DHC Working Group Charles Monia
INTERNET DRAFT Josh Tseng
Expires: August 2003 Kevin Gibbons
Internet Draft
Document: <draft-ietf-dhc-isnsoption-05.txt> Nishan Systems
Category: Standards Track February 2003
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
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Comments
Comments should be sent to the IPS mailing list (ips@ece.cmu.edu) or
to the authors.
Table of Contents
Monia, et-al Standards Track [Page 1]
DHCP Option Number for iSNS Revision 5 February 2003
Status of this Memo...................................................1
Comments..............................................................1
Abstract..............................................................3
Conventions used in this document.....................................3
1.Introduction.......................................................3
2.iSNS Option for DHCP...............................................4
2.1 iSNS Functions Field.............................................5
2.2 Discovery Domain Access Field....................................6
2.3 Administrative Flags Field.......................................7
2.4 iSNS Server Security Bitmap......................................9
3.Security Considerations...........................................10
4.Normative References..............................................10
5.Non-Normative References..........................................11
6.Author's Addresses................................................11
Full Copyright Statement.............................................12
Monia, et-al Standards Track [Page 2]
DHCP Option Number for iSNS Revision 5 February 2003
Abstract
This document describes the DHCP option to allow iSNS clients using
DHCP for IPv4 to automatically discover the location of the iSNS
server. iSNS provides discovery and management capabilities for
iSCSI and Fibre Channel 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
devices using TCP/IP. iFCP maps the Fibre Channel transport and
fabric services to TCP/IP.
1. Introduction
The Dynamic Host Configuration Protocol for Ipv4 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
Monia, et-al Standards Track [Page 3]
DHCP Option Number for iSNS Revision 5 February 2003
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:
a) 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
b) 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 iSNS services available to an 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 Functions |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DD Access | Administrative FLAGS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| iSNS Server Security Bitmap |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| a1 | a2 | a3 | a4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| b1 | b2 | b3 | b4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . . . |
| Additional Secondary iSNS Servers |
| . . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 -- iSNS Server Option
The iSNS Option specifies a list of IP addresses used by iSNS
servers. The option contains the following parameters:
Length: 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 Functions, Discovery Domain Access, and
Administrative Flags fields.
Monia, et-al Standards Track [Page 4]
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iSNS Functions: A bitmapped field defining the functions supported
by the iSNS servers. The format of this field is described
in section 2.1.
Discovery Domain Access: A bit field indicating the types of iSNS
clients that are allowed to modify Discovery Domains. The
field contents are described in section 2.2.
Administrative Flags field: Contains the administrative settings for
the iSNS servers discovered through the DHCP query. The
contents of this field are described in section 2.3.
iSNS Server Security Bitmap: Contains the iSNS server security
settings specified in section 2.4.
a1...a4: Depending on the setting of the Heartbeat bit in the
Administrative Flags field (see section 2.3), this field
contains either the IP address from which the iSNS heartbeat
originates (see [ISNS]) or the IP address of the primary
iSNS server.
b1...b4: Depending on the setting of Heartbeat bit in the
Administrative Flags field (see section 2.3), this field
contains either the IP address of the primary iSNS server or
a secondary iSNS server.
Additional Secondary iSNS Servers: Each set of four octets specifies
the IP address of a secondary iSNS server.
2.1 iSNS Functions Field
The iSNS Functions Field defines 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 providing simple discovery information, or as
significant as providing IKE/IPSec security policies and
certificates for the use of iSCSI and iFCP devices. The format of
the iSNS Role bit field is shown in Figure 2:
1 2 3
6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Vendor-Specific |RESERVED |S|A|E|
+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 -- iSNS Functions
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Bit field Significance
--------- ------------
31 Function Fields Enabled
30 DD-Based Authorization
29 Security policy distribution
28 - 24 Reserved
23 - 16 Vendor-specific
Enabled: This bit specifies the validity of the
remaining iSNS Function fields. If set to
one, then the contents of all other iSNS
Function fields are valid. If set to zero,
then the contents of all other iSNS
Function fields MUST be ignored.
DD-based Indicates whether or not devices in a
Authorization: common Discovery Domain (DD) are implicitly
authorized to access one another. Although
Discovery Domains control the scope of
device discovery, they do not necessarily
indicate whether or not a domain member is
authorized to access discovered devices.
If this bit is set to one, then devices in
a common Discovery Domain are automatically
allowed access to each other (if
successfully authenticated). If this bit
is set to zero, then access authorization
is not implied by domain membership and
must be explicitly performed by each
device. In either case, devices not in a
common discovery domain are not 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 set to one, then the policy is stored in
the iSNS server and must be used by the
iSNS client for its own security policy.
If set to zero, then the iSNS client must
obtain its security policy configuration by
other means.
Vendor- These bits are used to indicate the vendor-
Specific: specific capabilities supported by the
indicated iSNS server.
