Wireless kit

[eean]

Webman, that's interesting - I've never heard that before. I'm no expert but I can say from my own experience that 802.11a drops out significantly sooner than b/g.

From http://en.wikipedia.org/wiki/802.11 :

Since the 2.4 GHz band is heavily used, using the 5 GHz band gives 802.11a the advantage of less interference. However, this high carrier frequency also brings disadvantages. It restricts the use of 802.11a to almost line of sight, necessitating the use of more access points; it also means that 802.11a cannot penetrate as far as 802.11b since it is absorbed more readily, other things (such as power) being equal.

[/Quote]

and, related:

The maximum range of 802.11g devices is slightly greater then that of 802.11b devices, but the range in which a client can achieve full (54 Mbit/s) data rate speed is much shorter than that of 802.11b.

 

These sources tell the same story:

http://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htm

http://www.wi-fiplanet.com/tutorials/article.php/1009431

[webman]

I'd tend to agree with most of that eean.

 

Apparently I'm not allowed to copy text from that 5GHz PDF (), but the first paragraph about scatter on page 3 explains how 11a uses scatter of that frequency to its own advantage. Of course, it all varies from building to building and it's juse the best tool for the job

[ajbritton]

The nice thing about 11a is that it gives you more non-overlapping channels so it is possible to have a denser mesh of APs that will not interfere with each other. 11b/g only gives you 3 non overlapping channels so if you are going for blanket coverage it can be difficult to come up with a design with no dead spots and no interference. I tend to agree with Ric that the way to go is to have an access controller which manages the APs and also provides authentication services/policy management.

[spc-rocket]

My advice on wireless is to hold back a bit and wait for the 802.11n standard as this will provide better coverage and security. Of course this is easy said than done when's there manangement pressure etc.

 

At our place we practically advised not to go for wireless as we already have a good wired infrastructure in place, but the management wanted it anyway, but we kepy trying to pursusade them against it.

 

Even with the G standard the speed is still not that good and needs reliability. Hopefully the 802.11n standardised kit will be out by the end of this year or early next year. Most modern laptops have the mini-pci cards installed on them and i'm sure people like intel will develop the N standard wireless cards that fit into the existing laptops so there will be little cost involved but it should be worthwhile in the long run.

 

Ashok.

[Ric_]

The Bluesocket equipemtn I have has a/b/g APs so I get the best of both worlds (although I currently have no 802.11a clients).

 

Bluesocket has also released a pre-n AP with MIMO.

 

All these APs are 'thin' devices and as the technology moves forwards there will be a simple upgrade path.

 

@ashok: I think that you are being a little optomistic about 802.11n being ratified this year... there seems to have been a lot of set backs to date.

[GrumbleDook]

From a conversation with Intel bloke at Becta event ... 802.11n ... 2008 ... as long as someone doesn't bugger things up again.

It may move forward (3rd quarter 2007) but approx 60% of Pre-N kit will need flash upgrades, and a further 20% will not comply with final standards.

 

This is compared to 30% and 5% of the Pre-A kit.

 

I am going to wait ... and if I do buy it is kit that can be have modular upgrades with the new chips.

[spc-rocket]

@Ric_,

 

Probably but i guess i was thinking of our setup. I guess it all depends on how badly a school requires wireless, if it is justified then people should go for it, but if you can get away with it for about a year or year and half then you will get better speed and security with 802.11n when it is released. Another factor with this is that it gives you time to prepare for wireless as well not just from a technical configuration point of view but also from budgeting aspect as well.

 

Stuff like RM CC3 doesn't work very well with wireless and it takes ages to logon and use it effectivitly. We tested these with two APs, but suppose with native windows network it may be a lot better, knowing RM they got all sorts of components that just kills the logon process!.

 

The Bluesocket setup uses the wireless setup as switched wireless where the brain the main appliance and all you got is the dummy APs which doesn't have much config. I do see it wireless going this way because of the centralised management point of view.

 

Ashok.

[complete_phreak]

If you want better range/coverage you should look into the 802.11a (5.8GHz) access points. I believe Solwise sell them, but they are expensive.

 

11a has a poorer range but more available channels

[webman]

Ok, maybe range was a bad choice of word. 11a has better penetration and scatter than 11b/g.