I've installed two cisco 1841 routers with csu/dsu cards in them to
support
a closed circuit t1.  The configuration for the serial port is as
follows:

Router A:
interface serial 0/0/0
  ip address 192.168.1.1 255.255.255.0
  ip access-group 101 in
  ip access-group 102 out
  encapsulation ppp
  service-module t1 clock source internal
  service-module t1 timeslots 1-24
  crypto map myMap

Router B:
interface serial 0/0/0
  ip address 192.168.1.2 255.255.255.0
  ip access-group 101 in
  ip access-group 102 out
  encapsulation ppp
  service-module t1 cablelength short 220ft
  service-module t1 timeslots 1-24
  cypto map myMap

Everything seems to work fine, except the serial connection goes down
for
30secs about every 30min.  We had the ISP out there to test the line
and
they tried to sync up the oscillators with some magical machine, and
that
helped the timing a little bit, but we still see the problem.

Our guess at this point is that there is a hardware problem, and we are
considering swapping out both routers.  Does anybody have any other
ideas at
this point that I can try?  Or even commands I can use to test the line
and
narrow down the problem?  I tried following the Cisco troubleshooting
guide
for t1 lines, but maybe I missed something.

Also, Router B is connected from the terminal to the serial port with a
cable that is roughly 140ft.  Perhaps the cable is messing things up?

Thanks.

--

On Sep 18, 5:12 pm, "John" <johnthomps... at (no spam) hotmail.com> wrote:
I've installed two cisco 1841 routers with csu/dsu cards in them to
support
a closed circuit t1.  The configuration for the serial port is as
follows:

Router A:
interface serial 0/0/0
  ip address 192.168.1.1 255.255.255.0
  ip access-group 101 in
  ip access-group 102 out
  encapsulation ppp
  service-module t1 clock source internal
  service-module t1 timeslots 1-24
  crypto map myMap

Router B:
interface serial 0/0/0
  ip address 192.168.1.2 255.255.255.0
  ip access-group 101 in
  ip access-group 102 out
  encapsulation ppp
  service-module t1 cablelength short 220ft
  service-module t1 timeslots 1-24
  cypto map myMap

Everything seems to work fine, except the serial connection goes
down for
30secs about every 30min.  We had the ISP out there to test the line
and
they tried to sync up the oscillators with some magical machine, and
that
helped the timing a little bit, but we still see the problem.

Hi John, what kind of card are you using ?
- What does 'sh controller t1 0/0/0' look like, taken 4 times every 10
mins (ie: across a failure), do your slip seconds increment?


Our guess at this point is that there is a hardware problem, and we
are considering swapping out both routers.  Does anybody have any
other ideas at
this point that I can try?  Or even commands I can use to test the
line and
narrow down the problem?  I tried following the Cisco
troubleshooting guide
for t1 lines, but maybe I missed something.

A hard loop on both sides will tell you if this is a hardware problem
(assuming this is already done). I've found it helps if you loop at
the router, then loop at the CSU/DSU (ie: test the length of your
cable). Then loop at the remote CSU/DSU (test the full circuit). This
is quite invasive testing tbh...

Keep an eye on the counters from 'sh controller t1 0/0/0' to see
what's incrementing. Also keep an eye on the serial interface counters
also...

Also, Router B is connected from the terminal to the serial port
with a cable that is roughly 140ft.  Perhaps the cable is messing
things up?

Could be, see above, looping the circuit at various points on the
line, usually helps narrow down what introduces your issue.


Thanks.

--

Ruairi Carroll wrote:

On Sep 18, 5:12 pm, "John" <johnthomps... at (no spam) hotmail.com> wrote:
I've installed two cisco 1841 routers with csu/dsu cards in them
to support
a closed circuit t1.  The configuration for the serial port is as
follows:

Router A:
interface serial 0/0/0
  ip address 192.168.1.1 255.255.255.0
  ip access-group 101 in
  ip access-group 102 out
  encapsulation ppp
  service-module t1 clock source internal
  service-module t1 timeslots 1-24
  crypto map myMap

Router B:
interface serial 0/0/0
  ip address 192.168.1.2 255.255.255.0
  ip access-group 101 in
  ip access-group 102 out
  encapsulation ppp
  service-module t1 cablelength short 220ft
  service-module t1 timeslots 1-24
  cypto map myMap

Everything seems to work fine, except the serial connection goes
down for
30secs about every 30min.  We had the ISP out there to test the
line and
they tried to sync up the oscillators with some magical machine,
and that
helped the timing a little bit, but we still see the problem.

