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New Member

To achieve one trunk as active and the other as backup or redundancy.

Hi Sir,

I have tried to configure backup interface for ethernet port, int fastethernet 8/0/0 that configured as subinterface (intervlan) to int fastethernet 8/0/1 within the same router. This C7513 have two fast ethernet connecting to C2948 as trunk (At C7513 configured as subinterface and at C2948 configured as trunk).

At the end of the day, we want to achieve one trunk as active and the other as backup or redundancy.

What I have tried;

1) I have tried backup interface for the physical ethernet interface as below example.

2) What alternative solution can be use beside backup interface to achieve one active trunk and backup trunk with same subinterface IP within the same router C7513 Fast Ethernet. ?

My backup configuration maybe wrong ? Please advise !!!!!

Example;

Int fastethernet 8/0/0

Backup interface int 8/0/1

No ip address

Int fastethernet 8/0/0.1

Ip add 1.1.1.1 255.255.255.0

Encapsulation dot1q 1

Int fastethernet 8/0/0.2

Ip add 1.1.2.1 255.255.255.0

Encapsulation dot1q 2

!

!

Int fastethernet 8/0/1

No ip address

Int fastethernet 8/0/1.1

Ip add 1.1.1.1 255.255.255.0

Encapsulation dot1q 1

Int fastethernet 8/0/1.2

Ip add 1.1.2.1 255.255.255.0

Encapsulation dot1q 2

Note:

Configuration at C2948;

1) int fa8/0/0 is physical connected to port 2/1 (trunk port of C2948 that allow only vlan 1 and 2 only)

2) int fa8/0/1 is physical connected to port 2/2 (trunk port of C2948 that allow only vlan 1 and 2 only)

Thanks.

2 REPLIES
Silver

Re: To achieve one trunk as active and the other as backup or re

I am not sure if backup interface will work with dot1Q but if it is going to work you need to apply the backup interface statements on the subinterfaces .

New Member

Re: To achieve one trunk as active and the other as backup or re

Hi Deilert,

I have tried on the C7513 subinterface, I can key in backup interface cmd in the subinterface but not the "backup interface with the subinterface port".

For example;

int fa8/0/0.1

backup int fa8/0/1.1 ----> cannot key this.

encap dot1q 1

ip address.....

If I can key in the above it should be okay, my problem is that I can't key in the ".1" for the subinterface.

Can you ? Or any alternative ways for my solution. Need to implement soon for customer.

Thanks in advance,

Raymond

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