Re: PPP Clocking Issues

somwicked · ‎04-12-2005

PPP (full T1) WAN with 1750s at each end.

(router 1:clock=internal and router 2:clock=line) = no link (line down, protocol down)

(router 1:clock=line and router 2:clock=line) = link with lots of CRC and frame errors

I've done lots of digging and ran across enabling SCTE, inverting the transmit clock, setting the clock rate, etc .. and it makes my head hurt - very confusing.

How do I ensure the settings for clocking on the WICs and routers are set properly? How can I tell what they are set at now? And how do I change them if necessary?

I know router 1 should be clock internal and router 2 should be line but that is far as I understand this portion.

Guidance appreciated.

smif101 · ‎04-13-2005

Are these routers directly connected to each other or do they go through a service provider for the T1 access? If directly connected then you would use a line/internal situation like described. However I believe that you are connected via the service provider and then you should have it setup as line/line. Is this a new circuit? Don't worry about inverting TC, that is done sometimes when the clock is out of phase with the data on a serial links and that doesn't apply because you have T1's. What you should do is work with the telco and start to loops on the circuit inhouse first and make sure you come up good, no errors and the line is up, after that, juat move the loop further to the distant end until you find the problem.

teyobanilom · ‎04-13-2005

Try the link below.

http://www.cisco.com/univercd/cc/td/doc/cisintwk/itg_v1/tr1915.htm#xtocid33

It has help me a lot.

Boyet

somwicked · ‎04-13-2005

Thanks for the info.

I've been working with the telco who has swapped out some equipment, exercised the jacks(?), etc .. and I am currently monitoring.

The telco insists they are not providing any clocking on the line.

As far as I know, its a clear channel T1 and even they agree one of my routers should be providing clocking.

When i switch over to clock source internal, the line disappears & never comes back up. I've also noticed that adding the clock rate shows nothing in the running config - which I think is kinda odd.

h.parsons · ‎04-13-2005

Can you post your configs?

somwicked · ‎04-13-2005

Not a problem.

These do not show the clock set to internal - yet this is the only way to get a link between the sites.

The telco has recently mentioned something about a transmit frequency - which i am totally lost about. Not quite sure what they are looking for.

main#show startup-config

Using 954 out of 29688 bytes

!

version 12.2

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname mcv-zeeland

!

enable secret xxxx

enable password xxxx

!

memory-size iomem 25

ip subnet-zero

no ip domain-lookup

!

ip audit notify log

ip audit po max-events 100

call rsvp-sync

!

class-map match-all VOIP

match access-group name VoiceOverIP

!

policy-map SET_PRECEDENCE

class VOIP

set ip precedence 5

!

interface FastEthernet0

ip address 192.168.0.5 255.255.255.0

service-policy input SET_PRECEDENCE

speed auto

!

interface Serial0

description WAN to remote

ip address 192.168.33.1 255.255.255.0

encapsulation ppp

!

router rip

version 2

network 192.168.0.0

network 192.168.33.0

no auto-summary

!

ip classless

ip route 0.0.0.0 0.0.0.0 192.168.0.1

no ip http server

!

line con 0

password mcv

login

line aux 0

line vty 0 4

password mcv

login

!

end

remote#show startup-config

Using 1239 out of 29688 bytes

!

version 12.2

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname mcv-bearlake

!

enable secret xxxx

enable password xxxx

!

memory-size iomem 25

ip subnet-zero

no ip domain-lookup

no ip dhcp conflict logging

ip dhcp excluded-address 192.168.2.1 192.168.2.99

!

ip dhcp pool DPL

network 192.168.2.0 255.255.255.0

default-router 192.168.2.5

domain-name domain.com

dns-server 192.168.0.2

netbios-name-server 192.168.0.2

netbios-node-type h-node

!

ip audit notify log

ip audit po max-events 100

call rsvp-sync

!

class-map match-all VOIP

match access-group name VoiceOverIP

!

policy-map SET_PRECEDENCE

class VOIP

set ip precedence 5

!

interface FastEthernet0

ip address 192.168.2.5 255.255.255.0

service-policy input SET_PRECEDENCE

speed auto

!

interface Serial0

description WAN to main

ip address 192.168.33.2 255.255.255.0

encapsulation ppp

!

router rip

version 2

network 192.168.2.0

network 192.168.33.0

no auto-summary

!

ip classless

ip route 0.0.0.0 0.0.0.0 192.168.0.1

no ip http server

!

line con 0

password xxx

login

line aux 0

line vty 0 4

password mcv

login

!

end

rgodden · ‎04-14-2005

can you post the output of show controllers s0.

The clockrate command will work if you have dce cables not dte.

somwicked · ‎04-14-2005

Off on a tangent .. we've been fighting this for a week or so. Out of curiosity, I replaced the 1750 with a 1720 and everything worked as expected.

Apparently, there are issues with the 1750 that we originally tried using.

Thanks for your assist to this point - looks like it was a hardware issue.