On Mar 15, 2011, at 10:28 AM, Rémi Després wrote:

> 3.2 and remainder of the document.
> The word datagram seems to be used instead of packet:
> - RFC 2460 doesn't use the word datagram for IPv6, even in case of 
> fragmentation 
> - In any case, NPTv6 operates individually on packets without concern with 
> reassembling fragments. 

You're correct that I used "datagram" interchangeably with "packet". Are you 
asking me to explicitly globally replace "packet" with "datagram" for 
consistency? I can do that.

This is a point where people often get into hissy fits and I start seeing 
double as my eyes cross and roll to the back of my head. "Packet" is a general 
term for "a bit of data wandering around as a quantum", but in X.25 refers to a 
PDU at the packet layer. Sometimes it's called a "frame", usually at the link 
layer. TCP calls it a "segment", DCCP calls it a "packet", SCTP sometimes calls 
it a packet and sometimes refers to "payload", and UDP calls it a "datagram". 
There are various words used by various applications. Anything ISO calls it a 
Protocol Data Unit or PDU, and may prepend a word/letter to indicate the layer 
in question; TP4, for example, exchanges TPDUs. But of course, since many PDUs 
in fact are parameters of API events as opposed to messages in the network, I 
tend to think of a PDU as a quantum of data passed through an API.

There are 1215 RFCs that refer to a packet containing an IP header and whatever 
happens to be inside it as a "datagram"; there are 2814 RFCs that refer to 
"packets", many of them in an IP context. RFC 1594 defines "datagram" as "a 
self-contained, independent entity of data carrying sufficient information to 
be routed from the source to the destination computer without reliance on 
earlier exchanges between this source and destination computer and the 
transporting network." 
http://searchnetworking.techtarget.com/definition/datagram has a fairly clean 
definition of the term. I find myself referring to IP's messages specifically 
as "datagrams", and quanta of data at any layer as "packets" pretty 
generically, and in any Internet context to view the two terms as largely 
interchangeable - as do, it would appear, 6028 of my colleagues that write 
RFCs. And no matter what I call them, I get a comment from someone telling me 
they wished I would call them something else.

I'll do the global replace.
_______________________________________________
nat66 mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/nat66

Reply via email to