Sat, 10/18/2008 - 12:56
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Hello Rudy,

the DMT bits per tone/subcarrier says what modulation is used for a specific tone/subcarrier. Technically it is not a direct signal strength measure but your suggestions are correct there is something that disturbes in this range of frequencies and the modems have self-adapted using less bits/tone provide more noise margin


Hope to help

Giuseppe



Giuseppe Larosa Sat, 10/18/2008 - 13:04
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Hello Colin,

we can see there are errors not very high but not neglectible.


Speed (kbps): 0 11853 0 1021

Cells: 0 5856966 0 24296518

Reed-Solomon EC: 0 4195 0 0

CRC Errors: 0 371 0 0

Header Errors: 0 379 0 0

>>Total BER: 0E-0 1922E-9

>>Leakage Average BER: 0E-0 1171E-9

Interleave Delay: 0 16 0 8


bit error rate is 1922 * 10^-9

371 /5856966

6,3343376075599551030345745561781e-5

Ask your provider to qualify the line and have the line fixed if necessary.


Hope to help

Giuseppe


cmgowcity Mon, 10/20/2008 - 07:00
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Thanks again for helping me with this. I have been onto my ISP and they have confirmed there is not an issue with the line - this is confirmed by the fact the line doesn't drop when connected to the free eircom adsl router. Would a software upgrade on the router help or could it be a faulty card? I have a fixed port 1801W?


Thanks


Colin

Giuseppe Larosa Mon, 10/20/2008 - 09:15
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Hello Colin,


>> there is not an issue with the line - this is confirmed by the fact the line doesn't drop when connected to the free eircom adsl router


I would consider a DSL firmware upgrade: this can be done without changing the current IOS image or by changing the IOS image.

If you have a chance to try with another DSL Wic this is also a viable option.

So also using the 1801W can be a viable option: if you are sure you don't need to add any module this router can be fine.


I would:

try with 1801W to see if behaviour changes

if the problem is fixed and you don't mind about the fact it is a closed box stop

otherwise if 1801W works but it can be a limit in the future try to upgrade firmware or to have another WIC installed.


Hope to help

Giuseppe


cmgowcity Thu, 10/23/2008 - 02:35
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I also have the following logged when the tunnel is connected...


%CRYPTO-4-IKMP_NO_SA: IKE message from has no SA and is not an initialization offer


I have checked the SA and ISAKMP lifetimes on the 1800 and on the ISA box and I think they match - the tunnel is up most of the time


Thanks


Colin

Giuseppe Larosa Thu, 10/23/2008 - 02:54
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Hello Colin,

if you receive this message from time to time (not often) don't worry about it.

SA have also a traffic volume lifetime and the first to expire will cause SA negotiation again.

We had an issue with hub routers 7206VXR using stateful IPSec but in your case at the other end there is a different device.


Hope to help

Giuseppe




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