[ NNSquad ] Re: define: "service providers have to manage their networks somehow, especially during peak times."

[Barry Gold <bgold@matrix-consultants.com>]

Colin May wrote:
> Generally speaking it can often be said that a minority of high speed 
> broadband connected end users account for the majority of ISP traffic - 
> with this in mind,  I cannot realistically see any ISPs wanting to pay 
> attention to any QoS bits that may be set in the TCP headers that 
> originate from beyond the network edge (e.g. any connection coming into 
> DSL termination equipment from end users).   Surely there is too much 
> chance of abuse from the people who are using the majority of bandwidth 
> to flag all their traffic up for preferential treatment?

That's been hashed over before.  QoS bits are to determine the relative
priority of traffic within a user's stream.

There are basically two ways of implementing this:

1. We will give you X MB/sec of bandwidth (plus a variable amount "Y"
more at off-peak times).  When your usage exceeds X+Y, we drop the
lowest priority packets first.  If all your packets are marked highest
priority, we drop them at random.

2. We use QoS globally -- the highest priority packets get through, the
lower ones get dropped.  A given tier of service allows you to mark up
to X MB/month at Priority 1 (highest), Y > X at P2, Z > Y at P3.  All
the rest are treated as P4.  If you mark more than your allocation at a
given priority, we route the first X (or Y or Z) at that priority; the
rest get downgraded to the next priority that you have paid-for but
unused capacity in.

So, if you want your VOIP traffic to get through, you mark that P1.  If
you mark your web traffic P1 as well, you may find your VOIP sounding
watery or even dropping calls, because a random selection of your
packets will get downgraded to P2 (or P3 or P4).  Mark your intense P2P
traffic as P1 and watch your VOIP become unusable and your websurfing
slow to a crawl -- or buy a higher service tier.

Once we do that, the heaviest users have an incentive to either cut
back, or pay more.  Which gives the ISPs more money to upgrade their
networks, and to buy more capacity from _their_ upstream providers --
which gives them money to build a heavier backbone.

That's the way capitalism is supposed to work.