IP NETWORKS I II Internet Protocol Networks CIS

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

Internet – The History • Two nodes and Arpanet. • 1969 – Kleinrock. • First data sent, “login”. CIS 585 IP Networks

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

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

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

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

Internet Protocol Hierarchy browser Video tool RTP Application DNS SNMP SMTP UDP PPP modem ISDN ftp http Transport TCP IPv 4, IPv 6 PPP, SLIP NNTP ICMP, IGMP datalink X. 25 Token ring Ethernet FDDI CIS 585 IP Networks ATM HIPPI

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

Internet Domain Name System • • • By Paul Mockapetris in 1984. Name-to-address mapping. Distributed database. TLD & CCTLD, Host. suborgn. tld. - www. cis. temple. edu - www. att. net and www. att. com CIS 585 IP Networks

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

DNS Resolution me LNS What is the IP of www. cnn. com? I don’t know, this rootserver may know Temple 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 me What is the IP of www. cnn. com? CIS 585 IP Networks

Internet Addresses • 32 bit long. • For routing & identifying nodes. IPv 4 • 132. 1. 2. 3 • 1080: : 8: 800: 200 C: 417 A CIS 585 IP Networks IPv 6

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

IP Address Class thanks to henning schulzrine CIS 585 IP Networks

IP Addresses • • Class A, B, C, D & E type of addressing. Classless Interdomain routing. Architectural problems with IP. NAPT & NAT. CIS 585 IP Networks

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

IP Forwarding et router ck pa packet router t ke c a p node pac ket router node CIS 585 IP Networks

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

IPv 4 Packet Format Version(4) Header length Type of service total length in bytes . DTRC 0 Flags identification time-to-live 0 DFMF protocol id fragment offset (x 8) header checksum source IP address destination IP address IP options data CIS 585 IP Networks

IPv 4 Packet Header • • Consist of packet header & payload. Packets are fragmented. Fragmentation – unreliable for audio/video. Header variables manipulated by router. CIS 585 IP Networks

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

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

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

UDP • Used for streaming multimedia applications - Loss Tolerant. • Other uses: - with DNS - with SNMP CIS 585 IP Networks

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

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

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

Multicast and Multimedia • Reduces network bandwidth. • Ex : for a MPEG 1 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

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

Internet Quality of Service Principal Quality of Service Impairments delay packet loss CIS 585 IP Networks

End-to-End Delay • Propagation delay. • Transmission delay N - p ( 1 / Ri ). i=1 • Variable delays. • Application & coding added delays. CIS 585 IP Networks

Variable delays • • Resource contention. Link-layer retransmissions. Queuing delay. Delay by Ethernet & Ethernet switches. CIS 585 IP Networks

Application delay • Look-ahead delay. • Operating system delay. • Coding delay. CIS 585 IP Networks

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

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 Europe-N. Z. 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 0. 58% CIS 585 IP Networks

IP architecture for media Media Transport protocols Qo. S protocols architecture Signaling protocols CIS 585 IP Networks

IP architecture for media Quality of Service Role of SNMP, RTCP Resource Management Differentiated services CIS 585 IP Networks

IP architecture for media Signaling: • Media on demand. RTSP • Internet Telephony. SIP • Internet broadcast. SAP CIS 585 IP Networks

RTP for Multimedia Data Common requirements of media streams: § Sequencing. § Intra-Media Synchronization. § Inter-Media Synchronization. § Payload Identification. § Frame indication. CIS 585 IP Networks

RTP functionality Multicast friendly Media-Independent Qo. S feedback RTP Mixers / Translators Loose session Control Encryption CIS 585 IP Networks

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

RTCP Control Management RTCP Packet Sender reports Receiver reports Source descriptor Bye ! BYE CIS 585 IP Networks am I leaving?

Real-Time Streaming Protocol RTSP Features: ü Relationship with HTTP ü Timing ü Aggregate and Stream Control ü Caching CIS 585 IP Networks

Real-Time Streaming Protocol • proposed standard for control of streams. S 1 S 2 Client CIS 585 IP Networks S 3

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

RTSP Timing • SMPTE time - h: m: s: f: sf. • Normal playtime - h: m: s: fraction of sec. • Absolute time CIS 585 IP Networks

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

Session Description Protocol s s s 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

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

Session Initiation Protocol q What is SIP ? q Message Encoding q Addressing and Naming q Basic Operations and Telephony services q Multiparty calls q SDP & SAP CIS 585 IP Networks

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