T1 Internet Line Serial Interface

[ryu1]

Hi,

I am currentlt learning configuring router, so please help a novice to figure out what is the problem. I currently have a T1 internet line with a Cisco 1720 router (Came with
ISP), and I have a spare Cisco 2610. I am trying to configure this spare
router exactly as the 1720 router, and when I plug the cable to this spare
router WIC DSC T1 card, the light turn green, so the serial link is OK. I
plug a pc to the router ethernet port, and I was able to ping the router e0
ip address. However, I was not able to ping the ip on the serial0 interface
and couldn't get out to the internet. Why can't I even ping the Serial0
interface ip address? I compare the configuration on my Cisco 1720 and Cisco
2610, and they are exactly the same? Did I configure something wrong on my
Cisco router (The config is not the real ip address, not the real one
assigned by my
ISP)? His is a "Show Version" and "Show Running-Config" on my Cisco 2610
router. Is it beacause of the image file? I know there are
many version of an image file for a particular router and feature sets. Does
my router have the feature sets to be used for this purpose based on the "sh
ver" Please tell me what I did wrong.

Thanks,
Alan

CISCO#sh ver
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-IS-M), Version 12.0(7)T, RELEASE SOFTWARE
(fc2)
Copyright (c) 1986-1999 by cisco Systems, Inc.
Compiled Tue 07-Dec-99 02:21 by phanguye
Image text-base: 0x80008088, data-base: 0x80C524F8

ROM: System Bootstrap, Version 11.3(2)XA4, RELEASE SOFTWARE (fc1)

MRBI uptime is 3 days, 33 minutes
System returned to ROM by power-on
System image file is "flash:c2600-is-mz_120-7_T.bin"

cisco 2610 (MPC860) processor (revision 0x203) with 30720K/10240K bytes of
memory.
Processor board ID JAD03423750 (2465751866)
M860 processor: part number 0, mask 49
Bridging software.
X.25 software, Version 3.0.0.
1 Ethernet/IEEE 802.3 interface(s)
1 Serial network interface(s)
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

CISCO#sh run
Building configuration...

Current configuration:
!
version 12.0
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname CISCO
!
logging buffered 4096 debugging
!
!
!
!
!
memory-size iomem 25
ip subnet-zero
ip name-server 16.194.38.63
ip name-server 16.14.38.64
!
!
!
!
!
interface Ethernet0/0
ip address 12.11.3.211 255.255.255.0
no ip directed-broadcast
!
interface Serial0/0
ip address 12.11.33.14 255.255.255.252
no ip directed-broadcast
no fair-queue
!
ip classless
ip route 0.0.0.0 0.0.0.0 12.11.33.13
no ip http server
!
!
line con 0
transport input none
line aux 0
line vty 0 4
login
!
end

 

[plshlpme]

when you plug the 2600 in.. does the serial interface go up/up?
if it is in a down state you will not be able to ping it...

maybe post the serial interface config off the 1700 as well.

 

[ryu1]

Hi,

Yes, the serial link is up. I checked by looking at "sh interface serial 0/0", and the back of the WIC card CD is green, no alarm light" This is a "sh ver" and "sh runnning-config" of my working cisco 1700 router.

Cisco Internetwork Operating System Software
IOS (tm) C1700 Software (C1700-Y-M), Version 12.1(8a), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2001 by cisco Systems, Inc.
Compiled Tue 22-May-01 23:52 by yiyan
Image text-base: 0x80008088, data-base: 0x805ECA74

ROM: System Bootstrap, Version 12.0(3)T, RELEASE SOFTWARE (fc1)

Multi_C uptime is 14 weeks, 17 hours, 43 minutes
System returned to ROM by power-on
System image file is "flash:c1700-y-mz.121-8a"

cisco 1720 (MPC860) processor (revision 0x601) with 24576K/8192K bytes of memory
.
Processor board ID JAD05300A83 (826521832), with hardware revision 0000
M860 processor: part number 0, mask 32
Bridging software.
X.25 software, Version 3.0.0.
1 FastEthernet/IEEE 802.3 interface(s)
1 Serial network interface(s)
WIC T1-DSU
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

**This is the running-config**

Building configuration...

Current configuration : 845 bytes
!
version 12.1
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname eee
!
no logging console

!
!
!
!
!
memory-size iomem 25
ip subnet-zero
ip name-server 16.194.38.63
ip name-server 16.14.38.64

!
!
!
!
interface Serial0
ip address 12.11.33.14 255.255.255.252
no ip redirects
no fair-queue
!
interface FastEthernet0
ip address 12.11.3.211 255.255.255.0
no ip redirects
speed auto
full-duplex
!
ip classless
ip route 0.0.0.0 0.0.0.0 12.11.33.13
no ip http server
!

!
line con 0

line aux 0
line vty 0 4

login
!
no scheduler allocate
end

 

[Ru55ell]

What is the speed of the T1? Can you access the config on the 1720? There is more than likely missing config lined on the S0/0. Like plshlpme ask.. Is the interface up, up?

We doubt it.
look for a line similar to this
service-module t1 timeslots 1-8

or transfer all the lines unter the serial interface of the 1720 to the 2600.

 

[ryu1]

Hi,

I just did a "sh interface serial 0/0" , and it is showing the serial0 is up, line protocol is down. Why is that? The serial0 interface configuration on Cisco 1700 is

interface Serial0
ip address 12.11.33.14 255.255.255.252
no ip redirects
no fair-queue

It doesn't use the line service-module t1 timeslots. I configure the Cisco 2600 exactly the same as Cisco 1700. What makes the line protocol down? I even tried to put encapsulation ppp to replace the HDLC.

Thanks,
Alan

 

[Ru55ell]

There is something missing. What kind of service is the ISP providing? Does the 2600 have the same module as the 1700. The output from the show version commands are different. I have never had a serial interface up with the minimal config you've shown.

 

[pgaliardo]

What are the clock source, framing and linecodes at the controller level. Do they match what your ISP says they should be? Depending on the type of WIC card in the 2600, either a show controller or show service-module T1 should give you this info.

 

[ryu1]

Hi,

The "sh running-config" is exactly what I have in the cisco 1700 router, I didn't remove anything except the encrypted password line. The T1 is the full 1.5Mbits internet line (not Frame Relay or private point to point line) with 5 usable public ip address assigned to my host.

The card that I have for the serial connection on both routers is "WIC 1DSU T1" card, and they are identical.

Thanks,
Alan

 

[doublea1535]

Like the guys have already said, there needs to be more configuration information applied. It needs to know which timeslots to use, which framing/coding and where to get timing from (internal or loop).

Are you connecting this back-to-back for testing? Or are you putting the 2600 in place of the 1700 when you are doing your testing?

The fact that the interface shows up/down shows that layer 1 is up (end-to-end physical connectivity is in place) but the protocol layer (either layer 2 or layer 3) is down. In my experience this has generally been due to timing not being set correctly. Post the output from "show controllers" from both routers.

Also: If you want to test a T1 interface you can make a hard loop-back plug with pins 1-4 and 2-5 that you can then plug into a DSU/CSU to see if it comes up.

HTH

 

[plshlpme]

you are pluggin into the serial port right.. so the telco terminates the T1 on a CSU in front of your router?

if thats the case and its a serial connection between the two you won't need to set service module or line coding stuff. but if your isp brings it in and you are using the csu in the router then youll need to build it out withthe service module commands...

 

[doublea1535]

The show run for his 1700 show a "WIC T1-DSU