Question on performance

[mmolyneux]

Daft question, but would one access point (802.11b) provide sufficient bandwidth for 17 PCs in one office? Currently office is using old Coaxial cable and thinking of upgrading to wireless rather than CAT5.
Would one access point be sufficient for bandwidth (signal coverage is fine) and would there be a visible performance difference (better or worse!) moving away from coax?
Many thanks

[Sam Cheung]

Probably significant slow down in file transfer traffics. Internet connections and word processing should be OK.

[delxu]

I think WLAN (shared 11Mbps)'s performance is almost same as Shared 10M coax LAN (such as 10Base5 or 10Base2)

[Sam Cheung]

The one computer nearest to the wireless router/AP will probably get 4 or 5 Mb/s. Furthest away will probably get 1 Mb/s and when all 17 computers are competing for wireless traffics, it could be disastrous.

[Uncle Ken]

Our tests show Orinoco AP-2000 access points capable of handling around 30 clients doing random web surfing and small file transfers, and that's with 11mbps radios. A home-style product like Linksys or D-Link would probably not handle as many, but you can always use several access points to cover the same area by using different, non-overlapping channels. I'd definitely consider 802.11a for this environment -- 54mbps raw speed, 100mbps wired connection, 8 non-overlapping channels.

[beta999]

What about 802.11g? Is it faster than 802.11b?

[Uncle Ken]

Although 802.11g products are already on the market, none are yet certified interoperable with other brands. Also, 11g is not yet a ratified IEEE standard. 11g can communicate at up to 54mbps, but it shares the same crowded 2.4GHz frequency and 3 channel limit of 802.11b. To its credit, 11g signals can penetrate obstacles better than 11a and most 11g products come with removable antennas, for better signal shaping. 11a is preferable to 11g for small, indoor, business environments like I understood yours to be.

[RandyW]

One thing you didn't mention is how spread out the 17 clients are. If the clients are fairly close to each other (max distance within 20-30ft or so), there may be acceptable performance. Any further and some clients may be transmitting at lower rates, reducing channel availability at higher rates. If they are spread out enough, hidden node issues will occur where some clients can't hear others and talk over them. Back off times for channel access will exponentially increase, killing throughput across the network. You would be doing well if you had the equivalent of 56k connections at that point.

Another point: 11 Mbps over 17 clients does not mean 11Mbps/17 average throughput per client. An addition of each client will hurt throughput more then expected as a result of higher order affects related to the CSMA channel access protocols in 802.11.

To suggest a solution, I would like to know a little more about the throughput desired and the reasoning behing going wireless. For desktop computers that are not frequently moved and in the case that installing cat-5 wiring would not be cost prohibited, I think you would do better with a wired network.

If you want to go wireless, I would suggest the following in order of throughput:
- One AP (enterprise grade, such as a Proxim/ORiNOCO or Cisco single radio AP running 802.11b) All clients must be close to AP.
- Same scenario, 802.11a
- Multiple AP's, or dual radio AP's (AP-2000 mention before). ORiNOCO AP's along with ORiNOCO client cards implement an effective load balancing algorithm that will maximize performace across all clients and adjust according to usage patterns. Use up to three for 802.11b.
- Same scenario, 802.11a

I wouldn't suggest 802.11g without explaining why b/c I'm afraid of turning this thread in another 802.11a vs. g debate.

[Wifi-Guru]

Also remember to take security into the picture. The most, and only truly secure so far, wireless setup is with using a Cisco AP, with Cisco's TKIP and LEAP authentication. In order to do this right, it takes an extensive amount of set up.

If you company is sending private data, and this is going to be on the company network. IE, not used just for web browsing like laptops mainly use it. I would put in Cisco and secure it.

If you do NOT use Cisco, any good wireless person can hack your networks in less then 1 hour...easy! WEP is crackable...actually REALLY easy to crack. MAC authentication can be spoofed. Any linux user can tell you that. Espcially when all network packets have a sourse, dest, and BSSID(wireless id) in every packet. All you need to do is spoof a PC and the job is done.

Now Cisco with its version of TKIP, which is a rotating Encryption key, somewhat. But in short no 2 packets are sent out on thw wireless with the same encryption pattern so it is so far unhacked.

Of course Cisco is going to cost more then the other AP's. If you still want to go wireless, you can alway put a few Cisco AP's and bridge them together. But you still NEED SECURITY.

~WiFi~

[RandyW]

Cisco does make excellent wireless products so you can never go wrong by purchasing one. I would like to mention though that Proxim/ORiNOCO client cards implement a feature called WepPlus that avoids traditionally weak WEP keys. That will stop any type of currently available key hacking tool such as airsnort. That along with 802.1x support and RADIUS would provide adequate protection until 802.11i solutions are completely available. If security is really a concern, there are other solutions available.

Many vendors are currently offering VPN between client and wireless edge. In addition, I think Proxim still offers the AS-2000 or Access Server-2000 which provides an extra layer of authentication and encryption that is outside of the 802.11 MAC. That security has never been compromised as far as I know.