Solaris PPP vs DP-3

Solaris PPP vs DP-3

Post by Jason Patters » Fri, 25 Nov 1994 10:21:48



Hi All,

I'm about to set up a PPP link between a SPARCstation10 running
Solaris 2.3 (soon 2.4) connected to a small ethernet LAN with a
couple of other workstations on it (this is my home network), and
a non-sun machine (probably a DECstation 5000 running Ultrix)
connected to internet by ethernet and thence fiber optic cable
(this is the network at my university).

It seems that on the SPARC end (home) I have two options:

  * The PPP which comes with Solaris 2.3 (with patch 101425-04)
  * The latest version of DP-3 (currently 3.1.2a)

The PPP FAQ mentions that most people prefer DP-3.1, but not why.
So, I have the following questions:

  1) I seems that Solaris's PPP can't run on slow modems. From
     the TCP/IP and PPP Answerbook:

      "To run PPP, each end-point workstation must have a modem
       which supports at least 9600 bps or faster bidirectional
       connections. Such a modem would implement the V.32 or
       V.32bis specification".

     Is this an absolute requirement, or just a suggestion? The
     uni currently only has 2400 baud modems, but they might be
     upgrading soon :-) So does this rule out Solaris's PPP?

  2) I'll be setting the SPARCstation10 up as a firewall, so does
     Solaris's PPP offer a packet filtering capability (ie: drop
     all packets which are coming into IP port X? I noticed that
     a patch is available for DP-2.3 which does this (infilt-0.6).
     Is an equivalent patch available for DP-3.1? Or is there a
     newer version of DP-3 which has this capability built in? Or
     is it better to use the more general tcp_wrapper from CERT?

  3) On such a slow link, it would seem that some kind of Type Of
     Service (TOS) priority queuing would be advisable to give
     interactive packets priority over large file transfers. Does
     Solaris's PPP offer this? DP-3.1.2a's documentation mentions
     this as possible future work. Is a patch or newer version of
     DP-3 available which does TOS queuing? A beta release of the
     next version, perhaps? I noticed that the infilt-0.6 patch
     for DP-2.3 has a form of TOS style queuing (window clamping).
     Again, is an equivalent patch available for DP-3?

  4) Are there any other reasons why people (and the FAQ) prefer
     DP-3 over Solaris's PPP? Faster? Friendlier? More reliable?
     More configurable?

Many thanks for any help or advice...


  Imagine that CRAY decides to make a personal computer. It contains 16
  `Alpha' based processors executing in parallel, has 500 megabytes of RAM,
  2500 Megabytes of disk storage, a resolution of 4096 x 4096 pixels, does
  24bit 3D graphics in realtime, relies entirely on voice recognition for
  input, fits in your shirt pocket and costs $300. What is the first
  question the computer community asks?

  "Is it DOS compatible?"