DHC Josh Tseng Internet Draft Nishan Systems Expires August 2002 February 2002 DHCP Options for Internet Storage Name Service 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. 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Table of Contents Status of this Memo...................................................1 Comments..............................................................1 Abstract..............................................................2 Conventions used in this document.....................................2 1.Introduction.......................................................2 2.iSNS Option for DHCP...............................................3 3.Security Considerations............................................4 4.References.........................................................4 5.Author's Addresses.................................................5 Full Copyright Statement..............................................6 Tseng [Page 1] DHCP Option Number for iSNS February 2002 Abstract This document proposes a new DHCP option number to allow iSCSI and iFCP devices using DHCP to discover the location of the iSNS server. iSNS provides discovery and management capabilities for iSCSI and Fibre Channel (FCP) storage devices in an enterprise-scale IP storage network. iSNS provides intelligent storage management services comparable to those found in Fibre Channel networks, allowing a commodity IP network to function in a similar capacity as a storage area network. Conventions used in this document iSNS refers to the framework consisting of the storage network model and associated services. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. All frame formats are in big endian network byte order. This document uses the following terms: "iSNS Client" - iSNS clients are processes resident in iSCSI and iFCP devices that initiate transactions with the iSNS server using the iSNS Protocol. "iSNS Server" - The iSNS server responds to iSNS protocol query and registration messages, and initiates asynchronous notification messages. The iSNS server stores information registered by iSNS clients. "iSCSI (Internet SCSI)" - iSCSI is an encapsulation of SCSI for a new generation of storage devices interconnected with TCP/IP. "iFCP (Internet Fibre Channel Protocol)" - iFCP is a gateway-to- gateway protocol designed to interconnect existing Fibre Channel and SCSI devices using TCP/IP. iFCP maps the existing FCP standard and associated Fibre Channel services to TCP/IP. 1. Introduction The Dynamic Host Configuration Protocol provides a framework for passing configuration information to hosts. Its usefulness extends to hosts and devices using the iSCSI and iFCP protocols to connect to block level storage assets over a TCP/IP network. The iSNS Protocol provides a framework for automated discovery, management, and configuration of iSCSI and iFCP devices on a TCP/IP network. It provides functionality similar to that found on Fibre Channel networks, except that iSNS works within the context of an IP Tseng [Page 2] DHCP Option Number for iSNS February 2002 network. iSNS thereby provides the requisite storage intelligence to IP networks that are standard on existing Fibre Channel networks. Existing DHCP option numbers are not plausible due to the following reasons: 1) iSNS functionality is distinctly different from other protocols using existing DHCP option numbers. Specifically, iSNS provides a significant superset of capabilities compared to typical name resolution protocols such as DNS. It is designed to support client devices that allow themselves to be configured and managed from a central iSNS server. 2) iSNS requires a DHCP option format that provides more than the location of the iSNS server. The DHCP option number needs to specify the subset of iSNS services that will be actively used by the iSNS client. The proposed DHCP option for iSNS is used by iSCSI and iFCP devices to discover the location of the iSNS server. Although a standard one-byte DHCP option number is strongly desired, the assignment of a two-byte option number implemented by options 126 and 127 is acceptable. 2. iSNS Option for DHCP This option specifies the location of the primary and backup iSNS servers and the subset of iSNS services that will be used by the iSNS client. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Code = TBD | Length | Usage | Heartbeat | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | a1 | a2 | a3 | a4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | b1 | b2 | b3 | b4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . . . . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The iSNS Option specifies a list of IP addresses used by iSNS servers. Length indicates the number of bytes that follow the Length field. The minimum value for the Length field is 2 in order to account for the Usage and Heartbeat bytes. The Usage byte indicates whether the DHCP option overrides the static configuration of the iSCSI or iFCP device, as well as the subset of iSNS features that are to be used by the iSNS client device. The following table indicates how iSNS is to be used by the DHCP client. Tseng [Page 3] DHCP Option Number for iSNS February 2002 Value iSNS Usage ----- ---------- 0 DISCOVERY Only 1 DISCOVERY and AUTHORIZATION 3 DISCOVERY, AUTHORIZATION and SECURITY All other values are reserved and should not be used A Usage byte value of 0 indicates that iSNS is to be used for discovery only, and that static or manual configuration of the iSCSI or iFCP device overrides any discovery or configuration information found in the iSNS server through iSNS protocol messages. Although the Discovery Domain/Zoning features of the iSNS may be used to manage the discovery process, Discovery Domain membership does not indicate authorization to establish a session with any storage device. A Usage byte value of 1 indicates that iSNS is used for both discovery and authorization. Information discovered from the iSNS server overrides any static or manual configuration of the iSCSI or iFCP device. The Discovery Domain/Zoning membership configuration stored in the iSNS provide authorizations that determine whether storage sessions may be established between peer devices. A Usage byte value of 3 indicates that in addition to discovery and authorization, the iSNS is used to distribute IKE/IPSec security policy configuration to iSCSI and/or iFCP devices. The Heartbeat byte determines if the IP address indicated in a1-a4 is the iSNS heartbeat multicast address. If the Heartbeat byte is 0, then then a1-a4 is the IP address of the primary iSNS server. Any additional IP addresses are the iSNS backup servers, listed in order of precedence. If the Heartbeat byte is 1, then a1-a4 is the iSNS heartbeat multicast address, b1-b4 is the primary iSNS server IP address, and any following IP addresses are the iSNS backup servers listed in order of precedence. 3. Security Considerations DHCP currently provides no authentication or security mechanisms. Potential exposures to attack are discussed in section 7 of the DHCP protocol specification [DHCP]. iSNS security considerations are discussed in [iSNS] and [SEC-IPS]. 4. References [DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, Bucknell University, March 1997. Tseng [Page 4] DHCP Option Number for iSNS February 2002 [iSCSI] Satran, J., et al., "iSCSI", Internet draft (work in progress), draft-ietf-ips-iSCSI-10.txt, January 2002 [iFCP] Monia, C., et al., "iFCP - A Protocol for Internet Fibre Channel Storage Networking", Internet draft (work in progress), draft-ietf-ips-ifcp-09.txt, January 2002 [iSNS] Tseng, J. et al., "iSNS - Internet Storage Name Service", Internet draft (work in progress), draft-ietf- ips-isns-08.txt, February 2002 [SEC-IPS] Aboba, B., et al., "Securing IP Block Storage Protocols", draft-ietf-ips-security-09.txt, February 2002 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 5. Author's Addresses Josh Tseng Nishan Systems 3850 North First Street San Jose, CA 95134-1702 Phone: (408) 519-3749 Email: jtseng@nishansystems.com Tseng [Page 5] Internet Storage Name Service (iSNS) November 2001 Full Copyright Statement "Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." 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