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NG_ONE2MANY(4)	       FreeBSD Kernel Interfaces Manual		NG_ONE2MANY(4)

NAME
     ng_one2many -- packet multiplexing	netgraph node type

SYNOPSIS
     #include <netgraph/ng_one2many.h>

DESCRIPTION
     The one2many provides a simple mechanism for routing packets over several
     links in a	one-to-many (and in the	reverse	direction, many-to-one)	fash-
     ion.  There is a single hook named	one, and multiple hooks	named many0,
     many1, etc.  Packets received on any of the many hooks are	forwarded out
     the one hook.  Packets received on	the one	hook are forwarded out one of
     the many hooks; which hook	is determined by the node's configured trans-
     mit algorithm.  Packets are not altered in	any way.

     Each of the connected many	links may be considered	to be up or down.
     Packets are never delivered out a many hook that is down.	How a link is
     determined	to be up or down depends on the	node's configured link failure
     detection algorithm.

TRANSMIT ALGORITHMS
     At	this time, the only algorithm for determing the	outgoing many hook is
     a simple round-robin delivery algorithm.  Packets are delivered out the
     many hooks	in sequential order.

     In	the future other algorithms may	be added as well.

LINK FAILURE DETECTION
     At	this time, the only algorithm for determining when a link has failed,
     other than	the hook being disconnected, is	the ``manual'' algorithm: the
     node is explicitly	told which of the links	are up via the
     NGM_ONE2MANY_SET_CONFIG control message (see below).  Newly connected
     links are down until configured otherwise.

     In	the future other algorithms may	be added as well.

HOOKS
     This node type supports up	to NG_ONE2MANY_MAX_LINKS hooks named many0,
     many1, etc., plus a single	hook named one.

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

     NGM_ONE2MANY_SET_CONFIG
	  Sets the node	configuration using a struct ng_one2many_link_config
	  as the control message argument:

	  /* Node configuration	structure */
	  struct ng_one2many_config {
	    u_int32_t	xmitAlg;	/* how to distribute packets */
	    u_int32_t	failAlg;	/* how to detect link failure */
	    u_char	enabledLinks[NG_ONE2MANY_MAX_LINKS];
	  };

	  Currently, the only valid setting for	the xmitAlg field is
	  NG_ONE2MANY_XMIT_ROUNDROBIN; this is also the	default	setting.  The
	  only valid setting for failAlg is NG_ONE2MANY_FAIL_MANUAL; this is
	  also the default setting.

     NGM_ONE2MANY_GET_CONFIG
	  Returns the current node configuration in a struct
	  ng_one2many_link_config.

     NGM_ONE2MANY_GET_STATS
	  This command takes a 32 bit link number as an	argument and returns a
	  struct ng_one2many_link_stats	containing statistics for the corre-
	  sponding many	link, which may	or may not be currently	connected:

	  /* Statistics	structure (one for each	link) */
	  struct ng_one2many_link_stats	{
	    u_int64_t	recvOctets;	/* total octets	rec'd on link */
	    u_int64_t	recvPackets;	/* total pkts rec'd on link */
	    u_int64_t	xmitOctets;	/* total octets	xmit'd on link */
	    u_int64_t	xmitPackets;	/* total pkts xmit'd on	link */
	  };

	  To access statistics for the one link, use the link number -1.

     NGM_ONE2MANY_CLR_STATS
	  This command takes a 32 bit link number as an	argument and clears
	  the statistics for that link.

     NGM_ONE2MANY_GETCLR_STATS
	  Same as NGM_ONE2MANY_GET_STATS, but also atomically clears the sta-
	  tistics for the link as well.

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

EXAMPLES
     The following commands will set up	Ethernet interfaces fxp0 to deliver
     packets alternating over the physical interfaces corresponding to net-
     working interfaces	fxp0 through fxp3:

       # Plumb nodes together
       ngctl mkpeer fxp0: one2many upper one
       ngctl connect fxp0: fxp0:upper lower many0
       ngctl connect fxp1: fxp0:upper lower many1
       ngctl connect fxp2: fxp0:upper lower many2
       ngctl connect fxp3: fxp0:upper lower many3
       # Allow fxp1 through fxp3 to xmit/recv fxp0 frames
       ngctl msg fxp1: setpromisc 1
       ngctl msg fxp2: setpromisc 1
       ngctl msg fxp3: setpromisc 1
       ngctl msg fxp1: setautosrc 0
       ngctl msg fxp2: setautosrc 0
       ngctl msg fxp3: setautosrc 0
       # Configure all four links as up
       ngctl msg fxp0:upper \
	 setconfig "{ xmitAlg=1	failAlg=1 enabledLinks=[ 1 1 1 1 ] }"
       # Bring up interface
       ifconfig	fxp0 192.168.1.1 netmask 0xfffffffc

     With a similar setup on a peer machine (using the address 192.168.1.2), a
     point-to-point Ethernet connection	with four times	normal bandwidth is
     achieved.

BUGS
     More transmit and link failure algorithms should be supported.  A good
     candidate is Cisco's Etherchannel.

SEE ALSO
     netgraph(4), ng_bridge(4),	ng_ether(4), ngctl(8)

HISTORY
     The ng_one2many node type was implemented in FreeBSD 4.2.

AUTHORS
     Archie Cobbs <archie@FreeBSD.org>

FreeBSD	10.1		       November	15, 2000		  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | TRANSMIT ALGORITHMS | LINK FAILURE DETECTION | HOOKS | CONTROL MESSAGES | SHUTDOWN | EXAMPLES | BUGS | SEE ALSO | HISTORY | AUTHORS

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