Chapter 10 Advanced Network Architectures Integrated Services in the Internet RSVP Differentiated Services Network Interconnection Models MPLS Multimedia Networking Real-Time Transport Protocol Session Control Protocols Chapter 10 Advanced Network Architectures Integrated Services in the Internet Integrated Services IP Model z Defines a flow as a stream of IP packets z z z Provides QoS to individual flows in the Internet z z z “Better than Best Effort” for some applications Support for real-time voice and video applications Requires traffic management mechanisms to deliver appropriate QoS to each flow z z Generated by a sender and destined to a destination That require the same QoS Packet classification, scheduling, admission control Explicit reservation of buffers and bandwidth resources for individual flows at every node z Resource Reservation Protocol (RSVP) provides means for making reservations Network Service Models z Best effort service z z z Guaranteed service z z z No guarantees; suitable for elastic traffic At low loading, suitable for many traffic classes bound on maximum delay guarantee on available bandwidth Controlled load service z delay consistent with lightly loaded network IntServ Router Model Routing agent Reservation agent Management agent Admission control Routing database Traffic control database Accept/reject a flow Identify a packet’s flow Buffering to control loss Transmission scheduling to control delay Classifier Input driver Internet forwarder Packet scheduler Output driver Traffic management mechanisms discussed in Chapter End-to-End Performance z End-to-end performance for an individual flow is the result of per-switch performances z z Per-switch performance depends on: z z z delay, jitter, loss, bandwidth per-packet processing common to all packets specific per-connection or per-class treatment Resources must be allocated by RSVP at each node for each flow Router Router Router Admission Control Individual flow negotiates admission into the network Flow Descriptor has two parts Filter specification (filterspec) provides information required by classifier to identify the packets in the flow Flow specification (flowspec) describes traffic properties of flow and QoS requirements z z z z z Traffic Specification (Tspec) describes traffic in terms of a token bucket Request Specification (Rspec) describes QoS in terms of bandwidth, delay, loss Each node along path must decide whether a flow can be accepted Guaranteed Service z z Intended for flows that require real-time packet delivery Provides a firm delay bound z z z z Each flow is shaped by (b,r) leaky bucket z b token bucket size z r token rate Police the flow to ensure compliance Reserve bit rate R>r at every node (weighted fair queueing) Account for other network parameters b ( H − 1)m H M D≤ + +∑ R R j =1 R j From Chapter 7: m maximum packet size in flow M max packet size in network Rj bit rate of link j H number of hops in path Controlled Load Service z Intended for flows that can tolerate some delay but are sensitive to traffic overload z z z Equivalent to “Best Effort under Light Traffic” Low delay and low loss, but no quantitative guarantees Less complex than guaranteed service z z z z Each flow is shaped by (b,r) leaky bucket Use admission control to limit volume of controlled load service Reserve bit rate for the entire class to ensure light traffic mode Police each flow to ensure compliance; Non-conforming packets accorded best effort service IntServ involves High Complexity z Routing agent Reservation agent Management agent z Admission control Routing database z Number of (application) flows can become extremely large Per-flow treatment involves high complexity Traffic Management z z Traffic control database z z z Classifier Input driver Internet forwarder Packet scheduler Admission Control z z Output driver Per-flow classifier Per-flow queueing Per-flow scheduling Hugh table sizes & high hardware complexity Set up & maintenance of individual flows High processing load IntServ is not scalable TRYING: User1 trying to connect to User2 Header Description of Trying Packet: RINGING: Packet Description: Connection has been established with User2, waiting for User2 to answer the call OK and ACK : Connection