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T1 line errors

Hi,

We have point to point T1 line with two 1841 routers on both ends. Lately we see a lot of errors on the serial interfaces.

Here is an example:
57222 input errors, 57222 CRC, 31319 frame, 17809 overrun, 0 ignored, 34138 abort.

They are input errors on both ends although I don't know if this means anything.

The problem is so bad that the line comes to a halt. The errors increase by seconds.

I thought is a Qwest problem but they test it on both ends and told the line seems to be clean. I replaced cables and routers and nothing changed. The tech also told me that it could be an "option mismatch". I don't know what that really means.

This line use to work fine for some time so I don't think configuration on routers would be the issue.

If you need more info please let me know.

Any help would be very appreciated.

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foresthome
Asked:
foresthome
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3 Solutions
 
wantabe2Commented:
I'd unplug the routers from the T1 to make sure the errors were not coming from inside either networks. If they go away once unplugged & come back after you connect the T1 it almost has to be duplex/mismatch settings. That may have been what the tech was refering to.
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foresthomeAuthor Commented:
Thank you for your response!

You were right, the errors did go away as soon as I unplug the router from the T1 and come back when I plug it back.

Sorry for my ignorance but where do I have to check for this duplex/mismatch?

Thank you for your help!
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logic2Commented:
duplex is on ethernet networks and not on serial interfaces
can you please illustrate the setup for this ?

usually it is as below

router1 -- modem1----qwestdemarc1 ----------Quest Network --------qwestdemarc2 ----modem2 -- router2

so if this is the same as ur setup then its obvious that there r several points of failure
please illustrate your exact setup
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wantabe2Commented:
ok, now, are you able to unplug the T1 from router A & leave it plugged up to router B to see if the errors are still seen on router B? Do you have a Cisco router?
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foresthomeAuthor Commented:
This is my configuration indeed.

Thank you!
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wantabe2Commented:
yes & if you could post the interface settings from CLI from both routers that would be helpfule too.
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foresthomeAuthor Commented:

Current configuration : 2365 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Clack1
!
boot-start-marker
boot-end-marker
!
logging buffered 51200 warnings
!
no aaa new-model
!
resource policy
!
clock timezone PCTime -8
clock summer-time PCTime date Apr 6 2003 2:00 Oct 26 2003 2:00
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip subnet-zero
ip cef
!
!
no ip dhcp use vrf connected
!
!
ip domain name yourdomain.com
ip name-server 192.168.1.34
!
!
!
!
interface FastEthernet0/0
 description connected to Main Lan
 ip address 192.168.1.3 255.255.255.0
 speed auto
 full-duplex
!
interface FastEthernet0/1
 description $ES_LAN$
 ip address 192.168.2.3 255.255.255.0
 shutdown
 speed auto
 full-duplex
!
interface Serial0/0/0
 description Link to clack2
 ip address 192.168.6.2 255.255.255.0
 encapsulation ppp
!
ip default-gateway 192.168.1.1
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.1.1
ip route 192.168.8.0 255.255.255.0 192.168.6.1
!
ip http server
ip http access-class 23
ip http authentication local
ip http timeout-policy idle 60 life 86400 requests 10000
!
!
control-plane
!
banner login ^C







Main Router:

Current configuration : 2365 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Clack1
!
boot-start-marker
boot-end-marker
!
logging buffered 51200 warnings
!
no aaa new-model
!
resource policy
!
clock timezone PCTime -8
clock summer-time PCTime date Apr 6 2003 2:00 Oct 26 2003 2:00
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip subnet-zero
ip cef
!
!
no ip dhcp use vrf connected
!
!
ip domain name yourdomain.com
ip name-server 192.168.1.34
!
!
!
!
interface FastEthernet0/0
 description connected to Main Lan
 ip address 192.168.1.3 255.255.255.0
 speed auto
 full-duplex
!
interface FastEthernet0/1
 description $ES_LAN$
 ip address 192.168.2.3 255.255.255.0
 shutdown
 speed auto
 full-duplex
!
interface Serial0/0/0
 description Link to clack2
 ip address 192.168.6.2 255.255.255.0
 encapsulation ppp
!
ip default-gateway 192.168.1.1
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.1.1
ip route 192.168.8.0 255.255.255.0 192.168.6.1
!
ip http server
ip http access-class 23
ip http authentication local
ip http timeout-policy idle 60 life 86400 requests 10000
!
!
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API_NOCCommented:
Did the Telco dispatch a tech and test through the demarc?  The backside of the Smartjack could be an issue.  The cabling from the smartjack could be an issue.  Is there an extended demarc?  If so, have you tried bypassing the demarc and plug directly into the smartjack with the router?  Is the ISP providing the timing?  If not, then one of your routers has to be the DCE and the other the DTE (ie one router set to internal timing and the other set to line).  
Get yourself one of these T1 plugs and test with the LEC.  These plugs have a male end that you can give the LEC a hard loop from the smartjack, and then another hard loop from he end of the cable.
http://www.smartronixstore.com/index.cfm?fuseaction=category.display&category_ID=1
 Have the LEC throw you a loop.  You will need to change your enapsulation to HDLC, clear your counters and see if you still increment errors.  If you do not, then the errors are coming from a higher level (ie DS3 or higher).  If you are getting errors, then the issue is between you and the test point of the Telco.
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foresthomeAuthor Commented:
Not sure if this would help figure out where the problem relies but here is the sh service-module command from both routers:

