North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: [nsp] Cisco DS3 Questions..

  • From: Jesper Skriver
  • Date: Fri Feb 22 14:49:01 2002

On Fri, Feb 22, 2002 at 11:27:16AM -0600, Stephen Sprunk wrote:
> Thus spake "Gyorfy, Shawn" <[email protected]>
> > Since the topic exploded, what are your opinions on encapsulation of
> leased
> > line DS3s.  We currently use Frame Relay for out Point to Point DS3
> > connections.  Personally, I don't know why we use FR as our encapsulation,
> > and so the question to all.  If you are running Cisco to Cisco, would it
> be
> > wise to run HDLC or PPP?  Our DS3s' here are hardly maxed out, 15% or so,
> so
> > I'm not complaining about the few extra bits I can squeeze out them but
> > maybe that 15% can shrink to 10% with less overhead.  Opinions or examples
> > of life appreciated.
> As you're finding out, this is largely a religious issue.  There are no
> significant differences in overhead between HDLC, PPP, and FR.  Any
> performance difference can be more easily attributed to vendor
> implementation than to protocol efficiency.
> In practice, HDLC is the dominant encapsulation, primarily since it's
> Cisco's default.  If for no other reason, you should use HDLC because almost
> everyone expects you to be using it.  PPP is obviously present in non-Cisco
> shops, and anywhere MLPPP or LFI is needed.  FR is only used as a p-t-p
> encapsulation in certain cases that require it; almost nobody uses it
> without a good reason.

We allways use PPP, the primary reasons being:

- The line protocol goes down when the line is looped.
- It's easier to debug than HDLC


Jesper Skriver, jesper(at)skriver(dot)dk  -  CCIE #5456
Work:    Network manager   @ AS3292 (Tele Danmark DataNetworks)
Private: FreeBSD committer @ AS2109 (A much smaller network ;-)

One Unix to rule them all, One Resolver to find them,
One IP to bring them all and in the zone to bind them.