CIS .com recently acquired a smaller competitor. The acquired company is not currently using Cisco routers, so you have connected the two WANs via an authenticated PPP link. After configuration both routers, issuing the show interface s0/0 command on the Cisco Router shows the interface to be in the up/down state.
Which two of these are possible causes? （）

You are working with a client to classify the different types of application traffic they will have on their network and to assign a QoS value to each traffic flow. The client has identified the following applications: Internet traffic, Oracle, network-based backups, AOL Instant Messenger, IP routing, voice, and voice signaling.
Given these types of applications, how many different classes will need to be configured in QoS?（）