QoSing on WAN traffic for beginner

[xshawn117x]

Hi everyone,

I've been in the Cisco networking field for about 6 months now. I understand LAN switching and routing pretty well. However, my understanding of QoSing is limited despite having read about it several times and seen videos about it. 

My current issue is that numerous people at my job from different sites have complained about the internet connection being very slow. A little background about my job:

1. We have 6 sites total including a NAP.
2. Every site is connected via AT&T Metro-Ethernet on a hub and spoke logical topology.
3. At every site, the edge device is a router, with the exception of two sites which are core (Catalyst 6506) switches.
4. All sites access our ISP at the NAP.
5. The Metro-E connection at the NAP connects to a WS-C3560 switch.
6. We have a straight 100 Mbps connection for every Metro-E connection.
7. We are an education institution and as such require frequent multimedia access such as YouTube videos. 
8. We have about 2, 600 combined students, faculty, and staff.
9. Our ISP connection is 100 Mbps which is shared among the 6 sites via the Metro-E network.

Having said that, I decided to investigate on the Metro-E switch at the NAP (4). When looking at the interface of the switchport where the Metro-E connection plugs to, the input value of the interface is almost always at 98 Mbps which means this is the sum of the output from all other sites. The output of that interface is usually around less than 40 Mbps, which means it pushes out that to all other sites. However, this figure is only during the day.

We have checked that backups are not running during the day, Windows imaging is not being performed, and that there is no constant replication between sites going on. It appears that most of our traffic is web browsing or accessing resources from servers across our sites.

Yes, I understand this is starting to sound like a bad network and server design, but that is why I am here to fix that until the whole network gets rebuilt. Having said that, I wanted to implement some sort of QoS that will give the highest priority to voice, then to web browsing (including watching YouTube videos), and finally any other data. I may also want to police the traffic to not go over 95 Mbps, or so.

So, having said that, what is the best solution I can implement, where would I implement this (core switches, routers, firewall, or edge router at the NAP, etc), and how exactly would I implement this?

One last thing, I'm pretty sure the issue lies with the Metro-E switch at the NAP because whenever I perform a SpeedTest, the download speed is always lower than the upload speed. Normally I got about 20 Mbps for download and 30 Mbps for upload. 

I really appreciate your prompt response and assistance.

[Joseph W. Doherty]

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Posting

Most LAN switches, compared to WAN routers, have weak QoS support.  (It would be helpful if you would describe the topology in detail.)

Managing Internet ingress bandwidth is very difficult.  (Normally, you want to manage the "far side's" egress.)  You can selectively police certain Internet ingress traffic, but the overall effect will often not be as effective as what's desired.  3rd party traffic management appliances can often do much more.

You're hub and spoke topology creates a QoS problem as it's very easy for the spokes to congest the ingress to the hub (which might already be happening based on your 98 Mbps ingress).  Does your MetroE provider offer any QoS support?  If not, if the remote sites support shaping, you can shape to insure the sum of the remotes egress does not overrun your hub's ingress.  Here too, a 3rd party traffic management appliance might be helpful.