One document matched: draft-ietf-ipfc-fcoverip-01.txt

Differences from draft-ietf-ipfc-fcoverip-00.txt







IPFC Working Group                 M. Rajagopal, R. Bhagwat, W. Rickard
INTERNET-DRAFT                                        Gadzoox  Networks
<draft-ietf-ipfc-fcoverip-01.txt>                   Elizabeth Rodriguez
(Expires November 15, 2000)                         Lucent Technologies



                            Fibre Channel Over IP (FCIP)

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC 2026 [1].

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and  its working groups. Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time. It is inappropriate to use Internet-Drafts as Reference
   material or to cite them other than as ``work in progress''.

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/lid-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

1. Abstract

   Fibre Channel(FC) is a dominant technology used in Storage Area
   Networks(SAN).  The purpose of this draft is to specify a standard
   way of encapsulating FC frames over IP and to describe mechanisms
   that allow islands of FC SANs to be interconnected over IP-based
   networks running over very reliable data links. FC over IP relies on
   IP-based network services to provide the connectivity between the SAN
   islands over LANs, MANs, or WANs.  The FC over IP specification is
   independent of the link level transport protocol such as Gigabit
   Ethernet, SONET, ATM, or DWDM, used for carrying the IP packets. This
   specification treats all classes of FC frames like datagrams.

2. Conventions used in this document

   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 RFC 2119 [2].

3. Motivation and Objectives

   Fibre Channel (FC) is a gigabit speed networking technology primarily
   used for Storage Area Networking (SAN). FC is standardized under
   American National Standard for Information Systems of the National



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   Committee for Information Technology Standards (ANSI-NCITS) and has
   specified a number of documents describing its protocols, operations,
   and services [13].

   The motivation behind connecting remote sites include disk or tape
   backup and live mirroring, or simply distance extension between two
   FC devices or FC Switch clusters (SAN islands).

   A fundamental assumption made in this specification is that the FC
   encapsulated IP packets are carried over very reliable data links and
   may span LANs, MANs, and WANs.

   This main objectives of this document are to:

        1) specify the IPv4 encapsulation, mapping and routing of FC
           frames
        2) apply the mechanism described in 1) to a FC backbone network
           or generally between any two FC devices

   The goal of this specification is to utilize the existing IP suite of
   protocols and address any FC concerns such as security, data
   integrity (loss), and performance when running over IP-based
   networks.

5. FCIP Protocol

5.1 FCIP Device

   In this specification, the term FCIP device generally refers to any
   device that encapsulates FC frames into IP packets and decapsulates
   IP packets to regenerate FC frames.

   Note: In an actual implementation, the FCIP device may be a stand-
   alone box or integrated with an FC device such as a FC Backbone
   Switch or integrated with any IP device such as an IP Switch or an IP
   Router.

   The FCIP device is a transparent translation point. The IP network is
   not aware of the FC payload that it is carrying. Likewise, the FC
   Fabric and the FC end nodes are unaware of the IP-based transport.


5.2 Protocol

   The FCIP protocol specifies the IPv4 encapsulation, mapping and
   routing of FC frames and applies these mechanisms to a FC backbone
   network or generally between any two FC devices. The FCIP protocol is
   summarized below:

     1. All FCIP protocol devices are peers and communicate
        using IP. Each FCIP device behaves like an IP host
        from the perspective of the IP-based network. That
        is, these devices do not perform IP routing or IP switching
        but simply forward FC frames.



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     2. There is no requirement for an FCIP device to establish
        a login with a peer before communication begins.
        However, FCIP devices may authenticate the IP packet
        before accepting it using the IPSec protocols.
        Each IPv4 datagram is treated independently and a FCIP
        device receiver simply listens to the Protocol
        value (Fibre Channel) contained in the IPv4 header.

     3. Each FCIP device may be statically or dynamically configured
        with a list of IP addresses corresponding to all the
        participating FCIP devices. It is outside the scope of this
        specification to describe any dynamic scheme for configuring
        the FCIP device with an IP address or the list of IP addresses
        of other participating FCIP devices.

