Chapter 10 - Quality of Service in the IMS

The IMS supports several end-to-end QoS models (described in 3GPP TS 23.207 [13]). Terminals can use link-layer resource reservation protocols (e.g., PDP Context Activation), RSVP, or DiffServ codes directly. Networks can use DiffServ or RSVP. The most common model when cellular terminals are involved is to have terminals use link-layer protocols and to have the GGSN map link-layer resource reservation flows to DiffServ codes in the network. As mentioned in Chapter 8, the PCC (Policy and Charging Control) architecture includes QoS control. That is, PCC can be used to enforce QoS-related policy decisions such as how much bandwidth is...