Any node (host or router) that configures a tunnel endpoint is the source of packets that it originates from its tunnel interface. As such, it may perform host-based fragmentation, receive ICMP errors, etc. in a way that is typically associated with a host.
Whether you view it as a router with an embedded host function or a host with an embedded gateway function is dependent on specific use cases and/or one's point of view. Fred fred.l.temp...@boeing.com > -----Original Message----- > From: Rémi Després [mailto:remi.desp...@free.fr] > Sent: Thursday, August 13, 2009 10:20 AM > To: Fred Baker > Cc: Margaret Wasserman; ipv6@ietf.org; l...@ietf.org; Dino Farinacci; Noel > Chiappa > Subject: Re: [lisp] Judging Consensus on the UDP Checksum Issue > > > Le 13 août 09 à 17:33, Fred Baker a écrit : > > > that of course begs the question of what a system that forwards > > traffic from an interface to a tunnel-like encapsulation is; I tend > > to think that it did something with a packet not directed to it and > > is therefore a router, > > The distinction between a router and a host is not always clear. > Basically, a node acts "as a host" on packets > - it receives with a destination address that is one of its own > addresses > - it sends with a source address that is one of its own addresses. > It acts "as a router" on other packets > > Thus, an encapsulating function: > - acts "as a host" on the link where outer headers are routed. > - acts as link layer interface module to a "router function" on its > side where packets have only the inner headers. > > Would this clarify (or make things worth)? > > Regards, > RD > > > > > > but your text below would suggest that it is a host. > > > > On Aug 13, 2009, at 8:13 AM, Rémi Després wrote: > > > >> Fred, > >> > >> Your proposal seems to me in the best direction. > >> > >> For a full agreement, it would however be appropriate IMHO to be > >> more precise: > >> - A v4 to v6 translator MAY (for efficiency) not recalculate > >> checksums of UDP datagrams received with zero checksums. > >> - If it doesn't recalculate them, it SHOULD forward datagrams with > >> their zero checksum > >> - An IPv4 host MAY transmit zero-checksum UDP datagrams and MUST > >> accept them > >> - An IPv6 host MUST transmit UDP datagrams with non-zero checksums > >> and MAY accept them with zero checksums. > >> > >> Would this fit with what you wish? > >> > >> Regards, > >> RD > >> > >> > >> > >> Le 11 août 09 à 19:13, Fred Baker a écrit : > >>> I would expect a NAT that saw a zero value to not recalculate the > >>> checksum. > >>> > >>> I agree that the unilateral change to the UDP protocol built into > >>> RFC 2460 was a bad idea; if you want to change UDP, change UDP. > >>> That is probably water under the bridge now. > >>> > >>> I think that I would word this as: > >>> > >>> UDP Checksum: this field MAY be transmitted as zero, and the > >>> receiver MAY ignore the checksum on receipt. > > > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