has been established and user1 sends out a “OK” packet Packet Description for “OK”: User1 sends an “ACK” packet to user2 Packet Description for “ACK”: BYE: User2 wants to disconnect, sends a BYE packet Packet Description for BYE: User2 is trying to disconnect and hence sends “Trying” Packet “OK” is sent by User2 once call is successfully disconnected Chapter 10 Advanced Network Architectures Session Control Protocols H.323 Communications Systems H.323 Systems z z z z z z Support for real-time multimedia communications on LANs & packet networks H.323 provides call control, multimedia management, bandwidth management, interfaces to other networks H.323 terminals carry voice, audio, video, data, or combination Gateways handle signaling messages between packet network & other networks Gatekeeper handles call control inside H.323 net Multipoint control unit combine media streams Gatekeeper MCU Telephone Gateway Public Telephone Network IP network H.323 Terminal H.323 Terminal Scope of H.323 Microphone Speakers Audio Codec Camera, Display Video Codec Data Equipment System Control User I/F Receive Path Delay System Control H.245 Control Call Control RAS Control H.225 Layer LAN I/F H.323 Protocols z z z z z H.225: call control within H.323 net RTP/RTCP used for audio/video streams H.245: control channel to set up logical channels RAS: registration, admission control, bandwidth management RSVP – Resource Reservation Protocol: allows user to request a specific amount of bandwidth Typical H.323 Stack H.323 User Interface Multimedia Applications, Data Applications V.150 T.120 Media Control T.38 Audio Video Codecs Codecs G.711 H.261 G.723.1 H.263 G.729 H.264 Terminal Control and Management H.225.0 RTCP Call H.245 Signaling H.225.0 RAS RTP UDP TCP TCP/UDP UDP IP TCP/UDP TCP UDP Basic Call Setup Signaling H.225.0 Setup Optional Call Proceeding Progress Alerting Connect GW GW CONNECTED Release Complete Call Setup Capture TCP Control Packets No Time Source Destination Protocol Info 18.904189 192.168.0.149 192.168.0.143 TCP 1748 > 1720 [SYN] Seq=1739645016 Ack=0 Win=16384 Len=0 18.905196 192.168.0.143 192.168.0.149 TCP 1720 > 1748 [SYN, ACK] Seq=4252100644 Ack=1739645017 Win=17520 Len=0 18.905366 192.168.0.149 192.168.0.143 TCP 1748 > 1720 [ACK] Seq=1739645017 Ack=4252100645 Win=17520 Len=0 11 19.497846 192.168.0.149 192.168.0.143 H.225.0 CS: Setup-UUIE 12 19.769449 192.168.0.143 192.168.0.149 TCP [Desegmented TCP] 13 20.099818 192.168.0.149 192.168.0.143 TCP 1748 > 1720 [ACK] Seq=1739645217 Ack=4252100649 Win=17516 Len=0 14 20.101044 192.168.0.143 192.168.0.149 H.225.0 CS: Alerting-UUIE 16 20.501086 192.168.0.149 192.168.0.143 TCP 1748 > 1720 [ACK] Seq=1739645217 Ack=4252100688 Win=17477 Len=0 20 29.091030 192.168.0.143 192.168.0.149 TCP [Desegmented TCP] 21 29.329256 192.168.0.149 192.168.0.143 TCP 1748 > 1720 [ACK] Seq=1739645217 Ack=4252100692 Win=17473 Len=0 22 29.330385 192.168.0.143 192.168.0.149 H.225.0 CS: Connect-UUIE 23 29.400799 192.168.0.149 192.168.0.143 TCP 1749 > 1862 [SYN] Seq=1740980379 Ack=0 Win=16384 Len=0 24 29.401781 192.168.0.143 192.168.0.149 TCP 1862 > 1749 [SYN, ACK] Seq=4253464033 Ack=1740980380 Win=17520 Len=0 25 29.401944 192.168.0.149 192.168.0.143 TCP 1749 > 1862 [ACK] Seq=1740980380 Ack=4253464034 Win=17520 Len=0 26 29.405685 192.168.0.149 192.168.0.143 TCP [Desegmented TCP] 27 29.453530 192.168.0.143 192.168.0.149 TCP [Desegmented TCP] 28 29.453752 192.168.0.149 192.168.0.143 H.245 TerminalCapabilitySet MasterSlaveDetermination 29 29.455958 192.168.0.143 192.168.0.149 H.245 TerminalCapabilitySet MasterSlaveDetermination 30 29.465312 192.168.0.149 192.168.0.143 TCP [Desegmented TCP] 31 29.471165 192.168.0.143 192.168.0.149 TCP [Desegmented TCP] 32 29.471402 192.168.0.149 192.168.0.143 H.245 TerminalCapabilitySetAck MasterSlaveDeterminationAck 33 29.472271 192.168.0.143 192.168.0.149 H.245 TerminalCapabilitySetAck MasterSlaveDeterminationAck 34 29.678682 192.168.0.149 192.168.0.143 TCP [Desegmented TCP] 35 29.679868 192.168.0.143 192.168.0.149 H.245 OpenLogicalChannel OpenLogicalChannel OpenLogicalChannel 43 30.532924 192.168.0.149 192.168.0.143 TCP 1749 > 1862 [ACK] Seq=1740980892 Ack=4253464654 Win=16900 Len=0 45 35.545028 192.168.0.143 192.168.0.149 RTCP Receiver