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lovegnome
03-10-2003, 05:35 PM
Has anyone actually taken a good look at why extraction via wireless is so slow?

Here's what I know. I've got two friends with tivos connected via wet11s and they each get less than 500kb/s doing extraction with tytool v6.

I've confirmed this on my network. My tivo is hardwired via a turbonet card and I'm getting around 1.5Mb/s to my wired computers, under 500kp/s to my laptop via wireless. Confirmed same/worse performance with mfsstream.

So what's the deal? Has anyone actually put a packet sniffer on the job yet?

Note: Now that tytool6 multiplexes output, I can watch shows directly off the tivo onto my wired machines using VideoLan to open the files as soon as they start extracting. It would be nice to enjoy some television on my porch using my laptop, but perfomance is not fast enough.

Also, a 'View' button in tytool that piped the output straight to Videolan would be awfully cool!!!!

BubbleLamp
03-10-2003, 06:05 PM
Originally posted by lovegnome
Has anyone actually taken a good look at why extraction via wireless is so slow?

Here's what I know. I've got two friends with tivos connected via wet11s and they each get less than 500kb/s doing extraction with tytool v6.

I've confirmed this on my network. My tivo is hardwired via a turbonet card and I'm getting around 1.5Mb/s to my wired computers, under 500kp/s to my laptop via wireless. Confirmed same/worse performance with mfsstream.

So what's the deal? Has anyone actually put a packet sniffer on the job yet?

Note: Now that tytool6 multiplexes output, I can watch shows directly off the tivo onto my wired machines using VideoLan to open the files as soon as they start extracting. It would be nice to enjoy some television on my porch using my laptop, but perfomance is not fast enough.

Also, a 'View' button in tytool that piped the output straight to Videolan would be awfully cool!!!!

Because wireless sucks and the "11Mbps" it's rated for is a pipe dream. :(

lovegnome
03-10-2003, 06:15 PM
Ah yes.

And before we have a spat of more "wireless sucks" posts, let's be clear that I can download to my laptop from other sources at much better than the 1.5Mb/s rate the tivo is capable of.

So while wireless may actually suck, it doesn't suck 500kb/s worth. Looking for another problem.

BubbleLamp
03-10-2003, 06:22 PM
Originally posted by lovegnome
Ah yes.

And before we have a spat of more "wireless sucks" posts, let's be clear that I can download to my laptop from other sources at much better than the 1.5Mb/s rate the tivo is capable of.

So while wireless may actually suck, it doesn't suck 500kb/s worth. Looking for another problem.

Then you might be suffering from the bug in Tytools. Try an ftp from the Tivo and see what kind of throughput you get.

lovegnome
03-10-2003, 06:45 PM
Nope.

Both tyhttp (mfsstream) and tivoftpd give 1.2Mb/s or better via wired, under 500kb/s via wireless.

Also, just for kicks, I booted my laptop over to debian to make sure it wasn't a Windows XP networking oddity. Same performance w/ tyhttp and ftp.

Unless all three pieces of software suffer from the same networking bug (which is a remote possibility) I would guess it's either an oddity with the tivo's networking code, or maybe (far less likely) that it's a flaw in the turbonet driver?

I should mention, I'm using Tivo's 3.0 turbonet driver.

My main point, is that a lot of people have been assuming their poor performance is due to wireless connectivity (low signal, etc). This is not true in my case.

So back to my original question...has anyone sniffed any packets looking for excessive retries or something else the tivo networking code may not be handling correctly?

neuroman
03-10-2003, 07:55 PM
Originally posted by lovegnome
Nope.

My main point, is that a lot of people have been assuming their poor performance is due to wireless connectivity (low signal, etc). This is not true in my case.

So back to my original question...has anyone sniffed any packets looking for excessive retries or something else the tivo networking code may not be handling correctly?


I'm running WinXP Pro and WinXP Home on to separate laptops wirelessly. Performance is actually pretty good with my D-Link Wireless Access Point. One of my wireless NICs is a Compaq WL110 and the other is a WL100. Both have configurable paramters to adjust for low speed (2Mbit) or high speed (11Mbit) transmission speeds.

