Categories
BGP Networking

Soft Reconfiguration inbound

Several people have been asking what soft Reconfiguration Inbound is on a BGP peer.

In the dark days of BGP you had to tear down the BGP session and do a full reestablishment in order to bring it up.  What soft reconfiguration does is copies of all routes received (this is why it is called inbound) are stored separately from the regular BGP table.   When a change is made the new change is applied to the stored copy of the BGP routes.

Disadvantage? This takes up memory because you have two files basically.

So how is this different than route refresh described in RFC 2918? This is a standard, with an RFC unlike Soft Reconfiguration inbound, which is a Cisco thing. Route refresh asks the peer to resend all its routes.