On 9/21/07, jamal <[EMAIL PROTECTED]> wrote: > Hope that makes sense. [cut] > cheers, > jamal
Hi all, as far as I understand ieee docs both 64 and 68 approaches are fine... --- Std 802.1Q-2005, 6.5.1 --- On receipt of an M_UNITDATA.request primitive that represents a tagged frame, the implementation is permitted to adopt either of the following approaches with regard to the operation of Transmit Data Encapsulation for frames whose length would, using the procedure as described, be less than 68 octets: a) Use the procedure as described in 6.5.1 of IEEE Std 802.1D. This procedure can result in tagged frames of less than 68 octets (but at least 64 octets) being transmitted; or b) Include additional octets before the FCS field in order for the transmitted frame length for such frames to be 68 octets. This procedure results in a minimum tagged frame length of 68 octets. When a tagged frame of less than 68 octets in length is received on a CSMA/CD LAN segment, and is forwarded as an untagged frame, the provisions of 6.5.1 of IEEE Std 802.1D, result in additional octets being included before the FCS field on transmission in order that the transmitted frame length meets the minimum frame size requirements of 3.2.7 in IEEE Std 802.3. ------------------------------ and --- Std 802.1Q-2005, C.4.4.1 --- When tagged frames are transmitted by a Bridge on an IEEE Std 802.3 MAC, there are two permissible approaches (7.2), as follows: a) Keep the minimum frame size generated by the Bridge equal to 64 octets. This implies that the number of pad octets in a received untagged IEEE Std 802.3 frame would be reduced by up to 4 octets when that frame was tagged; b) Adopt a minimum tagged frame length of 68 octets. This implies that the number of pad octets in a received untagged IEEE Std 802.3 frame would not be adjusted when tagging such frames; equally, if subsequently untagged, no pad adjustment would be necessary before transmission on IEEE 802.3/Ethernet. ------------------------------ might this problem be solved using a configurable parameter? (default=68) my 0.02 euro Ciao FF - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
