[HECnet] What use are *you* making of HECnet?

[Jason Stevens]

TCP/IP don't care about the source MAC address. And destination MAC address
is just used to make the packet end up at the right destination, without any
other meaning to it. And the mapping between destination IP address and MAC
address is solved by ARP. And several different IP addresses can use the
same MAC address. Exactly how that MAC address looks like isn't an issue
either. So, for TCP/IP, everything will work fine if you just use the actual
MAC address the card have, even though you might be doing traffic both from
the host, and from a simulator within the host. Reception is a bit worse,
since you need to figure out if the received packet should go to the host or
the simulator.

DECnet works in a very different way, where each host *must* have a unique
MAC address, and where the recipient really checks that the source MAC
address is consistent with what was expected, or else the packet is dropped
(yes, I'm writing and meaning source address here). And sending data is done
to a specific MAC address without ARP. Instead the MAC address is calculated
from the DECnet address, and is thus "known" already. For all hosts on the
network.

Believe me. You are not really seeing or understanding the problem yet, with
the tests you are doing.

Parts are things you need to read up on, on how DECnet works. And parts
you'll only find out the hard way, as I did. :-)

           Johnny

--
Johnny Billquist                           || "I'm on a bus
                                                  ||   on a psychedelic trip
email: bqt at softjar.se                   ||   Reading murder books
pdp is alive!                               ||   tryin' to stay hip" - B. Idol


I see... yeah I have a VMS image, but really no idea how to setup it's
networking... I 'used' VMS as a user ages ago, although it was mostly
using EDT and fighting the gold key thing on terminals....

Anyways is there some online docs on setting up VMS's networking?   I'd
love to be able to dig deeper into this....