Choice of PoE Switch for new wireless network?

[_Jo_]

Hi All,

I'm looking for advice on PoE switches. We will shortly be purchasing approx 60 WiFi access points and need a few PoE switches.
I haven't purchased PoE switches for more than 10 devices before now, and as we're in a hurry to spend the money (end of financial year), I don't have a lot of time to research.

We will probably need a 48 port (or 2 x 24 port) switch in one building, and a 24 port in another. I've been looking at the Netgear ProSafe GS728TPSB but I'm worried it won't be able to power an AP on every port.

It claims a "PoE budget" of 384W. An Aerohive AP claims a 14.5W max power draw on 802.3af.
I'm assuming this then means the total power available divided by the max draw (384W/14.5W) = 26.48, so that should be enough, yes?

Any experts out there who can point me in the right direction or recommend (better) hardware?

Jo

[uffy2000]

I have just got a couple of HP V1910-24G POE (170W) (they also do the in 384W) for my Ruckus APs and they work fine. They also have a lifetime warrenty from HP which is one of the reasons i got these.

[Michael]

I can recommend an HP 2910 al 24 or 48 port. This handles PoE 802.3af and delivers up to 15W and PoE+ = 802.3at delivers up to 30W and is starting to be used by newer Wireless Access Points (WAPs). It also means you're delivering a full 1000Mbps to each WAP instead of 100Mbps.

[CyberNerd]

I really wouldn't put a 1910 in there, and I'd be skeptical about a 2910. The reason I say this is that they are edge switches. For something that is going to have a lot of access points, and presumably 30 machines per access point, I would be looking for something with near edge or core capabilities such as a 5500EI, 3800 series etc.
Sure a 2910 would 'work' - until you started to get a lot of AP connections JG240A would be better by a clear mile.

[Michael]

I've had no probs with the HP 2910 al with many WAPs. The HP 1910 isn't worth looking at I agree. It's a much lower spec switch.

[CyberNerd]

I've had no probs with the HP 2910 al with many WAPs. The HP 1910 isn't worth looking at I agree. It's a much lower spec switch.

It'll all depend upon the expected load. If your planning 30 machines per AP and 10 AP's ie 300 machines+ then a single 2910 isn't going to cut it.

[Michael]

In my experience it's more so the computer on the other end being the bottleneck rather than the server or indeed the switch pushing data out wired or wirelessly.

[Michael]

The JG240A is a great switch, but more expensive than the J9148A. The switching capacity is also very similar, so it's more a question of the manageable options available - many of which most schools do not even use.

[psydii]

I'm running lots of aps of lots off v1910s. They are great. The switching capacity of your edge is not hugely important. You are unlikely to have more than 2/4Gb links back to the servers anyway.

I use in-line injectors though since for my highly distributed switch/ap infrastructure the price per port was far to high justify poe switches.

[_Jo_]

This is all really helpful, thanks everyone. At the moment the expected use is for iPads / netbooks. The numbers will be low to start with (200 distributed between depts) but we expect numbers to increase over the next 2-3 years.

[Michael]

You certainly need a switch with optional 10Gb uplinks and the HP 2910 al offers this. You can buy the switch now and buy the modules to increase speeds 12 months later. Ideally you need OM3 fibre to connect switches at a distance with 10Gb speeds.

[_Jo_]

Hmm. Interesting but looking a lot more expensive than we had hoped.

[psydii]

You certainly need a switch with optional 10Gb uplinks and the HP 2910 al offers this. You can buy the switch now and buy the modules to increase speeds 12 months later. Ideally you need OM3 fibre to connect switches at a distance with 10Gb speeds.

Perhaps. Perhaps not. If you have 10GbE already, then yes 10Gb/E makes sense. Rather than 1 x 48PoE GBe switch with 10GB uplinks, consider two 24 ports switches with link aggregation, it may be more cost effective and improve your wireless resiliency in the event of a switch failure.

A typical 2 radio AP does not come anywhere near making use of 300Mbit/sec on wired side.
design_guide_c07-693245-25.jpg
Spread across three 24 port switches: 20AP x 150Mbit/sec (say) 3Gb/Sec.
However this is assuming every AP is running at maximum likely throughput simultaneously. This will simply not likely to occur.

[Michael]

I suppose there are lots of things to take into consideration including price, cab space availability but also future proofing to an extent. I would say that if you had multiple notebooks connecting at full wireless N @ 300Mbps, this is when the gigabit link to the switch comes into play. Plus if you look at 802.11ac it can achieve 1300Mbps in 5GHz mode, so it's certainly well worth investing in a switch with 10Gbps options.

[nicklec]

Unless you have a well organised new build you're probably not running APs back to the same switch? This was the case in our building so we're just using our normal 'edge' switches with a PoE midspan for the amount of APs in that location: PowerDsine 6500/6500G PoE Midspan Family