Hi John, what kind of card are you using ?
- What does 'sh controller t1 0/0/0' look like, taken 4 times every
10 mins (ie: across a failure), do your slip seconds increment?


Our guess at this point is that there is a hardware problem, and
we are considering swapping out both routers.  Does anybody have
any other ideas at
this point that I can try?  Or even commands I can use to test the
line and
narrow down the problem?  I tried following the Cisco
troubleshooting guide
for t1 lines, but maybe I missed something.

A hard loop on both sides will tell you if this is a hardware
problem (assuming this is already done). I've found it helps if you
loop at the router, then loop at the CSU/DSU (ie: test the length
of your cable). Then loop at the remote CSU/DSU (test the full
circuit). This is quite invasive testing tbh...

Keep an eye on the counters from 'sh controller t1 0/0/0' to see
what's incrementing. Also keep an eye on the serial interface
counters also...

Also, Router B is connected from the terminal to the serial port
with a cable that is roughly 140ft.  Perhaps the cable is messing
things up?

Could be, see above, looping the circuit at various points on the
line, usually helps narrow down what introduces your issue.


Thanks.

--

Hey guys.

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the
line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC, frame,
and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now. I can try
more later. Thanks again for the reply. Any more ideas?

John wrote:

Hey guys.

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC,
frame, and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now. I can try
more later. Thanks again for the reply. Any more ideas?

I find "nothing on the line" claim highly suspicious. The only time
you would run into such situation is when T1 are provisioned over
plain copper runs directly to the same central office from both
locations. In every other case there is something on the line and
this something does provide clocking. Have you tried to set both
ends to "line"?

Regards,
Andrey.

Hey guys.

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the
line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC, frame,
and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now. I can try
more later. Thanks again for the reply. Any more ideas?

Andrey Tarasov wrote:
John wrote:

Hey guys.

Thanks for the input.  The "closed circuit T1" that I have
is a point-to-point connection.  The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the  line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU.  This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC,
frame, and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now.  I can try
more later.  Thanks again for the reply.  Any more ideas?

I find "nothing on the line" claim highly suspicious. The only time
you would run into such situation is when T1 are provisioned over
plain copper runs directly to the same central office from both
locations. In every other case there is something on the line and
this something does provide clocking.  Have you tried to set both
ends to "line"?

Regards,
Andrey.

Thanks Andrey,

We all thought it was weird too when he set it up.  In fact,
everyone I talk to (and I'm sure everyone reading this)
thought it sounded weird when they told us to do it.

However, I had them both set to line for several months
and we saw the same problems.  The ISP came out with
some machine and was able to sync up the oscillators in the
routers, and that seemed to help out, but we still saw
the same problems.  So we started blaming either the cisco
hardware or the long cable on the other end.

Our next plan is to replace the cisco hardware with some
2600 routers, but we would take the CSU/DSU module out of
our existing 1800 series routers and place it in the 2600
series.

--- Hide quoted text -

- Show quoted text -

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC,
frame, and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now. I can try
more later. Thanks again for the reply. Any more ideas?
I find "nothing on the line" claim highly suspicious. The only time
you would run into such situation is when T1 are provisioned over
plain copper runs directly to the same central office from both
locations. In every other case there is something on the line and
this something does provide clocking. Have you tried to set both
ends to "line"?

Regards,
Andrey.

Thanks Andrey,

We all thought it was weird too when he set it up. In fact,
everyone I talk to (and I'm sure everyone reading this)
thought it sounded weird when they told us to do it.

However, I had them both set to line for several months
and we saw the same problems. The ISP came out with
some machine and was able to sync up the oscillators in the
routers, and that seemed to help out, but we still saw
the same problems. So we started blaming either the cisco
hardware or the long cable on the other end.

