2.7.7 IP Storage (ips)

NOTE: This charter is a snapshot of the 62nd IETF Meeting in Minneapolis, MN USA. It may now be out-of-date.

Last Modified: 2005-02-09


Elizabeth Rodriguez <Elizabeth.Rodriguez@DotHill.com>
David Black <black_david@emc.com>

Transport Area Director(s):

Allison Mankin <mankin@psg.com>
Jon Peterson <jon.peterson@neustar.biz>

Transport Area Advisor:

Allison Mankin <mankin@psg.com>

Technical Advisor(s):

Keith McCloghrie <kzm@cisco.com>
Murali Rajagopal <muralir@cox.net>
Franco Travostino <travos@nortelnetworks.com>
John Hufferd <hufferd@us.ibm.com>

Mailing Lists:

General Discussion: ips@ietf.org
To Subscribe: https://www1.ietf.org/mailman/listinfo/ips
In Body: subscribe
Archive: http://www.ietf.org/mail-archive/web/ips/index.html

Description of Working Group:

There is significant interest in using IP-based networks to transport
block storage traffic. This group will pursue the pragmatic approach of
encapsulating existing protocols, such as SCSI and Fibre Channel, in an
IP-based transport or transports. The group will focus on the
or transports and related issues (e.g., security, naming, discovery,
configuration), as opposed to modifying existing protocols. Standards
for the protocols to be encapsulated are controlled by other standards
organizations (e.g., T10 [SCSI] and T11 [Fibre Channel]). The WG cannot
assume that any changes it desires will be made in these standards, and
hence will pursue approaches that do not depend on such changes unless
they are unavoidable. In that case the WG will create a document to be
forwarded to the standards group responsible for the technology
explaining the issue and requesting the desired changes be considered.
The WG will endeavor to ensure high quality communications with these
standards organizations. The WG will consider whether a layered
architecture providing common transport, security, and/or other
functionality for its encapsulations is the best technical approach.

The protocols to be encapsulated expect a reliable transport, in that
failure to deliver data is considered to be a rare event for which
time-consuming recovery at higher levels is acceptable. This has
implications for both the choice of transport protocols and design of
the encapsulation(s). The WG's encapsulations may require quality of
service assurances (e.g., bounded latency) to operate successfully;
WG will consider what assurances are appropriate and how to provide
in shared traffic environments (e.g., the Internet) based on existing
IETF QoS mechanisms such as Differentiated Services.

Use of IP-based transports raises issues that do not occur in the
existing transports for the protocols to be encapsulated. The WG's
protocol encapsulations will incorporate the following:

- Congestion control suitable for shared traffic network
  environments such as the Internet.

- Security including authentication, keyed cryptographic data
  integrity and confidentiality, sufficient to defend against threats
  up to and including those that can be expected on a public network.
  Implementation of basic security functionality will be required,
  although usage may be optional.

The WG will also address the following issues related to its protocol

- Naming and discovery mechanisms for the encapsulated protocols on
  IP-based networks, including both discovery of resources (e.g.,
  storage) for access by the discovering entity, and discovery for

- Management, including appropriate MIB definition(s) for the

- By agreement with the IESG, the WG will additionally develop MIB
  definitions for the SCSI and Fiber Channel standards.

The WG specifications will allow the implementation of bridges and
gateways that connect to existing implementations of the encapsulated
protocols. The WG will preserve the approaches to discovery,
multi-pathing, booting, and similar issues taken by the protocols it
encapsulates to the extent feasible.

It may be necessary for traffic using the WG's encapsulations to pass
through Network Address Translators (NATs) and/or firewalls in some
circumstances; the WG will endeavor to design NAT- and
firewall-friendly protocols that do not dynamically select target
or require Application Level Gateways.

Effective implementations of some IP transports for the encapsulated
protocols are likely to require hardware acceleration; the WG will
consider issues concerning the effective implementation of its
protocols in hardware.

The standard internet checksum is weaker than the checksums use by
other implementations of the protocols to be encapsulated. The WG will
consider what levels of data integrity assurance are required and how
they should be achieved.

The WG will produce requirements and specification documents for each
protocol encapsulation, and may produce applicability statements. The
requirements and specification documents will consider both disk and
tape devices, taking note of the variation in scale from single drives
to large disk arrays and tape libraries, although the requirements and
specifications need not encompass all such devices.

The WG will not work on:

- Extensions to existing protocols such as SCSI and Fibre Channel
  beyond those strictly necessary for the use of IP-based transports.

- Modifications to internet transport protocols or approaches
  requiring transport protocol options that are not widely supported,
  although the WG may recommend use of such options for block storage

- Support for environments in which significant data loss or data
  corruption is acceptable.

- File system protocols.

Operational Structure:

Keith McCloghrie (kzm@cisco.com) will serve as the MIB and Network
Management advisor for the WG.

Due to the scope of the task and the need for parallel progress on
multiple work items, the WG effort is organized as follows:

A technical coordinator will be identified and selected for each
protocol encapsulation adopted as a work item by the group. This
will be responsible for coordinating the technical efforts of the
with respect to that encapsulation, working with and motivating the
document editors, and evangelizing the group's work within both the
community and relevant external organizations such as T10 and T11.

