* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download IP Networks
Survey
Document related concepts
SIP extensions for the IP Multimedia Subsystem wikipedia , lookup
Point-to-Point Protocol over Ethernet wikipedia , lookup
Asynchronous Transfer Mode wikipedia , lookup
Distributed firewall wikipedia , lookup
TCP congestion control wikipedia , lookup
Computer network wikipedia , lookup
Piggybacking (Internet access) wikipedia , lookup
Multiprotocol Label Switching wikipedia , lookup
Wake-on-LAN wikipedia , lookup
Internet protocol suite wikipedia , lookup
Cracking of wireless networks wikipedia , lookup
Deep packet inspection wikipedia , lookup
Zero-configuration networking wikipedia , lookup
Recursive InterNetwork Architecture (RINA) wikipedia , lookup
Transcript
IP NETWORKS – I & II Internet Protocol Networks CIS 585 Theoretical Presentation 28 Feb 2002 What This Paper/Topic Is About: • Operation of internet and protocols. • Internet architecture and multimedia. • Nothing about infrastructure and web pages. CIS 585 IP Networks 2 Internet – The History • Two nodes and Arpanet. • 1969 – Kleinrock. • First data sent, “login”. CIS 585 IP Networks 3 Internet Concepts and Protocols • • • • Protocols & Layering in IP. Internet and internet. Layers recurse or no strict layering. Layers include, - Physical, Link, Network,Transport and Application layer. CIS 585 IP Networks 4 IP Layer definition • Physical layer - point to point or point-to-multipoint - wires, optical fibers or free space - common link speed - 14.4 kb/s - 2.4 Gb/s - end-to-end delays - micro sec in LAN - milliseconds on multiple hop paths. CIS 585 IP Networks 5 IP Layer Definition • Link Layer features include: - point-to-point, multipoint service, broadcast or non-broadcast multiple access. - detect bit errors & retransmit. • Network Layer services include: - carry packets across subnets (end-to-end), - packets use routers & routing protocols . CIS 585 IP Networks 6 IP Layer Definition • Transport Layer - operates only within end systems or hosts, - Built around TCP & UDP. • Additional protocol layers support - HTTP,SMTP,Telnet etc… • Nodes, Routers, Multi-homed hosts. CIS 585 IP Networks 7 Internet Protocol Hierarchy browser Video tool RTP Application DNS SNMP SMTP NNTP ftp http Transport UDP TCP IPv4, IPv6 PPP,SLIP PPP modem ISDN ICMP,IGMP datalink X.25 Token ring Ethernet FDDI CIS 585 IP Networks ATM HIPPI 8 Names, Addresses and Routes • • • • • • Shoch naming convention. Network Object, addresses and routes. MAC/NIC address. IP address. Host name. Dial-ups & “Lease” address. CIS 585 IP Networks 9 Internet Domain Name System • • • • • By Paul Mockapetris in 1984. Name-to-address mapping. Distributed database. TLD & CCTLD, Host.suborgn.orgn.tld. - www.cis.temple.edu - www.att.net and www.att.com CIS 585 IP Networks 10 Terms in Domain Name System • • • • • Primary name server. Secondary name server. Division of zones. Authoritative / master name server. Temporary domain or pseudo domain. CIS 585 IP Networks 11 DNS Resolution me What is the IP of www.cnn.com? I don’t know, this rootserver may know LNS Temple me What is the IP of www.cnn.com? I don’t know, but com name server is Root server me What is the IP for www.ccn.com? I don’t know, but cnn name server is… Com NS me What is the IP for www.cnn.com? It is 132.151.1.35 CNN NS CIS 585 IP Networks 12 Internet Addresses • 32 bit long. • For routing & identifying nodes. IPv4 • 132.1.2.3 • 1080::::8:800:200C:417A CIS 585 IP Networks IPv6 13 IP Addresses • 62.3 million hosts (Oct 1999) on net. • Addresses assigned topologically. Host part Network part 132.65.22.1 CIS 585 IP Networks 14 IP Address Class thanks to henning schulzrine CIS 585 IP Networks 15 IP Addresses • • • • Class A,B,C,D & E type of addressing. Classless Interdomain routing. Architectural problems with IP. NAPT & NAT. CIS 585 IP Networks 16 NAT & NAPT Internet 122.28.99.144 NAT Enabled Router 10.25.1.1 10.25.1.5 10.25.1.6 CIS 585 IP Networks 10.25.1.7 17 IP Forwarding router packet packet packet router router node node CIS 585 IP Networks 18 IP Service Model • Simple network-layer service model. • Datagram or connectionless delivery. • Packets transmitted arrive, - Out of order, - On a best-effort basis, - Duplicated, - Fragmented. CIS 585 IP Networks 19 IPv4 Packet Format Version(4) Header length Type of service total length in bytes . DTRC0 Flags identification time-to-live 0DFMF protocol id fragment offset (x8) header checksum source IP address destination IP address IP options data CIS 585 IP Networks 20 IPv4 Packet Header • • • • Consist of packet header & payload. Packets are fragmented. Fragmentation – unreliable for audio/video. Header variables manipulated by router. CIS 585 IP Networks 21 Routing of Packets in IP Two forms of source routing: • Loose source routing. • Strict source routing. CIS 585 IP Networks Hey, your route should be : 155.247.166.60 18.181.0.31 Hey, your route 169.232.33.130 will be : 66.158.17.20 155.247.166.60 In between, 18.181.0.31 hop as u 169.232.33.130 wish! 66.158.17.20 155.247.71.60 Strictly , no other routes 22 Transport Protocols in IP • Commonly used – TCP & UDP • Both support “ multiplexing “ • UDP packet header 0 16 32 16-bit source port number 16-bit destination port number 16-bit UDP