Chapter 7 Protocols for Qos Support 7.0 Increased demands o Need to incorporate bursty and stream traffic in TCP/IP architecture ◆ ncrease capacity Faster links, switches, routers Intelligent routing policies End-to-end flow control ◆ Multicasting o Quality of Service( Qos) capability o Transport protocol for streaming
1 Chapter 7 Protocols for QoS Support 7.0 Increased Demands Need to incorporate bursty and stream traffic in TCP/IP architecture Increase capacity ◼ Faster links, switches, routers ◼ Intelligent routing policies ◼ End-to-end flow control Multicasting Quality of Service (QoS) capability Transport protocol for streaming
71 Resource reservation Unicast Prevention as well as reaction to congestion required e Can do this by resource reservation ◆ Unicast End users agree on Qos for task and request from network May reserve resources a Routers pre-allocate resources If Qos not available, may wait or try at reduced Qos
2 7.1 Resource Reservation - Unicast Prevention as well as reaction to congestion required Can do this by resource reservation Unicast ◼ End users agree on QoS for task and request from network ◼ May reserve resources ◼ Routers pre-allocate resources ◼ If QoS not available, may wait or try at reduced QoS
7.1 Resource Reservation- Multicast o Generate vast traffic High volume application like video Lots of destinations ◆ Can reduce load Some members of group may not want current transmission ◆“ Channels” of video Some members may only be able to handle part of transmission Basic and enhanced video components of video stream o Routers can decide if they can meet demand 3
3 7.1 Resource Reservation – Multicast Generate vast traffic ◼ High volume application like video ◼ Lots of destinations Can reduce load ◼ Some members of group may not want current transmission “Channels” of video ◼ Some members may only be able to handle part of transmission Basic and enhanced video components of video stream Routers can decide if they can meet demand
Resource reservation problems on an internet Reservations must follow chan o Must interact with dynamic routin langes in route o Soft state-a set of state information at a router that expires unless refreshed End users periodically renew resource requests
4 Resource Reservation Problems on an Internet Must interact with dynamic routing ◼ Reservations must follow changes in route Soft state – a set of state information at a router that expires unless refreshed ◼ End users periodically renew resource requests
7.1.1 Resource Reser Vation Protocol (RSVP) Design Goals o Enable receivers to make reservations Different reservations among members of same multicast group a allowed o Deal gracefully with changes in group membership Dynamic reservations, separate for each member of group o Aggregate for group should reflect resources needed Take into account common path to different members of group o Receivers can select one of multiple sources(channel selection) o Deal gracefully with changes in routes Re-establish reservations o Control protocol overhead o Independent of routing protocol 5
5 7.1.1 Resource ReSerVation Protocol (RSVP) Design Goals Enable receivers to make reservations ◼ Different reservations among members of same multicast group allowed Deal gracefully with changes in group membership ◼ Dynamic reservations, separate for each member of group Aggregate for group should reflect resources needed ◼ Take into account common path to different members of group Receivers can select one of multiple sources (channel selection) Deal gracefully with changes in routes ◼ Re-establish reservations Control protocol overhead Independent of routing protocol
RSVP Characteristics Unicast and multicast Simplex f Unidirectional data flow Separate reservations in two directions ◆ Receiver initiated i Receiver knows which subset of source transmissions it wants o Maintain soft state in internet Responsibility of end users o Providing different reservation styles a Users specify how reservations for groups are aggregated Transparent operation through non-RSVP routers o Support IPv4 (Tos field) and IPv6(Flow label field) 6
6 RSVP Characteristics Unicast and Multicast Simplex ◼ Unidirectional data flow ◼ Separate reservations in two directions Receiver initiated ◼ Receiver knows which subset of source transmissions it wants Maintain soft state in internet ◼ Responsibility of end users Providing different reservation styles ◼ Users specify how reservations for groups are aggregated Transparent operation through non-RSVP routers Support IPv4 (ToS field) and IPv6 (Flow label field)
7.12 Data flows Session e Data flow identified by destination Resources allocated by router for duration of session ◆ Defined by Destination IP address ◆ Unicast or multicast IP protocol identifier ◆ TCP, UDP etc Destination port May not be used in multicast
7 7.1.2 Data Flows - Session Data flow identified by destination Resources allocated by router for duration of session Defined by ◼ Destination IP address Unicast or multicast ◼ IP protocol identifier TCP, UDP etc. ◼ Destination port May not be used in multicast
Flow Descriptor ◆ Reservation Request Flow spec Desired Qos Used to set parameters in node's packet scheduler Service class, Rspec(reserve), Tspec(traffic) a Filter spec Set of packets for this reservation Source address, source prot
8 Flow Descriptor Reservation Request ◼ Flow spec Desired QoS Used to set parameters in node’s packet scheduler Service class, Rspec (reserve), Tspec (traffic) ◼ Filter spec Set of packets for this reservation Source address, source prot
Treatment of packets of one session at one router packets that Packet scheduler s packets of one session flowspec Qas delivery (addressed to one destination) espec Best-effo other packets delivery
9 Treatment of Packets of One Session at One Router
RSVP Operation Diagram (a) Data distrubution to a multicast group b)Filtering by Source (c)Filtering a Substream (d) Merged Resv Messages 10
10 RSVP Operation Diagram
