le, which may include (but are not limited to) the following: Classification based on ports. Ports are used by transport layer protocols such as TCP and UDP to identity applications on the top. For example, port 80 (HTTP, i.e. the Web) may take precedence over port 21 (FTP). Classification based on application type. Different applications may be treated differ- ently. For example, carrier grade VoIP takes precedence over HTTP, BitTorrent, and other OTT services used over Internet access service. Classification based on user type. There are typically different types of users of telecommunication services. For example, home and business users may get normal service, but hospitals, police, or fire departments get highest priority service and no mandatory requirement for users' authentication (e.g. emergency services number 112 in Europe, or 911 in the U.S.). Classification based on subscription. Different users may pay different prices for the same services with different QoS. For example, a user may need to pay $50 for high-speed Internet access (with guaranteed maximum access bitrates in down- stream and upstream) and $10 for fair-usage policy-based Internet (e.g. bitrates are proportionally downgraded with higher usage). Besides the above classification of IP packets and sessions or calls to which they belong, there are other options and possibilities which may be created for classification of user traffic and hence IP packets. Regardless of the approach used, it is always implemented via certain traffic management techniques. Thus there is technical classification of IP packets which is similar to port-based classification. 2.5.2 Packet Classification From the Technical Side Packet classification is needed to sort packets into flows and then to group the flows into classes. This is further needed for scheduling purposes, such as FIFO (first in first out), PQ (priority queuing), or some of many other techniques. Considering the Internet net- working principles, based on identification of a connection with the IP 