More on PC Routers from BGPD

Thu Apr 28 15:17:44 UTC 1994

> >I don't think a PC today can realistically handle even one T1 at full
> >capacity.  Also PC ethernet cards are sufficiently miserable that you
> >can only put one in a PC and get it to use the full ethernet
> >bandwidth.
>  
>    I'd be happy to prove this statement wrong. A 66Mhz 486 with the right
> ethernet boards (16bit WD/SMC type), and running a recent version of 'FreeBSD',
> can easily fully saturate 2 ethers and possibly 3...and this is all the way
> to/from a client application. With bus mastering EISA adapters, the same PC
> should be capable of routing traffic between two T3's at full T3 speeds (this
> assertion is unproven, however).
>  
> -DG
>  
> David Greenman
> FreeBSD development group

David,

My comment was incorrect on T1/E1.  We were trying to do full DES
encryption of a T1 stream and couldn't saturate the link using a
modified BSDI kernel and a 486/66.  Full T1/E1 is possible using
existing cards if you don't try to encrypt.

Wrt ethernet - I was under the impression that the fastest EISA card
was the 3C579 and the fastest ISA the TN-1500.  I'd be surprised to
hear that a WD/SMC EISA card can saturate 2-3 ethernets at small
packet sizes (typical traffic seen by a router).  This is more a
reflection of my opinion of PC card technology, not FreeBSD or BSDI.
If anyone has measured troughput under small packet load, I'd be
interested in hearing the result.

Wrt DS3 - I didn't think a HSSI card for EISA existed.  Does one
exist?  Also, keep in mind that routers see an average packet size on
the order of 200 bytes.  Do you really think an EISA bus can handle
the small packet throughput?  Big packets are easy, too bad real
traffic isn't all big packets.

Curtis

BTW - I've corrected my own untruths by way of Cc.  Thanks for the
note and the good work that you are doing on FreeBSD.