Hello!
> A vlan device could be a simple IP-alias.
Sorry, Jamal you messed all the things completely.
ifaddr is not a virtual device. "Alias" was virtual device, but
this was bogus ill-defined device which created nothing but problems for
routing,
that's why we have no "aliases", but use plain ifaddrs.
VLAN is true "virtual" device, using nice well-defined encapsulation,
and from viewpoint of routing/addressing such device is not distinguishable
of "physical" one. The question: "physical" or "virtual" is just meaningless
from the viewpoint of routing and from any other viewpoint but packet
scheduling and policing.
What's about VLANs, they can be handled as separate virtual devices
provided you have _couple_ of them. It the number is higher, they must
be clustered as single nbma interface via framing (i.e neighbour) level
or via tags in routing tables. The same thing is with MPLs.
That's why I strongly dislike the idea to create zillions of net_devices
and consider that approach to VLANs as stupid one. And this is reason
why hashing device list (being great in principle) is not considered
to be some really required feature.
Alexey
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