How many BGP peers are supported X670-48x?

[Kajetan_Staszki]

I wonder how many BGP peers can I connect to the switch? I have a BGP session to datacenter provider who gives as the default gateway for IPv4 and IPv6 via 2 separate BGP sessions. I have a whole bunch of loadbalancers (>30 machines) which I want to connect to the switch via BGP Each one needs to establish 2 sessions for IPv4 and IPv6 (restriction of BIRD).

How many BGP sessions are safe for this switch? I'm currently using OSPF for this purpose but I'd like to give BGP a try for some reasons.

[Chad_Smith1]

Kajetan,

As Stephane has said, BGP peer limit is 128. However, it is important to determine how many routes will be learned from each peer as it is more likely you will reach the route table limitations when adding a large number of peers.

X670 maximum Unique IPv4 BGP Routes: 25,000
X670 Maximum non-Unique IPv4 BGP routes: 25,000
X670 Maximum Unique IPv6 BGP Routes: 8000
X670 Maximum non-Unique IPv6 BGP Routes: 24,000

It is also important to understand that the routing table limits are shared. These numbers are maximums, assuming no other routing protocol is in use. Using multiple routing protocols or using IPv4 and IPv6 will reduce the maximum limits for each protocol.

[Chad_Smith1]

Generally speaking, you should not exceed the supported limits. Once the hardware routing table is filled, traffic from all other routes would have to be slow path forwarded by the CPU. This is not ideal. Eventually, if the limits were sufficiently exceeded it is possible a crash may occur.

The following GTACKnowledge Article has some information that you may find interesting regarding this topic: Unexpected Reboot When BGP Learnt Routes Exceed the Supported Limit.

[welisson]

thank you Chad,
in this case when the switch received the routers from bgp peer, and it is exceed limitation non-unique and unique, what is the behavior expected of routes exceeded?
In this case it will fill at RIB just amount permit on RIB, or will it received the full-routing and take crashed the switch?

[Chad_Smith1]

Yes that is essentially what it means. For example, a non-unique route would be a redundant route learned from another BGP peer that is not preferred/active.

[welisson]

Chad when you said unique IPV4, did you mean is it the amount route that x670 support in FIB and non-unique will be RIB?