PDA

View Full Version : Idea about 100Mbps speed problems



BubbleLamp
02-03-2003, 02:01 PM
Was just thinking this morning, a lot of the people reporting bad performance on 100Mbs, yet decent on 10Mbps. Are you guys crimping your own connectors? Are you using CAT5-rated or better cable(s) and connectors? Plenty of shitty cables/connectors will work fine at 10Mbps but cause all sorts of issues at 100. If you are having these sorts of problems, try running a single CAT5 cable directly from your Turbonet card to your switch, and see if the situation changes.

pbar
02-03-2003, 05:24 PM
Another thing it's worth checking is that link speed / duplex autonegotiation has not screwed up... You'd be amazed how many network cards and switches from even reputable manufacturers manage to mess this up. Often you end up with one end running half-duplex and the other full-duplex.

The symptoms of this are that one end of the link will see collisions... you can often check the collision count stats for the network interface and if you have any collisions at all on a 100mbps full-duplex link you have bad problems!
(the reason performance sucks is that TCP segments often collide with the ACKs coming the other way)

On a TiVo you can get at these stats by typing

cat /proc/net/dev

or

ifconfig


If the eth0 collision count is non-zero when connected to a 100mbps swithc this would indicate badness.

You can often fix things up by disabling autonegotiation.

In any event, you're not going to get anywhere near 100mbps out of a TiVo due to the inherent limitations of the ISA bus.

lophophore
02-03-2003, 08:47 PM
I thought I would check this out. Here's the data from my DSR6000. No collisions shown.

How can I determine if the TiVo is operating full duplex or half-duplex? The full-duplex light on my LinkSys switch is lit.

bash-2.02# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Bcast:127.255.255.255 Mask:255.0.0.0
UP BROADCAST LOOPBACK RUNNING MTU:3584 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 coll:0

eth0 Link encap:Ethernet HWaddr 00:0B:AD:69:C6:67
inet addr:192.168.1.222 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:675354 errors:0 dropped:0 overruns:0 frame:0
TX packets:2102515 errors:0 dropped:0 overruns:0 carrier:0 coll:0
Interrupt:29

bash-2.02# cat /proc/net/dev
Inter-| Receive | Transmit
face |packets errs drop fifo frame|packets errs drop fifo colls carrier
lo: 0 0 0 0 0 0 0 0 0 0 0
eth0: 675433 0 0 0 0 2102556 0 0 0 0 0
bash-2.02#

lophophore
02-03-2003, 08:54 PM
More data:

The performance was good on my old box under Win2k. I just upgraded that box to XP Pro. Now I have the same poor TyTool performance, same as the new computer. I wanted to rule out the network interface on the new computer. I feel pretty confident that the network interface (NIC) is not the problem.

Even more interesting data:

The bad performance occurs when the TiVo and the computer(s) are plugged into the same LinkSys 8-port 10/100 switch.

I accidentally moved the ethernet cable from the TiVo into a spare port on a LinkSys printserver with it's own 4-port 10/100 switch, which is plugged into the 8-port switch the computers are all connected to.

The poor performance problems went away.

If anybody else has this problem, I wonder what kind of 10/100 switch they are using.

BubbleLamp
02-03-2003, 09:11 PM
Originally posted by lophophore
Even more interesting data:

The bad performance occurs when the TiVo and the computer(s) are plugged into the same LinkSys 8-port 10/100 switch.

I accidentally moved the ethernet cable from the TiVo into a spare port on a LinkSys printserver with it's own 4-port 10/100 switch, which is plugged into the 8-port switch the computers are all connected to.

The poor performance problems went away.

If anybody else has this problem, I wonder what kind of 10/100 switch they are using.

So far I'm leaning towards a crappy switch, or incorrect auto-negotiation.

jaja
02-03-2003, 09:24 PM
I also get no collisions:


bash-2.02# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0B:AD:69:C6:67
inet addr:192.168.1.109 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:451179 errors:0 dropped:0 overruns:0 frame:0
TX packets:812609 errors:0 dropped:0 overruns:0 carrier:0 coll:0
Interrupt:29

Also, all the lights on the Linksys router are lit so everyone thinks it's 100.

Oddly, when I look at the DHCP clients table, my TiVo doesn't show up.

lophophore
02-03-2003, 09:34 PM
I don't think it is switch related. I think it is Windows XP related. The computer that worked well under Windows 2000 started having these performance problems as soon as I installed XP Pro.

