D-Link Forums

D-Link FAQ => Router FAQs => FAQs => Topic started by: bs27975 on May 05, 2013, 02:29:19 PM

Title: Jumbo Frame Info
Post by: bs27975 on May 05, 2013, 02:29:19 PM
Intervening (GB) switch or no ... if the endpoint ain't happy with a jumbo frame, communicating to it with a jumbo frame is going to make you unhappy. (If it doesn't just toss the packet, something along the way may take so much time reassembling the fragments that you may be better off not using a jumbo frame in the first place.)

Allowing jumbo frames in a switch (and multi-lan port routers contain switches) merely lets it pass it ... doesn't mean what it's passing it to is happy with jumbo frames.

So, YMMV.

And ... make sure what you're trying to send jumbo frames to is happy about it, and that other endpoints don't get also get caught with a jumbo frame it isn't prepared to handle.

Lest I be misinterpreted ... if it isn't normal or reasonable to send a jumbo frame to something that isn't prepared to handle it, don't worry about the above. i.e. Just because jumbo frames are enabled, and a particular device can't handle them, don't worry about it if it isn't usual to send a jumbo frame to such a device - it will never receive a super-sized packet it then has to munge.

-----

"... Jumbo Frames. I don't think it's recommended to use them unless your connected with a external Gb switch and doing heavy traffic data management and flow. "

Doesn't have to be "heavy", only needs to be 'particular' - and flinging HD video around your network, presumably not unusual these days, constitutes 'heavy'. Even if only between a single sender and receiver.

Jumbo frames reduce the IP processing overhead. For each IP packet, a certain amount of processing takes place just to process the packet. So, inherently, 2 x 512 packets takes more processing than 1 x 1,024 packet. Whether that overhead matters / time sensitive, is significant, is a different story. Over the course of thousands of packets it will add up - IF the receiver is time sensitive. (Dropped frames?)

One might also think, for example, flinging multi-GB backups around the network would also be an issue, but is not particularly time sensitive. If you're flinging such backups around the house, you're in bed or not otherwise using the network - even web performance of other machines at the time suffers dramatically. Since you're in bed, jumbo frames may be less worthwhile vis a vis the aggravation it involves.

In the end, if you're going to use jumbo frames, make sure each intervening piece of equipment, router, switch, or otherwise, is happy about it, or you're not going to be.