Virgin Media and Jumbo Frames on Ethernet

[Luca Belpassi]

I am about to have Virgin Media installed when I move into my renovated house. I have put CAT6 throughout the house to create a robust Gigabit ethernet network running with Jumbo Frames. 

I have a Synology NAS DS411 (hence wanting to use Jumbo Frames), Time Capsule, connecting to 2/3 macs and maybe even an amplifier with airplay technology.

All my hardware, bar potentially the amp, will support Jumbo Frames. 

How do I ensure that on select pieces of equipment I can get the MTU of 9000 to stick rather than default back to 1500?

Do I have to set up different subnets? Do I need to isolate physically the networks? I have done some web searching but am no expert on networking hence my question to the floor!

Luca

[Sam - MacAmbulance]

To support an MTU of 9000 across the network you'll need hardware that supports it. When we had BT Infinity installed the BT "Business" Hub refused to support Jumbo frames and as such would not communicate properly with my server or MacPro. In the end I replaced it with an Asustek RT-N56U. 

While quite expensive at £80, it supported everything I needed and far outperformed the BT hub on the WAN port. With the BT router i was getting 30mb consistently on a 40mb connection. As soon as I replaced it with the Asustek, the speeds went straight up to 39.9mb (I'm still chasing that extra 100kb/sec). 

BT's explanation was that I was using the internet connection too much and stressing out the BT Business Hub. My response was a) I'm not the right person to make such incredible claims to and b) It's not exactly "Business" class for a router to be outperformed by one person and one server.

With a decent cat6 network & managed switch, you might find that you can manage without jumbo frames, as having them enabled is an all or nothing situation. If you have one link in the chain that doesn't support them then it can bring that device to a standstill.

Regards

Sam

MacAmbulance

Providing affordable Apple & PC services

Sam Mullen
07747 778022
http://www.macambulance.co.uk
in...@macambulance.co.uk

[itsa...@mac.com]

Yea, what he said! ;)

Stephen

Anxiety does not empty tomorrow of its sorrows, but only empties today of its strength. - Unknown

[Luca Belpassi]

Thanks for the advice. 

I have hardware that supports it but not sure if the Virgin Super Hub does. Ideally want to use my Virgin router as an ethernet bridge and then have the time capsule as my wireless router. Would that make a difference too? 

--
You received this message because you are subscribed to the Google Groups "Sussex Mac User Group" group.
To post to this group, send an email to sm...@googlegroups.com.
To unsubscribe from this group, send email to smug+uns...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/smug?hl=en-GB.

[Robin Brown]

I can confirm that the Virgin Superhub does not support jumbo frames either in modem or router mode, it is a rather primitive (cheap) device which supports single frequency wireless and gigabit wired ethernet ports. In router mode there is only one ethernet output port to connect to your own router. I do not know if it would fragment packets or reject it as malformed, either way its a whole world of pain.
The only way to use it is as a standard packet size modem, forget the other functions.

Robin Brown