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     ng_rfc1490 — RFC 1490 netgraph node type


     #include <netgraph/ng_rfc1490.h>


     The rfc1490 node type performs protocol encapsulation, de-encapsulation, and multiplexing
     according to RFC 1490 (which has since been updated by RFC 2427).  This particular type of
     encapsulation is often used on top of frame relay DLCI channels.

     The downstream hook is used to transmit and receive encapsulated frames.  On the other side
     of the node, the inet and ppp hooks are used to transmit and receive raw IP frames and PPP
     frames, respectively.  PPP frames are transmitted and received according to RFC 1973; in
     particular, frames appearing on the ppp hook begin with the PPP protocol number.  The
     ethernet hook can be used to transmit and receive Ethernet frames (without a checksum) in
     RFC 1490's bridging format.

     Typically the inet hook is connected to the inet hook of an ng_iface(4) node.


     This node type supports the following hooks:

     downstream  Connects to the RFC 1490 peer entity.

     ethernet    Transmits and receives bridged raw Ethernet frames, without a checksum.

     inet        Transmits and receives raw IP frames.

     ppp         Transmits and receives PPP frames.


     This node type supports the generic control messages, plus the following:

     NGM_RFC1490_SET_ENCAP (setencap)
          This command sets encapsulation method for the node.  The desired method must be passed
          as a string message argument, and must be one of the following supported encapsulation

          "ietf-ip"    IP packets are sent using simple RFC1490/2427 encapsulation.

          "ietf-snap"  IP packets are sent inside SNAP frames.  Also conforms to RFC1490/2427.

          "cisco"      IP packets are sent and received using proprietary Cisco encapsulation

     NGM_RFC1490_GET_ENCAP (getencap)
          This command returns current encapsulation method on the node.


     This node shuts down upon receipt of a NGM_SHUTDOWN control message, or when all hooks have
     been disconnected.


     netgraph(4), ng_frame_relay(4), ng_iface(4), ngctl(8)

     C. Brown and A. Malis, Multiprotocol Interconnect over Frame Relay, RFC 2427.

     W. Simpson, PPP in Frame Relay, RFC 1973.


     The ng_rfc1490 node type was implemented in FreeBSD 4.0.


     Julian Elischer <>


     Not all of RFC 1490 is implemented.