In addition to the normal responsibilities of IETF working group
chairs, the IPS chairs are responsible for selection of coordinators,
identifying areas of technical commonality and building
cross-technology efforts within the group.

Coordinators for initially important encapsulations:

SCSI over IP (aka iSCSI): John Hufferd (hufferd@us.ibm.com)

Fibre Channel (FC-2) over IP: Murali Rajagopal (muralir@cox.net)

iFCP: Franco Travostino (travos@nortelnetworks.com)

Goals and Milestones:

Done  Submit the initial protocol encapsulations as working group Internet-Drafts.
Done  Submit initial version of framework document as an Internet-Draft.
Done  Discuss drafts and issues at the IETF meeting in San Diego.
Done  Discuss framework, specification and related drafts (e.g., MIBs, discovery) for the protocol encapsulations at IETF meeting in Minneapolis.
Done  Submit final version of iSCSI requirements draft to the IESG for consideration as Informational RFC.
Done  Submit initial Internet-Draft of FCIP/iFCP common encapsulation format
Done  Begin revision of WG charter in consultation with the Area Directors.
Done  Meet at IETF meeting in London to discuss specification and related drafts (e.g., MIBs, discovery) for the protocol encapsulations
Done  WG Last Call on IPS security considerations document.
Done  WG Last Calls on iSCSI, iSCSI naming/discovery, and iSCSI MIB.
Done  WG Last Calls on all WG drafts intended to be published as RFCs, except NAA naming draft
Done  Submit remaining non-MIB protocol drafts intended to be published as RFCs to IESG, except NAA naming draft
Done  Revise iSCSI boot draft to address security issues and submit to IESG
Done  Determine whether to advance NAA naming draft for publication as an RFC in consultation with Technical Committee T10
Done  Submit draft on iSCSI ordering considerations for SCSI commands to IESG for consideration as Informational.
Feb 04  Submit all remaining MIB drafts to IESG.
Mar 04  Review with ADs what (if any) additional work the WG should undertake.
Done  Submit NAA naming draft to IESG for publication as an RFC


  • draft-ietf-ips-iscsi-boot-12.txt
  • draft-ietf-ips-isns-22.txt
  • draft-ietf-ips-ifcp-14.txt
  • draft-ietf-ips-iscsi-slp-09.txt
  • draft-ietf-ips-iscsi-mib-10.txt
  • draft-ietf-ips-fcip-mib-07.txt
  • draft-ietf-ips-ifcp-mib-06.txt
  • draft-ietf-ips-scsi-mib-07.txt
  • draft-ietf-ips-fcmgmt-mib-06.txt
  • draft-ietf-ips-auth-mib-06.txt
  • draft-ietf-ips-iwarp-da-01.txt
  • draft-ietf-ips-iser-01.txt

    Request For Comments:

    RFC3347 I Small Computer Systems Interface protocol over the Internet (iSCSI) Requirements and Design Considerations
    RFC3643 Standard FC Frame Encapsulation
    RFC3720 Standard Internet Small Computer Systems Interface (iSCSI)
    RFC3721 I iSCSI Naming and Discovery
    RFC3722 Standard String Profile for iSCSI Names
    RFC3723 Standard Securing Block Storage Protocols over IP
    RFC3783 I SCSI Command Ordering Considerations with iSCSI
    RFC3821 Standard Fibre Channel Over TCP/IP (FCIP)
    RFC3822 Standard Finding FCIP Entities Using SLPv2
    RFC3980 Standard T11 Network Address Authority (NAA) naming format for iSCSI Node Names

    Current Meeting Report

    The IP Storage (ips) WG met 0900-1130 on Tuesday,
    March 8 at the IETF meetings in Minneapolis, MN.


    Letter in [square brackets] is first letter of presentation file name.

    Administrivia, agenda bashing, draft status review, etc.: 15 min [A]
    David L. Black, EMC (co-chair)
    Blue sheets
    Note Well
    Out of date on web site. Update discussion postponed to end of meeting.

    Draft status
    All non-MIB drafts except iSER and DA are RFCs or in RFC Editor's queue.

    Elizabeth Rodriguez (co-chair) continues to work with authors on resolving expert review comments on remaining MIBs. FC Management MIB has finally made it through this process, new versions of iSCSI and iSCSI Authorization MIBs coming soon. iSNS MIB has expired from Internet Draft servers, new version expected shortly.

    iSER and DA status discussion postponed to end of meeting.

    iSER and DA: 45min Mike Ko, IBM [B]
    iSER = iSCSI Extensions for RDMA
    DA = Datamover Architecture for iSCSI

    No open technical issues on DA draft - it's ready for WG Last Call.

    The open issues on the iSER draft centered on the new MaxOutstandingUnexpectedPDUs key. The key needs to be specified so that if the sender violates it (sends too many Unexpected PDUs), the receiver is *allowed* to drop the connection, but is *not required* to drop it.

