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    RE: iFCP as an IP Storage Work Item



    
    We are also not in support of picking up iFCP as a IP Storage Work Item. As
    we indicated in earlier posts (FC-BB-2 exists thread and the FCIP support
    for N_Port etc.) we would not be in support of multiple ways (i.e., FCIP and
    iFCP) in which FC and IP networks/devices are made to coexist.
    
    In particular, our reasons for not supporting iFCP as a work item are the
    following.
    
    1. Confusion in market place
    
    The overall goal of iFCP appears to be to leverage investment in IP
    networking technology for networking storage. In this respect, it is closer
    in the goal of iSCSI. In a storage network based on IP networking
    technology, we see iSCSI as a better alternative. It would be confusing to
    present both iSCSI and iFCP as two technologies for using the IP network for
    storage. Since the IP Storage Working Group and its members have already
    invested heavily in standardizing iSCSI, we do not see much value in
    diluting the efforts on multiple technologies towards the same end goal.
    
    2. Support for existing FC networks
    
    FCIP and its coordinated effort with FC-BB-2 supports existing FC networks
    better. The interoperability issues between FC and IP networks are
    restricted to the border switches. Other infrastructure needs such as FC
    Name Server, Fabric Controller etc. are leveraged from standards work
    already done in T11 working groups. The argument that iFCP is useful in a
    world of FC devices is not very strong, since FCIP is a solution that not
    only preserves investment in FC end nodes but also in FC switches.
    
    3. iFCP does not support FC loops and FC E_Port
    
    The drafts as submitted do not handle FC loops and FC switches. There were
    some email discussions where authors indicated that these are trivial to add
    to iFCP. We do not think it would be trivial to add E_Port support and work
    through the interoperability issues between iFCP gateways and FC switches.
    Adding FC loop support and E_Port support to an iFCP gateway would make that
    gateway device closer to an FC switch, so one could simply use FC switches
    with B_Port support and FCIP as the tunneling protocol.
    
    4. iFCP adds cost to deployment
    
    End nodes may be forced to support both FC N_Port and iSCSI. It is easier
    for end nodes to just support iSCSI when storage network is based on an IP
    network. There is also an additional cost in testing a pure iSCSI end node
    with a bridged FC-iFCP end node.
    
    5. FCIP has broader coverage
    
    iFCP implies that it is only useful for translating FCP traffic. FCIP is
    able to tunnel all FC traffic through its border switches. It is also
    possible to add N_Port connectivity using FCIP, although such an attempt
    would also compete with the goals of iSCSI.
    
    6. iFCP addds processing overhead to frames
    
    In contrast to iSCSI, iFCP requires examination of every frame and
    substitution of addresses at both iFCP Portals. This has the potential to
    add unwanted latencies as well as consume processing overhead on gateways.
    Given this, it would be hard to compete with cut-through routing based
    products in a pure FC or IP based storage network. We also do not believe
    the NAT like function should really be the top priority for the working
    group to address. As an example, the first NAT RFC was RFC 1631 (which was
    an Informational RFC from the one vendor), well after several other higher
    priority items were addressed. We do not believe that FC networks (when
    deployed in the context of back-end storage) are running out of address
    space to warrant this to be addressed immediately.
    
    Venkat Rangan
    Rhapsody Networks Inc.
    http://www.rhapsodynetworks.com
    
    
    -----Original Message-----
    From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
    David Peterson
    Sent: Wednesday, January 03, 2001 9:42 AM
    To: Ips@Ece. Cmu. Edu
    Subject: iFCP as an IP Storage Work Item
    
    
    The iFCP proposal for encapsulating Fibre Channel frames should not be a
    work item for the IP Storage working group.
    This view is taken by Cisco Systems and Brocade Communications for the
    following technical reasons.
    
    1. FCIP is aligned with the existing FC-BB-2 work in progress.
    2. FCIP will function with any existing/future FC-4 protocol such as
    FCP/FCP-2, VI, SRP.
    3. A native iSCSI device will provide the same functionality as a device
    connected to an iFCP gateway.
    4. Combining iFCP and FCIP does not make any sense since they are
    implemented using two different routing planes. In addition, FCIP is a
    tunneling protocol and requires mimimal processing of the Fibre Channel
    frame. In contrast, iFCP is a gateway protocol and requires much more
    processing such as the reading and modification of the Fibre Channel header,
    augmentation data for specific Fibre Channel Extended Link Services, and
    special handling of specific Fibre Channel Extended Link Services.
    5. Existing Fibre Channel device addressing capability in conjunction with
    FCIP is viable at this point in time.
    6. Manipulation of N_Port ID's as specified in iFCP will make
    debugging/analysis extremely difficult.
    
    In summary, FCIP exists today and is well-defined. FCIP provides all of the
    features
    necessary to tunnel Fibre Channel over IP networks.  Similarly, iSCSI
    provides the
    capability for executing the SCSI command set over IP networks.  Creating
    yet another
    protocol, such as iFCP, is redundant.
    
    David Peterson
    Cisco Systems, Inc (SRBU)
    Lead Architect - Standards Development
    Office: 763-398-1007
    Cell: 612-802-3299
    e-mail: dap@cisco.com
    
    Bob Snively
    Brocade Communications Systems
    Principal Engineer
    Office:  408 487 8135
    e-mail:  rsnively@brocade.com
    
    Mark Bakke
    Cisco Systems, Inc (SRBU)
    Chief Architect
    
    


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Last updated: Tue Sep 04 01:05:59 2001
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