Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

Remote Office WAN Link Issues

Hi All,

I have a simple setup with 7 branch offices connected to an e1 controller at head office, as follows

controller E1 1/0

channel-group 0 timeslots 1 speed 64

channel-group 1 timeslots 3 speed 64

channel-group 2 timeslots 5 speed 64

channel-group 3 timeslots 7 speed 64

channel-group 4 timeslots 21 speed 64

channel-group 5 timeslots 13 speed 64

channel-group 6 timeslots 11 speed 64

Recently, the branch with channel-group 4, timeslot 21 was hit by lightning and I had to put up new equipment (CSU, 1841 router & WIC-2T). Now, the interface can't come up at either end.

Remote site keeps flapping up & down while central site remains down.

A debug serial interface at the remote gives:

*Sep 3 12:26:41.971: Serial0/0/0: HDLC myseq 5, mineseen 0*, yourseen 1, line up

*Sep 3 12:26:42.971: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0,

changed state to up

*Sep 3 12:26:51.971: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE

*Sep 3 12:26:51.971: DTE idb->dte_interface = DTE

*Sep 3 12:26:51.971: Dscc4(Serial0/0/0): DCD is up.

*Sep 3 12:26:51.971: Serial0/0/0: HDLC myseq 6, mineseen 0*, yourseen 2, line up

*Sep 3 12:27:01.971: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE

*Sep 3 12:27:01.971: DTE idb->dte_interface = DTE

*Sep 3 12:27:01.971: Dscc4(Serial0/0/0): DCD is up.

*Sep 3 12:27:01.971: Serial0/0/0: HDLC myseq 7, mineseen 0*, yourseen 3, line down

*Sep 3 12:27:02.971: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0,

changed state to down

*Sep 3 12:27:11.971: Serial0/0/0: HDLC myseq 8, mineseen 0*, yourseen 4, line up

*Sep 3 12:27:12.971: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0,

changed state to up

*Sep 3 12:27:21.971: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE

*Sep 3 12:27:21.971: DTE idb->dte_interface = DTE

*Sep 3 12:27:21.971: Dscc4(Serial0/0/0): DCD is up.

while the same interface at Head Office gives:

*Sep 4 16:04:20.033: Serial1/0:4: HDLC myseq 1, mineseen 0, yourseen 0, line down

*Sep 4 16:04:25.625: Serial1/0:4: attempting to restart

*Sep 4 16:04:30.033: Serial1/0:4: HDLC myseq 2, mineseen 0, yourseen 0, line down

*Sep 4 16:04:40.033: Serial1/0:4: HDLC myseq 3, mineseen 0, yourseen 0, line down

Looks like the Remote site (serial0/0/0) can send and receive HDLC keepalives while the Head Office (serial1/0:4) sends but does not receive any keepalives

I'm stuck since the telco says their links are clean and show now alarms

Bernard

6 REPLIES
Hall of Fame Super Bronze

Re: Remote Office WAN Link Issues

Can you post config from each router along with the 'show service-module' output ?

Thanks

Silver

Re: Remote Office WAN Link Issues

Did you confirm you copy the config. from old router to new router ?

Did you ask the PPT to carry the line test ? If all H/W are ok, it looks like config. problem.

Please provide the Hub router, one working router and the new router config.

Wait for your update.

New Member

Re: Remote Office WAN Link Issues

Hi Again,

I have attached:

- Head_Office_Cisco_2821 - Head Office (sh run, sh controllers e1, sh int s1/0:4)

- remote_4_Cisco_1841_problematic - Remote Site 4 which is having the problems (sh run)

- remote_5_Cisco_1841-working - Remote Site 5 which is working (sh run , sh int s0/0/0, sh controllers s0/0/0)

I'm sorry I mentioned CSU which might be misleading, I was referring to the telco's DTU , a Marconi MAT6D.

I can't paste the sh controllers s0/0/0 from the remote site, though I have this kind of output

Interface Serial0/0/0

Hardware is GT96K

DTE V.11 (X.21) TX and RX clocks detected.

idb at 0x629DAC10, driver data structure at 0x629E237C

wic_info 0x629E2978

Physical Port 0, SCC Num 0

Today I asked the telco to give me a point-to-point from the problematic remote site to another site that is working - in a simple p-t-p leased line using HDLC on both ends. This removed it from the Head Office E1 and made it just an ordinary p-t-p link. The problematic site gets it serial0/0/0 coming up & going down every 20 seconds. It can send and receive HDLC keepalives from the good site but the good site does not see any HDLC keepalives, so it's s0/0/0 stays down.

So, looks like I have one-way traffic at this remote site. The keepalives it sends cannot be picked up by any link partner on a p-t-p link and the link partner just stays down, but tries to send it's own keepalives which are picked up by the problematic site.

I'm now thinking of asking the telco to provision a new link so that we try isolating the original copper pairs.

Bernard

Hall of Fame Super Bronze

Re: Remote Office WAN Link Issues

Bernard,

Config looks good. It seems to be a telco issue.

Silver

Re: Remote Office WAN Link Issues

Agreed. Wait for your update after the telco provision a new line.

New Member

Re: Remote Office WAN Link Issues

Hi,

The telco finally re-run the cabling and changed the network termination unit, and the link was up and running in seconds!

Conclusion: it was a telco issue (cabling & termination)

Thank you all for your kind input.

Bernard

729
Views
0
Helpful
6
Replies
CreatePlease to create content