    There was a long discussion on when an unsolicited NOP can be considered "retired" and its "Unexpected PDU" credit can be safely reused by the sender. Pat Thaler will send detailed text to specify this to the list.

    The draft needs to add advice to implementers on how to deal with potentially tight target limits on unexpected immediate commands - the basic idea is to send non-immediate commands, which aren't subject to the limit, and can cause some preceding immediate commands to be considered "retired".

    The details of the specification of the MaxOutstandingUnexpectedPDUs key will be:
    Default: "None" (4 letter text string, indicating no limit)
    Minimum allowed value: 2
    Maximum allowed value: 232 - 1

    Section 8 of the iSER contains some considerable changes for which the details matter - WG members are asked to review it carefully.

    The X# syntax will not be used with keys added by iSER - they will be specified by the iSER draft when it becomes a Proposed Standard RFC (as a modification of the iSCSI RFC, 3720), hence IANA does not need to register the new iSER keys, and they should not be described as "extension keys".

    Schedule discussion on these drafts deferred to after next agenda item.

    iSER over InfiniBand: up to 1 hour 30min John Hufferd, IBM [C]

    This draft is a proposal to generalize iSER to non-TCP RDMA transports. There are no changes to iSER over TCP.

    The draft requests several changes:
    1) Generalize terms/wording in iSER to allow non-TCP RDMA transports such as RDDP/SCTP and InfiniBand's RDMA service (with RC). This includes a redefinition of iWARP to encompass SCTP.
    2) Generalize wording in iSER to allow a transport to start in native RDMA mode (with Sends for messages) as opposed to TCP starting in Stream mode and switching to the RDDP native RDMA mode.
    3) Add some sections on how InfiniBand RDMA works as an example.
    4) Extend iSCSI discovery mechanisms to support different transports.
    5) Exempt non-IP transports (e.g., InfiniBand) from "MUST implement IPsec" requirements.

    There were a number of administrative/procedural matters raised by these requests that were dealt with the WG co-chair (in consultation with the Area Director (Allison Mankin) in some cases:

    a) Item 5) was rejected - the IETF will not approve a blanket exemption of usage of a protocol from security requirements. The right approach is to refer to RFC 3723 for the security concerns that apply to iSCSI, and draft text to require that they are addressed as appropriate in different transport environments.

    b) The authors of this draft have no plans for a draft on iSCSI over SCTP without iSER. Absent such a draft, iSCSI/iSER/SCTP cannot be specified, and hence should be removed from the proposal. NB: subsequent list discussion has indicated possible interest in writing an iSCSI over SCTP (without iSER) draft, which would make it possible to specify iSCSI/iSER/SCTP.

    c) Infiniband-specific issues, such as dealing with possible lack of ZBTO support should be dealt with in the InfiniBand Trade Association, not the IETF.

    d) The RDMAP and DDP drafts have passed WG Last Call in the RDDP WG with a definition of "iWARP" that is TCP-only (does not include SCTP). The usage of the term "iWARP" in this (ips) WG must respect that usage in the RDDP WG, and hence generalizing "iWARP" beyond TCP is not appropriate.

    At this point, discussion proceeded to the main issue - whether rough consensus exists in the IPS WG to change the iSER draft to accommodate to-be-specified usage of iSER over InfiniBand. Making these changes will likely result in delaying iSER while the details of the expanded support (e.g., protocol selection information in discovery) are worked out.

    After the discussion, based on a show of hands in the room, the WG co-chair running the meeting determined that rough consensus to make these changes does not exist, and hence the iSER draft will proceed to WG Last Call without any changes proposed in this draft. During WG Last Call, it will be possible to re-raise these proposed changes as WG Last Call comments for further discussion.

    Given this situation, all InfiniBand-specific material for iSER should be submitted as a separate individual submission draft (or multiple individual submission drafts) that make changes to (update) the main iSER draft and the iSCSI discovery mechanism drafts/RFCs as necessary. Whether and what of these proposals to adopt as official IPS WG work items will be considered at the Paris meeting in early August.

    Based on this, the planned schedule is to issue a WG Last Call for the DA and iSER drafts in April - authors should prepare versions ready for WG Last Call by April 15 (tax day), and the WG Last Call will follow the conclusion of the imminent WG Last Call in the RDDP WG for the remaining drafts there.

    The IPS WG milestones have been accordingly revised to:

    Jul 05 Submit iSER (iSCSI Extensions for RDMA) and DA (Datamover Architecture) drafts to IESG
    Aug 05 Submit all remaining MIB drafts to IESG
    Sep 05 Review with ADs what (if any) additional work the WG should undertake

    In other words, the intent is to complete the iSER and DA drafts on the mailing list before the Paris meeting (first week of August). The Paris meeting will be used to resolve any final MIB issues and discuss proposed InfiniBand and SCTP extensions to iSCSI and iSER, with charter revision to follow (Sep) if any of these extensions are added to the IP Storage (ips) WG's program of work.


    iSER Draft Status
    iSER on SCTP & IB