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Network slowdowns when a certain computer gets on
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imitchellg5
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Oct 12, 2009, 08:44 PM
 
I have a somewhat unique issue, or so I believe. My internet is usually pretty quick. Until my mom gets on with her iMac. She connects via ethernet to my Time Capsule. I'm connected wirelessly to the TC. What's odd is that no other devices are affected (and there are quite a few other ones on the network). Now honestly, I suck at networking. If anyone could give me guidance, I'd be forever appreciative. I've attached screenshots of my setup. The iMac has Tiger, the MBP Snow Leopard.





     
Simon
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Oct 12, 2009, 08:47 PM
 
How do you experience the slowdown? Have you measured actual throughput? How are you comparing your MBP's throughput to that of the several other unaffected devices?

Have you checked it's not just a DNS issue? What happens when you remove the OpenDNS IPs?
     
Camali
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Oct 12, 2009, 08:52 PM
 
I experience the same thing. However, both computers connect via Airport. My Mac Pro (and previously my G5) both experience slower internet speeds, when a PowerMac G4 (MDD) connects. I just have them shut off the G4 once they are off.
     
ibook_steve
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Oct 12, 2009, 09:12 PM
 
Yes, what exactly are the slowdowns you are experiencing? Local transfers? Internet transfers? What is your mom doing on her machine when the slowdowns occur? Downloading large files are watching streaming video? More detail is needed here.

Steve
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imitchellg5  (op)
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Oct 12, 2009, 09:45 PM
 
Oops sorry for being short on info. Internet in general slows down... I'm only downloading about 3 to 10kbps on my MBP at the most. She never does anything too intensive, the most intensive that she does is Hulu. I will take off OpenDNS and see how that works. According to speedtest.net (when I'm not getting the slowdown) I DL at 11.88Mbps, upload at 8.67. So my internet itself is fine.

Edit: Without OpenDNS my network speed went up to 13.43Mbps. Wow.
( Last edited by imitchellg5; Oct 12, 2009 at 09:54 PM. )
     
reader50
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Oct 12, 2009, 10:02 PM
 
I don't know if Time Capsule has QoS settings, but it may have them with the default being to favor the ethernet connection. If she likes HD hulu programs, that could cause a slowdown for 50 minutes at a time. x number of programs watched.
     
imitchellg5  (op)
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Oct 12, 2009, 10:28 PM
 
Apple routers don't have QoS support.
     
imitchellg5  (op)
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Oct 13, 2009, 06:05 PM
 
It's still going on. My MBP's internet slows down no matter what the iMac is doing...
     
reader50
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Oct 13, 2009, 07:00 PM
 
All the Network pane shots appear to be from the MBP. Perhaps the shots from the iMac would reveal something. Some configuration miscue that conflicts with the MBP and/or Time Capsule.
     
imitchellg5  (op)
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Oct 17, 2009, 09:50 PM
 
I reset my modem and the Time Capsule... now everything seems fine. Except now YouTube videos don't play well... they start playing before it's loaded enough to play the whole video.
     
imitchellg5  (op)
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Dec 5, 2009, 06:25 PM
 
I'm sorry to rebump this thread. But recently it seems as tho the iMac is slowing everything down again. I've trashed all the network-related .plists, reset my modem and Time Capsule, but it's still happening. What can I do to this stupid iMac? This is seriously pissing me off. Just turning it off isn't a solution, my mom needs to use it. And, unlike the original issue, this is affecting every computer/ iPod on the network.
     
Cold Warrior
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Dec 5, 2009, 06:47 PM
 
Some ideas:
1. Does the iMac have wifi? If so try it over wifi.

2. Try changing the ethernet port on the TC (use a different port).

3. Do you have another router in the house? Connect it to your TC, then iMac to that router. This creates a new network for the iMac. It's a way to troubleshoot.

4. iMac system prefs > ethernet > Configure IPv4: Using BootP. Reboot the iMac.

5. Are you on DSL? iMac sys prefs > ethernet > advanced > ethernet > Configure: Manually. MTU: Custom, 1450. Reboot. [edit: nevermind. I can see you're on cable.]
     
imitchellg5  (op)
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Dec 6, 2009, 08:09 PM
 
BootP fixed it! I have no clue what it does, but something's better I had my mom rent a movie on iTunes, and even during the download there was no slowdowns on the network from any device.

Random question: What would be an alternative for "Domain name" on the Time Capsule besides the standard Comcast address? Or is this just something I should leave alone. I want to use either OpenDNS or Google's DNS, would this conflict with the domain name? Sorry for the noob questions. I'm an advanced user in most areas, but networking confuses the crap out of me
     
Cold Warrior
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Dec 6, 2009, 10:59 PM
 
BootP is a simpler network configuration protocol compared to DHCP. I've seen it fix LAN issues on crappier hardware (linksys) but not Apple networking gear. Have you done an OS X reinstall on the iMac? I suspect something there; a reinstall could fix it. If not then a factory reset of the TC. There should be no downside to running bootp, but ideally your TC and iMac should run trouble-free.