Our next plan is to replace the cisco hardware with some
2600 routers, but we would take the CSU/DSU module out of
our existing 1800 series routers and place it in the 2600
series.

John wrote:

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC,
frame, and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now. I
can try more later. Thanks again for the reply. Any more
ideas?
I find "nothing on the line" claim highly suspicious. The only
time you would run into such situation is when T1 are provisioned
over plain copper runs directly to the same central office from
both locations. In every other case there is something on the
line and this something does provide clocking. Have you tried to
set both ends to "line"?

Regards,
Andrey.

Thanks Andrey,

We all thought it was weird too when he set it up. In fact,
everyone I talk to (and I'm sure everyone reading this) thought it
sounded weird when they told us to do it.

However, I had them both set to line for several months
and we saw the same problems. The ISP came out with
some machine and was able to sync up the oscillators in the
routers, and that seemed to help out, but we still saw
the same problems. So we started blaming either the cisco
hardware or the long cable on the other end.

Our next plan is to replace the cisco hardware with some
2600 routers, but we would take the CSU/DSU module out of
our existing 1800 series routers and place it in the 2600
series.

Long cable run can indeed be the problem. Is it proper T1 type of
cable or just Cat5 or something similar? Any fluorescent lights along
it?

Troubleshooting is really straightforward but require some downtime.
You will need hardware loopback - just normal RJ45 plug with pin 1
connected to 4 and 2 to 5 (if my memory is correct). Disconnect the
cable and plug loopback in its place, run extended ping with 0x00,
0xFF, 0x4040 and 0x8080 patterns from remote router. Check for errors
- if line is clean, repeat with cable in place and loopback on the
router.

Regards,
Andrey.

"bod43" <Bo... at (no spam) hotmail.co.uk> wrote in message

Andrey Tarasov wrote:

John wrote:

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

If I do a show interfaces serial 0/0/0, the input errors, CRC,
frame, and overrun erros are also increasing.

Sorry for the late reply, but I'm back in the office now. I
can try more later. Thanks again for the reply. Any more
ideas?
I find "nothing on the line" claim highly suspicious. The only
time you would run into such situation is when T1 are provisioned
over plain copper runs directly to the same central office from
both locations. In every other case there is something on the
line and this something does provide clocking. Have you tried to
set both ends to "line"?

Regards,
Andrey.
Thanks Andrey,

We all thought it was weird too when he set it up. In fact,
everyone I talk to (and I'm sure everyone reading this) thought it
sounded weird when they told us to do it.

However, I had them both set to line for several months
and we saw the same problems. The ISP came out with
some machine and was able to sync up the oscillators in the
routers, and that seemed to help out, but we still saw
the same problems. So we started blaming either the cisco
hardware or the long cable on the other end.

Our next plan is to replace the cisco hardware with some
2600 routers, but we would take the CSU/DSU module out of
our existing 1800 series routers and place it in the 2600
series.
Long cable run can indeed be the problem. Is it proper T1 type of
cable or just Cat5 or something similar? Any fluorescent lights along
it?

Troubleshooting is really straightforward but require some downtime.
You will need hardware loopback - just normal RJ45 plug with pin 1
connected to 4 and 2 to 5 (if my memory is correct). Disconnect the
cable and plug loopback in its place, run extended ping with 0x00,
0xFF, 0x4040 and 0x8080 patterns from remote router. Check for errors
- if line is clean, repeat with cable in place and loopback on the
router.

Regards,
Andrey.

Thanks again guys,

My connection from where I am is currently down with my T1
connection, and I don't think it will be up until tomorrow.
When it comes up tomorrow, I'll do all of the suggested
commands (sh controllers se x/x, etc.), and let everyone
know what's up.

In the meantime, I'm pretty sure the long cable on the
other end is just cat5 (I think a straight through going
from the smartjack to the csu/dsu card).
Anyway, I tried searching online for some proper T1 cable
(what exactly is proper t1 cable? from what I gather, it
looks like cat3?). I really like that suggestion and would
like replacing the cable with proper t1 cable. does anybody
have a good site I can go to in order to buy such cable?
I found a couple, but want to make sure I buy the right
thing. It looks like I need RJ48 cable (does this cable
have an RJ45 connector and the RJ48 is just the pin specs?).