2.2 Discovery Domain Access Field
The format of the DD Access bit field is shown in Figure 3:
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0 1 2 3 4 5 6 ... 15
+---+---+---+---+---+---+---+---+---+
| if| tf| is| ts| C | E | Reserved |
+---+---+---+---+---+---+---+---+---+
Figure 3 -- Discovery Domain Access
Bit field Significance
--------- ------------
0 iFCP Initiator Port
1 iFCP Target Port
2 iSCSI Initiator
3 iSCSI Target
4 Control Node
5 Enabled
6 ... 15 Reserved
Enabled: This bit specifies the validity of the
remaining DD Access bit fields. If this
bit is set to one, then the contents of
the remainder of the DD Access field are
valid. If this bit is set to zero, then
the contents of the remainder of this
field MUST be ignored.
Control Node: Specifies whether the iSNS server allows
Discovery Domains to be added, modified
or deleted by means of Control Nodes. If
set to one, then Control Nodes are
allowed to modify the Discovery Domain
configuration. If set to zero, then
Control Nodes are not allowed to modify
Discovery Domain configurations.
iSCSI Target, These bits determine whether the
iSCSI Initiator, respective registered iSNS client
iFCP Target Port, (determined by iSCSI Node Type or iFCP
iFCP Initiator Port Role) is allowed to add, delete, or
Port: modify Discovery Domains. If set to
one, then modification by the specified
client type is allowed. If set to zero,
then modification by the specified
client type is not allowed.
(A node may implement multiple node
types.)
2.3 Administrative Flags Field
The format of the Administrative Flags bit field is shown in
Figure 4:
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1 2 3
6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED |D|M|H|E|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 -- Administrative Flags
Bit Field Significance
--------- ------------
31 Enabled
30 Heartbeat
29 Management SCNs
28 Default Discovery Domain
27 - 16 RESERVED
Enabled: Specifies the validity of the remainder
of the Administrative Flags field. If
set to one, then the contents of the
remaining Administrative Flags are
valid. If set to zero, then the
remaining contents MUST be ignored,
indicating that iSNS administrative
settings are obtained through means
other than DHCP.
Heartbeat: Indicates whether the first IP address
is the multicast address to which the
iSNS heartbeat message is sent. If set
to one, 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
set to zero, 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 State Change Notifications
(SCN's). Management SCN's are a special
class of State Change Notification whose
scope is the entire iSNS database. If
set to one, then control nodes are
authorized to register to receive
Management SCN's. If set to zero, then
control nodes are not authorized to
receive Management SCN's (although they
may receive normal SCN's).
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Default Discovery Indicates whether a newly registered
Domain: 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 set to one, 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
set to zero, then devices not explicitly
placed into a DD are not members of any
DD.
2.4 iSNS Server Security Bitmap
The format of the iSNS server security Bitmap field is shown in
Figure 5. If valid, this field communicates to the DHCP client the
security settings that are required to communicate with the
indicated iSNS server.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |T|X|P|A|M|S|E|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5 -- iSNS Server Security Bitmap
Bit Field Significance
--------- ----------------
31 Enabled
30 IKE/IPSec
29 Main Mode
28 Aggressive Mode
27 PFS
26 Transport Mode
25 Tunnel Mode
24 -- 0 Reserved
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Enabled This bit specifies the validity of the
remainder of the iSNS server security
bitmap. If set to one, then the contents
of the remainder of the field are valid.
If set to zero, then the contents of the
rest of the field are undefined and MUST
be ignored.
IKE/IPSec 1 = IKE/IPSec enabled; 0 = IKE/IPSec
disabled.
Main Mode 1 = Main Mode enabled; 0 = Main Mode
disabled.
Aggressive Mode 1 = Aggressive mode enabled; 0 =
Aggressive mode disabled.
PFS 1 = PFS enabled; 0 = PFS disabled.
Transport Mode 1 = Transport mode preferred; 0 = No
preference.
Tunnel Mode 1 = Tunnel mode preferred; 0 = No
preference.
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].
With regard to security considerations specific to the use of this
DHCP option to discover the location of the iSNS server, exposure to
a "man-in-the-middle" attack by an hostile entity modifying or
replacing the original iSNS option message should be considered a
potential security exposure. To prevent an attacker from weakening
the required security and potentially tricking the iSNS client into
connecting into rogue iSNS servers, reliance on local security
policy configuration is an appropriate countermeasure.
4. Normative References
[DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, Bucknell University, March 1997.
[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
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5. Non-Normative References
[iFCP] Monia, C., et al., "iFCP - A Protocol for Internet Fibre
Channel Storage Networking", Internet draft (work in
progress), draft-ietf-ips-ifcp-13.txt, May 2002
[iSCSI] Satran, J., et al., "iSCSI", Internet draft (work in
progress), draft-ietf-ips-iSCSI-15.txt, August 2002
[iSNS] Tseng, J. et al., "iSNS - Internet Storage Name
Service", Internet draft (work in progress), draft-ietf-
ips-isns-12.txt, August 2002
[SEC-IPS] Aboba, B., et al., "Securing IP Block Storage
Protocols", draft-ietf-ips-security-14.txt, June 2002
6. Author's Addresses
Kevin Gibbons,
Charles Monia,
Josh Tseng
Nishan Systems
3850 North First Street
San Jose, CA 95134-1702
Phone: (408) 519-3700
Email: cmonia@nishansystems.com
jtseng@nishansystems.com
kgibbons@nishansystems.com
Monia, et-al Standards Track [Page 11]
Full Copyright Statement
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Reserved. This document and translations of it may be copied and
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