Internet-Draft K. Fujisawa <draft-ietf-ip1394-dhcp-02.txt> Sony Corporation Expires: February, 2000 August 1999 DHCP for IEEE 1394 Status of this memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract IEEE Std 1394-1995 is a standard for a High Performance Serial Bus. Since 1394 uses different link-layer addressing method than conventional IEEE802/Ethernet, the usage of some fields must be clarified to achieve interoperability. This memo describes the 1394 specific usage of some fields of DHCP messages. K. Fujisawa Expires February 2000 [Page 1]
Internet Draft draft-ietf-ip1394-dhcp-02.txt August 1999 1. Introduction IEEE Std 1394-1995 is a standard for a High Performance Serial Bus. IETF IP1394 Working Group specified the method to carry IPv4 datagrams and ARP packets over an IEEE1394 network [IP1394]. The Dynamic Host Configuration Protocol (DHCP) [RFC2131] provides a framework for passing configuration information to hosts on a TCP/IP network. Since 1394 uses different link-layer addressing method than conventional IEEE802/Ethernet, the usage of some fields must be clarified to achieve interoperability. This memo describes the 1394 specific usage of some fields of DHCP. See [RFC2131] for the mechanism of DHCP and the explanations of each fields. This document is a product of the IP1394 working group within the Internet Engineering Task Force. Comments are solicited and should be addressed to the working group's mailing list at ip1394@mailbag.intel.com and/or the author. 2. Issues related to 1394 link address By the conventional link-layer protocols, such as an Ethernet, the 'chaddr' (client hardware address) field may be used to return a reply message from a DHCP server (or relay-agent) to a client. Since 1394 link address (node_ID) is transient and will not be consistent across the 1394 bridge, we have chosen not to put it in the 'chaddr' field. A DHCP client should request the server to send a broadcast reply by setting the BROADCAST flag when ARP is not possible yet. Note: In general, the use of a broadcast reply is discouraged, but we consider the impact in a 1394 network is not an issue. 3. 1394 specific usage of DHCP message fields Following rules should be used when a DHCP client is connected to an IEEE1394 network. 'htype' (hardware address type) MUST be 24 [ARPPARAM]. 'hlen' (hardware address length) MUST be 0. The 'chaddr' (client hardware address) field is reserved. The recipient shall not check the value of this field. A DHCP client on 1394 SHOULD set a BROADCAST flag in DHCPDISCOVER and K. Fujisawa Expires February 2000 [Page 2]
Internet Draft draft-ietf-ip1394-dhcp-02.txt August 1999 DHCPREQUEST messages to request the server (or the relay agent) to send a broadcast reply if its 'ciaddr' (client IP address) is zero. Note: As described in [RFC2131], 'ciaddr' MUST be filled in with client's IP address during BOUND, RENEWING or REBINDING state, therefore, the BROADCAST flag MUST NOT be set. In these cases, the DHCP server unicasts DHCPACK message to the address in 'ciaddr'. The link address will be resolved by ARP. 'client identifier' option MUST be used in DHCP messages from the client to the server due to the lack of the 'chaddr'. 'client identifier' option may consist of any data. Every IP over 1394 node has an EUI-64 (node unique ID) [EUI64], it is useful for a 'client identifier'. When an EUI-64 is used as a 'client identifier', the type value for the EUI-64 is 27 [ARPPARAM], and the format is illustrated as follows. Code Len Type Client-Identifier +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ | 61 | 9 | 27 | EUI-64 (node unique ID) | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Note that the use of other 'client identifier' type, such as a fully qualified domain name (FQDN), is not precluded by this memo. For more details, see "9.14. Client-identifier" in [RFC2132]. Security Considerations Security issues are not discussed in this document. Acknowledgments The author appreciates the members of the Dynamic Host Configuration working group for their review and valuable comments. References [IP1394] P. Johansson, "IPv4 over IEEE 1394", draft-ietf-ip1394-ipv4-15.txt, work in progress. [RFC2131] R. Droms, "Dynamic Host Configuration Protocol", RFC2131, March 1997. [RFC2132] S. Alexander, R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC2132, March 1997. [EUI64] http://standards.ieee.org/regauth/oui/tutorials/EUI64.html K. Fujisawa Expires February 2000 [Page 3]
Internet Draft draft-ietf-ip1394-dhcp-02.txt August 1999 [ARPPARAM] http://www.isi.edu/in-notes/iana/assignments/arp-parameters Author's address Kenji Fujisawa Sony Corporation 6-7-35, Kitashinagawa, Shinagawa-ku, Tokyo, 141-0001 Japan Phone: +81-3-5448-8507 E-mail: fujisawa@sm.sony.co.jp K. Fujisawa Expires February 2000 [Page 4]