On my Tivo I am using a Zoom Air 4105 Wireless NIC with Externa antenna and I'm getting extremely slow throughput. My guess is the network stack on the Tivo version of Linux is not set for peak wireless performance. It may be tuneable or not. I'm not experienced with Linux networking so I don't have a clue. Maybe someone who is can hazard a guess or suggestion?

ronnythunder
03-10-2003, 08:00 PM
lovegnome, do a search here for "jafa"; he's the guy that created turbonet, and he's mentioned some issues with the tivo tcp stack and there's also a relatively recent turbonet driver update that sounds like it may be part of your problem. specifically, the update fixes a problem that can cause excessive retransmissions.

ronny

lovegnome
03-10-2003, 08:33 PM
Originally posted by ronnythunder
lovegnome, do a search here for "jafa"; he's the guy that created turbonet, and he's mentioned some issues with the tivo tcp stack and there's also a relatively recent turbonet driver update that sounds like it may be part of your problem. specifically, the update fixes a problem that can cause excessive retransmissions.

ronny

No joy.

1. Interesting enough, search for user name "jafa" only turns up one post for me. I know he's posted more...I've been lurking around for a while.

2. I've replaced the stock driver with the latest turbonet driver with no improvement in performance.

BubbleLamp
03-10-2003, 10:16 PM
Originally posted by lovegnome
No joy.

1. Interesting enough, search for user name "jafa" only turns up one post for me. I know he's posted more...I've been lurking around for a while.

2. I've replaced the stock driver with the latest turbonet driver with no improvement in performance.

jafa hangs out on the avs forums.

I have explained what the packet problem was, (and still is for some) in this thread (http://www.dealdatabase.com/forum/showthread.php?s=&threadid=20726). Basically on a ~10Mb/s connection, the small packet size swamps the available bandwidth.

Stephen
03-11-2003, 10:15 AM
Heck 500k is pretty good.. I can just get that ftping from one machine to another on my wireless network... (40 ft away from each other)

Schnitty
03-11-2003, 12:17 PM
bubblelamp -- i read your other thread and found it very informative. however, you asked jdiner to do some investigation for you and you even mentioned doing more yourself. any update on those efforts? was there any relatively obvious settings that could be changed to fix this?

BubbleLamp
03-11-2003, 12:22 PM
Originally posted by Schnitty
bubblelamp -- i read your other thread and found it very informative. however, you asked jdiner to do some investigation for you and you even mentioned doing more yourself. any update on those efforts? was there any relatively obvious settings that could be changed to fix this?

The change jdiner made was to add the double-socket option. That seemed to work for some number of folks. I don't know where the SACK (http://dealdatabase.com/forum/showthread.php?s=&threadid=22220#86413) issue fits in all of this, but I suspect it's another "to be resolved" issue. He'd be the one to ask.

AlphaWolf
03-11-2003, 12:34 PM
If you realy wanted wireless, wouldn't it be both cheaper and faster to just install a regular turbonet and then bridge it to wifi?

/me shrugs

My tivo is turbonet wired to a 54mbit (802.11g) wireless switch. Turbonet cost $69, switch cost $112, but I use it for other things as well. You could just get a regular bridge for ~$69...

Btw, my stream download speeds are in the ~1400k/sec over wifi...laptop is on a linksys 54mbit card I got for $50 opened box at best buy.

<brag> as I type this I am sitting in my school cafeteria with no wires :D </brag>

lovegnome
03-11-2003, 01:41 PM
Originally posted by AlphaWolf
If you realy wanted wireless, wouldn't it be both cheaper and faster to just install a regular turbonet and then bridge it to wifi?

/me shrugs

My tivo is turbonet wired to a 54mbit (802.11g) wireless switch. Turbonet cost $69, switch cost $112, but I use it for other things as well. You could just get a regular bridge for ~$69...

