morrison@accuvax.nwu.edu (Vance Morrison ) (08/12/89)
Hello again,
From the person who brought you PCroute we now bring you PCbridge.
Software that turns a PC into a Ethernet-Ethernet bridge. So for
all you DECNET, IPX, ISO people, here is you chance to join the fun.
PCbridge is availble from accuvax.nwu.edu (129.105.49.1) in the
directory ~ftp/pub/pcroute/bridge. The tar file contains both the
bridge executable and source.
As you might expect, bridging places more demands on the CPU so you
really should have an AT class machine unless your load is light.
Here are the vital statistics
Packet Filtering Packet Forwarding (60byte)
rate (PPS) rate (PPS)
-------------------------------------------------------------
4.77Mhz XT 4080 PPS 1677 PPS
10Mhz XT (est) 8000 PPS 3000 PPS
16Mhz AT 26214 PPS 5832 PPS
While packet filtering is independant of packet size, packet forwarding
is dependent on the size of the packet. The packets I used where the
smallest ethernet packet (60 bytes).
For comparison purposes a low end Retix bridge costs $2000 (actually
more if you want thin ethernet) and has a forwarding rate of 6000 PPS
and a filtering rate of 10000 PPS.
See the readme.doc on accuvax to see where I got these numbers.
As you can see, the XT clones are fine under low load, but you probably
don't need a bridge unless you net is loaded already, so an XT as a
bridge is dubious. On the other hand, a 16Mhz compares well, and can
be but together for about $1400.
(What I really need is a 16 bit memory mapped cheap ethernet card, then
the thing would really fly).
So, if this is useful to you, let me know. Also If any of you think
a bridge-router is useful let me know. I have the code to make PCroute
a bridge-router, but I have never taken the time to test it enough.
(We are an IP only house). Maybe I will take a crack at it if enough
people think it is useful.
Vance