[Asterisk-Dev] Anyone doing QOS routing on Linux for SIP/RTP?

[steve]

On Monday 12 May 2003 20:29, Eric Wieling wrote:
> On Mon, 2003-05-12 at 19:09, John Todd wrote:
> > The long answer is that you need to look at QOS (Quality Of
> > Service) and how your particular router vendor implements it. 
> > On the "global" Internet, you're pretty much out of luck since
> > very few providers exchange QOS information to ensure
> > end-to-end priority for packets with TOS (Type Of Service) bits
> > set in their headers.  If this is all within your own control,
> > you should talk to your router vendor (or your router
> > technician) and see what they can tell you about how to
> > implement QOS across your network.
>
> Are there ANY ISPs that support QoS on their backbones?

My lousy 2 cent...

I have seen indications that QoS is not as needed/useable as one 
would think. Looking into how to use it across the US I've come to 
the conclusion that the lag in the backbone is neglectable. ATM has 
QoS built into it but it was added to make it possible to share 
small connections like T1s with others. On bigger pipes it's not I 
really don't see it as very valuable.

The problem becomes obvious as you move down the tiers where some 
ISP has oversold his bandwidth to make more money. At that level it 
won't make a difference either as he usually does not use ATM in 
the first place.

You can argue that you should not use someone who cannot provide 
what you will need in the next couple of years (as far as you can 
tell). 

QoS in routers is not very useful either as either the packages 
arrive within, ideally, 200ms. Or they don't. In which case you 
have a loss of audio.

I mean the lag in routers and backbone are 1 ms. True, you could 
route it down the other provider but the problem lies further down 
where that kind of service is not available. 

Last century I designed a (real)audio network for a broadcaster with 
multiple redundancy. It was to cover the US. There was really not 
so much of a problem finding someone who had either a national 
backbone or enough access to it. The service I was looking for was 
to have six servers geographically positioned to give least lag to 
each client. At that time they could route the client to the 
closest server with no problem as each NOC had the fastest route 
available from each router. Which would then route it accordingly.

As you say not every ISP has it, which makes it a "unstable" network 
compared to TELCO lines, but probably as good as or better than 
cell phones. So the decision could be, is cell service good enough?

So now I've done all this rambling and not answered anything... : ) 
At least it felt good.