DHC Josh Tseng
Internet Draft Nishan Systems
<draft-ietf-dhc-isnsoption-00.txt>
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].
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Comments
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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.........................................................5
5.Author's Addresses.................................................5
Full Copyright Statement..............................................6
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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
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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 <<TBD>>.
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 | 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 2 in order to account for
the FLAGS field.
The format of the FLAGS field is shown below:
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1 2 3
6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Site-Spec | RESERVED |S|A|H|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bit field Significance
--------- ------------
31 Heartbeat
30 Authorization
29 Security
28-22 RESERVED
21-16 Site-specific or Vendor-specific use only
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.
Authorization: Indicates the role of the iSNS server in determining
device access authorizations. If disabled, then the role of the
iSNS server is only for discovery purposes only. Discovery Domains
MAY be used to manage the discovery process, but they do not
indicate 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.
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].
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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-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-09.txt, March 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
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