RFC 2090 (rfc2090) - Page 2 of 6

TFTP Multicast Option

RFC 2090                 TFTP Multicast Option             February 1997


   filename
      The name of the file to be read, as defined in [1]. This is a
      NULL-terminated field.

   mode
      The mode of the file transfer: "netascii", "octet", or
      "mail", as defined in [1]. This is a NULL-terminated field.

   multicast
      Request  for  multicast  transmission  of  the  file  option,
      "multicast" (case insensitive). This is a NULL-terminated
      field. The value for this option request is a string of zero
      length.

   If the server is willing to accept the multicast option, it
   sends an Option Acknowledgment (OACK) to the client including
   the multicast option, as defined in [2]. The OACK to the client
   will specify the multicast address and flag to indicate whether
   that client should send block acknowledgments (ACK).

     +-------+-----------+---+-------~~-------+---+
     |  opc  | multicast | 0 | addr, port, mc | 0 |
     +-------+-----------+---+-------~~-------+---+

   opc
      The  opcode  field  contains  the  number  6,  for  Option
      Acknowledgment, as defined in [2].

   multicast
      Acknowledges the multicast option. This is a NULL-terminated
      field.

   addr
      The addr field contains the multicast IP address. This field
      is terminated with a comma.

   port
      The port field contains the destination port of the multicast
      packets. The use of Registered Port number 1758 (tftp-mcast)
      is recommended. This field is terminated with a comma.

   mc
      This field will be either 0 or 1, to tell the client whether
      it is the master client, that is, it is responsible for
      sending ACKs to the server. This is NULL-terminated field.






Emberson                      Experimental