Case 9Adding wireless-N with Gigabit switch to current Wireless-G network
ArchitectureThe X2 has a gigabit inteface as it's network throughput exceeds what any 100 mbps interfaced router would allocate. But it still dosn't exceed wireless-N so the expense of a full gigabit network isn't needed (unless you have other reasons to justify it). So those who currently only have a wireless-G system may find this a simpler way to add Wireless-N to achieve better wireless streaming with the X2. A Wireless-N lan bridge equipped with a gigabit switch will remove the 100 mbps bottleneck between the X2 and wireless-N. A Wi-Fi lanbridge elliminates the overhead ascociated with the med itself handling Wi-Fi and as a result maximises the lan throughput.
1) Belkin F5D7633uk4A Wireless (2.4 Ghz) 125 Hi-Speed ADSL Modem Router. This is located in the lounge Home Theater Rack. PC, med500x2 and other permenent devices, given fixed IP's manually above 200, beyond the DHCP pool. Wireless only turned on when using laptop. When I set up my first lan bridge network I changed the lan bridge IP to match the primary router. This meant that whenever I pressed reset on the lan bridge router to recover from a bad experimental setup, it returned to it's IP, and I lost communication. I had to disconnect it, connect via cable and set it up again. This time I set up the primary router to match the lan bridge. Pressing reset wouldn't lose communication with the primary router. I could then setup the G300NH again via the wireless-G connection with the primary router. So since the Lan Bridge router was using 192.168.11.1, I changed the Primary router from 192.168.2.1 to 192.168.11.2, and the DHCP pool was raised to start at 3.
2)Buffalo WZR-HP-G300NH Nfiniti Wireless-N High Power Gigabit Broadband Router and Access Point (300Mbps). Also located in lounge Home Theater Rack. This has licenced DD-WRT firmware installed by Buffalo, and is connected via cable to the Belkin router, adding a Wireless-N connection to the network. The router is set up for Wireless-N only, in 40mhz mode.
Other makes of wireless-router can be turned into an Access Point/Lan Bridge using the opensource version of DD-WRT
The DD-WRT firmware can be found here:-
http://www.dd-wrt.com/site/indexThe G300NH was set up using these instructions:-
http://www.dd-wrt.com/wiki/index.php/Wireless_Access_PointOnce working, DHCP forwarding to the primary router was enabled.
3) Buffalo WLI-UC-G300HP Wireless (2.4 Ghz) N-300 High Power USB 2.0 Adapter. This is connected to the PC in the spare bedroom and 40mhz mode is enabled. The PC is a home constructed Q8400 Core 2 Quad PC using gigabyte X38 chipset motherboard running Windows 7 Home Premium (64) with 8 GB memory.
4) Med500X2. Connected by cable to the gigabit switch in the Buffalo Lan Bridge.
5)Sony S370 Bluray player. Linked by cable to Belkin router. Gives access to Internet TV sources such as BBC Iplayer.
Tweaks1) Single high quality ADSL filter placed in master phone socket. All phones connect to the phone side and the modem/ router is connected by a 25 ft fax cable.
Simplifying ADSL this way improved my ADSL connection by 20-30%.
2) TCP tweaked as described here:-
http://www.mede8erforum.com/index.php/topic,3504.0.html3) Channels selected by using the following guidence:-
http://www.dd-wrt.com/wiki/index.php/Wireless-N_ConfigurationSince I was using the DD-WRT router for wireless I decided to use it's comprehensive metrics to measure how good a given channel was. The wireless metrics show that actual Rx and Tx connection speeds for each wireless connection to the router, without having to measure actual throughput using a file transfer. It also allowed fine tuning of the Wireless-N USB stick aerial position. With this network the alignment of the G300NH also turned out to be crucial. There is no point going through this to end up with a reliable Transmission Speed of only 108 mbps! Transmission speed is not the same as Connection Speed. Connection Speed is the Protocol Speed. Many USB dongles report that speed and make out your working at 300 mbps. That is far from true. The transmission speed is the actual speed the link reduces too for a reliable connection within the set of speeds supported by 300-N.
So setting up the router in a standard position, that is either flat, or upright, cables coming out of the back and the aerials up was tried, and failed. It didn't matter what channel pairing was used, the connections never got reliably above 108 mbps, and many where well below. In the end the optimal position was flat, aerials down, and the router turned through 90 degrees so that the cables came in the left!
In this way the optimal channel selection was found to be 4 / Upper. The default transmission speed was 216 mbps, occasionally dropping to 162 mbps. Surprisingly the wireless strength was often down at 30% according to the PC! Having such metrics in the router would help setting up networks using the Med500 USB dongle as the PC isn't able to monitor the wireless connection in that situation.
Tests where performed to confirm that streaming HDV was acceptable during which the Link Speed was monitored using Windows Task Manager. Different lan drivers may use different metrics to report Link Speed.
The Buffalo Link Speed was dynamic under load and seemed to reflect the bandwidth allocated by TCP for each transaction. Based on 500X experience only high link speeds (81 mbps and above), in conjunction with low Utilization ( below 40%) produced stutter free streaming. Low link speeds and high utilization, even if they indicated the same bandwidth (utilization x Link speed) being used, stuttered. With this Network the speeds don't get below 162 mbps.
PerformanceMedX2 Firmware 1.0.0
1) Samba copying from PC to Med500X2 6.0-8.0 mb/s
2) Samba streaming from PC to Med500X2
HDV TS - 25 mbps
Bluray VC-1 M2TS - 40 mbps
Bluray ISO - 40 mbps
Transport Streams (TS) are the native format of the chip. These are the formats used on bluray. Other package formats have been added by OEM's but they require unwrapping by the support processor. The support processor also handles streaming. Using packages which require unwrapping reduces the maximum bitrate that can be streamed. The X2 has a support processor with twice the power. It can handle streaming and unpacking of even Bluray.ISO.
