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Cannot get Cisco routers to connect p2p T1

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RyanNSIT

Technical User
Joined
Mar 24, 2003
Messages
3
Location
US
I have a slight problem here.

I pre-configured two Cisco 1721 Routers for a point to point T1. Currently there is a T1 WIC CSU/DSU in both of them.

When I shipped it off to the customer, it did not work. I am using HDLC encapsulation on both of the Serial Interfaces. (Config Below)

Does anyone know why this would not work? Any help is greatly appreciated.

Thanks.

--

side 1:

Cisco-1#sh run
Building configuration...

Current configuration : 420 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Cisco-1
!
enable secret 5 $1$ZjnK$p6kC68YcGWICjbtlUD9ey1
enable password #!@%!@#%!%$#!
!
ip subnet-zero
!
!
!
!
interface FastEthernet0
ip address 192.59.201.13 255.255.255.0
speed auto
!
interface Serial0
ip unnumbered FastEthernet0
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0
no ip http server
!
!
!
line con 0
line aux 0
line vty 0 4
!
no scheduler allocate
end

Cisco-1#

--

side 2:

Cisco-2# sh run
Building configuration...

Current configuration : 483 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Cisco-2
!
enable secret 5 $1$8fls$FBXasSIJdywpFjA33EP2N0
enable password !@#%$!)#($!K
!
ip subnet-zero
!
!
!
!
interface FastEthernet0
ip address 192.59.201.12 255.255.255.0
speed auto
!
interface Serial0
ip unnumbered FastEthernet0
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0
no ip http server
!
!
!
line con 0
line aux 0
line vty 0 4
!
no scheduler allocate
end

Cisco-2#
 
Well you have the same IP subnet on each of the fast ethernet interfaces on both sides, so it will never try to go to the remote side. Does the T1 not even come up at all? Also you need to specify the clocking for the T1, on one side do internal and one side do network. All done under the "serial" interface using a command "service-module t1 clock"


Hope this helps

BuckWeet
 
Buck,

Thanks, I will give that a try. Also, I wanted to maybe pick them up from the customer and bring them back, and try to verify that the setup will work.

Do you know offhand how to simulate a point to point T1 with two Cisco routers? I thought there was a special type of cable to connect the WICs together, but I do not know the order of the pairs on each side.

Thanks again.
 
Yea, for a T1 X-over cable do 1 to 4 and 2 to 5..


BuckWeet
 
How about posting a "sh service-module ser 0/0" from both. Look for alarm lights on the WIC itself.
 
You're going to need a different IP range on the customer ethernet interface. I'd also use number IP on the serial ports so you can ping those interfaces to determine if they are up. If you have to share those addresses then you want bridging set up, not routing.

Serial0 on your end:
ip address 192.168.200.1 255.255.255.252

Serial0 on their end:
ip address 192.168.200.2 255.255.255.252

Do you have a full T1, all 24 channels? If not you'll need to set the channels with the service t1 command. Make sure you get a green light on the WIC when you plug the T1 in.

Make sure you have an ethernet plugged into both sides. If you don't unnumbered serial0 may have problems getting an IP from an interface that is down.

In your line vty 0 4 put
'login'
'password whatever'
that way you can telnet to the router to look at the messages.

You may also want 'logging buffered 4096' so you can do a 'show log' to see a history off errors if you're not on the router when they happen.

You're default routing both sites to each other so you will only be able to pass traffic that hits these routers between these 2 sites. This is fine as long as your network is only 2 sites.
Tom Bilan
TJBA, Inc.
CCNP, CCDP, MCSE & CNE
 
Things have changed. They are actually going to revamp their entire network. We're doing a complete redesign.

So here is my scenario:

I have two subnets on a point to point T1. Each is divided by a Cisco 1721 router. On the one side of the T1, there is a Netscreen firewall which is an Internet Gateway. My objective is to have both subnets communicating, and also the subnet opposite the firewall to be able to access the Internet by only using their router as the gateway.

I will be using HDLC encapsulation on both ends. I will also be configuring DHCP on the router on the 2nd subnet, as there are no servers located there and I would rather do this than create a dhcp relay agent. I will be excluding the first 20 for expansion if servers come into play in the future.

IP Addresses:

Router side 1: 192.9.200.1
Netscreen side 1: 192.9.200.2
Router side 2: 192.9.201.1

Here is my proposed configuration:


Side 1:

interface FastEthernet0
ip address 192.9.200.1 255.255.255.0
speed auto
!
interface Serial0
ip unnumbered FastEthernet0
!
ip route 192.9.201.0 255.255.255.0 Serial0 (To other side of p2p)
ip route 0.0.0.0 0.0.0.0 192.9.200.2 (If not to 201 subnet, to Netscreen)

##################################################

Side 2:

ip dhcp excluded-address 192.9.201.1 192.9.201.20
!
ip dhcp pool default-pool
network 192.9.201.0 255.255.255.0
dns-server 192.9.200.5 192.9.200.10
default-router 192.9.201.1
!
interface FastEthernet0
ip address 192.9.201.1 255.255.255.0
speed auto
!
interface Serial0
ip unnumbered FastEthernet0
!
ip route 0.0.0.0 0.0.0.0 Serial0


##################################################

What do you think? Yay or nay? I will be doing this remotely via console and the customer will be plugging them in themselves, so I would like to get this right the first try.

Thanks in advance!
Ryan
 
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