Btw, my stream download speeds are in the ~1400k/sec over wifi...laptop is on a linksys 54mbit card I got for $50 opened box at best buy.

<brag> as I type this I am sitting in my school cafeteria with no wires :D </brag>

That's interesting information.

Most of the people I know _are_ using turbonet cards and wireless bridges. I , myself, have my tivo hardwired to the network, but only experience slow performance when pulling video via the wireless laptop. Similiar results with my friends' WET11 wireless bridge.

Your experience makes t looks like the higher bandwidth allowed by 801.11g will handle the saturation problem seen by Bubblelamp. That's useful information.

Schnitty
03-11-2003, 01:48 PM
Originally posted by AlphaWolf
If you realy wanted wireless, wouldn't it be both cheaper and faster to just install a regular turbonet and then bridge it to wifi?

/me shrugs

My tivo is turbonet wired to a 54mbit (802.11g) wireless switch. Turbonet cost $69, switch cost $112, but I use it for other things as well. You could just get a regular bridge for ~$69...

Btw, my stream download speeds are in the ~1400k/sec over wifi...laptop is on a linksys 54mbit card I got for $50 opened box at best buy.

<brag> as I type this I am sitting in my school cafeteria with no wires :D </brag>


alphawolf -- very good info. i'm actually thinking of upgrading my 802.11b to a "g" network. what switch did you get for $112? i have an ok 802.11b to ethernet bridge (dlink) -- which companies are making "g" bridges?

AlphaWolf
03-11-2003, 03:15 PM
Well, its more than a switch, its a linksys broadband router with 54mbit wireless and 4 10/100 wired ports. I never owned any 802.11b stuff, I just saw this wireless card for real cheap one day, and thought "You know, it would be nice to not have to go to the library to use the internet at school", so I went and got the whole 9 yards at 54mbit.

I did recall you guys having problems with wifi and tivo, but they never surfaced here. I just assumed that it was because you were all using the airnet adapter, and the magnetic sheilding in the tivo cover was blocking the signal.

ctsshack
03-11-2003, 04:20 PM
I've had a problem using Wi-Fi with corrupted ty streams. If my wife is using the Cordless phone (AT&T 2.4 GHz phone) (she gets a lot of noise on it when transfering a ty stream) I'll get ty streams that will not demux properly. I'm using a SAT-T60, Xtreme 2.5 w/ kravens, turbonet hooked up to LinkSys WET11 and I also have a SMC2676W bridge with the same result. The WET11 will lockup and disconnect sometimes under heavy I/O where the SMC will do the same after a few hours of non use. I've always had a problem with the 2.4 GHz range in my area (900 MHz phones Digital phones work better). I've pretty much decided to just hardwire it and be done with the problems. Anyone else had any similar experiences?

BubbleLamp
03-11-2003, 04:34 PM
Originally posted by ctsshack
I've had a problem using Wi-Fi with corrupted ty streams. If my wife is using the Cordless phone (AT&T 2.4 GHz phone) (she gets a lot of noise on it when transfering a ty stream) I'll get ty streams that will not demux properly. I'm using a SAT-T60, Xtreme 2.5 w/ kravens, turbonet hooked up to LinkSys WET11 and I also have a SMC2676W bridge with the same result. The WET11 will lockup and disconnect sometimes under heavy I/O where the SMC will do the same after a few hours of non use. I've always had a problem with the 2.4 GHz range in my area (900 MHz phones Digital phones work better). I've pretty much decided to just hardwire it and be done with the problems. Anyone else had any similar experiences?

Wireless phones, microwaves, they all are in the same spectrum as 802.11b. It's just a crowded place to be.

lovegnome
03-11-2003, 04:38 PM
Originally posted by AlphaWolf
I did recall you guys having problems with wifi and tivo, but they never surfaced here. I just assumed that it was because you were all using the airnet adapter, and the magnetic sheilding in the tivo cover was blocking the signal.

