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Announcing ASN and prefixes over multiple ISPs


my company is an ISP with an AS number and public IP block of    /22.

for the purpose of high-availability and load balancing we announced our prefixes and ASN over 2 different  ISP connections with a BGP peering between each of our devices  and our service provider devices.the same IP address block of /22 was announced to both providers.find attached a schematic.

However we noticed that when both BGP instances to the different were activated the following happens:

1.some website become unavailable i.e cannot be accessed

2.internet users start experiencing very slow link speed

When one of the connection is disabled , everything normalizes.

However we need  to have both connections running at the same time.

please what is the solution to this kind of issue.


Sounds like you may have

Sounds like you may have traffic going in one way and coming back the other. From my experience I had multiple blocks and it worked well to advertise a single block per connection. Upon connection failure that block would fail over to another connection.

Not sure if you just missed

Not sure if you just missed it in the diagram, but you need to also have iBGP configured between your two BGP routers in order for the traffic to find it's original tcp session on the "other" BGP router (in the cases where one router originated the outgoing traffic and the other router received the incoming traffic from the ISP)