I found this, but I cannot confirm or deny it works because I cannot find the right registry keys to tweak:

http://support.microsoft.com/default.aspx?scid=kb;en-us;315237

(High Rate of Collisions on 100-MB Networks)

I think when I put the 2nd switch into the mix it affected the packet propagation time between the machines and reduced the occurence of the problem. (I am now getting about .5 megabyte/sec)

BubbleLamp
02-03-2003, 09:41 PM
Originally posted by lophophore
I don't think it is switch related. I think it is Windows XP related. The computer that worked well under Windows 2000 started having these performance problems as soon as I installed XP Pro.

I found this, but I cannot confirm or deny it works because I cannot find the right registry keys to tweak:

http://support.microsoft.com/default.aspx?scid=kb;en-us;315237

(High Rate of Collisions on 100-MB Networks)

I think when I put the 2nd switch into the mix it affected the packet propagation time between the machines and reduced the occurence of the problem. (I am now getting about .5 megabyte/sec)

Very interesting. This was a problem about 9 years ago when 100Mbps adapters first shipped. At that time Novell had lots of issues with their drivers and the IPG issue. Can't believe M$ has managed to push the clock back that far.

Edit: Ignore the e100b reference in their Q-doc. That's an Intel NIC. You should be able to locate your NIC there somewhere, then check its registry details. Might have to check the driver name under Network Settings first to zero in on the entry.

jaja
02-03-2003, 11:27 PM
Not sure exactly what you guys are saying but I'm not running Windows XP. I don't know what a Q-doc is or who M$ is.

jaja
02-03-2003, 11:28 PM
Didn't we already determine from ifconfig that I'm NOT suffering from network collisions?

BubbleLamp
02-04-2003, 12:08 AM
Originally posted by jaja
Didn't we already determine from ifconfig that I'm NOT suffering from network collisions?

Who said we were talking about YOUR problem? This thread isn't about you, it's about possible networking issues as it relates to 100Mbps.

Tell you what, I'll post a poll to see if the problem is mostly associated with XP, or if the OS isn't relevent.

tweaky
02-04-2003, 06:46 AM
No speed issues here. Running XP, with direct connection to the tivo via meter certified CAT5e cabling. Using the T568A wiring structure.

I go from the Tivo mounted in my rack, to a Patch panel, throw a jumper in and hit my second NIC card in my computer.
(I was a little paranoid about the thing calling home)

Silverdude
02-11-2003, 01:01 PM
This question was asked and not answered so i thought would ask again...

How can we tell if the tivo is half or full duplex?

I have do the test above, according to the Tivo there are no collisions, but accounding to my HUB i am getting plenty of collisions.

How do i check my NIC to see how many collisions it has had?

SD

bato
02-11-2003, 03:54 PM
Originally posted by BubbleLamp
Was just thinking this morning, a lot of the people reporting bad performance on 100Mbs, yet decent on 10Mbps.

In my case ZoneAlarm is causing the problem, at 100Mbps with ZoneAlarm running (Trusted Zone Security at Firewall off) I can only download around 500K and if I only change to 10Mbps full duplex I can download around 900K, now with ZoneAlarm not running and latest TyTool I can download when 100Mbps at 1400K and better.

Maybe I need to change something in ZoneAlarm, but I haven't found what yet.

Silverdude
02-11-2003, 04:47 PM
After posting my last message i did some testing.



NIC Speed_____dl from Xbox (ftp)___dl from Dtivo (tytool)
100 Full Duplex____1800kB/s_________1400kB/s

100 Half Duplex____2400kB/s_________1400kB/s

10 Full___________ 980kB/s___________700kB/s

10 Half___________980kB/s___________700kB/s

My network is set up so that the computer NIC is connected to a HUB, and on the HUB is the Dtivo, Xbox, and HighSpeed Modem. As it turns out i cannot connect to any device without an internet connection, so those speeds are through my PPoE protocols.

SD

BubbleLamp
02-11-2003, 05:36 PM
Originally posted by Silverdude
This question was asked and not answered so i thought would ask again...

How can we tell if the tivo is half or full duplex?

I have do the test above, according to the Tivo there are no collisions, but accounding to my HUB i am getting plenty of collisions.

How do i check my NIC to see how many collisions it has had?

SD

If it is a hub, then it CAN'T do full-duplex. Only a switch can.

BubbleLamp
02-11-2003, 05:37 PM
Originally posted by bato
In my case ZoneAlarm is causing the problem, at 100Mbps with ZoneAlarm running (Trusted Zone Security at Firewall off) I can only download around 500K and if I only change to 10Mbps full duplex I can download around 900K, now with ZoneAlarm not running and latest TyTool I can download when 100Mbps at 1400K and better.

Maybe I need to change something in ZoneAlarm, but I haven't found what yet.

Wow, something is wrong with ZA, or its config. Sure shouldn't be making that much of an impact on performance.