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.
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