VLAN interfaces on FreeBSD; performance issues

[Chuck Swiger]

Sten Daniel Sørsdal wrote:
> Chuck Swiger wrote:
[ ... ]
>> Because you cannot put one NIC into two genuinely distinct layer-2
>> collision domains.  Spanning Tree Protocol won't recognize a single NIC
>> as a potential connection or loop, depending.
> 
> A vlan should be a seen as a single nic.
> On other platforms, STP considers vlans as independant nics.
> But would it be multihoming if you are just bridging the vlans?
> I thought the essence of multihoming was multiple ip networks to which
> it was a member.

A VLAN is an abstraction, a way of logically grouping or seperating ports and 
tagging network traffic with a VLAN header, much as an IP subnet is an abstraction.

A NIC is a network interface.  It's a physical object.
The essence of multihoming is having two (or more) distinct NICs.

The most common application for multihoming is where a device performs layer-3 
routing between the two or more IP networks, but you could be using SPX/IPX, 
DECnet, or some other non-IP protocol.  You can also do bridging at layer-2, 
perhaps because the two sides use a different physical layer (Cat-5 ethernet 
cabling and wireless? Cat5 and thinnet? Cat5 and a dialup PPP link over POTS 
line, ...etc...)

-- 
-Chuck