• Hi all. I'm not sure this is the right forum section OR even the right site to post this question, as the forums here are all really related to the study for cwnp,

    AND I know this the oldest question / argument in the holy bible of wifi ;>) BUT anyone got any comments for against SCA as opposed to MCA?

    Is there a wifi site that you guys know that this would be better posted on? I've just passed my CWNA and now looking to do the CWAP.

    Ive worked in a MCA environment and now in a SCA environment and I can see pros and cons for both but the SCA thing has always left me with a 'contention' question that I never really get to the bottom of. The SCA folk argue that their algorithms manage the airwaves and contention but I still can't see it. 

    As I see it... 3 APs within range of each other, all on a different channel, can all transmit at the same time because they are all on different frequencies. So for that   single moment 3 clients could be transmitted to by 3 different APs, where as surely with 3 APs within listening distance all on the same channel, for any given moment only one can transmit? I know the argument that SCA have with it's ability to serve the up and coming 80Mhz channel sizes (bonding) 802.11ac easier than say multi channel but I still cannot see how the previous argument can be negated.

    My apologies for posting this if this is the wrong place to do so. I was looking for a general wifi forum/section to this site.

    My thanks to all the amazing people I've had the opportunity to speak with on this site. Compared to the knowledge of some of you guys, I am just starting out on the journey but I have an open mind, a curious questioning mind, and a whole tonne of enthusiasm :>)


  • I may do some reading about this subject from the folks at Meru, as far as I can tell they are the kings of SCA.

    The bad part of sca is a lot of it is proprietary, the question is, will they reveal their secrets?

    Looks like a great option for a network that demands the best mobility/roaming support.

    Back to my CWDP book, the AP still hasn't arrived hehe.

  • Hi Neal

    Thanks for your response. We are a meru site. It's really interesting. I've done a bunch of Iperfs and are getting some interesting results back. Not the results I would expect, I hasten to add!

    I can't fault the wireless system in its stability. By that I mean it does do what it says on the tin. BUT as a wifi person, I want to get under the lid of that tin and that's where I keep falling over. You simply can't get the background info of how it works. It''s like the KFC recipe ha ha.

    Yes it is proprietary BUT it still follows the standards in that if a laptop / device has a NIC that is on the wifi standards list, it supports it. To be honest we have a 101 different devices at our place, from old to new, laptops, phones, tablets, the lot and all connect and work perfectly. Th sonly issue I have at present is with the android (is it 3.4 or 4.3 - I can't rem...the latest) connecting to our BYOD but that's just because Android have ramped up the security. It'll be a certificate thing me thinks But if anyone knows the answer I'd be more than grateful to hear it. we have a load of androids connected pre this version. 

    Cheers again 


  • Rol.

    Glad you started this new thread re: SCA/MCA.

    I've never used Meru, but they might be the only vendor who does SCA (I thought there was one other vendor, but cannot remember the name).

    I think my big drawback on SCA is it is controller-based.  (help me out if it is not).

    I really see WLAN technology moving away from controller to controller-less (cloud based) management.  Look at all the big vendors...most have some type of controller-less solution, some by design and others because they are trying to keep up with cloud management.

    So again, the SCA technology seems to work OK (however, I too would like to know what is in Meru's "special sauce" that makes their SCA work...), but it is the required controller technology that gives me pause and points me toward other vendors.

    Other thoughts?

  • Hi yes there is another company that does the SCA stuff. I can't recall their name though either :>)

    Meru is a controller based system. We have the physical controllers (dual) here but you can get virtual controllers now. 

    We have a new build place and their was a pot of money specifically for this so we used it!

    I'd love to have the wifi crystal ball to see where it is all going but yes I can see your argument for controller-less. I think it will go that way but possibly a hybrid arrangement. Maybe APs will have such intelligence in them in due course they will all be mini controllers anyhow. I also read someones suggestion that the network itself i.e the switches would perhaps have more understanding and functionality to control part of the wifi system.

    We had an HP system at our last place and it was a nightmare. Sticky clients and all sorts of chaos. Even the HP switch guy put his head in his hands when we said we had their wifi. I know someone with one of the cloud based wifi systems and he is having terrible trouble with it. I don't know the details and it could just be the way it's been configured (probably in fact) but he's not a happy man. I work at an academy and the way wifi is used in education is very different to that of business. By that I mean we have set specific times during the day i.e start and end of lessons when we know there will be 600 laptops logging on at one time, then off again. The meru kit takes the hit very well. I like their EzRf app too and their IDM, both of which we have. I guess meru will have to cross the controller-less bridge when they get to it.

    It works well for our type of environment. If I were a wifi supplier I'm not sure I would put it in other places i.e. it would have to be a case for case analysis.

    I don't think we'll ever get to see the actual 'how it works' side of things. Their trade secret. From an RF angle though I can't see as it can work any different to how I described. What systems are you familiar with? 

    I'd love to have a look at the ruckus stuff to be honest.

  • Rol,

    Well, I don't want to get too far off topic (MCA/SCA), but a few comments here:

    Almost every vendor uses MCA.  So just thinking out loud, there has to be a good reason for this, right?  SCA is very proprietary, which means you have to learn their way of management. 

