Presentation on theme: "Faruk Hadziomerovic: Internet notes Internet: network nodes Host: any computer executing protocol Hub: repeats signal heard one each port to all ports."— Presentation transcript:
Faruk Hadziomerovic: Internet notes Internet: network nodes Host: any computer executing protocol Hub: repeats signal heard one each port to all ports. Bridge: understands physical layer addresses, MAC addresses, and learns where each device is located. It listens to all traffic on LAN. If it finds that packet should go to another segment it forwards the frame to it. It is store-and-forward device. Switch: same as bridge however much faster. It redirects a frame only after reading destination address on a ongoing basis. Router: Internetwork layer device. It reads entire packet, based on destination address finds the best route for the packet and sends it.
Faruk Hadziomerovic: Internet notes Internet: network of networks star Ethernet token ring hub bridge switch router
Faruk Hadziomerovic: Internet notes Internet protocol stack vs. OSI model (Fig. 1.2) Physical Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Application Layer Manchester Ethernet, Token ring (ATM, Frame Relay**) IP, ARP TCP, UDP , FTP, HTTP Physical Layer Host-to-host Layer Internet Layer MAC* Layer Process Layer * Medium Access Control. MAC and Physical layers are called Network Interface Layer. ** not exactly MAC, however, layer above physical
Faruk Hadziomerovic: Internet notes Two networks connected with a router (Fig. 1.3) FTP client TCP IP Ethernet driver Ethernet driver Token ring driver Token ring driver FTP server TCP IP FTP protocol TCP protocol Ethernet router Ethernet protocol IP protocol Ethernet protocol Token ring Ethernet host Token ring host
Faruk Hadziomerovic: Internet notes Internet protocol suite TelnetTelnet FTPFTP HTTPHTTP DNSDNS BOOTPBOOTP DHCPDHCP SNMPSNMP TFTPTFTP RIPRIP 23 20/ / / TCPUDP 617 IP IGRP 88 ICMP 01 OSPF 89 ARPRARP Process Layer Host to Host Layer Internet Layer Network Interface Layer Port Numbers Protocol Codes Ethernet, Token Ring, FDDI, SLIP, PPP, etc.
Faruk Hadziomerovic: Internet notes Internet protocols TELNET - remote terminal connection service. Allows user terminal to mimic the terminal at the remote side. FTP - File Transfer Protocol (put/get file to/from remote machine). HTTP - Hypertext Transport Protocol. DNS - Domain Name Server On-line distributed database for translating IP machine names into IP addresses. BOOTP - Bootstrap Protocol defines each device autoconfiguration on the server (improvement to the RARP). DHCP - Dynamic Host Configuration Protocol (improvement to BOOTP) allows network administrator to configure workstation by providing dynamic address assignment. TFTP - Trivial File Transfer Protocol (same as FTP with minimal capability). SNMP - Simple Network Monitoring Protocol used to monitor IP gateways and networks they are attached to. RIP - Routing Information Protocol used to exchange the routing information among small set of computers (every 30 sec hosts exchange information). TCP - reliable Transmission Control Protocol (connection oriented). UDP - unreliable Universal Transport Protocol (connectionless). IGRP - Interior Gateway Routing Protocol (proprietary routing protocol developed by Cisco). ICMP - Internet Control Message Protocol part of IP that handles error and control messages. OSPF - Open Shortest Path First routing protocol. ARP - Address Resolution Protocol used to dynamically bind IP addresses to physical addresses. RARP - Reverse ARP used by newly installed machine to find its IP address. IP - Internet Protocol.
Faruk Hadziomerovic: Internet notes Encapsulation (Fig. 1.7) Ethernet 14 bytes 20 to 60 bytes IP header UDP 8 bytes variable Application TCP 20 or 24variable Application ICMP 6 + bytes CRC 4 bytes
Faruk Hadziomerovic: Internet notes Sample (book) network aix.1.92 gateway.1.4 bsdi solaris.1.32 gemini.1.11 Solaris 2.2 SunOS Cisco router netb Telebit NetBlazer modem sun.1.29 SunOS modem SLIP (dialup) svr SVR4 BSD/ slip BSD/ Ethernet All IP addresses belong to class B network ID xxx.xxx
Faruk Hadziomerovic: Internet notes Link Layer (Fig. 2.1) SLIP (Serial Line IP) c0db dc db dd c0 db ESC Point-to-point (PPP) protocol IP datagram Flag 7E Contr 03 protocol up to CRCdata addr FF Flag 7E Link control data C021 network control data 8021
Faruk Hadziomerovic: Internet notes Ethernet Header Destin. Addr. Source Addr. Type Vendor addr component Broadcast ff ff ff ff ff ff c0 a Unicast ARP Multicast e c0 a Unicast IP Unicast c0 a c a7 81 4c Unicast SNMP Vendor ser. number
Faruk Hadziomerovic: Internet notes IP addressing convention 4 bytes (dec): = Class A: Large networks (GM, Ford, etc) 0NNNNNNN LLLLLLLL LLLLLLLL LLLLLLLL N-Network bits L-Locally administered 126 Class A networks 16,777,214 hosts/network 0 - unused, ; loop back 10NNNNNN NNNNNNNN LLLLLLLL LLLLLLLL 16,384 Class B networks 65,534 hosts/network (0 not used, all 1s broadcast) Class B: medium size (universities, medium business) 110NNNNN NNNNNNNN NNNNNNNN LLLLLLLL 2,097,152 Class C networks 254 hosts/network Class C: small networks (small business) 1110MMMM MMMMMMMM MMMMMMMM MMMMMMMM 2,097,152 Class C networks 254 hosts/network Class D: broadcasting
Faruk Hadziomerovic: Internet notes IP subnetting with subnet masks IP address: Subnet mask: Binary addr: Binary Mask: Address bits: NNNNNNNN NNNNNNNN SSSSSSI I I I I I I I I I N - network bits S - subnet bits I - Interface bits. Natural masks: Class A : B : C :
Faruk Hadziomerovic: Internet notes Subnetting example source: target: mask: = mask 121 = source subn= source subnet 248 = mask 248 = target subn= target subnet Are this two hosts in the same subnet?