RFC 3396 (rfc3396) - Page 2 of 9

Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4)

RFC 3396            Encoding Long Options in DHCPv4        November 2002


   However, in some cases it may be useful to send options that are
   longer than 255 bytes.  RFC 2131 [3] specifies that when more than
   one option with a given type code appears in the DHCP packet, all
   such options should be concatenated together.  It does not, however,
   specify the order in which this concatenation should occur.

   We specify here the ordering that MUST be used by DHCP protocol
   agents when sending options with more than 255 bytes.  This method
   also MUST be used for splitting options that are shorter than 255
   bytes, if for some reason the encoding agent needs to do so.  DHCP
   protocol agents MUST use this method whenever they receive a DHCP
   packet containing more than one occurrence of a certain type of
   option.

2. Terminology

   DHCP
      Throughout this document, the acronym "DHCP" is used to refer to
      the Dynamic Host Configuration Protocol as specified in RFC 2131
      [3] and RFC 2132 [4].

   DHCPv4
      We have used the term "DHCPv4" in the abstract for this document
      to distinguish between the DHCP protocol for IPv4 as defined in
      RFC 2131 and RFC 2132 and the DHCP protocol for IPv6, which, at
      the time that this document was written, was still under
      development.

   DHCP protocol agents
      This refers to any device on the network that sends or receives
      DHCP packets - any DHCP client, server or relay agent.  The nature
      of these devices is not important to this specification.

   Encoding agent
      The DHCP protocol agent that is composing a DHCP packet to send.

   Decoding agent
      The DHCP protocol agent that is processing a DHCP packet it has
      received.

   Options
      DHCP options are collections of data with type codes that indicate
      how the options should be used.  Options can specify information
      that is required for the DHCP protocol, IP stack configuration
      parameters for the client, information allowing the client to
      rendezvous with DHCP servers, and so on.





Lemon & Cheshire            Standards Track