[c-nsp] VoIP without QoS

[Jared Mauch]

On Tue, May 22, 2007 at 02:46:39PM -0400, Eric Kagan wrote:
> Who or why are people against using a policy map that allows "up to x" of
> bandwidth for the specified (ACL, class-map) but is available for all other
> traffic when there is no VOIP ?  This seems backwards / worse to me to
> restrict the pipe and loose that much available bandwidth for other apps
> when there is no VOIP ?

	I think the problem is the internet is quite diverse.  Today
it's SIP, CM and SKYPE.  Tomorrow it's Joost. you're talking about a
moving target that isn't the same for every customer.  Then you see
hardware limitations and if each customer wants their own customized
acl you get into support issues when trying to scale it and not
break it.  This is why you don't see a lot of the providers just blocking
stuff like the udp/1434 packets of 404 bytes in length that are likely
hosts that are still infected with ms-sql.  Some folks may, but others will
continue to leave it open because they have that remote DBA that needs access.
Instead of creating the support problem, folks just don't filter it.

	It also threatens the open-network model, and like I said before,
it really doesn't scale unless you have all hardware that has the same
advanced capabilities.  take a look at it historically, GSR has had numerous
hardware revisions that both increased bandwidth-per-slot and processing
capabilities of the cards (from Engine0, 1, 2, etc..)  Each with a different
set of features that would work in hardware, and in some cases features
that were not really compatible with each other.  As a SP, either you
need to closely track that "feature matrix", or just set a policy that
you don't do things that might aggrivate your production network and other
customers that may coexist on that linecard.

	For enough money, you can get someone to build you your ideal
network, but most people end up compromising on price at some point and
that may mean a provider that gives you those bits really cheap with no
frills, or more expensive with the ability to send them various dscp, etc..
to make sure the bits you say are important are most likely to get there
[first].

	- Jared


-- 
Jared Mauch  | pgp key available via finger from jared at puck.nether.net
clue++;      | http://puck.nether.net/~jared/  My statements are only mine.