I've got a few of questions on configured tunnels, as described in draft-ietf-ngtrans-mech-v2-01.txt.
- Section 3.2 discusses how to set the tunnel MTU. It covers the case where the tunnel MTU size is manually configured, with a default of 1280. While it discusses capping the tunnel MTU at 4400 when IPv4 path MTU discovery is used, it doesn't discuss a maximum configured value for the tunnel. Does this mean there is no cap when manually configuring the tunnel MTU (i.e., the configured tunnel MTU may be as large as 65515, or even larger if jumbograms are used?) - The same section does not discuss what a host should do if it receives a Router Advertisement with an MTU option. Should the MTU value received be used? If so, is there a cap associated with this MTU value? In other words, if it exceeds 4400 bytes should the value be used? - In section 3.5, the TOS byte is defined as being set to 0 unless otherwise specified. What exactly does this mean? That, if RFC 2893 is followed the DSCP in the TOS byte may be set to a non-zero value? Or that RFC 2893 and RFC 3168 should explicitly NOT be implemented for configured tunnels? If the latter, I think some discussion on exactly WHY these two RFCs are not to be implemented would be helpful. - In section 3.6, the TOS byte of the inner packet is left unmodified at the tunnel egress. This seems to contradict some of the referenced. For instance, RFC 3168 defines both limited-functionality and full-functionality support for ECN support over tunnels. For limited-functionality, which seems to most closely match what is described in this draft, it discusses what to do at the tunnel egress if the CE option is set in the outer packet header but not the inner packet header. This processing does not seem to match what is described in this draft. Is this intentional? Roy -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
