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cisco 2600 router - csd/dsu serial interface configuration

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8 replies

by rionelj

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I have 2 routers. each router has a csu/dsu - wic t1 interface:
- Router 1 is connected to router 2 through a cross over cat5 cable using the csd/dsu interfaces

Router1 has the following config:

interface Serial0/0
bandwidth 1544
ip address 24.1.1.1 255.255.255.0

Router1 has the following config:
interface Serial0/0
bandwidth 1544
ip address 24.1.1.2 255.255.255.0

- I add clock rate 64000 to both routers.

Why can router 1 can not ping router 2?

Router#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES NVRAM administratively down down
Serial0/0 24.1.1.1 YES NVRAM down down
FastEthernet0/1 unassigned YES NVRAM administratively down down
Loopback0 unassigned YES unset up up

why the serial interfaces are down?
How can i fix it.

8 replies

by Former member

Is your bandwidth too high?
Could bring it down to "1499" and try it to see if resolves your problem. That is if your bandwidth is the same as "MTU".

Please post back if you have anymore problems or questions.

by dumphrey

Serial0/0 24.1.1.1 YES NVRAM down down

The interface looks down to me. Try issueing the no shut command in the int config for s0/0.

A few hints for cisco troubleshooting:
1) is interface enabled?
2) Ip address and subnet mask correct?
3) cables plugged in and tested to be good.
4) Routing statements correct?

by rionelj

s0/0 of my router has the following config:
Note: this is a csu/dsu t1 interface with rj45 connector.

interface Serial0/0
bandwidth 1544
ip address 24.1.1.2 255.255.255.0
service-module t1 clock source internal
service-module t1 timeslots all speed 56

-why can't i ping 24.1.1.2 from the router itself?

Router#ping 24.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 24.1.1.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

by synner

A T1 RJ48C uses 1<->4,2<->5 pinout for a back to back t1 crossover cable.

Make sure your cable is pinned out correctly, and make sure you one of your router is a DTE and the other is a DCE.

by nimmo

In a back to back router configuration make sure that only the DCE has the clock rate set.

by rionelj

s0/0 of my router has the following config:
Note: this is a csu/dsu t1 interface with rj45 connector.

interface Serial0/0
bandwidth 1544
ip address 24.1.1.2 255.255.255.0
service-module t1 clock source internal
service-module t1 timeslots all speed 56

-why can't i ping 24.1.1.2 from the router itself?

Router#ping 24.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 24.1.1.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

by kiveli

Hi,
please check your router connection media.use straight through cable instead of cross-over cable.

thanks
regards

clinton

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