I am new to QoS/Networking and I have a few questions so I hope you can help me.
1. ToS is older than DiffServ so how does the router know that the bits are set by DiffServ and not ToS? 2. Why should I use L3 prioritization instead of L2? If I have Switches on the way from the frame I have to use L2 priorization right? 3. Do I need L2 and L3 priorization if I use Router and Switches or is the Router able to interpret the 802.1p CoS Tags, too? 4. I don't understand the way how Cisco Switches are queueing traffic. I read about some specification like "1P4Q4T". I know it's about priority- and standart queues and bandwith thresholds but how does they work? 4.1 How do you define the bandwith thresholds? What does 4 thresholds mean? 4.2 How are the Queues used if I don't use QoS? 4.3 How are the queues used if I prioritize 1 VLAN?
I watched a few tutorials and read a lot in the world wide web but I haven't found the answers, yet. I hope you can help me.