Report 48 35.546773 192.168.0.149 192.168.0.143 RTCP Receiver Report 50 1239.290373 192.168.0.149 192.168.0.143 RSVP PATH Message SESSION: IPv4, Destination 192.168.0.143, Protocol 17, Port 49608 SENDER TEMPLATE: IPv4, Sender 192.168.0.149, Port 49608 51 1239.322672 192.168.0.143 192.168.0.149 RSVP RESV Message SESSION: IPv4, Destination 192.168.0.143, Protocol 17, Port 49608 H.225.0 setup Alerting Connecting Negotiating Channel Usage Requesting Bandwidth Data Transfer Capture RTP video H.263 Packet No Time Source Destination Protocol Info 62 1240.429251 192.168.0.143 192.168.0.149 TCP 1862 > 1749 [ACK] Seq=4253464654 Ack=1740980896 Win=17004 Len=0 63 1240.429470 192.168.0.149 192.168.0.143 H.245 OpenLogicalChannelReject OpenLogicalChannelAck OpenLogicalChannelAck MiscellaneousCommand MiscellaneousCommand OpenLogicalChannelConfirm 65 1240.622962 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12977, Time=3017250 66 1240.623218 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12978, Time=3017250 71 1240.854456 192.168.0.143 192.168.0.149 TCP 1862 > 1749 [ACK] Seq=4253464654 Ack=1740980980 Win=16920 Len=0 72 1240.854730 192.168.0.143 192.168.0.149 TCP 1503 > 1752 [ACK] Seq=4255085782 Ack=1742545885 Win=17315 Len=0 74 1240.915746 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12980, Time=3030750 75 1240.916004 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12981, Time=3030750 76 1240.916239 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12982, Time=3030750, Mark 87 1240.977683 192.168.0.149 192.168.0.143 TCP 1753 > 1503 [PSH, ACK] Seq=1742695460 Ack=4255248829 Win=17520 Len=25 88 1240.979358 192.168.0.143 192.168.0.149 TCP 1503 > 1753 [PSH, ACK] Seq=4255248829 Ack=1742695485 Win=17495 Len=21 89 1241.212546 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12983, Time=3044070 90 1241.212801 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12984, Time=3044070, Mark 91 1241.231672 192.168.0.149 192.168.0.143 TCP 1753 > 1503 [ACK] Seq=1742695485 Ack=4255248850 Win=17499 Len=0 92 1241.231775 192.168.0.149 192.168.0.143 TCP 1749 > 1862 [ACK] Seq=1740980980 Ack=4253464658 Win=16896 Len=0 93 1241.232617 192.168.0.143 192.168.0.149 H.245 MiscellaneousCommand 97 1241.364228 192.168.0.143 192.168.0.149 RTP Payload type=ITU-T H.263, SSRC=4062428632, Seq=32093, Time=1885770, Mark 98 1241.366210 192.168.0.149 192.168.0.143 TCP [Desegmented TCP] 99 1241.380190 192.168.0.149 192.168.0.143 TCP 1753 > 1503 [PSH, ACK] Seq=1742695485 Ack=4255248850 Win=17499 Len=268 100 1241.384497 192.168.0.143 192.168.0.149 TCP 1503 > 1753 [PSH, ACK] Seq=4255248850 Ack=1742695753 Win=17227 Len=106 Time=51984, Mark 163 1242.823618 192.168.0.143 192.168.0.149 RTP Payload type=ITU-T G.723, SSRC=756814963, Seq=32091, Time=52704 164 1242.836785 192.168.0.149 192.168.0.143 TCP 1753 > 1503 [ACK] Seq=1742695794 Ack=4255249018 Win=17331 Len=0 165 1242.836872 192.168.0.149 192.168.0.143 TCP 1754 > 1503 [ACK] Seq=1742808026 Ack=4255332966 Win=17168 Len=0 166 1242.897739 192.168.0.143 192.168.0.149 RTP Payload type=ITU-T G.723, SSRC=756814963, Seq=32092, Time=53424 167 1242.908675 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12996, Time=3120210 168 1242.908963 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12997, Time=3120210 173 1243.099425 192.168.0.143 192.168.0.149 RTP Payload type=ITU-T H.263, SSRC=4062428632, Seq=32109, Time=1963890, Mark 174 1243.107713 192.168.0.143 192.168.0.149 RTP Payload type=ITU-T G.723, SSRC=756814963, Seq=32093, Time=54144 175 1243.202816 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=12999, Time=3133620 176 1243.203076 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=13000, Time=3133620 177 1243.205246 192.168.0.149 192.168.0.143 RTP Payload type=ITU-T H.263, SSRC=1488263488, Seq=13001, Time=3133620, Mark More Control RTP Audio G.723 Media Gateway Control Protocols z z Enable simple terminal equipment (i.e telephone) to connect to Internet for IP telephone service Two components: z z Media Gateway: performs media format conversion between telephone & Internet Residential Gateway: interacts between telephone and call agents in Internet z z Call agents interact with SS7 signaling network to setup calls Call agents use Media Gateway Control Protocol