Jason Stevens wrote:
Right now testing, although I'm making a 'stub' version to run under
windows so I can setup a bridge on a windows hosting box I have...
Hmm. I suspect that might turn out to be very hard, if not impossible...
One of the serious problems is that you need to be able to send out packets with faked source MAC addresses. And all tools I've ever worked with in Windows which need to use some other MAC address have been tricky to say the least, not to mention that you need to reconfigure, and for some, also reboot the machine to use another MAC address. Transparent ethernet access from Windows seems to be difficult.
I noticed from the source there is no way to handle packets of 1500
bytes, as it would invariably require fragmentation... is
LAT/MOP/DecNET all smaller then 1500 bytes?
I'm not sure how you mean. The code bridge ethernet. Ethernet packets are (normally) a maximum of 1518 bytes. 1500 bytes of data, 6 bytes source and destination MAC, two bytes with protocol number, and four bytes of CRC.
Is there somewhere where you have identified that the bridge program don't handle 1500 bytes of data?
I'm not really interested in jumbo ethernet frames. No DEC equipment relevant here supports it anyway, so there is no need.
As for fragmentation... Now I assume you are talking about the encapsulation of ethernet packets in UDP packets. Those will be a bit larger still, and will almost certainly be fragmented when sent over the internet, yes. I don't see a problem with that. Do you?
I've only used decnet in the 'wild' once, but we moved from the VAX to
PC's... but then our VAX was weird as it ran Novell Netware..... I
wish I had saved the tapes, as netware for the vax has to be super
ultra rare...
Yeah. That would have been fun to have kept around.
Anyways I was thinking of adding compression support (zlib style)... I
should test it some more as I figure if the packet compresses somewhat
it'll be under the 1500 snaplen for ethernet....
Feel free. I'm not sure there is a point of doing so, but anyway.
If you want to avoid fragmentation of packets, you need to find out what the minimum MTU are along the whole path between two nodes. And your packet then needs to fit both the data to carry as well as the UDP and IP header within that packet size. The minimum size that is guaranteed by IP to not be fragmented is 576 bytes. For UDP that means a size of the data part of just 548 bytes.
And that means you need to do fragmentation yourself, since you'll never be able to squeeze 1500 byte packets into 548 bytes with any kind of certainty. And if you start doing the fragmentation yourself, you will in fact add to the overhead, since then you'll create a separate packet for each fragment, all with their IP *and* UDP headers. And you'll need to do fragment reassembly, and what will you do if some fragment is missing? Do retransmissions? Now we're getting into a very complex protocol with acknowledgements and whatever. And don't forget the cpu overhead of doing the compression/decompression of each packet. And if you start to have fragments, acknowledgements and so on, you'll have to add information to each packet to handle all this information, which means extra overhead there as well. In the end, you should not be surprised if your packets end up being larger than the current ones.
And in the "normal" case, each packet is still just generating a single, unfragmented IP packet anyway.
Like I said. Feel free to play with it, and see what you can do. But personally I don't think it's a good idea. You add complexity, processing overhead, protocol overhead, and possibly a whole new level of communication overhead, to probably no gain at any corner, but at a cost of having a protocol that makes it harder to troubleshoot. :-)
Ok enough rambling for now.
I hope my ramblings don't scare you off, or turns you off from experimenting. Having fun and experimenting is after all what HECnet is all about.
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
Right now testing, although I'm making a 'stub' version to run under
windows so I can setup a bridge on a windows hosting box I have...
I noticed from the source there is no way to handle packets of 1500
bytes, as it would invariably require fragmentation... is
LAT/MOP/DecNET all smaller then 1500 bytes?
I've only used decnet in the 'wild' once, but we moved from the VAX to
PC's... but then our VAX was weird as it ran Novell Netware..... I
wish I had saved the tapes, as netware for the vax has to be super
ultra rare...
Anyways I was thinking of adding compression support (zlib style)... I
should test it some more as I figure if the packet compresses somewhat
it'll be under the 1500 snaplen for ethernet....
Ok enough rambling for now.
Marc Chametzky wrote:
I don't have a current use for HECnet other than the novelty of being connected. I just got my SIMH VAX back up and running, now on a dedicated virtual host running under ESXi. I need to tweak my IP address and send that to Bob to update my MultiNet circuit.
I think for most people it's more about fun than actual real use...
I'd love to get it to the point that I've got a guest account for people to play what games I've got installed (including a collection of Infocom games I put on there).
Speaking of infocom, do people know about ZEMU?
