On Fri, Mar 12, 2004 at 10:40:59AM -0500, Chuck Swiger wrote: > You can use "ifconfig ... alias" to bind more than one IP address to a NIC; > you must you a different subnet mask, however (usually 0xfffffff). You > also can use netgraph (ng_many2one?) to trunk several NICs together for > fault-tolerance.
ng_one2many(4). This you can use for channel bonding -- to make a virtual network interface out of several physical NICs, with the implied extra bandwidth available. However, one thing it doesn't actually do is provide failure tolerance. As the man page says: 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. That is, you have to manually reconfigure the interface group if one of it's components should happen to fail. There's no means of automatically testing that all of the components are still working properly, and if not, of reconfiguring the interface group to work around the problem. ng_one2many is clearly the basis upon which such failure tolerance could be built, but so far no one has committed the necessary patches to ng_one2many to do that. If you need failover, what you can apparently use is the ng_fec module by Bill Paul which implements the Cisco Fast EtherChannel mechanism, but which apparently has no man pages or other docs available. See Bill's announcement message at http://docs.freebsd.org/cgi/getmsg.cgi?fetch=700715+0+archive/2001/freebsd-hackers/20010211.freebsd-hackers However, you either need to be using a point-to-point link or via a Cisco switch that supports FEC. Cheers, Matthew -- Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks Savill Way PGP: http://www.infracaninophile.co.uk/pgpkey Marlow Tel: +44 1628 476614 Bucks., SL7 1TH UK
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