[HECnet] Phase V Routing Specification

[Rob Jarratt]

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of Paul_Koning at Dell.com
Sent: 18 December 2012 22:30
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] Phase V Routing Specification


On Dec 18, 2012, at 5:07 PM, Rob Jarratt wrote:


http://bitsavers.trailing-edge.com/pdf/dec/decnet/EK-DNAPV-
GD_DECnet_Phase_V_General_Description_Sep87.pdf


Thanks for the link. I had a quick look. It does not go into the
details of the message formats, but it does say it interoperates with
Phase IV, so I just wonder if it was sufficient for me to accept Phase
V messages as if they were Phase IV and just ignore the version bytes.
I might just give that a quick go, which host is Phase V on HECnet now?

The way to interoperate with a version newer than what you implement is
to speak the protocol as you know it.   That includes ignoring fields
you're
supposed to ignore, and messages for protocols (such as Ethertypes or
802.2
DSAPs) you don't implement.   If you do that, the rest is up to the newer
version.


What I am doing is checking for routing specification 2.0.0 (in the hello
messages), but not checking for later versions. I have disabled the check
temporarily and it seems to work. But I seem to be getting
EthernetRouterHello messages from node 12.2 with the R/S LIST always empty,
so I never get an adjacency with the node. Not sure if this is because I am
not sending myself to 12.2, but an empty list suggests it can't talk to any
of the other routers in the network.

Regards

Rob



In the case of DECnet Phase V, that's essentially the OSI protocols --
such as
OSI ES-IS and IS-IS.   Those run over 802.2 LLC type 1, DSAP address 0xFE.
So
those packets are completely invisible to a Phase IV implementation.   What
the DECnet Phase V node does is also listen to the Phase IV protocol
(Ethertype 60-03); if it sees those, it records the sender as a Phase IV
neighbor and sends whatever it has to say to such neighbors using Phase IV
packets.

	paul