Wireless Virtualization - Part 1 of 3
The purpose of this video is to describe how Meru's wireless virtualization architecture works. So what I'm going to do in this video is describe a very high-level concept in terms of the overall picture of wireless LAN virtualization, and then setup the problem in terms of what we need to address or the different dimensions we need to address in order to provide a predictable, high-quality user experience, and then zoom on one specific area and start expanding the problems.
So at a high level, the wireless virtualization architecture is the following. In a typical coverage area, users are walking around with 802.11 enabled devices, or Wi-Fi enabled devices. There are different devices with different chipsets, different drivers, different settings. There's over 5,000 combinations of Wi-Fi certified options. And wireless LAN, unlike a cellular network, is inherently a client-centric protocol. The client decides which AP or access point to connect to, the client decides when to talk, the client decides when to move from access point to access point. In order to provide a predictable network, it is really important as in a cellular network to take control away from the client and pull it into the infrastructure, but the key issue is how to do it transparently and in a standards-compliant manner.
So different vendors have taken different approaches. One approach is try to design away the problem of, or the tradeoff between co-channel interference and coverage. So fundamentally, the problem is as follows. We need to be able to provide high-quality coverage in an entire coverage area, and at the same time we need to make sure that the multiple access points that together provide this coverage do not interfere with each other on the same channel.
So Meru's approach to this problem is the following. So assume that you have one large coverage area. So we take multiple access points. Each access points transmits at peak power. And all of these access points live on the same channel, and they expose the abstraction of a single access point. So in other words, even though there are four different access points providing coverage, from a client's perspective -- a client that's sitting here right in the middle and sees these four different access points, cannot tell it sees four APs. It sees only a single access point. So how do we do that? We make all of these access points actually behave like one.
So from a client's perspective, the coverage really looks as follows. So all of these access points advertise the same Virtual Port or BSSID with respect to the client, so when the client comes into the network and seeks access into the network, it gets only one Virtual Port or BSSID that it can respond to. Now all of these access points of course, on the back end, have communications through the switch fabric to a centralized controller. So when a client comes in and asks for a network, in other words asks to connect to an SSID, each of these access points sends this information back to the controller. The controller decides which is the best access point to serve a client, and transparently moves that client to that access point. So for example, if there were a client sitting here and it asks for a network, the infrastructure would decide that this access point would serve this client.
Now, there's a lot of details and nuances behind how this transparent connectivity works, and that's going to be dealt with in a separate video. The key point there is, regardless of the client's chipset or driver or settings, with this architecture we are able to guarantee that a client is always connected to the access point that is best suited to serve it, and it is not a client's prerogative, it is the infrastructure's prerogative. And notice that at the controller we have global knowledge, therefore on the basis of global optimization we are able to move a client to the appropriate access point. So that's one aspect of it, which is how we are able to create a simple deployment and how we are able to create a cellular-like deployment where infrastructure guides the client transparently towards the best access point.
So the first one is adapting contention parameters, the second one is scheduling transmissions uplink and downlink, and the third one is coordinating across access points. In order to describe this in a little bit more detail, or to understand this in a little bit more detail, I need to -- at least at the high level -- present how the standard works. I'll present it at a high enough level that it's possible for you to understand the key aspects without getting into the real nuances of the standard because that can get fairly heavy.
......Please See Interactive Transcript For Full Text......
For more info visit: http://www.merunetworks.com
Loading...
8:13
Meru Networks Wireless Virtualization Architecture - Part 2by merunetworks979 views
Link to this comment:
All Comments (0)