[j-nsp] ospf refresh traffic

[sthaug at nethelp.no]

> Recently we found that the amount of refresh traffic in a stable
> ospf topology is really frightening. Every 30 mins, the network is
> stormed. My suggestion is that a router send only one packet to tell
> every other router that it wants to refresh all its LSAs.

The behavior you see is according to the OSPF RFC (RFC 2328):

    LSRefreshTime
	The maximum time between distinct originations of any particular
	LSA.  If the LS	age field of one of the	router's self-originated
	LSAs reaches the value LSRefreshTime, a	new instance of	the LSA
	is originated, even though the contents	of the LSA (apart from
	the LSA	header)	will be	the same.  The value of	LSRefreshTime is
	set to 30 minutes.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no