rfc1582.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

     0                   1                   2                   3 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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      sequence number (2)      | fragment (1)  |no of frags (1)|
     +-------------------------------+-------------------------------+

           Followed by up to 50 routing entries (each 8 octets)

     0                   1                   2                   3 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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       network number (4)                      |
     +---------------------------------------------------------------+
     |       number of hops (2)      |      number of ticks (2)      |
     +---------------------------------------------------------------+
                                     .
                                     .

     The format of a Netware RIP datagram in octets, with each tick
     mark representing one bit.  All fields are in network order.

     The four octets: sequence number (2), fragment number (1) and
     number of fragments (1) are not present in the original RIP
     specification.  They are only present if operation takes the
     values 7 or 8.

        Figure 3.   Netware Routing Information Protocol packet format




Meyer                                                          [Page 18]

RFC 1582                       Demand RIP                  February 1994


       TRIGGERED REQUEST (6)

                 A request for the responding system to send all of its
                 routing database.

                 Only the first 2 octets of the packet format shown in
                 figure 3 are sent, since all routing information is
                 implied by this request type.

       TRIGGERED RESPONSE (7)

                 A message containing all of the sender's routing
                 database, excluding those entries learned from the
                 interface to which the routing information is being
                 sent.

                 This message may be sent in response to a triggered
                 request, or it may be an update message resulting
                 from a change in the routing database.

                 A triggered response message MUST be sent in response
                 to a triggered request message even if there are no
                 routes to propagate.  This would be the case for a
                 host which had a WAN interface only, but which wished
                 to run the triggered update protocol.

       TRIGGERED ACKNOWLEDGEMENT (8)

                 A message sent in response to every triggered
                 response packet received.

                 Only the first 6 octets of the packet format shown in
                 figure 3 are sent.

   SEQUENCE NUMBER

             This is a new field inserted if operation takes the
             values 7 or 8.

             The sequence number MUST be incremented every time
             updated information is sent out on a WAN.  The sequence
             number wraps round at 65535.

             When a triggered acknowledgement is sent the sequence
             number is set to the same value as the triggered response
             packet being acknowledged.





Meyer                                                          [Page 19]

RFC 1582                       Demand RIP                  February 1994


             The sequence number MUST be identical over fragments.  If
             a fragment is retransmitted the sequence number MUST not
             change.

   FRAGMENT NUMBER

             The fragment number is one for the first fragment of a
             routing update, and is incremented for each subsequent
             fragment.  A fragment can contain up to 50 routing entries.

             When a triggered acknowledgement is sent the fragment
             number is set to the same value as the triggered response
             packet being acknowledged.

   NUMBER OF FRAGMENTS

             In a triggered response packet this indicates the number
             of packets required to complete the routing update.

             This field has no relevance for triggered acknowledgement
             packets so should be set to zero.

   For triggered response packets the rest of the datagram contains a
   list of networks, with information about each.  Each entry in this
   list contains a destination network, and the number of hops and
   number of ticks for each.

   The maximum datagram size is 406 octets, excluding the IPX header (a
   further 30 octets).

6. Netware Service Advertising Protocol

   This section should be read in conjunction with references [3], since
   it only describes differences from the specification.

   Netware [3] also supports a mechanism that allows servers on an
   internetwork to advertise their services by name and type using the
   Service Advertising Protocol (SAP) which runs over the Internetwork
   Packet Exchange (IPX) protocol using socket number 452h.

   SAP operates on similar principals to running RIP.  Routers act as
   SAP agents, collecting service information from different networks
   and relay it to interested parties.

   To support the triggered update mechanism outlined in this proposal
   the packet format for Netware SAP is modified as shown in Figure 4.

   Every Service Advertising Protocol datagram contains the following:



Meyer                                                          [Page 20]

RFC 1582                       Demand RIP                  February 1994


   SAP OPERATION

             Operations supported in standard Netware SAP are: general
             service query (1), general service response (2), nearest
             service query (3) and nearest service response (4).

