We are currently getting full BGP routes from 2 ISP's. We're running into a problem with our router not being able to support that number of routes. We're considering going with partial routes with each provider.
It was suggested we do the following:
Start with the ISP who is less preferred. Have them send us partial routes with a default route. (in our case outbound traffic is preferred through one provider. The other provider is there for failover)
Once we're sure that is working, then have the other provider do the same.
Then test failover.
I don't think we're are interested in prefix filtering.
I was told I would not have to make any changes on my end, and the changes will be transparent to me.
Does anyone have suggestions about this approach?
I need to avoid any downtime.
We're using a Cisco 6509 with FLEX WAN module. It can handle 256k routes according to Cisco.
Here's the relevant portion of the config
router bgp no synchronization bgp log-neighbor-changes network x.x.x.x mask 255.255.255.0 neighbor y.y.y.y remote-as neighbor y.y.y.y description BGP Session to Less Preferred ISP neighbor y.y.y.y ebgp-multihop 5 neighbor y.y.y.y update-source Multilink2 neighbor y.y.y.y distribute-list 50 out neighbor y.y.y.y route-map AS-PATH out neighbor y.y.y.y filter-list 40 out neighbor z.z.z.z remote-as neighbor z.z.z.z description BGP Session to Preferred ISP neighbor z.z.z.z update-source Multilink1 neighbor z.z.z.z distribute-list 50 out neighbor z.z.z.z route-map WEIGHT in neighbor z.z.z.z filter-list 40 out no auto-summary
Any help is appreciated.