Posted: Sat Feb 19, 2011 9:02 Post subject: How to activate jumbo frames on E3000
I tried to activate jumbo frames for my Linksys E3000
with the following command:
ifconfig eth1 mtu 9000
But I only get an error message:
ifconfig: SIOCSIFMTU: Invalid argument
I've not found another possibility to enable the jumbo frames support (yet). I tried Tomato. In the misc settings you can enable jumbo frames and it really works. As the chipset seems to support it I wonder why it doesn't work with DD-WRT. I'm using DD-WRT 15962 (dd-wrt.v24-15962_NEWD-2_K2.6_std_usb_nas-e3000.bin)
Help appreciated...
The switch driver dd-wrt uses currently doesn't support jumbo frames. _________________ Read the forum announcements thoroughly! Be cautious if you're inexperienced.
Available for paid consulting. (Don't PM about complicated setups otherwise)
Looking for bricks and spare routers to expand my collection. (not interested in G spec models)
Jumbo frames seems to be the request of the month for some obscure reason.
Many Gigabit Ethernet switches and NIC's support jumbo frames while Fast Ethernet (100Mbps) only support standard size frames.
Jumbo frames are useful for squeezing out the last piece of bandwidth in a Gigabit lan but they have a very small impact on the overall throughput, around 5%.
The theoretical max throughput on a Gigabit lan with normal frame size (1500) is ~940Mbps and increases to ~990Mbps with 9K jumbo frames which is what most ethernet adapters are capable of handling.
Super jumbo frames , 30K as example, would bring the theoretical max throughput up to almost 1000Mbps.
I can explain why I'd like to have jumbo frames. I already read that theoretically there not a big benefit, but accessing my Zyxel NSA210, jumbo frames simpy double the transfer rates (practically). Maybe the reason is the small processor used in a NAS which needs more power interpreting the header than just receiving data....
I hope for an update of DD-WRT with a jumbo capable driver.
I can explain why I'd like to have jumbo frames. I already read that theoretically there not a big benefit, but accessing my Zyxel NSA210, jumbo frames simpy double the transfer rates (practically). Maybe the reason is the small processor used in a NAS which needs more power interpreting the header than just receiving data....
Yes there can't be any other reason than the weak cpu being helped by not having to process the same amount of packets.
The NSA210 is a cheap NAS both from cost and hardware point of view and I'm surprised that this single-chip NAS has jumbo frame support.
I don't think you will see jumbo frame support in dd-wrt in the nearest future. _________________ Kernel panic: Aiee, killing interrupt handler!
As DD-WRT seems to be more stable and also has a much higher wlan performance on my E3000 than tomato, I solved the issue in this way:
I stay with dd-wrt on my router and added another switch for the NAS and the desktop. The switch is also connected to the E3000. The transition between switch and router seems to be ok. The desktop can access the NAS with 9k and seems to be fine with the internet connection over the E3000. As almost every simple switch supports jumbo frames, this is not a big deal.
Reading all the dd-wrt and tomato posts, there seem to be plenty of people with the same issue (espacially in conjuction with NAS)
