Re: Juniper BGP Convergence Time

[Thomas Bellman <bellman () nsc liu se>]

On 2018-05-16 15:22, Adam Kajtar wrote:

> I wasn't using per-packet load balancing. I believe juniper default is per
> IP.

The Juniper default is to not do ECMP at all.  Only a single route is
programmed into the FIB for each prefix in your RIB.  If you e.g. have
routes to 198.51.100.0/24 pointing to ten different ports, all traffic
to that entire /24 will go out over a single port, unless you have
explicitly enabled ECMP.

To enable ECMP, you need this:

    policy-options {
        policy-statement ecmp {
            then {
                load-balance per-packet;
            }
        }
    }
    routing-options {
        forwarding-table {
            export ecmp;
        }
    }

in your configuration.  Note also that "per-packet" is a mis-nomer; it
is really "per flow", based on a hash of the L3/L4 headers.

'show route forwarding-table destination 198.51.100.0/24' shows if you
actually have multiple routes in your FIB.


        /Bellman

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