network protocols handbook.pdf

229Protocols GuideSAN ProtocolsProtocol NameFCIP: Fibre Channel overTCP/IPProtocol DescriptionFibre Channel Over TCP/IP (FCIP) describes mechanisms thatallow the interconnection of islands of Fibre Channel storagearea networks over IP-based networks to form a unified storagearea network in a single Fibre Channel fabric. FCIP relies onIP-based network services to provide the connectivity betweenthe storage area network islands over local area networks, metropolitanarea networks, or wide area networks.The primary function of an FCIP Entity is forwarding FC Frames,employing FC Frame Encapsulation. Viewed from the IP Networkperspective, FCIP Entities are peers and communicateusing TCP/IP. Each FCIP Entity contains one or more TCPendpoints in the IP-based network. Viewed from the FC Fabricperspective, pairs of FCIP Entities, in combination with their associatedFC Entities, forward FC Frames between FC Fabricelements. The FC End Nodes are unaware of the existence ofthe FCIP Link.FC Primitive Signals, Primitive Sequences, and Class 1 FCFrames are not transmitted across an FCIP Link because theycannot be encoded using FC Frame Encapsulation. The path(route) taken by an encapsulated FC Frame follows the normalrouting procedures of the IP Network.An FCIP Entity MAY contain multiple FCIP Link Endpoints, buteach FCIP Link Endpoint (FCIP_LEP) communicates with exactlyone other FCIP_LEP. FCIP Entities do not actively participatein FC Frame routing. The FCIP Control & Services moduleMAY use TCP/IP quality of service features.It is necessary to statically or dynamically configure each FCIPentity with the IP addresses and TCP port numbers correspondingto FCIP Entities with which it is expected to initiate communication.If dynamic discovery of participating FCIP Entities issupported, the function SHALL be performed using the ServiceLocation Protocol (SLPv2). Before creating a TCP Connectionto a peer FCIP Entity, the FCIP Entity attempting to create theTCP connection SHALL statically or dynamically determine theIP address, TCP port, expected FC Fabric Entity World WideName, TCP Connection Parameters, and Quality of Service Information.FCIP Entities do not actively participate in the discovery of FCsource and destination identifiers. Discovery of FC addresses(accessible via the FCIP Entity) is provided by techniques andprotocols within the FC architecture.To support IP Network security, FCIP Entities MUST: 1)implementcryptographically protected authentication and cryptographicdata integrity keyed to the authentication process, and2) implement data confidentiality security features.On an individual TCP Connection, this specification relies onTCP/IP to deliver a byte stream in the same order that it wassent.Protocol StructureFibre Channel Frame Encapsulation Header Structure – FCIPspecific8 16 24 32bitProtocol # Version -Protocol # -Versionreplication of encapsulation word 0pFlags Reserved -pFlags -ReservedFlags Frame Length -Flags -Frame LengthTime Stamp (integer)Time Stamp (fraction)CRCCommon fields:• Protocol# - IANA-assigned protocol number identifyingthe protocol using the encapsulation.• Version - Encapsulation version as specified in [EN-CAP]• -Protocol# - One’s complement of the protocol#• -Version – One’s complement of the version• Flags - Encapsulation flags• Frame Length - Contains the length of the entire FCEncapsulated frame including the FC EncapsulationHeader and the FC frame (including SOF and EOFwords) in units of 32-bit words.• -Flags – One’s complement of the Flags field.• -Frame Length – One’s complement of the FrameLength field.• Time Stamp [integer] - Integer component of theframe time stamp as specified in [ENCAP].• Time Stamp - Fractional component of the time stamp[fraction] as specified in [ENCAP].• CRC - Header CRC. MUST be valid for iFCP.FCIP specific fields:Word 1 of the Protocol Specific field SHALL contain an exactcopy of word 0 in FC Frame Encapsulation.The pFlags (protocol specific flags) field provides informationabout the protocol specific usage of the FC EncapsulationHeader.Ch Reserved SFThe SF (Special Frame) bit indicates whether the FCIP Frame isan encapsulated FC Frame or an FSF (FCIP Special Frame).