As far as domain names, where are you seeing that?

Any manually-input dns would be fine. Many of us use OpenDNS.
     
imitchellg5  (op)
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Dec 6, 2009, 11:13 PM
 
Under the internet tab on the Time Capsule. I really want to reinstall OS X, but both my Tiger and Leopard install discs were borrowed and never returned...

And now it's doing it again. I guess I need a reinstall...
     
Cold Warrior
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Dec 6, 2009, 11:15 PM
 
you could always hit up an apple store for the $29 snow leopard disc.

edit: http://support.apple.com/kb/HT3728
That is Apple's document describing a TC reset. I recommend a factory reset.
     
imitchellg5  (op)
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Dec 6, 2009, 11:52 PM
 
I've done factory reset like 4 times.

This is a G5, so SL is no go.
     
Simon
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Dec 7, 2009, 04:46 AM
 
Originally Posted by imitchellg5 View Post
Random question: What would be an alternative for "Domain name" on the Time Capsule besides the standard Comcast address? Or is this just something I should leave alone. I want to use either OpenDNS or Google's DNS, would this conflict with the domain name? Sorry for the noob questions. I'm an advanced user in most areas, but networking confuses the crap out of me
I'd say the domain isn't important in your situation. You can use both OpenDNS (208.67.222.222, 208.67.220.220) and Google (8.8.8.8, 8.8.4.4).

I have just started using Google and it's working well. I used OpenDNS for a long time, but lately I have been bothered by the way they handle lookup misses (by displaying a list of links instead of giving a 404). OTOH I guess that's the way they generate revenue with their free service. From what I can tell Google doesn't do any of that and I like that.
     
imitchellg5  (op)
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Dec 14, 2009, 05:54 PM
 
Thanks for the info, Simon.

I realized today that if I turn Airport off and then back on on the computers/iPods attached to the network that everything works just fine...
     
imitchellg5  (op)
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Jan 1, 2010, 06:38 PM
 
Sorry to bump an old thread, I was wondering if anybody else had any ideas.
     
Cold Warrior
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Jan 1, 2010, 06:50 PM
 
I'd try to reinstall the latest combo updater for whatever point-release OS X version you're running.

If that doesn't work, create a guest wifi network and connect your MBP to that to see if your slowdowns persist. (This creates a separate subnet for your MBP.)

Are you running any file or other sharing on the iMac? Try turning those off.

Apart from that, a reinstall would be my next step (which it sounds like you're working on from your Marketplace thread).
     
imitchellg5  (op)
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Jan 1, 2010, 07:01 PM
 
OMG! How did I not think of the combo updater. Off to try that, thanks... if that doesn't do anything, I'll give the guest network a go.
     
seanc
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Jan 1, 2010, 07:06 PM
 
My idea involves booting the install of OS X on the iMac on another machine, such as your PowerBook (if you still have it) then hook that up via Ethernet and ask your Mum to use it for a while.

Do problems persist?

I'm trying to rule out a faulty Ethernet card, since there's no way of changing it.

Alternatively, take away the Ethernet cable and turn on AirPort...
     
imitchellg5  (op)
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Jan 1, 2010, 07:45 PM
 
It does the same thing over AirPort... It's funny though... the instant that I disconnect the iMac from the network, everything speeds up instantly.

Someone on the Apple discussion forum suggested that perhaps my HDD is going wrong... but right now I'm installing the combo updater for 10.4.11.
     
seanc
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Jan 1, 2010, 08:00 PM
 
Well, you could get SMART Utility and run it, it never hurts to keep an eye on your HDD.
     
imitchellg5  (op)
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Jan 1, 2010, 08:27 PM
 
HDD seems to check out just fine.

I can't figure this out for the life of me... creating a guest account now.
     
seanc
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Jan 1, 2010, 08:33 PM
 
Run Wireshark on it and see if anything is sending lots of packets out on the network.
If this were a PC I'd say you had something using Kontiki to share downloaded TV programmes via P2P...
     
imitchellg5  (op)
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Jan 1, 2010, 08:36 PM
 
No P2P on the iMac, it's never even had a P2P app installed.

I made a guest network, still slow with the iMac on. Going to run Wireshark now.
     
imitchellg5  (op)
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Jan 1, 2010, 08:39 PM
 
Uh, never mind, Wireshark doesn't seem to have a 10.4 version. I guess I'll give the 10.5 version a try though.
     
seanc
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Jan 1, 2010, 08:43 PM
 
Here in the UK our TV networks 'catch up' programs that you can download automatically install Kontiki which is used to download and share your downloads of TV programs - you wouldn't necessarily know it's there.
     
imitchellg5  (op)
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Jan 1, 2010, 08:45 PM
 
Interesting.

Wireshark is a no go...

I guess I need an install disc, badly.
     
