vlans and cloning

[Dmitry Pryanishnikov]

Hello!

On Mon, 10 Jul 2006, Sam Leffler wrote:
>> ifconfig vlan0 create
>> ifconfig vlan0 vlan 1 vlandev em0
>>
>> sequence is required for now. Also, I thing it's perfectly correct to have
>>
>> cloned_interfaces="vlan30"
>>
>> while NOT having 'ifconfig_vlan30' assignment - system administrator
>> could just reserve a spare interface w/o assigning it's parameters. So I
>> think
>> that possibility of the specific device cloning w/o arguments, e.g.,
>>
>> ifconfig vlan30 create
>>
>> should be preserved.
>
> Clearly one would need to fix rc scripts.  The question is should the
> old behaviour be preserved; it provides no functionality--i.e. a cloned
> device is unusable until you set the tag+parent and you cannot set the
> tag or parent on an existing cloned device (once setup).  So the only

  I don't agree:

1) Cloned but unset device is perfectly legal for, e.g., mentioning
    in ipfw rules (or any other context which requires interface name);

2) Sure, you _can_ change tag+parent afterwards:

root at homelynx# ifconfig vlan32 create
root at homelynx# ifconfig vlan32 vlan 32 vlandev rl0
root at homelynx# ifconfig vlan32 -vlandev
root at homelynx# ifconfig vlan32 vlan 33 vlandev rl0
root at homelynx#

> preserve existing practice.  Removing the 2 step procedure would allow
> code to be removed and (IMO) clarify how a vlan is crafted.  In the
> future there will be cloned devices that cannot/will-not be specified
> with a 2-step procedure so having vlans work this way will violate POLA.

  Please don't break well-known and useful behaviour! Remember that it allows
to switch easily physical vlanXXX device assignment (e.g., migration to the
another trunk) w/o reloading firewall rules.

Sincerely, Dmitry
-- 
Atlantis ISP, System Administrator
e-mail:  dmitry at atlantis.dp.ua
nic-hdl: LYNX-RIPE