Alright. So, we covered a lot of material in this lecture and just to give a brief summary, we talked all about WiFi. We talked about its topology, how it's typically laid out and basic service sets, devices within service sets and access points as well within service sets. We talked about the differences between WiFi and cellular, you know a WiFi device is un, unregulated frequency band. It's, it's typically run over a much smaller range and has a much smaller number of devices within each basic server set, or on the other hand, within a cell, in a cellular network. And it has much varying data rate and that data rate's going to vary a lot depending upon how much we've backed off. And depending upon the current interference conditions. And that's something that doesn't necessarily happen as much with cellular, because it's much more regulated. And then, we talked about random access protocols and what exactly those are. We focused mainly on ALOHA, a protocol that was invented in Hawaii, a very simple and very non scalable as we saw. And we talked about CSMA, which is still largely in use today, and we talked about some of the concepts that underlies CSMA. And we just saw overall, how random access protocols work very well for a small number of devices. well ALOHA really doesn't, but CSMA works very well for a small number of devices. But it's not very scalable to a large number of devices. Which is why you can't get a very good data rate sometimes when you're near a hot spot, if there is a lot of other people trying to access the same access point. Because you're going to cause a lot of interference and collisions. And that's the price that we pay for simple protocols. So, some major themes we've saw again the idea of feedback here, in terms of sending acknowledgement packets back. In CSMA, the idea of feedback is really that you use the acknowledgement packets to know that you can keep sending without having to back off. Unless you don't see an acknowledgement, that really indicates you if, there's congestion, then you have to back off. So, this is a form of negative feedback. And we saw distributed implementation again, that CSMA can be done completely distributedly just like we've talked about with distributed power control in the last section. So, overall over the past two lectures, we've looked at all different methods of sharing. In the firsthand, we looked at cellular and how we have things like FDMA, TDMA, CDMA, and we looked at power control. And we looked at how your cellphone uses power control to determine what power to transmit. And then, in this section, we looked at random access methods for WiFi and why your WiFi device is going to have a better data rate at your house than it would at a hot spot. But overall we've really looked at the theme of how do we deal with lots of people in networks at the same time. And how do we share the air most efficiently. Whether the air is being shared over cellular network or over a WiFi network. And so, the, really the big theme is that sharing is hard to do. It's not easy. And to this day, researchers are still trying to develop methods to squeeze more capacity improvement out of what we have in the network and all the resources that we have. And so, that's the major theme that sharing is hard. And I hope you've enjoyed it.