PIX 515 Auto sense speed

[albertobrivio]

Dear ALL,

I have some win2003 servers connected to the INSIDE and DMZs and I experienced too much delay in

copying medium file size (like 50MB) between them. They are interconnected by Linksys switches and

speed and mode was 100full for all interfaces.

Changing speed and mode to "auto" I detect a big improvment in transfer of data, from some minutes to

some seconds.

Anyone of you could tell me reason of this ?

Regards

Alberto Brivio

[pcarvill]

Your switches were probably set for auto/auto for the ports connected to your firewall. The firewall ports were hard coded 100 Full. The problem arises due to how autodetect works. Your switch will start it's negotiations at 100 half and await a reply from the PIX. However, the PIX does not negotiate and therefore the switch gets stuck at 100 half and thus you have collisions causing latency.

Now that your PIX is set to auto-detect it will participate in negotiation with the switch and together they will decide on 100 Full - no more collisions and thus faster transfer.