Sorry cant keep up with all the overwhelming response ;->
I think i'll pick on Ben again since his post seems to capture mostly
everything.
On Fri, 2 Jun 2000, Ben Greear wrote:
> Rob Walker wrote:
>
> > Why should VLANs not be fake devices? How are they different from
> > aliased interfaces?
>
> I think most of us are in violent agreement that they should be devices,
> Alexey and Jamal seem to be the main dissenters, and at least IMO,
> they have not offered a reason good enough to make me consider trying
> to make VLANs anything other than devices...
>
Devices map to physical devices i.e ports in your lingo. How many of those
do you see in your average Linux machine?
Infact i have never seen a single switch blade with more than 48 ports
but even that is beside the point. The point really is the desiugn
abstraction.
VLANs are virtuals circuits which are abstracted on the device. So are
PPPOE sessions, ATM *VCs, MPLS LSPs, FR etc and the list goes on.
They all 'suffer' from the same problem as you, i dont understand why you
are such a special case.
I will argue that you _can not_ write a generic search algorithm for all
these protocols. Unfortunately if you enforce one then the device search
algorithm will have to be the same across the board.
It goes without any arguement that we have a very good worst case estimate
today, given the practical limits. You try adding all those thousands of
VLANs as devices and i can _guarantee you_ that you are not optimizing for
the common case.
I like Lennert and Gleb's because they dont use devices for the
abstraction rather they attach themselves to the device. You dont.
You could use the aliasing interface if you wanted to add extra IP
addresses (one per VLAN).
I dont understand the DHCP problem. What has an app got to do with
what happens at layer 2? Tcpdump is pretty straight
forward; you add another protocol, the rule is you extend tcpdump.
I was also kind of suprised to see that VLANs were being preached as a
replacement for aliasing. I have heard that the authors of 802.1q
have already apologized to the world for the mess ;-> Please dont spread
the 802.1q gospel incase some frail minds start believing you. the only
reason i am for it is because of what i would call "peer pressure" (win2k
has it as are other so called "enterprise ready" OSes).
cheers,
jamal
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