Subject: Re: kern/32900
To: None <,,>
From: Nino Dehne <>
List: netbsd-bugs
Date: 02/22/2006 14:50:02
The following reply was made to PR kern/32900; it has been noted by GNATS.

From: Nino Dehne <>
Subject: Re: kern/32900
Date: Wed, 22 Feb 2006 15:45:39 +0100

 On Wed, Feb 22, 2006 at 02:05:03PM +0000, Christos Zoulas wrote:
 >  Some cheap switches cannot process 1504 byte frames which is required
 >  for VLAN tags.
 Can this apply even when the switch is 802.1Q-compliant? I've been using
 that switch and VLANs for some time now and never noticed anything like
 this. The switch certainly wasn't cheap in the sense of inexpensive. :)
 I also tested the whole setup with an even more advanced switch (D-Link
 DES-3225G) which provides sophisticated traffic and error statistics per
 port and couldn't see any errors on the participating ports. The problem
 still persisted.
 Also, why doesn't this apply to packets that merely pass the router and
 are not originating from it?
 The vlan(4) man page says
   vlan can be used with devices not supporting the IEEE 802.1Q MTU, but
   then the MTU of the vlan interface will be 4 bytes too small and will not
   interoperate properly with other IEEE 802.1Q devices, unless the MTU of
   the other hosts on the VLAN are also lowered to match.
 However, sip(4) is listed as being supported.
 I'm at a loss now and still think this is a bug somewhere.
 Best regards,