man pages section 7: Device and Network Interfaces

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Updated: July 2014



fcip - IP/ARP over Fibre Channel datagram encapsulation driver




The fcip driver is a Fibre Channel upper layer protocol module for encapsulating IP (IPv4) and ARP datagrams over Fibre Channel. The fcip driver is a loadable, clonable, STREAMS driver supporting the connectionless Data Link Provider Interface, dlpi(7P) over any Sun Fibre Channel transport layer-compliant host adapter.

The fcip driver complies with the RFC 2625 specification for encapsulating IP/ARP datagrams over Fibre Channel, and allows encapsulation of IPv4 only, as specified in RFC 2625. The fcip driver interfaces with the fp(7d) Sun Fibre Channel port driver.



The cloning character-special device /dev/fcip is used to access all Fibre Channel ports capable of supporting IP/ARP traffic on the system.

fcip and DLPI

The fcip driver is a style 2 Data Link Service Provider. All M_PROTO and M_PCPROTO type messages are interpreted as DLPI primitives. Valid DLPI primitives are defined in <sys/dlpi.h>. Refer to dlpi(7P) for more information on DLPI primitives.

An explicit DL_ATTACH_REQ message must be sent to associate the opened stream with a particular Fibre Channel port (ppa). The ppa ID is interpreted as an unsigned long data type and indicates the corresponding Fibre Channel port driver instance number. An error ( DL_ERROR_ACK) is returned by the driver if the ppa field value does not correspond to a valid port driver instance number or if the Fibre Channel port is not ONLINE. Refer to fp(7d) for more details on the Fibre Channel port driver.

The values returned by the driver in the DL_INFO_ACK primitive in response to a DL_INFO_REQ from the user are as follows:

  • Maximum SDU is 65280 (defined in RFC 2625).

  • Minimum SDU is 0.

  • DLSAP address length is 8.

  • MAC type is DL_ETHER.

  • SAP length is -2.

  • Service mode is DL_CLDLS.

  • Optional quality of service (QOS) fields are set to 0.

  • Provider style is DL_STYLE2.

  • Provider version is DL_VERSION_2.

  • Broadcast address value is 0xFFFFFFFF.

Once in DL_ATTACHED state, the user must send a DL_BIND_REQ to associate a particular SAP (Service Access Point) with the stream. The fcip driver DLSAP address format consists of the 6–byte physical address component followed immediately by the 2–byte SAP component producing an 8–byte DLSAP address. Applications should not be programmed to use this implementation-specific DLSAP address format, but use information returned in the DL_INFO_ACK primitive to compose and decompose DLSAP addresses. The SAP length, full DLSAP length, and SAP/physical ordering are included within the DL_INFO_ACK. The physical address length is the full DLSAP address length minus the SAP length. The physical address length can also be computed by issuing the DL_PHYS_ADDR_REQ primitive to obtain the current physical address associated with the stream.

Once in the DL_BOUND state, the user can transmit frames on the fibre by sending DL_UNITDATA_REQ messages to the fcip driver. The fcip driver will route received frames up any of the open and bound streams having a SAP which matches the received frame's SAP type as DL_UNITDATA_IND messages. Received Fibre Channel frames are duplicated and routed up multiple open streams if necessary. The DLSAP address contained within the DL_UNITDATA_REQ and DL_UNITDATA_IND messages consists of both the SAP (type) and physical address (WorldWideName) components.

Other Primitives

In Fibre Channel, multicasting is defined as an optional service for Fibre Channel classes three and six only. If required, the Fibre Channel broadcast service can be used for multicasting. The RFC 2625 specification does not support IP multicasting or promiscuous mode.

fcip Fibre Channel ELS

The fcip driver will use the FARP Fibre Channel Extended Link Service (ELS), where supported, to resolve WorldWide Names (MAC address) to FC Port Identifiers(Port_ID). The fcip driver also supports InARP to resolve WorldWide Name and Port_ID to an IP address.



fcip character-special device


64–bit ELF kernel driver (x86)


64–bit ELF kernel driver (SPARC)


fcip driver configuration file


See attributes(5) for descriptions of the following attributes:


See also

netstat(1M), prtconf(1M), driver.conf(4), fp(7d), dlpi(7P)

Writing Device Drivers

IP and ARP over Fibre Channel, RFC 2625 M. Rajagopal, R. Bhagwat, W. Rickard. Gadzoox Networks, June 1999

ANSI X3.230-1994, Fibre Channel Physical and Signalling Interface (FC-PH)

ANSI X3.272-1996, Fibre Channel Arbitrated Loop (FC-AL)


If you use a Fibre Channel adapter with two or more ports that each share a common Node WorldWideName, the fcip driver will likely attach to the first port on the adapter.

RFC 2625 requires that both source and destination WorldWideNames have their 4 bit NAA identifiers set to binary '0001,' indicating that an IEEE 48–bit MAC address is contained in the lower 48 bits of the network address fields. For additional details, see the RFC 2625 specification.