Templin, Fred L wrote:
Hi,
Hi,
As the draft says;
o When the GRE ingress node receives a non-fragmentable packet with
length greater than the GMTU, it discards the packet and send an
ICMP PTB message to the packet's source.
the draft should clearly state that, if GMTU<1280B, it is a violation
of the following requirement of RFC2460:
IPv6 requires that every link in the internet have an MTU of 1280
octets or greater. On any link that cannot convey a 1280-octet
packet in one piece, link-specific fragmentation and reassembly must
be provided at a layer below IPv6.
and that 1280B IPv6 packets can not be carried over IPv6 with the
default GRE configuration.
We have been through this already. They want to say that widely deployed
implementations already ignore this requirement
How the requirement is ignored? Is GMTU<1280B or are GRE gateways
sending >1280B packets without PMTUD?
and so they want to document the behavior to make it all OK.
Then, the document should be on standard track updating RFC2460.
That's how the "running code" principle works, or, why implementations
and operational experiences are required for draft and full standards.
Let feedback from the real world work to fix poor specifications.
The non-robustness principle in action.
For the robustness, IPv6 capable hosts should not send, e.g., >1200B
packets without PMTUD, while links are still required to have
MTU of >=1280B.
Or, IPv6 capable hosts should not send, >1280B packets without
PMTUD, while links are required to have MTU of, e.g., >=1400B.
Masataka Ohta