     4. The reachable FC addresses behind each FCIP device and its
        IP address association can be statically configured
        or dynamically learnt from any FC layer routing protocol
        exchanged between these devices.

        In the case when the FCIP device is a Border Switch, the DMP
        routing protocol can provide this information. Routing in
        the IP plane and the FC plane are largely independent.

        The exact path (route) taken by the IP packet follows the normal
        procedures of any IP packet. From the perspective of the FCIP
        devices this communication is between only two FCIP for any
        given packet.

     5. A FCIP device may send FC encapsulated IP packets to
        more than one FCIP device. However, these are treated
        as separate instances and are not correlated in any way
        in the FCIP Protocol device. The FCIP device routes its
        packets based on the 3-byte FC Destination ID (D_ID) address
        contained in each FC frame.

     6. An IP packet may make use of the IPSec protocols to
        provide secure communications across the IP-based
        network.

     7. Any reordering of data link frames due to MTU fragmentation
        will be recovered in accordance with a normal IP host behavior.

        Any reordering of FC frames due to IP packet reordering will be
        recovered at the FC end nodes.

     8. FCIP assumes that error recovery due to any data loss of IP
        packets will be done at the FC end nodes. FCIP is expected to
        run on very reliable data links making the probability of data
        loss due to line Bit Error Rates extremely small and no worse
        than that of a FC optic link.

        Note: If the underlying data link is unreliable, then use of an
        upper layer protocol such as TCP is suggested. However, it is



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        beyond the scope of this draft to discuss any such error
        recovery and retransmission scheme.

     9. IPv4 packets shall indicate the use of the Premium Service
        in the DSCP bits in the IPv4 header.

6. FCIP Encapsulation


6.1 FC Frame Format

     All FC frames have a standard format much like LAN 802.x protocols.
     However, the exact size of each frame varies depending on the size
     of the variable fields.  The size of the variable field ranges from
     0 to 2112-bytes as shown in the FC Frame Format in Fig. 1 resulting
     in the minimum size FC Frame of 36 bytes and the maximum size FC
     frame of 2148 bytes.

          +------+--------+-----------+----//-------+------+------+
          | SOF  |Frame   |Optional   |  Frame      | CRC  |  EOF |
          | (4B) |Header  |Header     | Payload     | (4B) | (4B) |
          |      |(24B)   |<----------------------->|      |      |
          |      |        | Data Field = (0-2112B)  |      |      |
          +------+--------+-----------+----//-------+------+------+
                           Fig. 1 FC Frame Format

     SOF and EOF Delimiters:

     On a FC link, SOF and EOF are called Ordered Sets and are sent as
     special out-of-band words constructed from the 10-bit comma
     character (K28.5) followed by 3 additional 10-bit data characters.
     On a non-Fibre Channel link the Start of Frame (SOF) and End of
     Frame (EOF) delimiters are both byte-encoded and 4-bytes long.

     On a FC link the SOF delimiter serves to identify the beginning of
     a frame and prepares the receiver for frame reception. The correct
     SOF must be used that corresponds to the frame's Class of Service,
     position within a sequence and in some cases whether connection is
     established or not.

     The EOF delimiter identifies the end of the frame. It also
     identifies the final frame of a sequence.  In connection-oriented
     classes of service, it is used to end the connection. Besides the
     above uses, it also serves to force the running disparity to
     negative.

     It is therefore important to preserve the information conveyed by
     the delimiters across the IP-based network, so that the receiving
     FCIP device can correctly construct the FC frame in its original
     SOF and EOF format before forwarding it to its ultimate FC
     destination on the FC link.

     Start of Frame (SOF) and End of Frame (EOF) byte- encodings are
     defined in Annex A. Although, the SOF and EOF codes are 32-bits,the



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     format makes use of a single-byte to represent each FC Ordered Set.

     Frame Header:

     The Frame Header is 24-bytes long and has several fields that are
     associated with the identification and control of the payload.
     Current FC Standards allow up to 3 Optional Header fields [4]:

          - Network_Header (16-bytes)
          - Association_Header (32-bytes)
          - Device_Header (up to 64-bytes).

