rfc1963.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

   The size of the Length field is negotiated via the Length-Size
   parameter.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |  Length-Size  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      3

   Length

      3

   Length-Size

      0   No Length Field (default)
      1   Length field of 1 octet
      2   Length field of 2 octets

4.4.  Multi-Port

   By default, packets do not contain a port number and all packets are
   sent to the default port, Port 0.  The Successful negotiation of the
   Multi-Port configuration option means that every packet will contain
   a port number.  The maximum port number, and hence the number of
   ports, is negotiated by using the Max-Port-Num field.  A value of 0
   specifies that a single port is to be used and no port field will be



Schneider & Venters          Informational                     [Page 14]

RFC 1963                        PPP SDTP                     August 1996


   present in an SDTP packet.  (This is the same as not negotiating or
   rejecting this option.) Port numbers begin with 0 and range to 254.
   Port number 255 is reserved for control purposes (see section on flow
   control).

   Protocol Specific negotiations which are on a per port basis, require
   the port number to be specified as part of the configuration
   negotiation.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     | Max-Port-Num  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      4

   Length

      3

   Max-Port-Num

      The maximum port number that can be used.  The number of ports
      present is Max-Port-Num + 1.  The value can range from 0 to 254.

4.5.  Transport-Mode

   This parameter selects the mode of transport for the specified port.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |      Port     |     Mode      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      5

   Length

      4






Schneider & Venters          Informational                     [Page 15]

RFC 1963                        PPP SDTP                     August 1996


   Port

      The port for which this option applies.

   Mode

      The transport mode to be used for this port.

         0   HDLC Synchronous (default)
         1   Asynchronous

4.6.  Maximum-Frame-Size

   This parameter specifies the maximum number of octets allowed in a
   transported data frame.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |      Port     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Maximum-Frame-Size                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      6

   Length

      7

   Port

      The port for which this option applies.

   Maximum-Frame-Size

      The maximum allowed length of a transported data frame in octets.
      Default is 10,000.  Negotiable range is 1 to 2**31 - 1. The value
      0 is reserved to mean no limit.  This field is transmitted most
      significant octet first.

4.7.  Allow-Odd-Frames

   By default, only octet-aligned data frames are allowed for transport.
   Successful negotiation of this option allows the transport of non-
   octet aligned frames.  The size of the padding required to align the



Schneider & Venters          Informational                     [Page 16]

RFC 1963                        PPP SDTP                     August 1996


   frames is carried in the CS Header octet.

   Use of Header-Type H-Only is not permitted in conjunction with this
   option.

    0                   1                   2
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |      Port     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      7

   Length

      3

   Port

      The port for which this option applies.

4.8.  FCS-Type

   By default, the transported data frame FCS is transported.  This
   option allows the FCS to be removed by the transmitter and
   regenerated by the receiver.

   It is important that implementations not use regeneration unless they
   are using PPP Reliable Transmission [12] or operating over some other
   layer that will provide reliable notification of a dropped packet.
   Implementations are not permitted to send a incomplete or bad frame
   to the user with a good (regenerated) FCS.

   This option also selects the type of user FCS that will be
   regenerated.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |      Port     |    FCS-Type   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      8




Schneider & Venters          Informational                     [Page 17]

RFC 1963                        PPP SDTP                     August 1996


   Length

      4

   Port

      The port for which this option applies.

   FCS-Type

         0   Transparent-Transport (Default)
         1   16-bit ITU-T CRC
         2   32-bit ITU-T CRC

4.9.  Flow-Expiration-Time

   As described in section 2.2, Flow-Off messages expire after T1
   seconds.  By default, T1 is 10 seconds.  This configuration option
   allows the value of T1 to be changed.

    0                   1
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Flow-Expiration-Time      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      9

   Length

      5

   Flow-Expiration-Time

      The Flow-Expiration-Time field contains a 16 bit unsigned integer
      which is used to specify the value to be assigned to T1 as
      follows: T1 = Flow-Expiration-Time / 10 seconds.  Therefore this
      value is in units of 1/10 of a second, with allowable values from
      1 to 2^16-1 (0.1 to 6553.5 seconds).  It is transmitted most
      significant octet first.  The default value is 100 (10 seconds),
      which all must support.






Schneider & Venters          Informational                     [Page 18]

RFC 1963                        PPP SDTP                     August 1996


Security Considerations

   Security issues are not discussed in this memo.

References

   [1]    Simpson, W., ed., "The Point-to-Point Protocol (PPP)", STD
          51, RFC 1661, July 1994.

   [2]    CCITT Recommendation V.120 (09/92), "Support by an ISDN of
          Data Terminal Equipment with V-Series Type Interfaces with
          Provision for Statistical Multiplexing", 1993.

   [3]    Rand, D., "The PPP Compression Control Protocol (CCP)", RFC
          1962, June 1996.

   [4]    Friend, R., and W. Simpson, "PPP Stac LZS Compression
          Protocol", RFC 1974, August 1996.

   [5]    Rand, D., "PPP Predictor Compression Protocol", RFC 1978,
          August 1996.

   [6]    Petty, J., "PPP Hewlett-Packard Packet-by-Packet Compression
          (HP PPC) Protocol", Work in Progress.

   [7]    Carr, D., "PPP Gandalf FZA Compression Protocol", Work in
          Progress.

   [8]    Schryver, V., "PPP BSD Compression Protocol", RFC 1977,
          August 1996.

   [9]    Schremp, et. al., "PPP Magnalink Variable Resource
          Compression", RFC 1975, August 1996.

   [10]   Schneider, K., "PPP Stacker LZS Compression Protocol using a
          DCP Header (LZS-DCP)", RFC 1967, August 1996.

   [11]   Simpson, W.A., "PPP LCP Extensions", RFC 1570, January 1994.

   [12]   Rand, D., "PPP Reliable Transmission", RFC 1663, July 1994.











Schneider & Venters          Informational                     [Page 19]

RFC 1963                        PPP SDTP                     August 1996


Chair's Address

   The working group can be contacted via the current chair:

   Karl Fox
   Ascend Communications
   3518 Riverside Drive, Suite 101
   Columbus, Ohio 43221

   EMail: [e-mail]

Authors' Addresses

   Questions about this memo should be directed to:

   Kevin Schneider
   Adtran, Inc.
   901 Explorer Blvd.
   Huntsville, AL 35806-2807

   Phone: [phone]
   EMail:  [e-mail]


   Stuart Venters
   Adtran, Inc.
   901 Explorer Blvd.
   Huntsville, AL 35806-2807

   Phone: [phone]
   EMail: [e-mail]




















Schneider & Venters          Informational                     [Page 20]