View Full Version : Video extraction from the new HD10-250

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01-11-2006, 04:37 PM
Yes, not really worth arguing with you on this, but I notice you're now back-peddling on all your original points that have been shown to be incorrect. Specifically these ones:
9000 bytes is pretty much the standard for jumbo ethernet frames..
if a switch vendor says 9k bytes, they are always talking about the _ethernet_ frame size.
The fact that the SMC8505T can only handle 8982 IP MTU bytes makes it the exception not the standard.
we were implementing this stuff before there were really any NICs that could do jumbo frames, and so we overshot the NIC guys considerably Uh huh. My jumbo-frame capable marvell based nic has been around longer than these new SMC switches and do not have this problem.

I think you should read more of Dykstra's references, instead of just insisting that your vendor view is the "right" one.

01-11-2006, 07:12 PM
okay. whatever man. an ethernet switch is an L2 device. L2 vendors dont talk about IP MTUs. i dont care what dykstra or tanenbaum or van jacobsen or anyone else says, come to me after youve done a few asic tapeouts and we can talk about what ethernet MTUs are.

you are in good company though, i get emails practically every day from our SEs and QA people who cant figure out why the IP MTU as set in the CLI does not match the ethernet MTU in our hardware. the MPLS card confuses them all the time since they cant seem to remember that with martini encaps there is quite a bit of non IP frame overhead.

i didnt say i designed the SMC switches. i am talking about back in 1999 when we were working on the 2nd generation of our gigabit ethernet switch. at that time there was pretty much only one gigabit ethernet NIC that could do jumbo frames, and that was alteon's NIC.

03-01-2006, 06:02 PM
I've been reading this thread with great interest, and searching on keywords like "backport", but I'm a little behind the times.

How does one get on the machine to edit rc.sysinit.author? Is it still like the "olden" days when you had to move the drive to the PC, or is there a much simpler way?

Sorry, I've been out of action since I upgraded to the HD TiVo, but I used to have noscramle.o, tytools, and an ethernet card for my DirecTiVo. So I'm not a complete *****, I just need someone to bridge the gap in my knowledge between then and now!

Many thanks,

03-30-2006, 08:30 PM
What kernel should I run on my hr10-250 for best network performance? I am currently running the 3.1.5f software with the killhdinitrd 3.1.5 kernel which appears to have iptables enabled with no way of disabling it. So I assume I will need to monte into something else if I want to see speeds above 1.5MB/s. I know the unscramble kernel is faster but I wasn't sure if I should run it 24x7 when none of my shows are being scrambled anymore. So, what kernel are you folks with jumbo frames running?

BTW I am running the latest USB backport and I have one of the new Netgear GS108s so I should be able to test it as soon as I get my Airlink adapter...

08-08-2006, 05:57 PM
'scuse me... when you all refer to say 5.6 M/s, is it mega bits :( or mega Bytes ;) ?

08-08-2006, 06:06 PM
'scuse me... when you all refer to say 5.6 M/s, is it mega bits :( or mega Bytes ;) ?I'm not sure what "5.6 M/s" reference you are referring to, but with the airlink gigE adapters and jumbo frames enabled, 5-6 MBytes per second is a typical result.

08-08-2006, 06:22 PM
great!... thanks... (it was at the end of justdan's post #975)... that's a fifth of my disk to disk transfer rate!... not bad...