     Frame Payload:

     The FC Frame Payload is transparent to the FCIP device. An FC
     application level payload is called an Information Unit at the FC-4
     Level. This is mapped into the Frame Payload of the FC Frame. A
     large Information Unit is segmented using a structure consisting of
     FC Sequences. Typically, a Sequence consists of more than one FC
     frame. FCIP does not maintain any state information regarding the
     relationship of frames within a FC Sequence.

     CRC:

     The CRC is 4-bytes long and uses the same 32-bit polynomial used in
     FDDI and is specified in ANSI X3.139 Fiber Distributed Data
     Interface.

     Note: When FC frames are encapsulated into IP packets, the CRC is
     untouched.


6.2 FC Frame Mapping to IP Packet

     Fig.2 shows the mapping of the FC frame into an IPv4 Packet. The FC
     to IP mapping (and reverse) mapping is one-to-one since the maximum
     size of the encapsulated FC Frame along with the header fields does
     not exceed 2148 bytes.

     The minimum size FC Frame is 36 bytes resulting in a maximally
     minimum IP MTU size of 96 bytes.  (The Maximally minimum MTU size
     is the IP packet with the minimum size payload and the maximum size
     IP headers).

     The maximum size FC frame is 2148 bytes resulting in an (nominal)
     IP packet size of 2168 bytes.  Fig.2 shows the format of the IPv4
     packet with the standard 20-byte fixed header and a 40-byte
     optional header. For the case of the maximum size payload of 2148
     bytes, the maximum IPv4 packet size is 2208 bytes.

     The maximum size FC frame can cause the IP packet to be fragmented
     when the data link cannot support this MTU size. When an IP packet
     is fragmented, required parts of the header must be copied by all
     fragments and the option field may or may not be copied.



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                +---------- -+---------------+-------------+
                | IP Header  | IP Opt. Header|  FC Frame   |
                | (20 bytes) |   (40 bytes   | (2148 bytes |
                |            |     Max)      |   Max)      |
                +------------+---------------+-------------+

                Fig. 2 Format of an IPv4 Payload carrying FC


     If IPSec is used for security it introduces its own headers and the
     IP packet size increase depends on the exact mode of IPSec usage
     (AH versus ESP, Tunnel versus Transport). However, this additional
     increase in the IP packet size due to IPSec headers is relatively
     small (see [8], [9], [10]), and the maximum size IP packet will
     remain within its maximum size of 65535 bytes. Adding, IPSec header
     may in some cases may lead to fragmentation if it exceeds the data
     link MTU.

     IP Header Field Setting:

     DSCP (6 bits): The Differentiated Service Code Points (DSCP) [6]
     shall be set to correspond to the Premium Service. This service
     provides "Expedited Forwarding" at each IP hop (Per Hop Behavior
     (PHB)).

     Protocol (8 bits): This 8-bit field defines the higher level
     protocol that uses the service of the IP layer.  In this case, this
     is set to the Fibre Channel Protocol Value 133 defined in [12].

     Source IP Address (32 bits): This is the IP address of the ingress
     FCIP device that is transmitting the FC encapsulated IP packet.

     Destination IP Address (32 bits): This the IP address of the egress
     FCIP device that is receiving the FC encapsulated IP packet.

     FCIP specification treats all classes of FC frames as datagrams.
     There will be no F_BSY or F_RJT sent if a Class 2 frame is lost
     while in transit within the IP network.  FCIP may not be suitable
     for transport of Class 1 traffic since these frames are treated the
     same way as any Class 2 or 3 frame.

6.3 Fibre Channel Bit and Byte Ordering

     Fibre Channel's FC-1 Level defines the method used to encode data
     prior to transmission and subsequently decode the data upon
     reception. The method encodes 8-bit bytes into 10-bit transmission
     characters to improve the transmission characteristics of the
     serial data stream. In Fibre Channel data fields are aligned on
     word boundaries. A word in FC is defined as 4 bytes or 32 bits. The
     resulting transmission word after the 8-bit to 10-bit encoding
     consists of 40 bits.

