DHC Josh Tseng Internet Draft Kevin Gibbons Nishan Systems Expires January 2003 July 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. Comments Comments should be sent to the IPS mailing list (ips@ece.cmu.edu) or to the authors. 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...........................................6 4. References........................................................6 5. Author's Addresses................................................7 Full Copyright Statement..............................................8 Tseng [Page 1] DHCP Option Number for iSNS February 2002 Abstract This document describes the DHCP option to allow iSNS clients devices using DHCP to automatically 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. RESERVED fields SHOULD be set to zero. 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 DHCP option number for iSNS is used by iSCSI and iFCP devices to discover the location and role of the iSNS server. The DHCP option number assigned for iSNS by IANA is <>. 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 | iSNS Function | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | DD Access | Administrative FLAGS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 6 in order to account for the iSNS Function, Discovery Domain Access, and Administrative Flags field. iSNS Function is a bitmap field defining the iSNS server's operational role (i.e., how the iSNS server is to be used). The iSNS server's role can be as basic as to provide simple discovery information, or as significant as to provide IKE/IPSec security Tseng [Page 3] DHCP Option Number for iSNS February 2002 policies and certificates for the use of iSCSI and iFCP devices. The format of the iSNS Role bit field is shown below: 1 2 3 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Site-Specific |RESERVED |S|A|E| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Bit field Significance --------- ------------ 31 Enabled/Disabled 30 Authorization/Discovery Domains 29 Security 28-24 RESERVED 23-16 Site-specific or Vendor-specific use only Enabled/Disabled: This bit determines the validity of the iSNS Role field. If this bit is enabled, then the contents of the remainder of the iSNS Role field are valid. If this bit is disabled, then the contents of the iSNS Role field are invalid. Authorization: Indicates the role of the iSNS server in determining device access authorizations. If disabled, then the function of the iSNS server is for target discovery purposes only. Discovery Domains MAY be used to manage the discovery process, but they do not necessarily indicate authorization to access discovered devices. If enabled, then Discovery Domain/Zoning features of the iSNS indicate device access authorizations. Devices in a common DD SHALL be allowed access to each other if they are successfully authenticated. Devices not in a common DD shall not be allowed to access each other. Security: Indicates whether the iSNS client is to download and use the security policy configuration stored in the iSNS server. If enabled, then the AuthMethod and IKE/IPSec policy stored in the iSNS server SHALL be used by the iSNS client for its own security policy. If disabled, then the iSNS client SHALL NOT query for its own security policy attributes in the iSNS server. Site-Specific: These bits are used to indicate site-specific or vendor-specific capabilities in the indicated iSNS server. Discovery Domain Access is a bit field that indicates the types of iSNS clients that are allowed to modify Discovery Domains. The format of the DD Access bit field is shown below: Tseng [Page 4] DHCP Option Number for iSNS February 2002 0 1 2 3 4 5 6 7 +---+---+---+---+---+---+---+---+ | R | R | if| tf| is| ts| C | E | +---+---+---+---+---+---+---+---+ Bit field Significance --------- ------------ 7 Enabled/Disabled 6 Control Node 5 iSCSI Target 4 iSCSI Initiator 3 iFCP Target Port 2 iFCP Initiator Port 1 RESERVED 0 RESERVED Enabled/Disabled: This bit determines the validity of the DD Access bit field. If this bit is enabled, then the contents of the remainder of the DD Access field are valid. If this bit is disabled, then the contents of this field are invalid. Control Node: Determines whether Control Nodes are allowed to add, delete, or modify Discovery Domains. If enabled, then Control Nodes are allowed. If disabled, then Control Nodes are not allowed to modify Discovery Domains. iSCSI Target, iSCSI Initiator, iFCP Target Port, and iFCP Initiator Port: These bits determine whether the respective registered iSNS client (determined by iSCSI Node Type or iFCP Port Role) is allowed to add, delete, or modify Discovery Domains. If enabled, then the respective types of iSNS clients are allowed. If disabled, then they are not allowed to modify Discovery Domains. The Administrative Flags field configures the administrative settings for the iSNS server discovered through the DHCP option. The format of the Administrative Flags bit field is as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Site-Specific | RESERVED |D|M|H|E| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Bit field Significance --------- ------------ 31 Enabled/Disabled 30 Heartbeat 29 Management SCN's 28 Default Discovery Domain 26-8 RESERVED 7-0 Site-specific or Vendor-specific use only Enabled/Disabled: This bit determines the validity of the Administrative Flags field. If this bit is enabled, then the Tseng [Page 5] DHCP Option Number for iSNS February 2002 contents of the remainder of the Administrative Flags field are valid. If this bit is disabled, then the contents of this field are invalid, indicating that iSNS administrative settings are configured through alternative means other than DHCP. Heartbeat: Indicates whether the first IP address is the multicast address for the iSNS heartbeat message. If enabled, then a1-a4 contains the heartbeat multicast address and b1-b4 contains the IP address of the primary iSNS server, followed by the IP address(es) of any backup servers. If disabled, then a1-a4 contains the IP address of the primary iSNS server, followed by the IP address(es) of any backup servers. Management SCNs: Indicates whether control nodes are authorized to register to receive Management SCN's. Management SCN's are a special class of State Change Notification whose scope is the entire iSNS database. If enabled, then control nodes are authorized to register to receive Management SCN's. If disabled, then control nodes are not authorized to receive Management SCN's (although they may receive normal SCN's). Default Discovery Domain: Indicates whether a newly registered device that is not explicitly placed into a Discovery Domain (DD) and Discovery Domain Set (DDS) should be automatically placed into a default DD and DDS. If enabled, then a default DD shall contain all devices in the iSNS database that have not been explicitly placed into a DD by an iSNS client. If disabled, then devices not explicitly placed into a DD are not members of any DD. 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. [iSCSI] Satran, J., et al., "iSCSI", Internet draft (work in progress), draft-ietf-ips-iSCSI-13.txt, June 2002 [iFCP] Monia, C., et al., "iFCP - A Protocol for Internet Fibre Channel Storage Networking", Internet draft (work in progress), draft-ietf-ips-ifcp-11.txt, May 2002 [iSNS] Tseng, J. et al., "iSNS - Internet Storage Name Service", Internet draft (work in progress), draft-ietf- ips-isns-10.txt, May 2002 Tseng [Page 6] DHCP Option Number for iSNS February 2002 [SEC-IPS] Aboba, B., et al., "Securing IP Block Storage Protocols", draft-ietf-ips-security-13.txt, June 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 7] 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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