Date: Fri, 4 Aug 2000 10:46:38 -0400 (EDT) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: Bob Van Valzah <Bob@WhiteBarn.Com> Cc: freebsd-net@FreeBSD.ORG Subject: Re: VLAN MTU? 1500? 1504? Why? Message-ID: <200008041446.KAA27928@khavrinen.lcs.mit.edu> In-Reply-To: <398AB99C.9D5938B9@WhiteBarn.Com> References: <398A3549.902A31F5@WhiteBarn.Com> <200008040434.AAA41523@whizzo.transsys.com> <398AB99C.9D5938B9@WhiteBarn.Com>
next in thread | previous in thread | raw e-mail | index | archive | help
<<On Fri, 04 Aug 2000 07:39:56 -0500, Bob Van Valzah <Bob@WhiteBarn.Com> said: > Is there any existing mechanism for "negotiation" of MTU between the > physical layer and virtual layer? Yes. In FreeBSD's implementation, the network interface driver indicates its ability to handle 802.1p-enacapsulated frames (as used in 802.1Q) by advertising a header length of 18 rather than the standard (no encapsulation) 14 octets. (The current implementation does not, however, have a mechanism for rejecting 1518-byte *unencapsulated* packets, as should officially be done. I don't think this is a serious problem.) -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200008041446.KAA27928>