     Data words or Ordered Sets (special FC-2 Level control words) from
     the FC-2 Level map to the FC-1 Level with no change in order and



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     the bytes in the word are transmitted in the Most Significant Byte
     first to Least Significant Byte order. The transmission order of
     bits within each byte is the Least Significant Bit to the Most
     Significant Bit.

7. FCIP Network

7.1 FC Backbone Switches

     FC Standards [3] describe the operation and interaction of FC
     Switches. Two distinct levels of switch interconnections are
     specified. Autonomous Regions (AR) are defined to allow clusters of
     FC Switches to be connected across a backbone network called a DMP-
     backbone.  An AR is administratively defined with each AR
     encompassing one or more FC Address Domains.  The DMP-backbone
     network is formed from one or more Backbone Switches (BSW) that run
     the DMP routing and switch control protocol on FC links. DMP is
     based on OSPF and the DMP backbone may consist of an arbitrary mesh
     network. A BSW may communicate with multiple neighbors.  As
     specified in [3], native FC frames traverse the DMP backbone
     between DMP neighbors on FC links.  DMP Routing Protocol messages
     are exchanged between BSWs on this backbone.

     An example network consisting of 4 ARs and a DMP FC backbone
     consisting of 3 links is given in Fig. 1. There is no restriction
     in adding other links to this network as needed. The connection
     between BSWs below may in fact form a fully connected mesh.


 _______                                           _______
|       |                                         |       |
| AR #1 |_____                               _____| AR #4 |
|_______|     |                             |     |_______|
           ___|___                       ___|___  
          | BSW 1 |---------------------| BSW 4 |
          |_______|                     |_______|             
           ___|___                       _______       
          | BSW 2 |---------------------| BSW 3 |
          |_______|                     |_______|
 ___ ___      |                             |      _______
|       |     |                             |     |       |
| AR #2 |-----                               -----| AR #3 |
|_______|                                         |_______|


     Note:

     BSW 1 knows it is connected to BSWs 2 and 4;

     BSW 2 knows it is connected to BSWs 1 and 3;

     BSW 4 knows it is connected to BSWs 1.

     Fig. 1 Example Network showing DMP Backbone Switching Architecture



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     An FCIP device provides a single logical interface to the DMP
     protocol connecting multiple DMP neighbors on the IP network. From
     the DMP routing point of view, the connection to each neighbor on
     the IP network is treated as a separate logical FC link.

     In FCIP, the native FC frames are first encapsulated in IP packets
     which then traverse the IP-based network. The IP network provides a
     new transport path for each emulated DMP FC link.

     The IP network itself may consist of any number of hops between two
     FCIP devices. Also, the route taken by the IP packet between any
     two FCIP devices is dictated by the normal IP routing.

     A functional and logical diagram of an IP-based DMP backbone for
     the example network given in Fig. 1 is shown in Fig. 2. In this
     figure, each BSW is logically connected to other BSWs.


 _______                                              _______
|       |                                            |       |
| AR #1 |---                                         | AR #4 |
|_______|   |         ______    ________    ______   |_______|
          __|_ __    |      |  |        |  |      |   ___|___  
         | BSW 1 |---| FCIP |--|   IP   |--| FCIP |--| BSW 4 |
         |_______|   |______|  | Network|  |______|  |_______|
                               |        |
                                --------
                     ______      |   |    ______   
          ______    |      |     |   |   |      |    _______     
         | BSW 2|---| FCIP |-----|   |---| FCIP |---| BSW 3 |
         |______|   |______|             |______|   |_______|
 ________   |                                       ___|___
|        |  |                                      |       |
|  AR #2 |__|                                      | AR #3 |
|________|                                         |_______|


     Fig. 2 Example Network showing an IP-based FC Backbone Switching
     Architecture

     The IP-based network has transformed the DMP backbone into a fully
     connected network. From the perspective of each BSW all remote BSWs
     therefore appear to be neighbors.  The DMP routing protocol
     computation would make the IP based network topology appear as a
     fully connected mesh.

