Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[whywouldyoudothat]

Some background

Windows 7 64bit
NF5 590amd board
cat 6 cables all the way
gigabit switches
computer configured for gigabit ethernet and 9k jumbo packets
dns-323 configured for gigabit ethernet and 9k jumbo packets


Now, at some point I was able to use jumbo packets to increase the transfer speed up to around 30-40MB/s instead of the much more pathetic 5-12MB/s. Then seemingly randomly, without having changed any settings, I could no longer connect to the DNS-323 if I had jumbo packets enabled on the computer. The green progress bar would just go on forever as if it wasn't getting a response from the dns-323. I can only connect if I turn off jumbo packets on the computer now.

Why would I be able to use jumbo packets before and not now?

[fordem]

I would suspect your switch(es), mainly because of the "just go on forever" symptom, but I have no explanation for why it works sometimes.

Try reducing the frame size to 4000 and see what effect that has.

[whywouldyoudothat]

The only options I have in the computer settings are:
1514
2514
4514
9014

The options in the dns-323 are:
3000
4000
5000
6000
7000
8000
9000

I had previously read up on why the extra 14 are there and I think when the dns-323 says 9000 that it is the same as 9014 unless they are just wrong.

No idea why there is a 4514. I thought it was either 1514 for off or just go to 9014 for frames on.

I have the settings on the dns-323 set to enabled and 9000. The computer is right now set to 1514. If I change to 9014 it stops working. But that is exactly what I had changed to enable it the first time, and it worked. Until now anyways.

I also checked the stats on the gs605 which is the switches I use and they support 9k jumbo frames.

[fordem]

Technically speaking, a jumbo frame is anything over the standard 1514, the most common (in my experience) are 4000 & 9000.

The end points in a jumbo frame connection will negotiate a maximum segment size (MSS) that is acceptable to both, but any network devices in between are not a part of this negotiation, so if you configure a frame size that is acceptable to both, but larger than the switch can handle, the connection will fail, and in my experience, it will be extremely slow rather than timing out completely and reporting an error.

If you change either end to a smaller segment size, in this case, the computer end is being set to a regular (ie non jumbo) frame, the MSS acceptable to both becomes 1514, and the switch passes it.

If you drop the computer end to 4514, the DNS-323 will auto-negotiate an MSS of 4514, and if the switch can accomodate it, jumbo frame communications will occur, if not, it'll fail again.

You can try this quite easily and also verify the switch as being the problem - just set static ip addresses and then hardwire the DNS-323 directly to the computer.

[HSishi]

A lot of router's and switches are NOT able to handle Jumbo frames. You didn't mention what kind of switches you have so we can't check their features.

You can easily check if a particular swich is able (or not) to support Jumbo frames. Follow the article on

http://www.windowsitpro.com/article/john-savills-windows-faqs/q-how-can-i-test-if-two-machines-are-using-jumbo-frames-.aspx

Basically you "ping" your network devices with disabled packet fragmentation (means the packets are NOT cut into standard sized ones) and try if the packets make their way. In most cases packets larger than 1464 bytes of userdata (means 1514 "raw" size) won't make it.

Good luck.

//HSishi

[fordem]

Actually - he does mention the switch - it's a Netgear GS605.

whywouldyoudothat - I just came across this post ...

http://forums.cclonline.com/showthread.php?14898-Netgear-GS608-and-GS605-Jumbo-Frames

which suggests that the jumbo frame will only work if ALL of the connections to the switch are gigabit - which might explain why your works sometimes and not other times.

[47th_ronin]

um, i have dns-323, imac, trendnet and tp-link switches, fritzbox router. all they have gigabit interfaces and all support jumbo frames. still, network speed is mostly less than 6 MB/s (megabytes).

[whywouldyoudothat]

So I just disconnected the TV.

When I looked at the lights on the switch the tv one was yellow which is supposed to mean 100mbit and green is gigabit.

After disconnecting and trying again at 9000....it works.

36MB/s instead of 12MB/s.

Looks like I am getting a THIRD switch so I can keep my tv connected...although I am still assuming that will even work...

switch 1 with TV connected to switch 2
switch 2 with pc and ps3 connected to switch 3
switch 3 with dns-323 connected to router
router with another pc at 100mbit connected to modem.

That will let me keep jumbo frames on right?

Anyways, thanks all.

Oddly though, I can still get internet with jumbo frames enabled and the tv connected. Just no connection to the NAS.

[fordem]

You don't say which of those switches is gigabit, or what type of router and where it connects, but, if I were to assume all GS605s, then connecting the TV to the router would fix the problem - of course it may not be convenient.

