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Old February 12th 06, 11:16 PM posted to rec.radio.amateur.digital.misc
Braath Waate
 
Posts: n/a
Default Can't run TCP/IP through AX.25 using Linux

I've been running the ConnexLink 900 Mhz serial modems for over a year
now to connect my house network to my business network in a rural area.
The networks are Windows based and the link runs PPP using the
radio's full duplex setting.

The link is clean for ping, telnet, ftp, and email. Unfortunately, I
never was able to get any browser to work without it coming to a
screeching halt with lots of TCP/IP retransmissions. I contacted
Aerocomm tech support (Sean) about this several times, but it appears
that no one else really uses the ConnexLinks on TCP/IP (they have a
newer product ConnexNet that does).

I really don't have a clue why the link fails with a browser, except
that some piece of the hardware/software path must be failing with the
heavy full duplex traffic created by browser and then snowballs with
the TCP/IP retransmissions.

I am curious if you are able to get PPP to work reliably with a browser
to web sites with a lot of graphics that result in multiple
simultaneous connections. If you are (and I would not be surprised if
your link would work, given the different hardware/software pieces),
then it gives me hope that one day I might be able to get my link to
work properly when I have the time to fix it. And if you get the
radios to run faster on AX.25, then that is even a greater achievement.

By the way, my radio link is solid (no problem there). There are two
yagi antennas pointing at each other and the signal is great even
through the trees.


wrote:
Hi all,

I'm trying to setup a wireless link between two Linux using ConnexLink
900 MHz serial modems (
http://www.aerocomm.com/Devices/link.htm). One
side (ali) is a regular PC running Debian Linux testing and the other
side (SLUG) is a NSLU2 running N7IPB's OpenSlug mod
(http://wetnet.net/).

The AX.25 link seem to work fine, I'm able to communicate between the
two sides with "call", but I can't figure out how to pass TCP/IP
through the link.

Anyone idea about what's going on?

Here's the relevant (I think) data from both hosts:
========================================
root@SLUG:~# cat /etc/ax25/axports
#Name Callsign baudrate paclen window Description
connex VA2JF-0 115200 1500 1 ConnexLink 900 MHz
root@SLUG:/etc/ax25# /usr/sbin/kissattach -l /dev/ttyUSB0 connex
172.25.25.2
AX.25 port connex bound to device ax0
root@SLUG:~# ifconfig ax0
ax0 Link encap:UNSPEC HWaddr
AC-82-64-94-8C-40-00-FF-00-00-00-00-00-00-00-00
inet addr:172.25.25.2 Bcast:172.25.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MTU:1500 Metric:1
RX packets:301 errors:0 dropped:0 overruns:0 frame:0
TX packets:61 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10
RX bytes:17345 (16.9 KiB) TX bytes:2788 (2.7 KiB)
root@SLUG:~# /sbin/route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
172.25.25.0 0.0.0.0 255.255.255.0 U 0 0 0
ax0
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0
eth0
172.25.0.0 0.0.0.0 255.255.0.0 U 0 0 0
ax0
0.0.0.0 192.168.0.3 0.0.0.0 UG 0 0 0
eth0
root@SLUG:~# mheard
Callsign Port Packets Last Heard
VA2JF-1 connex 463 Mon Dec 19 21:08:44
root@SLUG:~# axparms -route list
callsign dev mode digipeaters

root@SLUG:~# ping -c 10 172.25.25.1
PING 172.25.25.1 (172.25.25.1): 56 data bytes

--- 172.25.25.1 ping statistics ---
10 packets transmitted, 0 packets received, 100% packet loss
========================================
root@ali:~# cat /etc/ax25/axports
# name callsign speed paclen window description
connex VA2JF-1 115200 1500 1 ConnexLink 900 MHz
root@ali:# kissattach -l /dev/ttyS1 connex 172.25.25.1
AX.25 port connex bound to device ax0
gfk@ali:~$ /sbin/ifconfig ax0
ax0 Link encap:AMPR AX.25 HWaddr VA2JF-1
inet addr:172.25.25.1 Bcast:172.25.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:165 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10
RX bytes:0 (0.0 b) TX bytes:8085 (7.8 KiB)

gfk@ali:~$ /sbin/route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
172.25.25.0 0.0.0.0 255.255.255.0 U 0 0 0
ax0
10.10.16.0 0.0.0.0 255.255.255.0 U 0 0 0
eth0
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0
eth0
172.25.0.0 0.0.0.0 255.255.0.0 U 0 0 0
ax0
0.0.0.0 192.168.0.3 0.0.0.0 UG 0 0 0
eth0
gfk@ali:~$ mheard
Callsign Port Packets Last Heard
VA2JF connex 118 Sat Jan 28 16:44:54
gfk@ali:~$ sudo axparms -route list
callsign dev mode digipeaters

gfk@ali:~$ ping -c 10 172.25.25.2
PING 172.25.25.2 (172.25.25.2) 56(84) bytes of data.
From 172.25.25.1 icmp_seq=1 Destination Host Unreachable
From 172.25.25.1 icmp_seq=2 Destination Host Unreachable
From 172.25.25.1 icmp_seq=3 Destination Host Unreachable
From 172.25.25.1 icmp_seq=4 Destination Host Unreachable
From 172.25.25.1 icmp_seq=5 Destination Host Unreachable
From 172.25.25.1 icmp_seq=6 Destination Host Unreachable
From 172.25.25.1 icmp_seq=7 Destination Host Unreachable
From 172.25.25.1 icmp_seq=8 Destination Host Unreachable
From 172.25.25.1 icmp_seq=9 Destination Host Unreachable
From 172.25.25.1 icmp_seq=10 Destination Host Unreachable


--- 172.25.25.2 ping statistics ---
10 packets transmitted, 0 received, +10 errors, 100% packet loss, time
9020ms
, pipe 4
========================================

Thanks a lot and 73,
GFK's

PS: I was able to make the link work with PPP, but PPP requires a
full-duplex link. So I had to enable the full-duplex simulation of the
modem. This cut the available bandwidth in half. I'm trying to see if
AX.25 would perform better since it doesn't require full duplex.

--
Guillaume Filion, ing. jr
Logidac Tech., Beaumont, Québec, Canada - http://logidac.com/
PGP Key and mo http://guillaume.filion.org/