Will jumbo frame work or befenit my network?

[mxnerd]

I have a PC with Realtek Gb adapter which supports 2K, 3K, etc,-9K (don't know K=1000 or 1024 here) MTU, my TrendNet non-managed 5-port switch and Netgear GS108Tv2 8-port smart switch supports 9216 bytes frame, the other PC with nVidia Gb adapter has a max 9014 (from 1514, 2514, 4514) bytes frame.

If I turn on jumbo frame support on all of these devices, will I get any speed benefit? Or instead it will slow down because each device has different sizes of packet frame? And why all these odd size frames?

Thanks.

 

[drebo]

You'll see large files transfer faster between compatible computers. If your router doesn't properly know how to fragment these larger packets, though, you can see connectivity issues.

For web surfing and general use, you'll not notice anything.

 

[Emulex]

ISCSI is where you'll see this. of course you keep storage networking on a separated segment from your main segment to prevent devices that can't handle jumbo (apple tv etc) from freaking out.

 

[yinan]

Jumbo frames have never proven to do anything except slow things down by a large percent for me. I have a Cisco switch and all Intel chipset based NICs and when I have turned it on it resulted in a performance decrease of about 50%. Therefore, I have turned it off. What will make a huge difference in file transfer speeds is enabling SMB 2.1. I turned it on and got about 20% increase in transfer speeds, to a constant ~112 MB/sec over a gig link.

Note: For this to work all of the systems need to be Windows 7 or Server 2008 R2.

 

[JackMDS]

To work you need al network devices involved in Giga LAN traffic supporting Jumbu Frames.

Does it work better?

When used in peer-to-peer Network it is YMMV, in most cases it does nothing.

If supported it takes few minutes to configure and try and make an informed self decision.

 

[imagoon]

I have a PC with Realtek Gb adapter which supports 2K, 3K, etc,-9K (don't know K=1000 or 1024 here) MTU, my TrendNet non-managed 5-port switch and Netgear GS108Tv2 8-port smart switch supports 9216 bytes frame, the other PC with nVidia Gb adapter has a max 9014 (from 1514, 2514, 4514) bytes frame.

If I turn on jumbo frame support on all of these devices, will I get any speed benefit? Or instead it will slow down because each device has different sizes of packet frame? And why all these odd size frames?

Thanks.

All devices must have the same MTU, because of this, the answer to "will it benefit me" is 99.9% of the time: No. Unless you have a separate storage segment. And even then it can be "arguable." I have seen benchmarks that showed that 1500MTU even on iscsi networks can be faster in cases where IP offload / iscsi offload and flow control is better optimized for 1500MTU.

 

[mxnerd]

Thanks guys. I think I'll test and see.

Regards,

 

[Emulex]

don't forget you need a switch with enough per packet buffer to handle jumbo (resends/stalls) the 2910al-24 (2 of them) is what i use. a 48 port should be about 3-4K . anything cheaper you are selling yourself short under high load it will drop packets. iscsi hates dropped packets

 

[Gooberlx2]

Yah, unless you're doing something serious like iSCSI on a dedicated network or VLAN (plus multipathing or aggregate linking if possible), you probably won't experience much benefit.