AKcrab
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Jan 1, 2010, 08:48 PM
 
Originally Posted by imitchellg5 View Post
I've trashed all the network-related .plists, reset my modem and Time Capsule, but it's still happening.
Did you nuke everything in /Library/Preferences/SystemConfiguration ?
     
seanc
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Jan 1, 2010, 08:49 PM
 
Try booting the iMac from another Mac via TDM and see if problems persist?
     
Cold Warrior
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Jan 1, 2010, 08:53 PM
 
Wireshark is problematic in OS X, at least the times I've used it. I prefer Download CocoaPacketAnalyzer for Mac - Network packet protocol analyzer. MacUpdate Mac Software Downloads
     
imitchellg5  (op)
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Jan 1, 2010, 09:00 PM
 
Originally Posted by AKcrab View Post
Did you nuke everything in /Library/Preferences/SystemConfiguration ?
Yes... I just did it again to be sure. No change.

Going to try Target Disk Mode after checking out the app that ColdWarrior linked to.
     
imitchellg5  (op)
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Jan 1, 2010, 09:04 PM
 
Err, that app is 10.5 only as well. Won't even open in Tiger.

TDM time.
     
imitchellg5  (op)
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Jan 1, 2010, 09:17 PM
 
Well, I'm booted up on the iMac via the PowerBook's internal HDD. Now I'm even more confused. The network is terribly slow, but it's useable. Before, it would log me off of iChat and I couldn't even load any pages on my MBP... but I could get here via my MBP, and I'm still logged into iChat. Thoughts?
     
seanc
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Jan 1, 2010, 09:18 PM
 
Now do it the other way round. Boot the iMac install of OS X on the PowerBook... see what happens.
     
imitchellg5  (op)
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Jan 1, 2010, 09:31 PM
 
Okie... booting off of iMac's drive via the PowerBook doesn't slow anything down... everything running full speed.
     
imitchellg5  (op)
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Jan 1, 2010, 10:27 PM
 
Oi! I fixed it! I changed it to half duplexing and some other options that I'm not sure about at all, and now it works fine, doesn't slow anything down. Thanks all for your input.

I'll be bookmarking this thread in case I run into any future networking issues, I've learned a lot through the process.

Thanks all!
     
AKcrab
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Jan 1, 2010, 10:28 PM
 
That is a very weird "fix"... but Congrats.
     
imitchellg5  (op)
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Jan 1, 2010, 10:33 PM
 
Ha ha thanks... It's a relief!

It still slows everything down when it's connected via AirPort though... I am wondering if it's a victim of bad capacitors that the G5 was crippled with so much... I might crack it open tomorrow and have a look-see.
     
seanc
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Jan 1, 2010, 10:43 PM
 
Originally Posted by imitchellg5 View Post
Ha ha thanks... It's a relief!

It still slows everything down when it's connected via AirPort though... I am wondering if it's a victim of bad capacitors that the G5 was crippled with so much... I might crack it open tomorrow and have a look-see.
I was thinking it might be... what revision is it?

I guess if the network hardware is getting a load of noise due to the bad capacitors, there may be a lot of extra data being sent and received to try and compensate for bad or lost packets.

FYI: Half-duplex means that data can only be sent one way at a time.
Think of it as a road with lanes of traffic flowing both ways. Both lanes flowing, full duplex, block one or the other off, half-duplex.

Should make network access on the iMac slower, which is probably why it has seemingly cured the problem.
     
imitchellg5  (op)
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Jan 1, 2010, 10:48 PM
 
It's a rev A.

Download speeds on the iMac are a lot slower now according to Speedtest.net, but it's not that noticeable during browsing, which is the main use of the machine.
     
seanc
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Jan 1, 2010, 10:50 PM
 
If it's not suffering from bad capacitors, I'd be very surprised, unless it's had a logic board/power supply replacement already...

I have a dead one sat on my desk.
     
imitchellg5  (op)
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Jan 1, 2010, 11:01 PM
 
No, it hasn't had anything replaced. Hopefully nothing worsens.
     
imitchellg5  (op)
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Jan 2, 2010, 10:03 PM
 
Blarg... it was working fine today, then got worse. Opened up the iMac... it's got quite a few of the things blown. I guess I'll have to find some way to live with it until somebody can afford to buy a new computer.
     
seanc
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Jan 2, 2010, 10:09 PM
 
There are plenty of skilled electronics engineers out there who will happily replace all of those bad capacitors for you, probably for a small amount of money. The parts would probably cost $20 to $30 including shipping.
     
imitchellg5  (op)
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Jan 2, 2010, 11:29 PM
 
I have a friend who fixed his actually... but the computer is old anyway, it'll be good to replace it soon. At least it works good, besides the network issue. I don't really think it can get worse if it's gone as far as it has without breaking.
     
AKcrab
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Jan 3, 2010, 12:25 AM
 
Originally Posted by imitchellg5 View Post
I don't really think it can get worse if it's gone as far as it has without breaking.
Not to be a downer, but it is probably on the road to complete death.
     
 
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