connect 2 routers

jhomason2003

I have 2 Cisco 1721 routers I'm trying to hookup back-back for CCNA studies. Each has a WIC-1DSU-56k4 card I'm using to cable together. The cable is pinned 1-7,2-8 and I all lights are green.
Problem is configuration:
RouterA: interface serial 0
RouterA: service-module 56k clock rate 56
RouterA: service-module 56k clock source internal
RouterA: ip address 192.168.0.1 255.255.255.0
RouterA: encapsulation ppp
RouterA: no shutdown

RouterB: interface serial 0
RouterB: service-module 56k clock rate 56
RouterB: service-module 56k clock source internal (** also tried 'line' here **)
RouterB: ip address 192.168.0.2 255.255.255.0
RouterB: encapsulation ppp
RouterB: no shutdown

problem is 'show interface serial0' states:
Serial0 is up, line protocol is down

and I can't ping IP addresses.....

BobNakamura

When you are using PPP, you need to decide which authentication you want to use (PAP or CHAP).

CHAP -> Encrypted
PAP -> Not Encrypted

Configuring PAP
Configuring CHAP

Hopefully this fixes your problem

YFZblu

Don't you only set clock rate on one side? Though I used serial cables in my labs, and not with 1721's.

Dynaice

I've never worked with 1721's so can't say for sure, but can you do a "show controllers serial 0" and see which end of your serial cable is the DCE? That should be the router used for clocking and no clock rate set on the DTE.

Also are you able to set the clock rate with the command, "clock rate 56000"?


You shouldn't need to configure CHAP or PAP to have the encapsulation work, only if you want to set an authentication.

Again, this could be different on the 1721's.

BobNakamura

I apologize. You don't need authentication (what was I doing? LOL)

And yea as with the other two people said, it might have to do with the clock rate.

jhomason2003

I've attempted clock rates settings, but line protocol is down...

on show controllers how do I know DCE vs DTE ?

bwillford

Show controllers serial 0
Interface Serial0/0/0
Hardware is XXXXX
DCE V.35, clock rate 64000

(or this is where you would see DTE)

and I agree it is a clock rate issue, or that is the normal issue when you have an up, down with 2 routers back to back, that or the cable..

jhomason2003

got it !

cleared the settings on both routers, verified the cable, and re-did the basic settings, and it came up ! the 2 routers are talking
thank you !

jhomason2003

fwiw, I've checked the WIC-1DSU-56k4 serial card, and it does not have a DCE / DTE setting, that's why I couldn't find it....

DCD

I saw this a couple of day ago and hadn't had time pull up my other lab. But I use a rollover cable and it work fine.