    You really do not need a Wi-Fi crystal ball:  Controller-less is here today!  I did a blog a few months ago and in my opinion, controller-less solutions are here and the way all WLAN configurations are going today (shameless plug:  "Braveheart and the controller vs. controller-less battle" at

    Systems I am famiiliar with?  We used Aerohive when we did my daughter's high school last summer.  Of the four vendors we looked at, they had the best management system and strong education vertical support.  And, the installed Wi-Fi network there works pretty well (controller-less).  I worked with an out of state colleague to set up Ruckus, and he has been very satisfied with the performance (controller-based).

    However, the company I am looking very closely at right now is AirTight . They have good APs, easy to install/configure, but their strength (to me...) is their managed service provider support.  Personally, AirTight has the best MSP I have seen to date.  No, I have not installed an AirTight system, but did get a free AP from attending a webinar and have used it a lot in my home lab.  Their WIPS is part of the DNA of their firmware and is outstanding.   My work is a Cisco shop, but I do other volunteer work, too.  AirTight is going to be toward the top of my vendor list for the next consult I do in the community,

  • Cheers for the info. Ive not heard of airtight. Looking at them now :>)

    Yeah I need to get to see a few more systems me thinks. I'll have to see if there is a wifi show of some format here in the UK and get to it. Maybe I should have gone to the BETT show here; probably had the wifi vendors there.

    The actual controller and management of the meru kit isn't all that different to other interfaces i've seen. Ok you have to get past that basic thing that all the APs are on one channel (or rather on one channel on 2.4 and another on 5) Ours being 6 and 36. But after that the front end, ssid management etc is similar to other systems Ive seen. I managed to work my way around it altho I'd much rather attend some proper training but that aint gonna happen at our place!

    On a more CWNP level of question - how much more complex is the CWAP to the CWNA. Does it build on the CWNA or is like just another great leap?

    It's taken me a good while to get ready for the CWNA, mainly due to workload. Is the CWAP like double the info? Much harder exam to pass?

    Cheers again for the info. Oh and another reason we ended up with meru was that out of the other vendors we approached, and one of them was aerohive, none were greatly confident in giving us some reference sites whereas meru couldn't give enough and I happened to know a network manager at a big private school who'd gone dow n the meru route so we got to see it first hand in an environment just like ours. Aerohive gave us a reference site and when we rang them they said they were only using a couple of APs in one building and their site was primarily another vendor altogether. I did a lot of chasing to get reference sites and support and i just wasn't getting the help or contact. Anyhow the IT Provider that did our new build only supplied a couple of different systems anyhow so they'd have probably thrown their teddies out of the pram if I'd have come up trumps with another bit of kit anyhow ;>) ha ha

    All the very best


  • Hi gcate

    I think I may have replied then lost the reply i.e I work off an EE dongle and somedays in this here olde ye village in England, it is as reliable as our UK weather!

    Going off a tangent here a bit (from the MCA / SCA) as I've been looking at CWSP and CWAP and I'm starting to sway back to the CWSP a td as I need to know more about the security side of things. Do you know much about the CWSP?

    The reason Im interested is that I come from a network and server side of things and the wifi guys that came in were pretty defined in what they knew i.e basically just wifi. When it came to the server side, i.e serve 2012, radius , certs and the rest of it, they were like a duck out of water. I had to set that side up myself and although it's in and running I won't make any statements about knowing my stuff in the cert / radius area properly. Just wondering if the CWSP covers much of this? It's a dark art the whole cert process. We have a wildcard cert now but it's not playing ball with android devices. Well the older ones, yes, but the newer ones, no!

    That aside...Ive looked up the info you gave me about that controllerless wifi co and I have to! I see where you are coming from now.

    I actually liked the aerohive kit a lot and had an AP sent to me. 

    Like I say, mate...I'm just a CWNA....I'm on the learning curve and looking to learn more. 

    I'm just happy to be on here and any info any of you guys can give will be totally absorbed. I know I'm a newbie with a long way to go but ya gotta start somewhere hey.

    Cheers again


  • Hi Rol,

    Saw your last post, but have not had time to respond (was out of town last few days, but did read it).

    I'll try a 'quick' answer on this one..and comment on your other post at a later time.

    In response to the CWSP, it sounds like you do have some good security background (certs, RADIUS, etc).  That's good...and it sound like you might benefit from taking the CWSP first.

    Here's what I would do:  download and read thoroughly the CWSP and CWAP test objectives (pdf files) on this web site.   If the CWSP sounds like it would benefit you the most if you were to study for that exam, then go for it.  There is no 'hard and fast' rule as to what exam order you take (post CWNA, that is).  But, if you are planning on the CWNE track, many WLAN professionals in the forums have strongly suggested the track they would follow is:  CWAP first, as it gives a huge foundation to the rest of the of the exams (CWSP, CWDP).

    Hope this helps some, and as always, other readers are invited to express their opinions as well.

    "Wanting to continue to learn" is a characteristic of a WLAN professional.  You are on the right track, Rol!!

  • Hi there. Both of these books seem a little out of date now. i.e 4 years old etc. I think I recall you mentioning that the CWAP would be getting an update (or did I dream that ha ha). What about the CWSP? Any ideas?

    Either way I'm still going to pursue one of them. I just want to make sure it's the right one for me and although I really like the look of the analysis side, I could really do with nailing the security side to fit in with my radius skills and certs skills etc. I'm looking more at the CWSP if I'm honest and will probably mail you in a year and say 'ya know wonder everyone does the CWAP rather than ha ha'. However, sometimes its good to take the less trodden path, hey.

    Cheers as always. 


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