[809] in North American Network Operators' Group
Re: bcast LQM
daemon@ATHENA.MIT.EDU (Curtis Villamizar)
Tue Oct 24 13:15:33 1995
To: "William Allen Simpson" <bsimpson@morningstar.com>
cc: nanog@home.merit.edu
Reply-To: curtis@ans.net
In-reply-to: Your message of "Tue, 24 Oct 1995 02:48:55 GMT."
<1904.bsimpson@morningstar.com>
Date: Tue, 24 Oct 1995 13:09:15 -0400
From: Curtis Villamizar <curtis@ans.net>
In message <1904.bsimpson@morningstar.com>, "William Allen Simpson" writes:
> > From: Curtis Villamizar <curtis@ans.net>
> > LQM on non-PPP links sure would be great. A number of times I've
> > suggested we consider LQM on bcast, with a set of LQM parameters per
> > ARP entry. This way one end sends a LQM packet that serves as a time
> > marker, counts packets, then includes the count in the next LQM time
> > marker. The receiver needs only count packets between LQM packets and
> > compare the local count against the count sent by the other end. This
> > is an enormously oversimplified summary of LQM, but it just to make
> > the point that LQM is Good Stuff.
> >
> Yes, but a bit tough on broadcast, as you would need all nodes sending a
> history of all the other LQM counts it heard. Quite a big packet or set
> of packets with many nodes participating.
You need to send one unicast packet to each ARP entry. You only want
a count of packets sent to that destination. You need to keep a
packet count per ARP entry and send it unicast. For example, MCI
doesn't need to count how many packets ANS sends to PSI (on a
gigaswitch they can't).
> What might be a better idea is to add it to BGP-n. Say between routing
> peers. That's what I did for IPng, in my (now mangled) Neighbor Discovery.
BGP is at a high level. LQM needs to be at a very low level to get an
accurate count.
> > In the absence of LQM we have the DS3 MIB (poor substitute)
>
> Hey, the original PPP LQM was designed and built for DS3 (at Network
> Systems). NSFnet was very interested at the time. Aren't we already
> running PPP LQM for all the DS3's?
IP over HDLC.
> Bill.Simpson@um.cc.umich.edu
> Key fingerprint = 2E 07 23 03 C5 62 70 D3 59 B1 4F 5E 1D C2 C1 A2
Curtis