length(incl. header) 16-bit UDP checksum data (if any) CIS 585 IP Networks 23 TCP With IP • • • • Is TCP or UDP the best for multimedia? TCP features – flow control, reliability. End-to-end delay of TCP and multimedia. Congestion control of TCP and multimedia. CIS 585 IP Networks 24 UDP • Used for streaming multimedia applications - Loss Tolerant. • Other uses: - with DNS - with SNMP CIS 585 IP Networks 25 IP Multicast • • • • Single IP packet to multiple receivers. Not connection oriented. Uses class D address format. Multicast can be achieved by, - Virtual circuit between sender & receiver - Include all receiver addresses in the packet - Radio-like model. CIS 585 IP Networks 26 IP Multicast • • • • Sent packets only to subscribers. Use TTL and scoped multicast address. Discover subscribers using IGMP & MLD Within an autonomous system use - MOSPF - DVMRP CIS 585 IP Networks 27 Multicast – Inter Domain Routing • • • • Developing field. PIM – dense mode and sparse mode. Core base tree protocol. Multicast is still an active research area. CIS 585 IP Networks 28 Multicast and Multimedia • Reduces network bandwidth. • Ex : for a MPEG1 video stream of 1.5 mbps with 10 receivers, Bandwidth needed at source (server) is For unicast – 15 mbps For multicast – 1.5 mbps CIS 585 IP Networks 29 Multicast - Today • • • • • Desktops & Server OS support multicast. Routers support some multicast protocols. Hubs & Switches need no modification. Still, multicast is spotty. Mbone & Multicast. The Multicast backbone CIS 585 IP Networks 30 Internet Quality of Service Principal Quality of Service Impairments delay packet loss CIS 585 IP Networks 31 End-to-End Delay • Propagation delay. • Transmission delay N - p ( 1 / Ri ). i=1 • Variable delays. • Application & coding added delays. CIS 585 IP Networks 32 Variable delays • • • • Resource contention. Link-layer retransmissions. Queuing delay. Delay by Ethernet & Ethernet switches. CIS 585 IP Networks 33 Application delay • Look-ahead delay. • Operating system delay. • Coding delay. CIS 585 IP Networks 34 Packet induced delays • Packet Loss - Packets that never arrive, - Packets that arrive late. • Packet loss and continuous media applications. • Packet Reordering. • Packet Duplication. CIS 585 IP Networks 35 Internet Measurements • Measurements of Internet Loss paths Entire day Worst 6 hrs Worst hour All paths 1084 1.06% 1.44% 4.88% Intra-US U.S.-Europe US-New Zealand 1060 1.04% 12 1.39% 10 2 2.58% 1.40% 1.52% 4.04% 1.51% 4.79% 5.71% 11.15% 6.97% Source / Destination Europe-N.Z. 0.58% CIS 585 IP Networks 36 IP architecture for media Media Transport protocols QoS protocols architecture Signaling protocols CIS 585 IP Networks 37 IP architecture for media Quality of Service Role of SNMP, RTCP Resource Management Differentiated services CIS 585 IP Networks 38 IP architecture for media Signaling: • Media on demand. RTSP • Internet Telephony. SIP • Internet broadcast. SAP CIS 585 IP Networks 39 RTP for Multimedia Data Common requirements of media streams: Sequencing. Intra-Media Synchronization. Inter-Media Synchronization. Payload Identification. Frame indication. CIS 585 IP Networks 40 RTP functionality Multicast friendly Media-Independent QoS feedback RTP Mixers / Translators Loose session Control Encryption CIS 585 IP Networks 41 RTP Header Format 32 bytes V P X CSRC count M payload type sequence number timestamp synchronization source identifier (SSRC) contributing source identifiers(CSRC) header extension payload(audio,video…) CIS 585 IP Networks 42 RTCP Control Management RTCP Packet Source descriptor Sender reports Receiver reports Bye ! BYE CIS 585 IP Networks am I leaving? 43 Real-Time Streaming Protocol RTSP Features: Relationship with HTTP Timing Aggregate and Stream Control Caching CIS 585 IP Networks 44 Real-Time Streaming Protocol • proposed standard for control of streams. S1 S2 S3 Client CIS 585 IP Networks 45 Real-Time Streaming Protocol • • • • • Can be used as a “conference recorder”. Syntax is similar to HTTP. Different from HTTP ‘TCP & REDIRECT’. Notion of session. Extendable using OPTIONS request. CIS 585 IP Networks 46 RTSP Timing • SMPTE time - h:m:s:f:sf. • Normal playtime - h:m:s: fraction of sec. • Absolute time CIS 585 IP Networks 47 RTSP Stream Control & Caching • Individual and Aggregate streams • Example of a movie. • Use of requests - DESCRIBE , SETUP,PLAY,RECORD,PAUSE,TEAR DOWN,REDIRECT. • Difference with web caching. CIS 585 IP Networks 48 Session Description Protocol Text format for multimedia sessions. SDP is not really a protocol. Example : linking a session to a web page. SDP can convey: - type of media. - media transport protocol. CIS 585 IP Networks 49 Session Description Protocol • • • • • • SDP can convey: - format of the media. - time and duration of the session. - security info: related to as encryption. - session names and subject information. - human contact information related to a session. CIS 585 IP Networks 50 Session Initiation Protocol What is SIP ? Message Encoding Addressing and Naming Basic Operations and Telephony services Multiparty calls SDP & SAP CIS 585 IP Networks 51 References for this presentation • • • • IP Networks by Henning Schulzrinne Mbone by Hans Eriksson IP Multicasting by Dave Kosiur RFC 2974 (exptl) CIS 585 IP Networks 52