At 08:38 AM 2/28/2002, you wrote:
On Thu, 28 Feb 2002, Bill Cunningham wrote:
> In what layer is PPP in the TCP/IP suite?
It's _everywhere_.
What started out as a roughly HDLC-equivalent framing encap for IP
with a checksum, intended for point-to-point links, has become deeply
embedded in network stacks for e.g. mobile operators, tied in with
AAA... anything PPP over L2TP (over UDP) over IP...
As the protocol that can tunnel everything (not just IP) over
everything, PPP forms the new waists in the overblown multi-tiered
hourglasses. PPP is the ubiquitous encapsulation that mpls or AAL5
always wanted to be.
When all you have is a hammer, everything looks like a nail.
L.
is waiting for someone to notice that ubiquitous PPP means that
multicast is doomed. Oh, and PPPoE dooms broadcast, too.
It is ugly, isn't it. But in a world where it is much easier to
authenticate and account for a circuit instead of a bunch of random
datagrams, are you surprised?
I must admit, we all laughed when Karl Fox indicated that he had
implemented PPP over TELNET back in 1993 or so. We thought it a hilarious
joke. I guess my blood should have run cold back then.
And to think that, the reason for PPP was a response to the limitations
of SLIP and, oh by the way, we can use it to encapsulate IP over T1 lines
between dissimilar routers.
Brian Lloyd
brian(_at_)lloyd(_dot_)com
+1.530.676.1113 - voice
+1.360.838.9669 - fax