Re: draft-bonica-tunneltrace-02

[Eric Rosen <erosen@cisco.com>]

Thanks for extracting Dave's note on security issues; I apologize for having
missed that in  the noise.  That is certainly a reasonable  set of issues to
discuss before turning the GTTP document into a Proposed Standard. 

I don't think your compatibility issues are valid.

> It is not compatible with RFC792 and RFC1122. 

> 1) RFC792 says: 

> "If the gateway processing a datagram finds the time to live field is zero
> it must discard the datagram" 

> GTTP draft says: 

> On TTL expiration forward the GTTP messages to a local GTTP module. 

I'm not sure  that I see what the incompatibility is;  "discard a packet" is
generally interpreted as  meaning "do not continue to  forward the packet to
its destination address". 

If you  can show  an interoperability  problem of some  sort, that  would be
interesting. 

> 2) RFC1122 says: 

> "An incoming Time Exceeded message MUST be passed to the transport layer." 

> GTTP draft says: 

> "The error-processing module sends an  ICMP Time Expired Message to D1. D1
> discards this ICMP message."

RFC1122  is  not   meant  to  apply  to  routers.  Even   so,  there  is  no
incompatibility, because it is not the IP layer at D1 that is discarding the
message, but  the higher layer.  Perhaps  what the doc should  really say is
that GTTP should discard the ICMP Time Expired Messages.

On  the issue of  layer violations,  I think  that if  you cannot  state the
problem   in  practical   terms,  without   using  the   words   "layer"  or
"architecture", then there is no problem.

On  the issue  of  ITU architectures,  as I  said,  the fact  that some  ITU
architecture says this or that is irrelevant.  (It does not follow from this
that everything the ITU does is wrong.) 

Now, if you think that the MPLS OAM proposal is alive and kicking, I suggest
you try to set up a BoF to discuss it ...