Removing a loopback interface

[singla_g]

in my router config i have configured 2 loopback interfaces loopback0 and loopback9 as follows

int loopback0

shutdown

exit

int loopback9

shutdown

exit

int fastethernet0

ip add 192.168.41.254 255.255.255.0

exit

int serial0

ip add 192.168.144.73 255.255.255.252

encapsulation ppp

bandwidth 2000

exit

ip route 0.0.0.0 0.0.0.0 s0

but i want to remove these loopback configured bacause i m getting some crc errors on serial interface and also not getting proper speed not even 50 % speed.

i have tried the command

config#no int loopback0

but a warning come

Warning: cannot remove loopback0

Can anybody please suggest how can i remove these interfaces configured and any suggestion about increasing speed.

Thank u very much

[spremkumar]

hi

i would suggest to chek u r physical serial link for CRC errors by taking a local loop from your telco.

to increase u r speed in u r serial itnerface just chek out whts the limit set at ISP side if its connected to ISP or if its a Point to point better chek the reliability of your link (by taking loop from ur telco).

regds

prem

[Georg Pauwen]

Hello,

you might want to try a 'no shut/shut' of the loopback interface, or try the 'clear interface loopback 0' command before erasing the loopback. If that does not help, reboot the router and try to erase the interface again.

Which IOS version are you running ? It might be a software bug...

Regards,

GP

[mshavrov]

Having / not having Loopback interfaces in your case is completely irrelevant to CRC errors on your Serial interface. There are some questions you should ask youself and your ISP:

1. Do you have embedded CSU/DSU card or you have external CSU/DSU? Does you CSU/DSU configured according to ISP's recomendations? Do you have proper clocking settings on the interface / controller?

2. How long are your cables between router/CSU/DSU and Telco equipment? I believe maximum length for cable between telco card and your device should be less than 50m.

3. Would ISP make quality test on their equipment? I have experienced this quite a few time, when you ask them to check a line, they tell that "everything is fine", "they didn't do anything", but usually after that problem is gone.

[CSCO12041069]

Singla_g:

I had the same problem on Cisco router 2651XM, IOS 12.4(17) today. By playing around with the CLI, I found the answer.

I had the following configuration:

R0 # do sh ip int br       

Interface                  IP-Address      OK? Method Status                Protocol

FastEthernet0/0            192.168.1.1     YES manual up                    up      

FastEthernet0/1            172.16.1.1      YES manual up                    down  

Loopback1                  unassigned      YES manual up                    up

Then I did the following:

R0(config)# no interface loopback 1

which removed the loopback interface.

--- Andrew Wang, 5/27/2015