IGPs in use

Wed Oct 14 16:08:39 UTC 1998

>By contrast, IGPs are *not* fundamentally rate-limited --
>retransmissions are not congestion avoiding in any IGP that
>I know of.  So, routing information heading into a congested
>link or router adds to congestion, which can lead to congestion
>collapse (and possibly consequent re-routing, moving the problem
>to another point).

  Depends on what you mean by "fundamentally rate-limited".
 IS-IS is rate-limited to 30 LSPs per second per interface.
 As per ISO-10589. In IOS you can do some more configuration tricks.
 Recent IOS has improvements for rate-limiting in OSPF. Thank you Derek.
 EIGRP has probably the best rate-limiting of them all. EIGRP will
 never send more EIGRP traffic than a certain (configurable) percentage 
 of the link bandwidth.

>Finally, as a side-note, TCP also gives BGP the proper data-stream
>ordering and dramatically improves the odds that the receiving
>process will get exactly what was sent by the transmitting process
>across the network.

  This can also be seen as a bug.

>   Many IGPs have really bad behaviours in the
>presence of lost frames/packets,

  This depends. Are we talking hellos here, or LSAs/LSPs ?
 IMHO when a Linkstate protocol is deployed in a dense link network,
 a few lost LSAs/LSPs don't matter much.

       Henk.