Ruairi Carroll wrote:
On Sep 18, 5:12 pm, "John" <johnthomps... at (no spam) hotmail.com> wrote:
I've installed two cisco 1841 routers with csu/dsu cards in them to
support
a closed circuit t1. The configuration for the serial port is as
follows:

Router A:
interface serial 0/0/0
ip address 192.168.1.1 255.255.255.0
ip access-group 101 in
ip access-group 102 out
encapsulation ppp
service-module t1 clock source internal
service-module t1 timeslots 1-24
crypto map myMap

Router B:
interface serial 0/0/0
ip address 192.168.1.2 255.255.255.0
ip access-group 101 in
ip access-group 102 out
encapsulation ppp
service-module t1 cablelength short 220ft
service-module t1 timeslots 1-24
cypto map myMap

Everything seems to work fine, except the serial connection goes
down for
30secs about every 30min. We had the ISP out there to test the line
and
they tried to sync up the oscillators with some magical machine, and
that
helped the timing a little bit, but we still see the problem.

Hi John, what kind of card are you using ?
- What does 'sh controller t1 0/0/0' look like, taken 4 times every 10
mins (ie: across a failure), do your slip seconds increment?

Our guess at this point is that there is a hardware problem, and we
are considering swapping out both routers. Does anybody have any
other ideas at
this point that I can try? Or even commands I can use to test the
line and
narrow down the problem? I tried following the Cisco
troubleshooting guide
for t1 lines, but maybe I missed something.

A hard loop on both sides will tell you if this is a hardware problem
(assuming this is already done). I've found it helps if you loop at
the router, then loop at the CSU/DSU (ie: test the length of your
cable). Then loop at the remote CSU/DSU (test the full circuit). This
is quite invasive testing tbh...

Keep an eye on the counters from 'sh controller t1 0/0/0' to see
what's incrementing. Also keep an eye on the serial interface counters
also...

Also, Router B is connected from the terminal to the serial port
with a cable that is roughly 140ft. Perhaps the cable is messing
things up?

Could be, see above, looping the circuit at various points on the
line, usually helps narrow down what introduces your issue.

Thanks.

--

Hey guys.

Thanks for the input. The "closed circuit T1" that I have
is a point-to-point connection. The ISP told us to set
1 side as internal and one side to line (just like a back-
to-back configuration) because they have nothing on the
line.

If I do a show controllers ..., the hardware is as follows:
Hardware is GT96K with integrated T1 CSU/DSU. This is true
on both routers.

On 23 Sep, 22:38, "John" <johnthomps... at (no spam) hotmail.com> wrote:
"bod43" <Bo... at (no spam) hotmail.co.uk> wrote in message

Sorry I think it's -
sh controllers t1 that is interesting

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00800a5cdc.shtml
shows the E1 version. T1 identical I think.


http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00801095a3.shtml

Has a number of links to promising material.

Does this at least narrow down which Router is getting out of sync? Thanks.

RouterB#show service-module serial 0/0/0

Total Data (last 96 15 minute intervals):
953406 Line Code Violations, 68 Path Code Violations
3 Slip Secs, 2635 Fr Loss Secs, 379 Line Err Secs, 8 Degraded Mins
22 Errored Secs, 1 Bursty Err Secs, 0 Severely Err Secs, 2635 Unavail

"John" <johnthompson1 at (no spam) hotmail.com> writes:
Does this at least narrow down which Router is getting out of sync?
Thanks.

Not out of sync, but it shows you which one is the problem one.

RouterB#show service-module serial 0/0/0

Total Data (last 96 15 minute intervals):
953406 Line Code Violations, 68 Path Code Violations
3 Slip Secs, 2635 Fr Loss Secs, 379 Line Err Secs, 8 Degraded Mins
22 Errored Secs, 1 Bursty Err Secs, 0 Severely Err Secs, 2635 Unavail

Are these incrementing currently? LCVs are a cabling problem somewhere
on this end, or a bad line card, or something telco/cabling related.

Get the telco out with their testset to run patterns to narrow this down.

They can jack in at the CO and run bert from there out for each leg.