I think that's the assumption a lot of people made. And it just ain't true (in all cases).

lovegnome
03-11-2003, 04:46 PM
Originally posted by ctsshack
The WET11 will lockup and disconnect sometimes under heavy I/O where the SMC will do the same after a few hours of non use.

I've seen the WET11 lock up quite a bit. Here's a bit some other people have posted about the problem:

http://www.dslreports.com/forum/remark,5413458~root=equip,16~mode=flat


I've always had a problem with the 2.4 GHz range in my area (900 MHz phones Digital phones work better). I've pretty much decided to just hardwire it and be done with the problems. Anyone else had any similar experiences?

Yeah. That's a common problem. 802.11b works in the 2.4Ghz range with a bunch of other stuff, mostly unregulated by the FCC. 802.11a works in a different spectrum, but doesn't penetrate walls nearly as well. 2.4Ghz DSS (Digital Spread Spectrum) phones are far bigger offenders than 2.4Ghz FH (Frequency Hopping) phones are. 900Mhz phones won't interfere, but are far less secure.

AlphaWolf
03-11-2003, 09:05 PM
You know, on second thought, I am not sure if I was using my wireless when I was downloading tystreams. I will have to double check that speed (I rarely do this) when I have my tivo back together again.

lovegnome
03-24-2003, 09:41 PM
Originally posted by AlphaWolf
You know, on second thought, I am not sure if I was using my wireless when I was downloading tystreams. I will have to double check that speed (I rarely do this) when I have my tivo back together again.

AlphaWolf-

Did you ever check this? I've been playing around trying to get decent performance over the wireless connection with no luck.

AlphaWolf
03-24-2003, 09:46 PM
Not yet, my "infrastructure" has just been a mess. I just finished replacing the OS on my server from redhat to gentoo, as well as upgrading one HDD from 60g to 120g. I am in the process of reformatting the HDD on my laptop. My tivo is actualy in peices, as I am preparing to replace the hard disk in it. Right now I am using a borrowed tivo, but I am going to be giving it back tommorow. I'll start working on this in a few days and confirm the speed I get over 54mbit.

edit: ah, one more thing, to add to it all, I have yet to move one of these HDDs into my xbox, which I want to do.

citivolus
03-24-2003, 09:51 PM
Originally posted by lovegnome
My tivo is hardwired via a turbonet card and I'm getting around 1.5Mb/s to my wired computers, under 500kp/s to my laptop via wireless.

are you sure you have your "b"s and "B"s right? using tivoweb and mfsstreamweb to extract the ty files from my HDVR2, I'm getting 500KB/s from my wired PC, which is about 4Mb/s. what rates are other people experiencing?

AlphaWolf
05-20-2003, 08:45 PM
Odd....When I download from the regular tivo ftp daemon, it goes exactly the same speed as my wired connection does. Yet, downloading with mfs_ftp gets 400k/sec range, where wired stays at max, and tystudio downloads in the 900k/sec range, where wired gets only 100k/sec faster. Something else interesting, when I set tivo ftp daemon to passive mode, it goes just as slow as mfs_ftp.

Something tells me that there is a bug in Jafas packet driver somewhere :confused:

AlphaWolf
05-20-2003, 09:47 PM
After speaking to embeem about this, it seems that the problem is caused by a faulty TCP implimentation in the tivo kernel which causes some packets to be sent with an MTU of 576. Unfortunately, nobody seems to have identified the cause of it.

Therefore we have two possible ways of fixing it. One way is to track down the bug in the kernel and fix it with a module. Another way is to find out exactly what triggers this bug, and write all future software to not do that.

This may yet improve the overall speed even on wired connections, so it would be worth looking into. All of this of course is beyond me however, we would need a serious kernel hacker to have a look at this one.

jodell
05-25-2003, 07:39 PM
Good work Alphawolf and Embeem,

Keep us posted on your progress. I don't have the skills to code my way out of a wet paper bag but I can test with the best of them... I can't be much help on finding and fixing the bug but I can put the fix through a pretty good test.

Jeff