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New Member

loopback interface on catalyset switches

Hello,

I need to know if I can configure loopback interfaces on L2 switches (2950) and if yes , in which IOS

Thanks

Moamen

1 ACCEPTED SOLUTION

Accepted Solutions

Re: loopback interface on catalyset switches

Hi Moamen,

The software will show you the presence of loopback option after interface command but this command is not supported in hardware as it is a layer 2 switch.

The IOS developed by Cisco is the general release and has some common commands but those commands will only be working if proper hardware is found.

A software loopback is a layer 3 interface and the 2950 is a layer 2 switch;the switch would need to support L3 for a loopback to work.

So this will not work on 2950 switch but will work on 3550 switch and above which are layer 3 switches.

HTH, please rate all post.

Ankur

5 REPLIES

Re: loopback interface on catalyset switches

Hi Moamen,

As the 2950 is a pure 2nd layer switch, you can only have one active 3rd layer interface on it at any given time. The most logical and usual option is to use a VLAN interface - in fact, I don't think you can use any other type of 3rd layer interface on them.

HTH

Ankur

Purple

Re: loopback interface on catalyset switches

Why would you think you need to use a loopback interface on a layer 2 switch ???

New Member

Re: loopback interface on catalyset switches

Hello,

for admin, I need to create loopback interface and use it as the admin IP to reach the switch

I know that the admin ip configured under interface vlan1

but I'm asking because I have a switch that has the int loopback in his menu when using

conf t# int ?

I can found loopback , but I can't configured it

#####

switch(config)#interface ?

Async Async interface

BVI Bridge-Group Virtual Interface

Dialer Dialer interface

FastEthernet FastEthernet IEEE 802.3

Group-Async Async Group interface

Lex Lex interface

Loopback Loopback interface<<<<<

Multilink Multilink-group interface

Null Null interface

Port-channel Ethernet Channel of interfaces

Tunnel Tunnel interface

Virtual-Template Virtual Template interface

Virtual-TokenRing Virtual TokenRing

Vlan Catalyst Vlans

range interface range command

#########

System image file is "flash:c2950-i6q4l2-mz.121-22.EA3"

but when I'm trying to configure it the switch refused

Thanks & BR

Moamen

Re: loopback interface on catalyset switches

Hi Moamen,

The software will show you the presence of loopback option after interface command but this command is not supported in hardware as it is a layer 2 switch.

The IOS developed by Cisco is the general release and has some common commands but those commands will only be working if proper hardware is found.

A software loopback is a layer 3 interface and the 2950 is a layer 2 switch;the switch would need to support L3 for a loopback to work.

So this will not work on 2950 switch but will work on 3550 switch and above which are layer 3 switches.

HTH, please rate all post.

Ankur

New Member

Re: loopback interface on catalyset switches

Hello Ankur

Thanks very much , it is clear now

Moamen

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