RouterBOARD 230 and Wireless performance with 2 Cards

RouterOS Wireless Networking
1

I’m doing some testing with the RouterBOARD 230 – very nice unit,
but I have some questions/observations…

I setup 2 pcmcia 802.11b cards and I get get about 650 KB/s
from each of them separately but not at the same time.

When I kick in 2 downloads (1 on each wireless card),
the speed goes to about 325 KB/s each …
The cards are on different channels (1 and 11, etc)

I have one incoming LAN interface but it’s set at 100 mbit and it’s not
limiting my tests.

Is the reason for this because I have a bridge and I’ve added the
Uplink + wlan1 + wlan2 to it? Is this creating overhead when doing
a download on one wireless card onto the other?

How can i correct this?

Should I setup 2 uplinks using the built-in network ports,
and have so only 1 is bridged with 1 wlan?

Thank You!

2

Update

I’ve setup 2 separate bridges, and again 650 KB/s on each,
but only 400 KB/s if 2 downloads from 2 wlans going at once.

I’m seeing 80% cpu usage with one download going at 650KB/s,
so I’m assuming it’s a cpu speed issue I’m running into?

3

I have been doing similar testing on RB532s.

RB532 ------> RB532 (Dual Card) ------> RB532
All links have excellent SNR, ACK, and CCQ rates. I can achieve >10 Mbps TCP to and from the centre repeater.
But if I test end to end, I only get 5Mbps (bridging), (7 Mbps routed).
CPU is not a problem, cpu usage is in the mid 40s. I believe it could be a bottleneck in the bus design of the two mpci. If you do the same test but use a ethernet connection for one of the links the bottleneck dissapears and I can achieve >10Mbps end to end.

4

Are you by any chance using intersil prism based cards?