In message <14214.4453.355809.780092@grasshopper.cs.duke.edu>, Andrew Gallatin writes:
>
>
>Older tulips (we have a batch of no-name 21140A cards in some older
>alphas & PCs here) also work reliably in full-duplex mode.
>

Since we had two old 21140's lying around, a netgear, and a cogent,
I decided it would make sense to try these two cards between
the two test alpha's...

To review: both alpha's have 10basetx-fdx set... both in the SRM
and in /etc/ifconfig.de0.  Visual verification of the lights on
the switch says they're in fdx.

    alpha1# ifconfig de0      
    de0: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	    media: Ethernet 100baseTX full-duplex
	    status: active
	    inet 192.168.129.1 netmask 0xfffff800 broadcast 192.168.135.255
    alpha1# 
and
    alpha2# ifconfig -a
    de0: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	    address: 00:00:92:96:92:f1
	    media: Ethernet 100baseTX full-duplex
	    status: active
	    inet 192.168.130.1 netmask 0xfffff800 broadcast 192.168.135.255

and when i ftp, the performance is still awful:

ftp> get netbsd.hold
local: netbsd.hold remote: netbsd.hold
227 Entering Passive Mode (192,168,130,1,255,252)
150 Opening BINARY mode data connection for 'netbsd.hold' (3890305 bytes).
100% |*************************************|  3799 KB   71.73 KB/s    00:00 ETA
226 Transfer complete.
3890305 bytes received in 00:52 (71.73 KB/s)

To see if collisions is the issue, I check netstat output:

alpha1# netstat -i
Name  Mtu   Network       Address              Ipkts Ierrs    Opkts Oerrs  Coll
de0   1500  <Link>        00:40:05:36:22:33     2978   105     2130     0     0
de0   1500  192.168.128/2 alpha1                2978   105     2130     0     0
lo0   33200 <Link>                                26     0       26     0     0

alpha2# netstat -i
Name  Mtu   Network       Address              Ipkts Ierrs    Opkts Oerrs  Coll
de0   1500  <Link>        00:00:92:96:92:f1     2126     0     3098     6     0
de0   1500  192.168.128/2 alpha2                2126     0     3098     6     0


No collisions, but the receiving machine is getting lots of input errors.


I also recall trying fxp's on these two machines, not getting any
collisions, but still getting very poor performance.  As i recall
when i tried running openBsd on one of the alpha's it told me
(when i used de0's) that the problem was framing errors.

When I was using tcpdump on both the sender, and the receiver, I could
see the sender was sending packets back to back.  When the sender would
ship more than, say, four packets back to back, the receiving machine
didn't receive all the packets.

It is as if the receiving alpha can't get four packets in a row back to back.

I tried modifying the if_de to allow for more interpacket spacing to
get the back-back data received... but that also didn't work.


mts.