Hi, the UDP checksum field is not a codepoint to exchange configuration information in.
In other words, zero has been a special case since the first specification of UDP. But all other values cannot be overloaded to have special meaning. Lars On 2015-6-25, at 15:59, Lucy yong <[email protected]> wrote: > > Ron, > > Quick fix. :) > > The GRE ingress node SHOULD set the Checksum Present field to zero. > However, implementations MAY support a configuration option that > causes the GRE ingress node to set the Checksum Present field to one. > > Does this mean that, by default, GRE ingress node sets Checksum Present field > to zero, and it is optional for an implementation to support GRE Checksum? > Please clarify. Should it be "implementations MUST support a configuration > option ...". > > IMHO: The text in Section 2.1 and 4.2 has some redundancy. Please check. > > Thanks, > Lucy > > -----Original Message----- > From: Ronald Bonica [mailto:[email protected]] > Sent: Thursday, June 25, 2015 4:21 PM > To: [email protected]; Lucy yong > Subject: RE: [Int-area] FW: I-D Action:draft-ietf-intarea-gre-ipv6-09.txt > > Lucy, > > Good point. I have posted a new version of the draft that omits the offending > paragraph. > > I tried to wordsmith the offending paragraph so that it would say what I > meant. However, when I did that, it became redundant with the preceding > paragraph. > > The final sentence in Section 2.1 encourages operators to evaluate the risks > in their network and configure the GRE ingress appropriately. So, if they > need the Checksum Present field to be set to one, they can configure that > behavior. > > Ron > > > >> >> Message: 3 >> Date: Thu, 25 Jun 2015 17:15:38 +0000 >> From: Lucy yong <[email protected]> >> To: "[email protected]" <[email protected]> >> Subject: [Int-area] FW: I-D Action: >> draft-ietf-intarea-gre-ipv6-09.txt >> Message-ID: <2691CE0099834E4A9C5044EEC662BB9D5718B286@dfweml701- >> chm> >> Content-Type: text/plain; charset="us-ascii" >> >> Some comments: >> >> Section 2.1 description is not right. GRE checksum can't detect a mis- >> delivered packet and neither the checksum function in the payload. GRE >> checksum only provides integrity check on GRE header and GRE payload. >> >> Only IPv4 payload has the equivalent payload integrity check as of GRE >> checksum. GRE does not directly carry TCP or UDP. When GRE payload >> protocol is not IPv6, the payload still can carry TCP or UDP. For >> example, GRE payload is either Ethernet or MPLS that carries >> IP/TCP/UDP flows. This satisfies "the payload carries TCP or UDP"; in >> this case, TCP and UDP checksum does not provide the same integrity check as >> of GRE checksum. >> >> GRE can be used in many ways. These examples seem not sufficient for >> the justification of GRE checksum zero. >> >> Since Ipv6 has flow label, it would be good for the draft to describe >> use of flow label in IPv6 header. >> >> Regards, >> Lucy >> >> >> >> >> -----Original Message----- >> From: Int-area [mailto:[email protected]] On Behalf Of >> internet- [email protected] >> Sent: Thursday, June 25, 2015 11:07 AM >> To: [email protected] >> Cc: [email protected] >> Subject: [Int-area] I-D Action: draft-ietf-intarea-gre-ipv6-09.txt >> >> >> A New Internet-Draft is available from the on-line Internet-Drafts >> directories. >> This draft is a work item of the Internet Area Working Group Working >> Group of the IETF. >> >> Title : IPv6 Support for Generic Routing Encapsulation (GRE) >> Authors : Carlos Pignataro >> Ron Bonica >> Suresh Krishnan >> Filename : draft-ietf-intarea-gre-ipv6-09.txt >> Pages : 10 >> Date : 2015-06-25 >> >> Abstract: >> Generic Routing Encapsulation (GRE) can be used to carry any network- >> layer payload protocol over any network-layer delivery protocol. GRE >> procedures are specified for IPv4, used as either the payload or >> delivery protocol. However, GRE procedures are not specified for >> IPv6. >> >> This document specifies GRE procedures for IPv6, used as either the >> payload or delivery protocol. It updates the GRE specification, RFC >> 2784. >> >> >> >> The IETF datatracker status page for this draft is: >> https://datatracker.ietf.org/doc/draft-ietf-intarea-gre-ipv6/ >> >> There's also a htmlized version available at: >> https://tools.ietf.org/html/draft-ietf-intarea-gre-ipv6-09 >> >> A diff from the previous version is available at: >> https://www.ietf.org/rfcdiff?url2=draft-ietf-intarea-gre-ipv6-09 >> >> >> Please note that it may take a couple of minutes from the time of >> submission until the htmlized version and diff are available at >> tools.ietf.org. >> >> Internet-Drafts are also available by anonymous FTP at: >> ftp://ftp.ietf.org/internet-drafts/ >> >> _______________________________________________ >> Int-area mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/int-area >> >> >> >> ------------------------------ >> >> Subject: Digest Footer >> >> _______________________________________________ >> Int-area mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/int-area >> >> >> ------------------------------ >> >> End of Int-area Digest, Vol 119, Issue 4 >> **************************************** > > _______________________________________________ > Int-area mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/int-area _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
