BGP with Cisco Catalyst 4500-X

[Abdurahman.Owag]

Hi All,

I have Cisco Catalyst 4500-X series (16 x 10 Gigabit Ethernet Port Switch  +Cisco IOS XE Software Enterprise Services ), and I want to use it for multiple BGP peering with multiple ISPs.

in my case , I need to receive multiple full internet routes from multiple upstream providers, but I have a concern that the resources of the switch will not handle the huge number of the internet prefixes .

Could someone advice us in this regards.

Thanks.

Abdurahman

[xthuijs]

hi abdurahman,

cat4k5 has 256 routing entries, so yeah a full internet table would not fit in there (~600k).

you could use a route-map or a route policy to aggregate routes of a smaller mask, but that requires a lot of (continuous) maintenance.

depending on the ISP's you have you could possibly use a default route inside your network and loadbalance between the ISP's. downside is that you lose visibility in the shortest as-path towards a destination in case ISP-1 has a shorter path to it then ISP-2

cheers

xander

[eduardopozo56]

Xander ninja´ed me while i was writing this:

As xander said, datasheet mentions 256K max ipv4 entries, which is roughly half of the internet ipv4 routing table so your concern is correct. The switch wont handle the full internet routing table.

You can peer with Multiple ISPs and just receive a default route from each of them and use local-pref/weight/etc to balance or choose your preferred exit point.

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-4500-x-series-switches/at_a_glance_c45-696621.pdf

[jvunc]

Hi

under 256K prefixes, is 4500-X a good choice to use as border network? or preferring asr model with 10G ports?

Jacques