tailieunhanh - Resource Management in Satellite Networks part 27

Resource Management in Satellite Networks part 27. This book provides significant knowledge on innovative radio resource management schemes for satellite communication systems that exploit lower layer adaptivity and the knowledge of layer 3 IP QoS support and transport layer behavior. The book integrates competencies considering all the parts of system design: propagation aspects, radio resource management, access protocols, network protocols, transport layer protocols, and more, to cover both broadband and mobile satellite systems | 246 Ulla Birnbacher Wei Koong Chai the same service as best-effort service in a lightly loaded network regardless of actual network conditions. Controlled-load service is described qualitatively in that no target values of delay or loss are specified. The IntServ architecture represents a fundamental change to the current Internet architecture which is based on the concept that all flow-related state information should be in the end-systems. The main problem of the IntServ model is scalability especially in large public IP networks which may potentially have millions of active micro-flows concurrently in transit since the amount of state information maintained by network elements tends to increase linearly with the number of micro-flows. Differentiated services One of the primary motivations for Differentiated Services DiffServ 6 was to devise alternative mechanisms for service differentiation in the Internet that mitigate the scalability issues encountered with the IntServ model. Scalable mechanisms are deployed within the DiffServ framework for the categorization of traffic flows into behavior aggregates allowing each behavior aggregate to be treated differently especially when there is shortage of resources such as link bandwidth and buffer space. A DiffServ field in the IPv4 header has been defined. Such field consists of six bits of the part of the IP header formerly known as TOS octet and it is used to indicate the forwarding treatment that a packet should receive at a node. Within the DiffServ framework a number of Per-Hop Behavior PHB groups have been also standardized. Using the PHBs several classes of services can be defined using different classification policing shaping and scheduling rules. Conceptually a DiffServ domain consists of two types of routers namely core router and edge router. Core router resides within the domain and is generally in charge of forwarding packets based on their respective DiffServ Code Point DSCP . The edge router is .