blueandwhiteg3
12-31-2008, 03:26 AM
I am experimenting with a point-to-point 802.11a 5 GHz link around 5.8 GHz. I need to pass IP traffic, both UDP and TCP, but there is no special 'logic' or additional functionality happening at the access point level.
I would like suggestions as to the best access point hardware. I'm looking for high power output and good sensitivity, plus the ability to pass the full 108 mbps without bottlenecking. I would like the option to use WPA2 Enterprise (RADIUS) without a throughput performance impact.
I've personally done setups that do 72+ mbps sustained TCP traffic using Atheros 802.11a with 40 MHz channels and access point hardware with an unknown CPU, so I know there's a huge amount of throughput possible here.
My concern is that CPU bottlenecks that cause my link to fail to achieve full throughput. People keep talking about this, but I can't find any hard numbers. I'd rather not run around and buy every possible configuration and test until I'm blue in the face to find out which do and do not have a bottleneck!
Cost-wise, an XR-5 plus a RouterBoard 411 seems like an excellent value. I get almost twice the CPU (300 MHz Atheros MIPS) of a PowerStation 5 plus more RAM and a bit more power output, all for around the same price point.
If that was not enough CPU, I could look at faster RouterBoards, or even AMD Geode systems. I have some of those and they're nice, 433 or 500 MHz, full x86 platform, low cost, practically no power required.
A PowerStation 5 would be more convenient as it is pre-enclosed, and appears to have identical sensitivity as the XR-5 and only 2 dBm lower transmit power than the XR-5 card. However, I am concerned the 180 MHz MIPS CPU and 16 MB of RAM might become a bottleneck, particularly given posts I have seen saying that the Bullet 5 can bottleneck due to CPU.
I don't think a Bullet 5 is appropriate for this setup due to limited output power, but I'd also be interested in knowing the degree of CPU bottleneck there.
Any ideas on the CPU bottleneck aspect of things?
I would like suggestions as to the best access point hardware. I'm looking for high power output and good sensitivity, plus the ability to pass the full 108 mbps without bottlenecking. I would like the option to use WPA2 Enterprise (RADIUS) without a throughput performance impact.
I've personally done setups that do 72+ mbps sustained TCP traffic using Atheros 802.11a with 40 MHz channels and access point hardware with an unknown CPU, so I know there's a huge amount of throughput possible here.
My concern is that CPU bottlenecks that cause my link to fail to achieve full throughput. People keep talking about this, but I can't find any hard numbers. I'd rather not run around and buy every possible configuration and test until I'm blue in the face to find out which do and do not have a bottleneck!
Cost-wise, an XR-5 plus a RouterBoard 411 seems like an excellent value. I get almost twice the CPU (300 MHz Atheros MIPS) of a PowerStation 5 plus more RAM and a bit more power output, all for around the same price point.
If that was not enough CPU, I could look at faster RouterBoards, or even AMD Geode systems. I have some of those and they're nice, 433 or 500 MHz, full x86 platform, low cost, practically no power required.
A PowerStation 5 would be more convenient as it is pre-enclosed, and appears to have identical sensitivity as the XR-5 and only 2 dBm lower transmit power than the XR-5 card. However, I am concerned the 180 MHz MIPS CPU and 16 MB of RAM might become a bottleneck, particularly given posts I have seen saying that the Bullet 5 can bottleneck due to CPU.
I don't think a Bullet 5 is appropriate for this setup due to limited output power, but I'd also be interested in knowing the degree of CPU bottleneck there.
Any ideas on the CPU bottleneck aspect of things?
