Enabling Jumbo Frames breaks ReadyNAS Ultra

Hm, well, this looks like it's a router issue — if I make a direct connection from my iMac to the Ultra and enable jumbo frames, everything works normally.

I suspect that the MTU setting of 9000 is the culprit here, since my router worked with the Ready NV's jumbo frame MTU of 7932 (or whatever it was), but that doesn't explain why the router can't cope with the higher value of the Ultra.

However, the other problem is that the Ultra won't allow an MTU setting other than 9000 with jumbo frames enabled, at least in FrontView. Is there a way to force an MTU setting via SSH?

Did you check for new firmware for your router?

some routers just can't handle 9k fames.

to change the mtu, diable the jumbo frames and set it to 7500 or whatever.

TeknoJnky wrote:
some routers just can't handle 9k fames. to change the mtu, diable the jumbo frames and set it to 7500 or whatever.

Easier said than done — the Ultra will only accept MTU settings of 1400 - 1500 with jumbo frames disabled, hence the need for an alternative way of setting it.

(No new router firmware, either...)

What router are you using? Devices should auto-negotiate down to the lower of the frame sizes.

yoh-dah wrote:
What router are you using? Devices should auto-negotiate down to the lower of the frame sizes.

Agreed, but this appears to be an issue with the Linksys WAG320N that I use. I'm running the latest firmware and am still looking for information on the router's gigabit capabilities — no luck so far.

jumbo frames with my Duo....no problems
jumbo frames with ultra 2 plus and breaks frontview

nph134 wrote:
jumbo frames with my Duo....no problems jumbo frames with ultra 2 plus and breaks frontview

You should open a new thread, not resurrect an ancient one with different equipment.