Vendor Private Extension

[James Luciani <[e-mail]>]

ROLCers,
  
  Since NHRP does not permit more than one instance of any given extension
type, this places a bit of a constraint on the vendor private extension.
What if a message traverses two vendors' NHRP speakers both of which wish to 
include private information in the message?  It can't be done now.  

I propose that the vendor private extension/TLV take on the following form:



5.7.8  NHRP Vendor-Private Extension
 
   Discretionary = 1
   Type = 8
   Length = variable
 
   The NHRP Vendor-Private Extension is carried in NHRP packets to
   convey vendor-private information or NHRP extensions between NHRP
   speakers.  This extension may be used at any time, and unlike other
   extensions, this extension may be added to a reply even if it was
   not present in the original request.  Because only one instance of
   an extension type is allowed in an NHRP message, this extension is
   formatted to allow one or more vendors to add private information 
   withing a single extension.  Each vendor's NHRP speaker may add to 
   this extension as the message is propagated to its destination.

   If the receiver does not handle this extension, or does not match
   any of the vendor IDs in the extension, then the extension may be
   the extension may safely be ignored.  Each NHRP speaker may add the
   following record to this extension:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Vendor ID             |    RVU        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Length              |   Data (variable length)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Vendor ID   
     24-bit 802 vendor ID as assigned by the IEEE
 
   RVU
     Reserved for vendor use.  This field can be used for whatever
     the vendor desires or it may not be used at all.

   Length
     The length in octets of the private data, beginning from the
     first octet of the Data field.

   Data
     The vendor-private data.  This field will always end on a 32-bit
     boundary, so its length will always be 2+4*n octets, where n>=0.

   Note that the extension can contain multiple vendor entries.
   If a vendor adds an entry to an existing extension, then the 
   overall extension length is increased by the total length of 
   the additional entry, including the Vendor ID, Length, 
   and Data fields.