DS3 Config Help

[grundy]

I can't get this darn DS3 to go UP/UP. When I switch to HDLC I can get it to go UP/UP but when I go back to the PPP, it goes UP/DOWN. The LEC throws a loop towards me and I show UP/DOWN (LOOPED) not sure if that's right. Config is below. AT&T can't get this thing working.

Anyone have any ideas?

controller T3 1/0
clock source line
cablelength 25
!
!
interface GigabitEthernet0/0
description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$
ip address 192.168.100.254 255.255.255.0
ip nat inside
duplex auto
speed auto
media-type rj45
negotiation auto
no mop enabled
!
interface Serial1/0
ip address 12.116.XX.XX 255.255.255.252
no ip redirects
no ip unreachables
no ip proxy-arp
ip nat outside
encapsulation ppp
dsu bandwidth 44210
!
ip classless
ip route 0.0.0.0 0.0.0.0 12.116.XX.XX
!

 

[datacom2007]

Hi, if you have HDLC UP/UP, why do you need to change to PPP? I believe when you change from HDLC to PPP, your service provider (ATT) must do that as well; otherwise, one side still HDLC and your side is PPP so encapsulation is different and the protocol goes down.

What is the information from your service provider?

 

[grundy]

We use HDLC just for testing. Then AT&T and I both switch to PPP which we can't get to go up. Keep alive is set to 10 sec on both sides. It's so strange why PPP doesn't work?

 

[burtsbees]

Have AT&T give you a sh int on their serial that's connected to your serial. Without that info, who knows? Also, please provide a sh int when the encaps is PPP---the strange thing is that if it were the other way, I.E. PPP working and HDLC not, then I would suspect that the AT&T router was a non-Cisco...

Burt

 

[chipk]

Are you sure they're providing the clock source? Try changing to clock source internal and see what happens.

 

[burtsbees]

I believe they would have to if HDLC is working...just when they both change to PPP.

Burt

 

[grundy]

I had clocksource set to internal and then they had me change it to line. Four provisioning techs on the line and they seem like they have never turned up a DS3

 

[chipk]

This sounds pretty typical to me. We usually end up telling the telco what the problem is before they figure it out.

How about the framing and linecdoe? Have you tried changing that around to see what happens? If you're linecode is b8zs, change it to ami and see what happens, etc.

 

[jdeisenm]

We had framing and channel issues with ATT. Once we got that resolved. The config that worked looked like this. This is on a cisco 7206.

interface Serial3/0
ip address 10.x.x.x 255.255.255.x
dsu bandwidth 44210
framing c-bit
cablelength 10
serial restart-delay 0

If you loop your cable, can you ping your interface?

Post the sh int and sh contr.

 

[burtsbees]

I wonder why it could be a framing issue---is this something that must be specified with PPP?

Burt

 

[rainman]

What type of DS3 port adapter are you using? Usually clear-channel DS3 interfaces do not have a "controller T3". Only time I have seen "controller T3" on a Cisco device is when it is a Multichannel DS3 port adapter which can not do clear channel functions.

Try this:

config term
!
controller T3 1/0
?

Check through the help menu and if you see a "channel-group" command then chances are you have a channelized DS3 port adapter and not clear channel. Also the markings on the card should reflect DS3 versus Channelized DS3.


Hope this helps.


-Rainman

 

[grundy]

I'm using an nm T3/E3. It's just a single port DS3.

 

[datacom2007]

Since you are detecting the loop and when you change to HDLC the interface comes UP, another option is that ATT may have your circuit looped from the begining and they hadn't change it yet. Probably you need to schedule some time with ATT to have loop test all the way from your router to their router and viceversa. Sometimes, ever a hard loop is set up some where in the path.