IP Storage

Document Charter IP Storage WG (ips)
Title IP Storage
Last updated 2007-11-01
State Approved
WG State Concluded
IESG Responsible AD (None)
Charter Edit AD (None)
Send notices to (None)


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)