grouping 2 or more interfaces as 1

[Helge Oldach]

Juan Rodriguez Hervella:
>On Thursday 11 December 2003 23:14, Michael Sierchio wrote:
>> Julian Elischer wrote:
>> >>>more likely he wants something like ng_fec or ng_one2many
>> >>
>> >>Unless performance is the reason for bonding the ether channels...
>> >>
>> >>Can't we steal the Linux code? ;-)
>> >
>> > is the netgraph version particularly slow?
>>
>> Not slower than a single ether channel, no ;-)  Considerably
>> slower than link layer bonding.   The netgraph version provides
>> a really useful functionality,  and I suppose that 2GB and 10GB
>> fiber interfaces will do away with any pressure to give us
>> bonding in the kernel.
>>
>For example, if we aggregate 4 ethernet cards into one
>virtual interface (fec), do this mean that the throughput is
>4 times the capacity of one ethernet card ?. 

In theory, yes. In practice, throughput is pretty often limited by PC
architectural issues. Consider, for example, PCI bus speed... Also
consider the overhead of actually distributing traffic between the
physical interfaces...

My personal experience tells me that channelling more than two FE
interfaces tends to be a slightly pointless exercise. On the other
hand, FECs are often implemented not for performance reasons but for
resilience reasons.

If you just need throughput, Gigabit is probably a better choice.

Channeling of gigabit interfaces IMHO doesn't make sense, given the
hardware choices that support FreeBSD.

>Also, if the pyshical interfaces are connected to different LANs,

They are not. A FEC (Fast Ether Channel) is a point-to-point link,
commonly between a terminal device (computer) and a network device
(switch). Both sides must have a common and identical understanding of
the remote end, and both ends necessarily belong to the same single
(V)LAN or 802.1Q trunk. Usually this also involves protocol support such
as PAgP.

Helge