6.1.2 ISA Approach o Provision of Qos over IP o Sharing available capacity when congested ◆ Router mechanisms Routing Algorithms Select to minimize delay i Packet discard Causes TcP sender to back off and reduce load ◆ Enahnced by IsA 6
6 6.1.2 ISA Approach Provision of QoS over IP Sharing available capacity when congested Router mechanisms ◼ Routing Algorithms Select to minimize delay ◼ Packet discard Causes TCP sender to back off and reduce load Enahnced by ISA
Flow o IP packet can be associated with a flow Distinguishable stream of related IP packets t From single user activity Requiring same Qos h E. g. one transport connection or one video stream Unidirectional t Can be more than one recipient ●Ⅳ Multicast Membership of flow identified by source and destination IP address, port numbers, protocol type IPv6 header flow identifier can be used but isnot necessarily equivalent to ISA flow
7 Flow IP packet can be associated with a flow ◼ Distinguishable stream of related IP packets ◼ From single user activity ◼ Requiring same QoS ◼ E.g. one transport connection or one video stream ◼ Unidirectional ◼ Can be more than one recipient Multicast ◼ Membership of flow identified by source and destination IP address, port numbers, protocol type ◼ IPv6 header flow identifier can be used but isnot necessarily equivalent to ISA flow
ISA Functions ◆ Admission control For Qos, reservation required for new flow Gv RSVP used ◆ Routing algorithn Base decision on Qos parameters ◆ Queuing discipline Take account of different flow requirements ◆ Discard policy Manage congestion Me leet Qos
8 ISA Functions Admission control ◼ For QoS, reservation required for new flow ◼ RSVP used Routing algorithm ◼ Base decision on QoS parameters Queuing discipline ◼ Take account of different flow requirements Discard policy ◼ Manage congestion ◼ Meet QoS
6.1.3 ISA Implementation in Router ◆ Background Functions Routing Reservation Admission Manage Protocol(s) Protocol Control ment Agent Traffic Routing Database Control Database ◆ Forwarding Classifier Packet oos queuing functions Route Scheduler Selection +best-effort queuing
9 6.1.3 ISA Implementation in Router Background Functions Forwarding functions
ISA Components-Background Functions o Reservation Protocol RSVP ◆ Admission control ◆ Management agent Can use agent to modify traffic control database and direct admission control ◆ Routing protocol 10
10 ISA Components – Background Functions Reservation Protocol ◼ RSVP Admission control Management agent ◼ Can use agent to modify traffic control database and direct admission control Routing protocol