--- name: "ng_one2many" section: "4" platform: "linux" package: "freebsd-manpages" version: "6.0-5" release: "Debian 4.0 (Etch)" platforms: ["linux", "freebsd"] url: "https://new.carta.tech/ng_one2many" --- # ng\_one2many(4) packet multiplexing netgraph node type ## NAME **ng\_one2many** – packet multiplexing netgraph node type ## SYNOPSIS **#include \** **#include \** ## 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) fashion. 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 or more of the many hooks; which hook(s) is determined by the node's configured transmit 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. Before an interface or link can be plumbed into a group, its status must be marked as being “up”. This is normally setup during the initial boot stages by [rc.conf(5)](/rc.conf/5.md). It is also possible to change an interface's status to “up” by using the [ifconfig(8)](/ifconfig/8.md) utility. ## TRANSMIT ALGORITHMS - NG\_ONE2MANY\_XMIT\_ROUNDROBIN Packets are delivered out the many hooks in sequential order. Each packet goes out on a different many hook. - NG\_ONE2MANY\_XMIT\_ALL Packets are delivered out all the many hooks. Each packet goes out each many hook. In the future other algorithms may be added as well. ## LINK FAILURE DETECTION The node distinguishes between active and failed links. Data is sent only to active links. The following link failure detection algorithms are available: - NG\_ONE2MANY\_FAIL\_MANUAL 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. - NG\_ONE2MANY\_FAIL\_NOTIFY The node listens to flow control message from *many* hooks, and considers link failed if NGM\_LINK\_IS\_DOWN is received. If the NGM\_LINK\_IS\_UP message is received, node considers link active. In the future other algorithms may be added as well. When all links are considered failed, node sends the NGM\_LINK\_IS\_DOWN message towards the *one* hook. When at least one link comes up, node sends the NGM\_LINK\_IS\_UP message towards the *one* hook. ## 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 valid settings for the xmitAlg field are NG\_ONE2MANY\_XMIT\_ROUNDROBIN (default) or NG\_ONE2MANY\_XMIT\_ALL. 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 corresponding 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 statistics 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 networking 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. ## SEE ALSO [netgraph(4)](/netgraph/4.md), [ng\_bridge(4)](/ng_bridge/4.md), [ng\_ether(4)](/ng_ether/4.md), [ng\_hub(4)](/ng_hub/4.md), [ifconfig(8)](/ifconfig/8.md), [ngctl(8)](/ngctl/8.md) ## HISTORY The **ng\_one2many** node type was implemented in FreeBSD 4.2. ## AUTHORS The **one2many** netgraph node (with round-robin algorithm) was written by Archie Cobbs ⟨archie@FreeBSD.org⟩. The all algorithm was added by Rogier R. Mulhuijzen ⟨drwilco@drwilco.net⟩. ## BUGS More transmit and link failure algorithms should be supported. A good candidate is Cisco's Etherchannel.