     The DMP routing protocol exchanges between BSWs occur transparently
     to the FCIP devices.  Encapsulated FC frames are routed on the IP
     network according to the normal IP routing procedures. In this
     mode, the DMP routing protocol lays over the IP network and has no
     knowledge of the underlying IP protocol and IP routing or the
     underlying technology that carries the IP datagram.  This concept
     is shown in Fig.3




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 ________                                             _______
|  AR #1 |                                           | AR #2 |
|        |--                                         |       |
|________|  |        ______    ________    _____     |_______|
          __|___    |      |  |        |  |     |   ____|__  
         | BSW 1|---| FCIP |--|   IP   |--|FCIP |--| BSW 2 |
         |      |   |      |  | Network|  |     |  |       |
         |______|   |______|  |________|  |_____|  |_______|
                           <-------------->
                              IP Routing
                <----------------------------------> 
                           DMP Routing Plane
      

                     Note: IP Network routing may consist of multiple
     paths

7.2 FC Device

     The protocol encapsulation and mapping of the FC frame described in
     earlier sections applies equally to any pair of FC device (e.g.,
     Server-to-server) wishing to tunnel FC frames across an IP-based
     network. Any FC routing protocol exchanges may still occur
     transparent to the FCIP devices.

8. Security Considerations

     For Virtual Private Networks , both authentication and encryption
     are generally desired, because it is important both to (1) assure
     that unauthorized users do not penetrate the virtual private
     network and (2) assure that eavesdroppers on the network cannot
     read messages sent over the network.

     IPSec provides 3 main facilities: an authentication-only function,
     referred to as Authentication Header (AH), a combined
     authentication/encryption function called Encapsulating Security
     Payload (ESP), and a key exchange function.

     Because both features are generally desirable, ESP may be more
     suitable than AH. The key exchange function allows for manual
     exchange of keys as well as an automated scheme.  The IPSec
     specifications described in [8], [9], [10], and [11] covers these
     topics. It is beyond the scope of this document to discuss specific
     use of the IPSec protocols.

     Note: Use of IPSec protocol is optional.

9. Data Integrity Considerations

     Loss:

     Recovery from data loss due to IP datagram loss is made at the end
     FC nodes. It is expected that such data losses are rare because the
     mechanism assumes extremely reliable data links.




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     Fragmentation:

     IP packets as noted earlier can exceed the standard maximum
     Ethernet frame size of 1526 bytes. Any reordering caused as a
     result of fragmentation is recovered according to normal procedures
     at IP hosts.

     Ordering:

     FC Over IP specification treats all Classes of FC frames alike and
     treats each FC frame like a datagram.  FCIP specification does not
     provide any support to maintain any ordering relationships that may
     exist between FC Frames.

     In FC Class 2 and 3 Service, the physical (temporal) ordering of
     the frames as it arrives at a destination can be different from
     that of the order sent because of traversing through a FC Network.
     FC frames in this sense are no different from IP datagrams. FCIP
     protocol does not provide any support to maintain any ordering
     relationships that may exist between frames related to a Sequence.

     FC Class 1 service requires that frames be delivered in the same
     order as transmitted. Since the FCIP protocol does not treat Class
     1 Frames differently, it does not provide support to ensure that
     these frames are in order.

10. Performance Considerations

     Mapping the IP header DSCP bits to correspond to a Premium Service
     provides a preferred service at each IP Router Per Hop Behavior
     (PHB) [6].

     Since FCIP protocol makes use of the layer 3 IP protocol rather
     than the layer 4 TCP, minimal buffering requirements are imposed on
     the FCIP device. However, this also means that no reliable
     transmission in the sense of retransmissions are supported. This
     aspect is important when engineering the data links between the
     FCIP devices.

     Note: We expect that technology advances in optics now have the
     ability to provide very large bandwidth links with very low error
     rates. Hence the need for a Layer 4 Transport protocol seems
     unnecessary. In the rare event, when an IP datagram is dropped
     (corrupted or due to congestion), then the FC end nodes are
     designed to recover from this situation.

     The FCIP protocol does not crack the FC Frame (except for attaching
     the correct byte-encoded SOF and EOF) nor does it do any FC payload
     processing. This allows any FC traffic to be tunneled across at
     high throughput rates.