On MIM::
.zem /li
-- System games --
Game Release Serial Inform Z-Machine
ADVENT 5 961209 6.05 5
AMFV 77 850814 4
BALLERINA 1 991128 6.21 8
BALLYHOO 97 851218 3
BEYONDZOR 57 871221 5
BOMBER 3 971123 6.13 5
BORDERZON 9 871008 5
BUREAUCRA 116 870602 4
CUTTHROAT 23 840809 3
DEADLINE 27 831005 3
DOGSLIFE 1 981015 6.15 5
DREAMHOLD 5 041231 6.21 8
ENCHANTER 29 860820 3
HEROINE 3 001211 6.21 8
HITCHHIKE 31 871119 5
HOLLYWOOD 37 861215 3
INFIDEL 22 830916 3
LEATHER 59 860730 3
LURKING 203 870506 3
MOONMIST 9 861022 3
NEVER 10 000928 6.21 5
NORDANDBE 19 870722 4
PLANETFAL 37 851003 3
PLUNDERER 26 870730 3
SAMEGAME 1 980731 6.15 5
SEASTALKE 16 850603 3
SHERLOCK 21 871214 5
SORCERER 15 851108 3
SPACEZ 1 980710 6.15 5
SPELLBREA 87 860904 3
STARCROSS 17 821021 3
STATIONFA 107 870430 3
SUSPECT 14 841005 3
SUSPENDED 8 840521 3
TRINITY 12 860926 4
TROLL 3 980518 6.15 5
WISHBRING 69 850920 3
WITNESS 22 840924 3
ZDUNGEON 13 040826 6.14 5
ZOKOBAN 1 990810 6.21 5
ZORK1 88 840726 3
ZORK2 48 840904 3
ZORK3 17 840727 3
ZTUU 16 970828 6.13 5
.
If someone have any problems, or find any bugs, just send them to me. :-)
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
Well I'm happy to inform that CHIMPY is back up again - there's a couple of captive accounts available (one gateway to my BBS with some games and FidoNet) and one offering VT100 tetris.
Sampsa
Bob,
I would like to talk to you about this offline when you have the time.
This cluster should be more than capable of this kind of activity,
besides it could be FUN! I have never set something like this up and
could use some guidance.
-Steve
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On
Behalf Of Bob Armstrong
Sent: Wednesday, February 25, 2009 13:21
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] What use are *you* making of HECnet?
If I remember right, it was/is Robert Armstrong who had that up and
running.
LEGATO used to relay email between HECnet (using MAIL11) and the
Internet/SMTP, but I quit doing that last fall when I switched
registrars.
There's no reason I couldn't - I just never bothered to set up the
necessary domain name and mail routing again.
It was pretty much never used, even by me - after all, everyone with a
HECnet connection already has an Internet connection.
Bob
I don't have a current use for HECnet other than the novelty of being connected. I just got my SIMH VAX back up and running, now on a dedicated virtual host running under ESXi. I need to tweak my IP address and send that to Bob to update my MultiNet circuit.
I'd love to get it to the point that I've got a guest account for people to play what games I've got installed (including a collection of Infocom games I put on there).
--Marc
If I remember right, it was/is Robert Armstrong who had that up and
running.
LEGATO used to relay email between HECnet (using MAIL11) and the
Internet/SMTP, but I quit doing that last fall when I switched registrars.
There's no reason I couldn't - I just never bothered to set up the necessary
domain name and mail routing again.
It was pretty much never used, even by me - after all, everyone with a
HECnet connection already has an Internet connection.
Bob
Dennis Boone wrote:
And then I use LAT and MOP a lot, both for printers and terminal
sessions. (But I don't bridge LAT to anyone else.)
Is there any magic involved in bridging LAT?
Not much. Both ends must just add the other remote end to the [LAT] section in my bridge.conf file. :-)
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
And then I use LAT and MOP a lot, both for printers and terminal
sessions. (But I don't bridge LAT to anyone else.)
Is there any magic involved in bridging LAT?
De
Steve Davidson wrote:
Johnny,
Could you expand on the "mail bridge"? That sounds useful.
If I remember right, it was/is Robert Armstrong who had that up and running.
It basically meant that you could send mail to anyone on the Internet from anyone on HECnet, and vice versa. You just need to know the correct syntax for the mail address.
I'll leave it to Robert to expand on this, if he still have the gateway up. I haven't tried it in over a year now.
Johnny
Thanks.
-Steve
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On
Behalf Of Johnny Billquist
Sent: Wednesday, February 25, 2009 04:26
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] What use are *you* making of HECnet?
Steve Davidson wrote:
Hi,
I was wondering what use everyone is making of HECnet. My environment
(DECnet area 19) has just come up. Johnny and I have done simple tests and everything that we have tried so far seems to work quite
well.
Comments?
For me, I use it a lot to transfer files between my own systems and MIM
(and occasionally other systems as well).
I occasionally use it for mail to some people as well (once in a while,
we even have a mail bridge to the internet, which is fun).
And of course, on MIM, there is a guest account for anyone to play.
And then I use LAT and MOP a lot, both for printers and terminal
sessions. (But I don't bridge LAT to anyone else.)
What else...? Hmm, it's a way to keep in touch with other odd people who
thinks this kind of stuff is fun.
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
