Re: [PATCH] hashed device lookup (Does NOT meet Linus' sumission

[Ben Greear <greearb@candelatech.com>]

Alan Cox wrote:
> 
> > Um, what about people running their box as just a VLAN router/firewall?
> > That seems to be one of the principle uses so far.  Actually, in that case
> > both VLAN and IP traffic would come through, so it would be a tie if VLAN
> > came first, but non-vlan traffic would suffer worse.
> 
> Why would someone filter between vlans when any node on each vlan can happily
> ignore the vlan partitioning

Suppose you have a 100bt link upstream, and want to re-sell that as 10 10Mb
links to all the customers in one building.  With VLANs, you can
haul all the data over one wire to a Linux box with 11 interfaces: 1 running
VLAN (100bt), and 10 others running 10bt ethernet.  Now, your uses are
segregated, and you only have 1 100bt wire running to the basement, instead
of 10.

Alternately, if you have a VLAN ethernet switch, your linux box just feeds
100bt into it, and acts as a router with 10 (vlan) interfaces.

In either of these cases, assuming the etherswitch and/or Linux box is secure,
the customers will not be able to be on other peoples VLAN.  This enables
all kinds of routing/billing possibilities...

> > So, how can I make sure that it is second in the list?
> 
> Register vlan in the top level protocol hash then have that yank the header
> and feed the packets through the hash again.

Thats what it already does, if I understand correctly.  Of course, if VLAN
is loaded as a module, then it will be in the hash before IP, right?


-- 
Ben Greear (greearb@candelatech.com)  http://www.candelatech.com
Author of ScryMUD:  scry.wanfear.com 4444        (Released under GPL)
http://scry.wanfear.com               http://scry.wanfear.com/~greear
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