     The case where there is no data link fragmentation, each FC frame
     which has a one to one mapping to an IP datagram also has a one-to-
     one mapping to a data link frame. This has the tendency to further



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     improve the throughput performance.

     Note: Class 1 FC traffic expects a dedicated bandwidth. This
     specification does not address this requirement.

     11. Flow Control

     FCIP does not provide any flow control support at the IP level. FC
     credit mechanism provides the required flow control at a higher
     level between switches. FCIP may be subject to data link level flow
     control when used.

12. References:

     [1] Bradner, S., "The Internet Standards Process -- Revision 3",
         BCP 9, RFC 2026, October 1996.

     [2] Bradner, S., "Key words for use in RFCs to Indicate
         Requirement Levels", BCP 14, RFC 2119, March 1997

     [3] NCITS 321-200x (ANSI) T11/Project 1305-D/Rev4.3 "Fibre Channel
         Switch-Fabric-2", March 2000 (www.t11.org)

     [4] Fibre Channel Physical and Signaling Interface -3 (FC-PH-3),
         Rev. 9.3, ANSI X3.xxx-199x

     [5] The Fibre Channel Consultant: A Comprehensive Introduction,
         "Robert W. Kembel", Northwest Learning Associates, 1998

     [6] Nichols, K., Blake, S., Baker, F.  and D. Black, " Definition
         of the Differentiated Services Field (DS Field) in the IPv4 and
         Ipv6 Headers", RFC 2474, December 1998.

     [7] NCITST11/Project 1238-D/Rev4.6 "Fibre Channel
         Backbone", April 17 2000 (www.t11.org)

     [8] Kent, S. and Atkinson, R., "Security Architecture for the
         Internet Protocol", RFC 2401, Nov 1998

     [9] Kent, S. and Atkinson, R., "IP Authentication Header",
         RFC 2402, Nov 1998

     [10] Kent, S. and Atkinson, R., "IP Encapsulating Security
          Payload (ESP)", RFC 2406, Nov 1998

     [11] Maughan, D. et all, "Internet Security Association and Key
          Management Protocol (ISAKMP)", RFC 2408, Nov 1998

     [12] http://www.isi.edu/in-notes/iana/assignments/protocol-numbers

     [13] http://www.t11.org


13. Acknowledgments



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14. Authors' Addresses

     Murali Rajagopal
     Gadzoox Networks, Inc.
     16281 Laguna Canyon Road, Suite 100
     Irvine, CA 92618

     Phone: +1 949 789 4646
     Fax: +1 949 453 1271
     Email: murali@gadzoox.com

     Raj Bhagwat
     Gadzoox Networks, Inc.
     16281 Laguna Canyon Road, Suite 100
     Irvine, CA 92618

     Phone: +1 949 789 4634
     Fax: +1 949 453 1271

     Email: raj@gadzoox.com

     Wayne Rickard
     Gadzoox Networks, Inc.
     16281 Laguna Canyon Road, Suite 100
     Irvine, CA 92618

     Phone: +1 949 789 4604
     Fax: +1 949 453 1271
     Email: wayne@gadzoox.com


     Elizabeth G. Rodriguez
     Lucent Technologies
     1202 Richardson Drive, Suite 210
     Richardson, TX 75080

     Phone: 972-231-0672
     Email: egrodriguez@lucent.com



















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            APPENDIX A: Fibre Channel EOF and SOF Encodings

A.1 Ordered Sets

     On a FC link, Ordered Sets (OS) are sent as special out-of-band
     words constructed of the 10-bit comma character (K28.5) followed by
     3 additional 10-bit data characters. The Ordered Sets defined by FC
     include the Frame Delimiter, Start of Frame (SOF) and End of Frame
     (EOF), and other Primitive Signals.

     When FC frames are encapsulated in an IP packet, the Byte-encoded
     frame format is used. The Byte-encoded frame format uses 32-bit OS
     Code Words to represent valid FC frame delimiter. This format uses
     a single-byte OS Code to represent each FC Ordered Set.

