Auto BGP
The NVIDIA® Cumulus Linux 4.2.0 release introduces a nifty new feature called auto BGP, which makes BGP ASN assignment in a two-tier leaf and spine network configuration a breeze. Auto BGP does the work for you without making changes to standard BGP behavior or configuration so that you don’t have to think about which numbers to allocate to your switches. This helps you build optimal ASN configurations in your data center and avoid suboptimal routing and path hunting, which occurs when you assign the wrong spine ASNs.
If you don’t care about ASNs then this feature is for you. But if you do, you can always configure BGP the traditional way where you have control over which ASN to allocate to your switch. What I like about this feature is that you can mix and match; you don’t have to use auto BGP across all switches in your configuration – you can use it to configure one switch but allocate ASN numbers manually to other switches.
So, how does auto BGP assign ASNs?
We use private 32-bit ASN numbers in the range 4200000000 through 4294967294. This is the private space defined in RFC 6996. Each leaf is Continue reading








