[HECnet] Circuit costs

[Steve Davidson]

I clearly forgot about the DECsystems!

The costs on my network were based on the fact that I run both the
bridge and the tunnels.   In addition I took into account that some areas
connect into my site as well as either Bob's or Sampsa's.   I calculated
the costs per circuit and came up with the values that I use.   My values
only work one way though and did not take into consideration what the
other end used UNLESS I could influence that end.   I do influence
several, but not all of the connections into this network.

I believe that we need a map to figure this out correctly.   Just stating
that everyone should be using a particular value does not always work.
As an example look at Fred's network (area 33 - mid America).   In theory
he is connected to both area 2 (West Coast), and area 19 (East Coast) -
let's forget the new link to Europe for the moment because that has
issues that have yet to be addressed.   The connection between the US and
Europe mostly goes from the East Coast, so in Fred's case the costs (at
Fred's end at a mimimum) should be set to favour the Eastern route.
This is just one example, I expect that this is not an isolated case.
Fred's network has multiple routes because, let's face it, links fail!
It is the right choice (for his network).

One way to look at this might be to declare a fixed set of Multinet hubs
and map against that.   In the US it does makes sense to pick a Western
and Eastern hub.   Each area in the US connects to both hubs.   These hubs
connect to Europe at the same points, either the bridge, the tunnels, or
both.   I see this as a maximum availability plan.   We would still need
to look at link speeds and Internet hop counts but it could (should)
work.   This same plan could be applied to anywhere. I only have first
hand knowledge of the US sites.

I prefer the tunnels for data intensive transactions but use the bridge
for LAT and MOM/MOP.   I do have the flexibility to manimulate the costs
at any time to deal with network loads.   I do this when I have to copy
large numbers of files to/form Europe against the requirement to use
LAT.   In the past this network (SGC::) has been used to backup files
from nodes in Europe (just in case).   The link favored has always been
the tunnel when available.   This can be controlled in an automatic
fashion and in fact is.   I suspect that noone has ever known when the
switches have occurred - just as it should be.

Regards,

-Steve



-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On
Behalf Of Peter Lothberg
Sent: Tuesday, December 27, 2011 1:22 PM
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] Circuit costs

LAN costs are 4 by default (for VMS nodes anyway).   

  Maybe on VMS, but check MIM - the UNA-0 cost is 3, not 4.

  I've seen both values used; I think the default must vary depending
on the
system or OS version.

Bob




Topsxx default

NCP>sh cir ni-0-0 char
NCP>
17:19:20               NCP

Request # 52; Show Circuit Characteristics Completed

Circuit = NI-0-0

  Service = Enabled
  Cost = 1
  Maximum Routers = 16
  Router Priority = 10
  Hello Timer = 15
  Type = Ethernet

  Adjacent Node = 59.11 (DIMMA)
  Listen Timer = 45

Circuit = NI-0-0


  Adjacent Node = 59.58 (STUPI)
  Listen Timer = 45


(if there are more than one area router on the same LAN it will
use the one with the highest node number, no metrics...)

-P