Part3: TCP/IP Protocol Suite and IP Addressing

Computer Network Table of Content References: 1. Data- Computer Communication handbook- William Stallings 2. TCP/IP Illustrated, Volume I - W.R. Stevens 3. CCNA- semester1-2-3-4 1 Part3. TCP/IP Protocol Suite and IP Addressing 1 Introduction to TCP/IP Model 2 Internet addresses 3 IP Format 3 ICMP 4 TCP 5 UDP INTRODUCTION TO TCP/IP TCP/IP protocol stack TCP/IP model development • The late-60s The Defense Advance Research Projects Agency (DARPA) originally developed Transmission Control Protocol/Internet Protocol (TCP/IP) to interconnect various defense department computer networks. • The Internet, an International Wide Area Network, uses TCP/IP to connect networks across the world. Cases of Access Network • Focus on IP Network level: •Multiple higher-layer protocols to applications •Multiple lower-layer protocols to physical links •Only IP protocol at the network layer. WAN WAN to WAN LAN to WAN LAN to LAN Internal Using in ptithcm 1 IP Suite: End Hosts vs. Routers The Network Access Layer host host HTTP message HTTP HTTP • Provide the ways and means to access to the internal network (LAN) or external network (WAN) • To LAN with Ethernet, Tokenring, FDDI TCP segment TCP TCP router router IP IP packet IP IP packet IP IP packet IP • To WAN with dial-up/PSTN, Frame relay, ADSL/ATM, lease-line … • Deals all the details in the OSI physical and data link layers. – Connectors with electrical, mechanical, procedural and functional specifications. – Media access control with • Data rate, Distances, synchronization Ethernet interface Ethernet interface SONET interface SONET interface Ethernet interface Ethernet interface • Frames, physical addressing, flow control, error control. 7 The internet layer • IP provide provides an unreliable connectionless best effort service (also called: “datagram service”). – Unreliable:IP does not make an attempt to recover lost packets – Connectionless: Each packet (“datagram”) is handled independently. IP is not aware that packets between hosts may be sent in a logical sequence – Best effort: IP does not make guarantees on the service (no throughput guarantee, no delay guarantee,…) • Consequences: – Higher layer protocols have to deal with losses or with duplicate packets – Packets may be delivered out-of-sequence Application layer • Multiplexing The Transport Layer • Responsibility – Provides reliable transport services from the source host to the destination host (end-to-end) over networks. • Concerns – Segments, data stream, datagram. – Defines end-to-end connectivity between host applications. – Transmission control protocol (TCP) – Connection oriented – User datagram protocol (UDP) – Connectionless Internet layer other protocols • Responsibility – Handles high-level protocols, issues of representation, encoding, and dialog control, and assures this data is properly packaged for the next layer. • Concerned – File Transfer ( TFTP, FTP, NFS) – E-Mail (SMTP) – Remote Login (Telnet, rlogin) – Network management (SNMP) – Name Management (DNS) • Internet Control Message Protocol (ICMP) −Provides control and messaging capabilities. – IP communication service messages like PING, TRACEROUTE and ROUTER • Internet Group Message Protocol (IGMP) – IP communications based on multicasting (sending to groups of hosts) • Address Resolution Protocol (ARP) −Determines the data link layer address, MAC address, for known IP addresses. • Reverse Address Resolution Protocol (RARP) −Determines IP addresses when the MAC address is known. Internal Using in ptithcm 2 Internet layer other protocols • Routing protocols: – RIP/ RIPng (for IPv6) – OSPF v2, v3 – BGP • For security: – 802.1x – IPsec – SSL/ TLS – SSH • For QoS control: RSVP… IP Datagram Format IP Datagram Format bit # 0 7 8 15 16 23 24 31 bit # 0 7 8 15 16 23 24 31 version length DS ECN D M QoS controlling at transit routers:F total length (in bytes) version Fragment offset header length Identification ECN D M F F total length (in bytes) Fragment offset ¾F¾DS- Differentiated Service /eType-of-Service (TOS) ¾Explicit Congestion Notification to TCP (ECN-2bits) • identification options (0 to 40 bytes) •don’t fragment • more flag payload •and fragment offset 4fields IP Datagram Format time-to-live (TTL) protocol header checksum •Time To Live (TTL) (1 b pecifying the higher-layer protocol. •Specifies longest paths before datagram is dropped •Role of TTL field: Ensure that packet is eventually dropped when a routing loop occurs •Used as follows: •Sender sets the value (e.g., 64) •Each router decrements the value by 1 •When the value reaches 0, the datagram is dropped IP Datagram Format bit # 0 7 8 15 16 version header DS ECN Identification 0 D M time-to-live (TTL) protocol 23 24 31 total length (in bytes) Fragment offset header checksum •In some cases option with source route also used for routing. Several options can be added to IP header: version length • So DS e route total length (in bytes) Identification ord route 0 F F Fragment offset time-to-live (TTL) • Ti protocol p header checksum source IP address • Header checksum field: idetects error occurring options (0 to 40 bytes) payload 4 bytes Internal Using in ptithcm source IP address destination IP address •Routing datagram by destination address and source address fields. •In some cases option with source route also used for routing. 4 bytes ... - tailieumienphi.vn