Main router:

Clack1#sh service-module
Module type is T1/fractional
    Hardware revision is 0.57, Software revision is 20051025,
    Image checksum is 0x3EFB7B, Protocol revision is 0.1
Receiver has no alarms.
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done at startup): Passed
Last clearing of alarm counters 01:04:52
    loss of signal        :    1, last occurred 01:04:52
    loss of frame         :    1, last occurred 01:04:52
    AIS alarm             :    0,
    Remote alarm          :    0,
    Module access errors  :    0,
Total Data (last 4 15 minute intervals):
    4579 Line Code Violations, 1742 Path Code Violations
    13 Slip Secs, 121 Fr Loss Secs, 1 Line Err Secs, 58 Degraded Mins
    542 Errored Secs, 526 Bursty Err Secs, 0 Severely Err Secs, 121 Unavail Secs
Data in current interval (289 seconds elapsed):
    0 Line Code Violations, 152 Path Code Violations
    1 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 4 Degraded Mins
    51 Errored Secs, 48 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Remote router:

branch#sh service-module
Module type is T1/fractional
    Hardware revision is 1.2, Software revision is 20071128,
    Image checksum is 0x3E88B0, Protocol revision is 0.1
Receiver has no alarms.
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done at startup): Passed
Last clearing of alarm counters 00:28:47
    loss of signal        :    0,
    loss of frame         :    0,
    AIS alarm             :    0,
    Remote alarm          :    1, last occurred 00:28:40
    Module access errors  :    0,
Total Data (last 1 15 minute intervals):
    0 Line Code Violations, 1023 Path Code Violations
    23 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 15 Degraded Mins
    461 Errored Secs, 453 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Data in current interval (828 seconds elapsed):
    0 Line Code Violations, 1023 Path Code Violations
    28 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 13 Degraded Mins
    453 Errored Secs, 442 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
branch#
branch#sh service-module
Module type is T1/fractional
    Hardware revision is 1.2, Software revision is 20071128,
    Image checksum is 0x3E88B0, Protocol revision is 0.1
Receiver has no alarms.
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done at startup): Passed
Last clearing of alarm counters 00:33:55
    loss of signal        :    0,
    loss of frame         :    0,
    AIS alarm             :    0,
    Remote alarm          :    1, last occurred 00:33:48
    Module access errors  :    0,
Total Data (last 2 15 minute intervals):
    0 Line Code Violations, 2046 Path Code Violations
    53 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 30 Degraded Mins
    952 Errored Secs, 932 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Data in current interval (236 seconds elapsed):
    0 Line Code Violations, 700 Path Code Violations
    3 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 3 Degraded Mins
    129 Errored Secs, 126 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

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API_NOCCommented:
You have slips on the line.  Check the timing with Qwest as I have advised.  If they are not providing any timing, then you will have to make one end DCE and the other DTE (ie one side "internal" timing and the one side "line" timing).
 Here is someone who had a similar issue
http://www.experts-exchange.com/Hardware/Networking_Hardware/Routers/Q_23015987.html
 
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logic2Commented:
my friend
look
simply here is the solution to your problem

1- replace both routers with brand new ones with new cards and everything. as well as the cabling between the routers and the modems
2- if problem stopped then the problem is resolved and would be in one of the routers or the cables
3- if the modems are managed by you then replace them as well and check their clocking and bandwidth config
4- if it didnt stop then please go ahead and escalate the issue in Qwest, contact their managers if they insisit there is no problems
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foresthomeAuthor Commented:
I hope I'm not talking to soon but I have not seen any errors in the last 12 hours. I did what API_NOC told me to do(THANK YOU!!!) and now I'm monitoring the line to see what happens. I will get back with news in a day or two. I will leave the question open.

Thank you all for your help! Much appreciated.
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logic2Commented:
you mean you did setup one side DCE and one DTE ?
if thats the case then i would think that one of the modems is faulty because this should not be the setup when there are modems installed
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