On Tue, Nov 30, 2004 at 08:05:17PM -0800, kingz wrote: > I posted this question several days before, as if no one reply, any > help, hint would be highly appreciated! On Tue, Nov 30, 2004 at 08:55:54PM -0800, kingz wrote: > Hi Peter, > > Thank you for your help, so that I got the archive of VLAN list! You're welcome. > Now I am in deep trouble on Ethernet bridge and VLAN, I posted my > issue, but no reply, so I only beg for your help! I actually see multiple other possibilities, searching the archive again, outsourcing the problem, and so on, if this is a really time- critical matter that you can't seem to solve yourself right away. Developer/hangaround support in open source projects is great because it doesn't cost you anything. But you shouldn't ask people for help privately since that will only make them more reluctant to help you. I'm chipping in on the VLAN mailing list for the benefit of the community. If you can run a business off of that, fine, that's a side-effect. Short conclusion: Keep it on the list. > Could you give me any comment, hint, way to fix my issue? Thank you > very much! Others have mentioned an "MTU issue" but there is no MTU issue. The issue is that the VLAN standard adds four extra bytes to all ethernet packets, extending the ethernet standard. As long as the ethernet frames being extended are less than 1496 bytes, there is no problem, everything works great. But when a frame larger than 1496 bytes gets extended it's total size will be above 1500 bytes, and hence be out-of-spec for plain ethernet even though it's valid because we're using VLANs. Some networking cards and/or drivers can not handle these larger packets. One way to solve the problem is to change the MTU of all operating systems in the same broadcast domain to some value below 1497. That's just a kludge, though, and a huge hassle with larger networks. The best solution is to use network adapters and drivers that know about, and can deal with, VLANs properly. My favorite such combination are the Intel networking cards and the e100 or e1000 driver. They will just work. Some have said that RTL8139 works equally well, but apparently not, since you are having problems with them. My suggestion is to only use e100/e1000 cards and drivers in any system that will see VLAN tags. //Peter
