Cisco Catalyst 3560G-TTS QoS Capabilities

The QoS control on any switch device is only going to be able to regulate traffic on its own ports, so in the configuration you're proposing, it will regulate traffic from each of the 2948G switches as a whole.  It *can* be specific in terms of addressing specific clients on the 2948G switches, but it will only be able to apply this control on the switch port that the 2948G is connected to.

That said, the 2948G units are essentially fixed-configuration versions of the Catalyst 4000 family and have QoS support in their CatOS.  If you want to bring QoS as close to the end stations as possible, you may want to look at what you can do on the 2948G units themselves.

http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.4/configuration/guide/qos.pdf

I was afraid of that.  This being the case, am I better off with some other configuration?  I have 65 PCs sharing a 1.5Mb internet connection.  I was going to but the Catalyst 3560G at the core with the WS-C2948Gs hooked up to it.  Am I better off with a more simple core, and more complex switches plugged into it?  We have two network closets and I was going to put a WS-C2948G in each one.  I read the link you provided, but I think I'm new enough to this that I don't understand the terminology well enough to know whether I'm on the right track.

I think one of the things I'm not clear on is how these devices can regulate traffic to the internet without slowing internal network traffic.  Is this done by just regulating port 80? or how?

Thanks.

Are you mostly concerned with prioritizing traffic on your 1.5Mb Internet connection?  If so, then doing it all on the 3560G is reasonable because all Internet traffic will have to go through it anyway.  You only need to go down to the 2948Gs if you're wanting to apply QoS to the LAN traffic.

QoS can be applied in a number of ways.  In most cases, you're just telling the network device that high-priority traffic gets to jump to the front of the queue when it's being sent to the Internet.  If there *is* no high-priority traffic, then everything functions normally.

Traffic can be assigned a priority by the sending device (in the case of VoIP devices and the like) or it can be applied based on other factors by a switch or router.  If, for example, you want to make sure that web browsing has to take the back seat to everything else, you can tell the switch or router to apply lower than normal priority to anything with a destination port of 80/tcp.  QoS can be manually set based on just about any factor that an extended access list can filter on.

My concern is primarily with regulating traffic to the internet.  1.5Mb/s shared by up to 65 people is not working well.  Granted, 65 people are not all using it at the same time.  However, there are some bandwidth hogs somewhere in the network, so I'm wanting some fine grain control.  If I regulate port 80 traffic on the 3560G and someone on one of the 2948Gs is heavily using the internet, then everyone on that 2948G switch would be affected right?  

My other concern is that intranet (not internet) access on port 80 would also be affected... or is there a way to regulate port 80 going outside the network without regulating port 80 inside the network?

Do these questions / concerns make sense?  I can try to re-explain them if I'm not expressing the concerns well enough.