Chapter 8
QoS
In this chapter, we concentrate on the QoS of the transport service. A starting point is in looking at the end user layer, the radio network layer, and the transport layer in Section 1.
End user services, based on TCP/IP and UDP/IP, are discussed in Section 2. These protocols are used to carry the end user applications over the mobile network. One well known aspect is that TCP reacts to packet loss as congestion. In the mobile network, packets may be lost due to the air interface. On the other hand, lost packets are retransmitted by the radio network layer – potentially recovering the packet before end user TCP reacts.
Section 3 discusses backhaul QoS marking. Traffic is classified and marked preferably at the sources. The traffic sources in the backhaul are the mobile network elements: base stations, controllers, gateways. QoS is marked to the Differentiated Services Code Point (DSCP). Further marking to MPLS and Ethernet (or yet other layers) is carried out based on the DSCPs.
Ingress and egress functions are the scope for Section 4. These are deployed at the IP layer, and also potentially at the lower layers. When the backhaul is provided as a service by a service provider, ingress policing by the service provider is an example of a topic that needs to be addressed at the user to network (UNI) interface.
Sections 8.5, 8.6 and 8.7 provide a radio network technology (2G, 3G, LTE) specific discussion, with ...
