View Single Post
  #7   (View Single Post)  
Old 28th June 2008
ai-danno's Avatar
ai-danno ai-danno is offline
Spam Deminer
 
Join Date: May 2008
Location: Boca Raton, Florida
Posts: 284
Default

Quote:
Originally Posted by Seb74 View Post
Wow, thanks for the help
This is the switch, that never seem to arrive
http://kbserver.netgear.com/products/GS108T.asp

The BSD-machine only got 100Mb so from what I've heard you cant set jumboframes on it (that is you cant change MTU upwards much at all I guess). Will very likely have it on its own routerinterface or VLAN so the jumboframes will be repackaged in the router anyway.

I tried running that command in Vista, but it gave me two outputs (one with MTU 1500 and another with MTU something very very large. Didn't say if my regular interface (the 1500 one) was subinterface 0 or 1 or 2, so feels scary changing MTU of subinterface 1 without knowing what interface that is.....I'll google some on it, might be able to set it within the registry or something, or just change it in gui to 7000K and then go check if it did set it to 7000 or 7x1024
One of my XP-machines only have Enable/Disable too choose for Jumbo Frames, so there indeed I have to set the MTU through CMD/Registry/whatever google will tell me.
1) I read your switch's documenation and saw that it's capable of full-sized Jumbo Frame support - 9,728 for the MTU... that's good. Because it's not originating traffic of it's own in great quantities, it doesn't need to be matched to anything in particular from what the hosts' settings are- you just need to be sure all the hosts in a particular VLAN are set to the same size so one doesn't transmit a frame larger than another can handle, otherwise the receiver of that frame will drop it (if it's the receiver that has the limitation. Frames sent in the other direction will not be effected.)

2) 100 Mbps ports can, in fact, have jumbo frame support- the support for jumbo frames is not a limitation of the 100Mbps, but the specific capabilities of the NIC in question (regardless of it's maximum bandwidth size, 100 or Gig.) This is good in that if you have a bunch of workstations on 100Mbps and a server on Gig and they all run at (let's say) an MTU of 7000 your network will be quite efficient. Again, just make sure that the server (or any host) isn't configured to send frames that are larger than any other host can handle. Not all frames sent from a particular host are sent at the largest size (just the ones where the IP packet encapsulated in the frame is large, and that is effected by the application, the data sent by the application, and (for TCP in particular) the TCP/IP window size at that moment in time for a particular connection transmition), but those that are need to be sent to recipients that can receive frames that large.

3) I could be wrong, but these subinterfaces you keep mentioning in your windows box sound like multiple ethernet interfaces. This means that you just need to figure out which is which by assiging dummy addresses for purposes of identification until you are confident of which ones you are dealing with- then re-assign the ones you are going to be dealing with in production. Then, in Network connections, where you see all the icons for the different interfaces, you can f2 each one of them and rename them. After that when you run ipconfig (or ipconfig /all) from the command prompt you will see the labels for each interface. Do me a favor, post the results of your "ipconfig /all" in your next reply here and that will help to clear some confusion you have on what you are dealing with.
__________________
Network Firefighter
Reply With Quote