[20478] in North American Network Operators' Group
Re: IGPs in use
daemon@ATHENA.MIT.EDU (Henk Smit)
Wed Oct 14 13:06:54 1998
Date: Wed, 14 Oct 1998 09:08:39 -0700 (PDT)
From: Henk Smit <hsmit@cisco.com>
To: smd@clock.org ("Sean M. Doran")
Cc: nanog@merit.edu
>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.