             The fields sequence number, fragment number and number of
             fragments MUST NOT be included in packets with these
             operation values.

             The following new operations are required:

       TRIGGERED GENERAL SERVICE QUERY (6)

                 A request for the responding system to send the
                 identities of all servers of all types.

                 Only the first 2 octets of the packet format shown in
                 figure 4 are sent, since all service types are
                 implied by this request type.

     0                   1         1
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       operation (2)           |
     +---------------+---------------+

        The following new fields are inserted for some operations

     0                   1                   2                   3 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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      sequence number (2)      | fragment (1)  |no of frags (1)|
     +-------------------------------+-------------------------------+

















Meyer                                                          [Page 21]

RFC 1582                       Demand RIP                  February 1994


           Followed by up to 8 service entries (each 66 octets)

     0                   1                   2                   3 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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Service Type (4)                        |
     +---------------------------------------------------------------+
     |                       Service Name (48)                       |
     +                                                               +
                                  .
     |                            .                                  |
     +---------------------------------------------------------------+
     |                       Network Address (4)                     |
     +---------------------------------------------------------------+
     |                        Node Address (6)                       |
     +                               +-------------------------------+
     |                               |      Socket Address (2)       |
     +---------------------------------------------------------------+
     |       Hops to Server (2)      |
     +-------------------------------+
                                     .
                                     .

     The format of a Netware SAP datagram in octets, with each tick
     mark representing one bit.  All fields are in network order.

     The four octets: sequence number (2), fragment number (1) and
     number of fragments (1) are not present in the original SAP
     specification.  They are only present if operation takes the
     values 7 or 8.


        Figure 4.   Netware Service Advertising Protocol packet format


       TRIGGERED GENERAL SERVICE RESPONSE (7)

                 A message containing all of the sender's services
                 table, excluding those entries learned from the
                 interface to which the service advertising
                 information is being sent out.

                 This message may be sent in response to a triggered
                 general service query, or it may be an update message
                 resulting from a change in the service advertising
                 database.





Meyer                                                          [Page 22]

RFC 1582                       Demand RIP                  February 1994


                 A triggered general service response message MUST be
                 sent in response to a triggered general request
                 message even if there are no services to advertise.
                 This would be the case for a router with a LAN
                 network which had work stations but no servers on it.

       TRIGGERED GENERAL SERVICE ACKNOWLEDGEMENT (8)

                 A message sent in response to every triggered general
                 service response packet received.

                 Only the first 6 octets of the packet format shown in
                 figure 4 are sent.

   SEQUENCE NUMBER

             This is a new field inserted if operation takes the values
             7 or 8.

             The sequence number MUST be incremented every time updated
             information is sent out on a WAN.  The sequence number
             wraps round at 65535.

             When a triggered general service acknowledgement is sent
             the sequence number is set to the same value as the
             triggered general service response packet being
             acknowledged.

             The sequence number MUST be identical over fragments.  If
             a fragment is retransmitted the sequence number MUST not
             change.

   FRAGMENT NUMBER

             The fragment number is one for the first fragment of a
             triggered general service response update, and is
             incremented for each subsequent fragment.  A fragment can
             contain up to 8 service entries.

             When a triggered general service acknowledgement is sent,
             the fragment number is set to the same value as the
             triggered general service response packet being
             acknowledged.

   NUMBER OF FRAGMENTS

             In a triggered response packet this indicates the number of
             packets required to complete the service update.



Meyer                                                          [Page 23]

RFC 1582                       Demand RIP                  February 1994


             This field has no relevance for triggered acknowledgement
             packets so should be set to zero.

   For triggered general service response packets the rest of the
   datagram contains a list of services, with information about each.
   Each entry in this list contains the service type, service name, full
   address (network, node and socket), and the number of hops to the
   server.

   The maximum datagram size is 534 octets, excluding the IPX header (a