RFC 3772 (rfc3772) - Page 2 of 10
Point-to-Point Protocol (PPP) Vendor Protocol
Alternative Format: Original Text Document
RFC 3772 PPP Vendor Protocol May 2004
First, because it would be in LCP, the negotiation of the use of the
protocol would begin before identification and authentication of the
peer had been done. This complicates the security analysis of the
feature and constrains the way in which the protocol might be
deployed.
Second, where compulsory tunneling is in use, the system performing
the initial LCP negotiation may be unrelated to the system that uses
the proprietary protocol. In such a scenario, enabling the protocol
at LCP time would require either LCP renegotiation or support of the
proprietary protocol in the initial negotiator, both of which raise
deployment problems.
Third, the fact that any protocol negotiated via such a mechanism
would necessarily use a protocol number that is not assigned by IANA
complicates matters for diagnostic tools used to monitor the
datastream. Having a fixed number allows these tools to display such
protocols in a reasonable, albeit limited, format.
A cleaner solution is thus to define a set of vendor-specific
protocols, one in each of the four protocol number ranges defined by
[1]. This specification reserves the following values:
Value (in hex) Protocol Name
005b Vendor-Specific Network Protocol (VSNP)
405b Vendor-Specific Protocol (VSP)
805b Vendor-Specific Network Control Protocol (VSNCP)
c05b Vendor-Specific Authentication Protocol (VSAP)
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119 [2].
2. PPP Vendor-Specific Network Control Protocol (VSNCP)
The Vendor-Specific Network Control Protocol (VSNCP) is responsible
for negotiating the use of the Vendor-Specific Network Protocol
(VSNP). VSNCP uses the same packet exchange and option negotiation
mechanism as LCP, but with a different set of options.
VSNCP packets MUST NOT be exchanged until PPP has reached the
Network-Layer Protocol phase. Any VSNCP packets received when not in
that phase MUST be silently ignored. If a VSNCP packet with an
unrecognized OUI is received, an LCP Protocol-Reject SHOULD be sent
in response.
Carlson & Winslow Standards Track