Re: QoS mapping

On Aug 3, 2005, at 4:58 PM, Ben Greear wrote:

> John T. Kamenik wrote:
>
>> I have a linux based bridge/router.  On one side is a VLAN  
>> network,  and on the other an Ethernet network.  The VLAN network  
>> uses the  user_priority field in the VLAN header to perform  
>> various forms of  QoS.  The ethernet network does a similar thing  
>> with the IP ToS  bits.  Is there an easy way to map the ToS bits  
>> to user_priority and  visa versa?  And the solution cannot be "use  
>> a Cisco" :).
>>
>
> I'm sure the linux iptables code can somehow do the translation
> for you...but I don't know the exact details...
>

Iptables is what I thought about using first.  However, iptables does  
not have an understanding of VLANs.  At least not to my knowledge.   
This means that iptables has no knowledge of the user_priority field  
and therefore cannot map to or from it.

The only solution I could think of was to modify the VLAN driver to  
allow the mapping between ToS and user_priority.  In the same vein as  
mapping between user_priority and linux priority.  Before I attempted  
it I wanted to know that I had no better options.