Subject: Re: TCP/IP Terms

From: Bob Braden <[email-masked]>
Date: Sat, 28 Sep 2002 20:21:53 -0700 (PDT)

*> 
  *> The terms can be TCP/IP layer dependant. For example,  rfc 1122 says a
  *> datagram is a "connectionless protocol" if I'm correct. Fine. UDP is at
  *> transport layer, IP and ICMP is at Internet layer. IP is called datagram.

Unnh, UDP stands for User Datagram Protocol.

But it is not particularly confusing.

Bob Braden

---

From: "Bill Cunningham" <[email-masked]>
Date: Sat, 28 Sep 2002 23:56:48 -0400

> But it is not particularly confusing.

User Datagram protocol is pretty self explanatory as far as datagrams go.
But there's so many protocols out there now some like PPTP that are
proprietary. I've read several books on TCP/IP and they can be contradictory
and more confusing than RFCs. If data is to pass from one level to another
and that's not true in all cases, then there should be a new term for the
data 'packet' at the new level. When someone says to me 'datagram.' I don't
know what level of TCP/IP they're talking about. It could be IP datagrams at
Internet layer, or UDP datagrams at Transport layer. Datagram only defines a
connectionless protocol according to rfc 1122. I hope that clears up any
misunderstanding. I don't want to take away the definition "connectionless
protocol" only somehow communicate to another what layer I'm talking about.
This can be done by saying UDP or IP datagram if one knows these protocols
are at Transport and Internet levels. But these are well known protocols
also. Some RFCs are vague enough and short enough to say datagram and not
mention a layer nowdays. Now if someone says to me 'frame.' I think PPP
first off, not necessarily Network layer, if that's where it is, rfc 1661
looks like it was written in accordance with the OSI model. I'm not sure of
that one.

As far as being confusing, maybe the most confusing part is that we have
TCP/IP and OSI. I claim to know nothing of OSI. Maybe common terms between
these two and other models based on info -packets and not layers would be a
way to go. Trying to fit 7 layers into 4 layers is a topic of networking
books everywhere. Maybe you and the others Bob can help clear my head and
focus on a common terminology, perhaps between different models such as OSI
and TCP/IP so that a datagram comes from one layer of perhaps each of these
models. TCP/IP and OSI.
    --Bill