[nos-bbs] IRTT etc

[Brian]

Jay/Skip/et al;

Here on the EastNet network we run FlexNet for the switching software.
What are the pros and cons about this?

Pros:
No netrom used. 20 Bytes per frame are saved. More room for data.

Digi frames are acknowledged hop to hop. Once your frame makes it to
flex, it'll insure to pass it to the next hop. (This also allows you to
set very high thresholds in xNOS so that you don't flood a busy link
with retry frames!)

Dynamic route handling of Virtual Circuits. If the path from point A to
point B changes to a path of a better quality, the VC will then break
and re-establish using the new path without dropping the pre-existing IP
sockets (similar to how the backbone routers on the wired internet
handle routing via BGP.. but on ax25).

Native linux TCP routing can be handled, no need for xNOS at all.

As a proof of concept I have an IP path (all RF) from Massachusetts to
Queens, NY. It's 8 hops away:
Route: N1URO-3 N1URO-1 N1URO-6 K1YON-2 K2PUT WB2CIK KC2COJ N2NSA-1
n1uro at n1uro.ampr.org:/uronode$ p ipqns
ICMP Echo request sent to: 44.68.32.2
ICMP Echo reply received from: 44.68.32.2
Ping completed in: 4214ms (ttl=63)

4.2ms over 8 hops is by any means nothing to sneeze at, and this path is
flooded with FBB pbbs mail forwarding and Spider link feeds. If you've
ever sniffed traffic on a dxcluster link, it's extremely chatty! I'm not
at all complaining about this what so ever.

Now, on the negative side of using FlexNet:

SSID handling is very tricky, but once figured out is easy to set up.

Jnos will not link properly through flex (I talked to Maiko about this a
while back).

Linux SSID must not appear in the flexnet desti table.


So in conclusion, if you eliminate any netrom overhead you speed things
up by saving 100 bytes every 5 frames, your retry timers can be of high
levels to give flex the opportunity to take the frame and just run with
it while cutting down on the number of retries... and in the end you get
a much cleaner and responsive RF network transporting IP. Currently the
only xNOS I know of that does play nicely with FlexNet is MFNOS (which
if you need to run a flavor of NOS on linux) does seem to work well
under DosEMU as I've run it for a few years now without any major issues
at all.
-- 
73 de Brian - N1URO
ax25: n1uro at n1uro.#wma.ma.usa.moan
ampr: n1uro at wmass.ampr.org
smtp: brian at uroweb.net
wl2k: sorry, I use axMail
--
Message sent using Evolution for Linux
protocol: SMTP
"How about a nice hot apple ie with that ax25 retry frame?"
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