     FC Over IP makes use of the OS Codes defined in Annex A of [7] for
     the frame delimiters. SOF and EOF codes defined in the figures (see
     below) in this Annex are inserted into the FC frame.

     Primitive Signals and Primitive Sequences are stripped at the FCIP
     boundary.

     The frame delimiters are identified by their position. An
     encapsulated Byte-encoded frame must use the corresponding 32-bit
     OS Code Word as the first and last words in the encapsulated PDU.

     FC frame delimiters shall be encoded in the format shown in Table
     below.


                       Table 1. Frame Delimiter Format

     +---+----------------+----------------+----------------+--------------+
     |Wrd|    <31:24>     |    <23:16>     |    <15:08>     |    <07:00>   |
     +---+----------------+----------------+----------------+--------------+
     |0  |  OS Code       |                  Reserved                      |
     +---+----------------+----------------+----------------+--------------+

     A.2 Encoded FC Frame Delimiters

     The SOF OS-codes are a single byte encoding of the SOF Ordered Set.
     The first word in an encapsulated Byte-encoded FC frame shall map
     the SOF Ordered Set to the corresponding 32-bit OS Code Word.

     The EOF OS-codes are a single byte encoding of the EOF Ordered Set.
     The last word in an encapsulated Byte-encoded FC frame shall map
     the EOF Ordered Set to the corresponding 32-bit OS Code Word.

                    +-----------------+----------------+
                    |     OS-Code     | Delimiter Name |
                    |      (hex)      |                |
                    +-----------------+----------------+
                    |      0x28       |     SOFf       |
                    +-----------------+----------------+



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Internet-Draft            Fibre Channel over IP               March 2000


                    |      0x3F       |     SOFc1      |
                    +-----------------+----------------+
                    |      0x2F       |     SOFi1      |
                    +-----------------+----------------+
                    |      0x37       |     SOFn1      |
                    +-----------------+----------------+
                    |      0x3D       |     SOFc2      |
                    +-----------------+----------------+
                    |      0x2D       |     SOFi2      |
                    +-----------------+----------------+
                    |      0x35       |     SOFn2      |
                    +-----------------+----------------+
                    |      0x3E       |     SOFc3      |
                    +-----------------+----------------+
                    |      0x2E       |     SOFi3      |
                    +-----------------+----------------+
                    |      0x36       |     SOFn3      |
                    +-----------------+----------------+
                    |      0x39       |     SOFc4      |
                    +-----------------+----------------+
                    |      0x29       |     SOFi4      |
                    +-----------------+----------------+
                    |      0x31       |     SOFn4      |
                    +-----------------+----------------+
                    |      0x38       |     SOFcf      |
                    +-----------------+----------------+
                    |      0x30       |     SOFnf      |
                    +-----------------+----------------+
                    |      0x41       |     EOFn       |
                    +-----------------+----------------+
                    |      0x42       |     EOFt       |
                    +-----------------+----------------+
                    |      0x46       |     EOFdt      |
                    +-----------------+----------------+
                    |      0x44       |     EOFrt      |
                    +-----------------+----------------+
                    |      0x49       |     EOFni      |
                    +-----------------+----------------+
                    |      0x4E       |     EOFdti     |
                    +-----------------+----------------+
                    |      0x4F       |     EOFrti     |
                    +-----------------+----------------+
                    |      0x50       |     EOFa       |
                    +-----------------+----------------+


     Full Copyright Statement

     Copyright (C) The Internet Society (1999).  All Rights Reserved.

     This document and translations of it may be copied and furnished to
     others, and derivative works that comment on or otherwise explain
     it or assist in its implementation may be prepared, copied,
     published and distributed, in whole or in part, without restriction



Rajagopal, et al.                                              [Page 14]





Internet-Draft            Fibre Channel over IP               March 2000


     of any kind, provided that the above copyright notice and this
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     Acknowledgement

     Funding for the RFC Editor function is currently provided by the
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     [draft-ietf-ipfc-fcoverip-01.txt] [This INTERNET DRAFT expires on
     November 15, 2000]






























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PAFTECH AB 2003-20262026-04-21 03:41:20