Re: Best practice for redundancy when there're more than 2x ISP

Hi TechGuy,

As I understood your case:
You want share the o/b traffic even if there is failure in one Primary ISP
link.
ie:
If primary ISP1 fail - traffic to be balanced between backup ISP1 & primary
ISP2
If primary ISP2 fail - traffic to be balanced between primary ISP1 & backup
ISP2

If so, I will use the following method:

Assign high local preference for the routes received from corresponding ISP
and its directly peered AS.
For example:
Primary ISP1 ^ISP1AS_[0-9]*$ = 250
Primary ISP2 ^ISP2AS_[0-9]*$ = 200
Backup ISP1 ^ISP1AS_[0-9]*$ = 150

By this you can some what share traffic between the links, but
never guarantee the symmetrical path.

*Regards,*
*John*

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Received on Fri Sep 24 2010 - 01:44:22 ART