With regard the router and internet - the router itself is unlikely to support jumbo frame even if the integrated switch does, so I would expect it to autonegotiate a standard frame size (or MSS), if it does support jumbo frame it will simply buffer the excess because the other interface wont.

It IS possible to mix jumbo & standard sized frames on the same network.

[fordem]

um, i have dns-323, imac, trendnet and tp-link switches, fritzbox router. all they have gigabit interfaces and all support jumbo frames. still, network speed is mostly less than 6 MB/s (megabytes).

Jumbo frame and the use of jumbo frame permits higher transfer speeds, but does not guarantee it.

Consider a scenario where you have a four lane highway which is gradually reduced to a single lane and then goes back to four lanes (there actually used to be a section of the I-75 like this in Michigan 30 years or so back) - let's say you could run 100 cars a minute past any given point on the four lane section, when you get to the single lane section that would be reduced to 25 cars a minute, and even less given the congestion as the drivers tried to switch lanes - your overall traffic flow for the entire highway would be limited to 25 cars a minute because of the bottle neck.

You need to find your bottleneck and eliminate it.

[47th_ronin]

Jumbo frame and the use of jumbo frame permits higher transfer speeds, but does not guarantee it.

You need to find your bottleneck and eliminate it.

agreed. somehow it seems to me that the imac is the slowest link here. with my hp laptop (other conditions the same) i usually get twice the speed from dns-323 than with imac.

devices i have on my home network:
fritzbox 7390 adsl2+ voip and wifi router (got it for testing from work, it does a bunch of other things, too) (Gb ethernet)
5-port trendnet Gb switch
imac (Gb eth.)
dns-323 (Gb eth.)
two hp laptops (both with Gb interface but mostly we use wifi)
5-port tp-link Gb switch
ps3 (Gb eth.)
wdtv live (fastethernet = 100 Mb/s)
wii (wifi)
htc desire (wifi)
cabling is cat5 utp
9K jumbo frames enabled on all Gb-capable devices, switches are not manageable but support jumbo frames according to their specs.

so the only device without gigabit interface is the wdtv live, which is behind the second switch and therefore should not be the problem.. oh, well, maybe it's time to take a tester home and check the cables.

[HSishi]

I know for sure the Fritz!Box 7390 does NOT support JumboFrames. I don't know if this is a hardware or a firmware problem. If the second option applies, I hope AVM looks into that after more important problems are solved.

My suggestion is:

7390 Router:
- wifi: Wii
- wifi: PS3
- wifi: HTC Desire
- wifi: Laptop 1
- wifi: Laptop 2
- cable: TV
- cable: Switch 1
- - PC
- - NAS
- - iMac
- - Laptop 1 (if cabled)
- - Laptop 2 (if cabled)

But - if two or more cabled devices are in the same room, you can use a switch to couple them so you don't have to make more than one cable connection bridging multiple rooms:

7390
- WiFi devices
- Cabled_Device_01
- ...
-> Switch 1
- - Cabled_Device_02
- - ...
- -> Switch 2
- - - Cabled Device_03
- - - ...

Hope it helps you out.
//HSishi

[47th_ronin]

I know for sure the Fritz!Box 7390 does NOT support JumboFrames.

now that was news to me.

7390
- WiFi devices
- Cabled_Device_01
- ...
-> Switch 1
- - Cabled_Device_02
- - ...
- -> Switch 2
- - - Cabled Device_03
- - - ...

that is basically the layout i use. and part of the problem at this moment is that both switches have one device connected at 100 Mb/s, thus effectively reducing network speed on all gigabit devices, too. so, next step would be one of following:
1. creative re-wiring (not that cute option)
2. find a router with full gigabit funcionality on lan side, including jumbo frames support (sounds expensive)
3. find another small gigabit switch (probably cheapest and fastest option)

thanks, i'll comment later how things went.

edit: ok, messed around a bit, still not working, even if i disconnect 100 Mb devices completely from network. i'll leave my imac last and check the cabling with proper tester.

[HSishi]

Mh, ok, that's new for me - one 100 MBit device slows down all Gigabit devices connected to the same switch / router. So it makes me thinking about a switch for me too - I have 3 GBit devices and 3 100 MBit devices (two of them support 2.4 GHz WLAN but I prefer wired connection) and it has to be a GBit switch.

My advantage is I have all devices in the same room so my wiring is a minimum.

//HSishi

[47th_ronin]

ok, so i checked all my cabling with fluke's cableiq tester and every single one of those was just fine (just as i expected, i made them myself, cat5, not cat5e or cat6). so it's either the cheap gigabit switches (tp-link and trendnet) or imac. probably imac as i get decent (not good, but decent) speeds with my hp laptop. kinda sad, really..