TCP/IP PROTOCOL UNIT 6

Overview of TCP/IP Application FTP, Telnet, SMTP, HTTP.. Presentation Session TransportHost-to-HostTCP, UDP NetworkInternetIP, ICMP, IGMP Data Link Network Access Ethernet, Token-Ring... Physical

TCP/IP Layers LayerPurpose of the Layer Application LayerDefines the application used to process request & what ports and sockets are used Transport LayerDefines the type of connection established between hosts and how acknowledgements are sent. Internet LayerDefines the protocols used for addressing and routing the data packets. Network LayerDefines how the host connect to the network

TCP UDP IP Process Layer Transport Layer Network Layer Data-Link Layer Process ICMP, ARP & RARP

What is an IP Address?(pg.no. 550 F) An IP address is a unique global address for a network interface. An IP address: - is a 32 bit long identifier - encodes a network number (network prefix) and a host number

Dotted Decimal Notation IP addresses are written in a so-called dotted decimal notation Each byte is identified by a decimal number in the range [0..255]: Example: st Byte = nd Byte = rd Byte = th Byte =

The network prefix identifies a network and the host number identifies a specific host Network prefix and Host number network prefixhost number

Find IP address E.g. 1) ) ) )

Classful Addressing(pg.no.552) Classes of IP addresses are identified by the decimal number of the 1st octet – Class A address begin with a 0 bit Range of class A addresses = to – Class B address begin with a 1 bit and a 0 bit Range of class B addresses = to – Class C addresses begin with two 1 bits & a 0 bit Range of class C addresses = to Class D is used for multicasting-used when single message is to be sent to a group of computers.

The four formats of IP Addresses 0 0 Net ID NetID 1110 Multicast Group ID HostID Net ID HostID 8 bits Reserved for future use

Classes

Find the class of each address: A) B) C) D)

Subnet Addresses An organization can subdivide it’s host address space into groups called subnets. The subnet ID is generally used to group hosts based on the physical network topology. 10 NetID SubnetID HostID

Subnetting router Subnet x Subnet x Subnet x

Subnetting Subnets can simplify routing. IP subnet broadcasts have a host ID of all 1s. It is possible to have a single wire network with multiple subnets.

IP Datagram(pg.no.583) Version (4bits) Hlen (4 bits) Service( 8 bits)Total Length (16 bits) Identifier (16 bits) Flag ( 3 bits) Fragmentation Offset (13 bits) Time To Live (8 bits)Protocol( 8 bits)Checksum (16 bits) Source Address Destination Address Options (if any)(Routing,Timing management and allignment) Data

IPv4 & IPv6

ARP The Address Resolution Protocol is used by a sending host when it knows the IP address of the destination but needs the Ethernet address. ARP is a broadcast protocol - every host on the network receives the request. Each host checks the request against it’s IP address - the right one responds.

ARP conversation HEY - Everyone please listen! Will please send me his/her Ethernet address? not me Hi Green! I’m , and my Ethernet address is 87:A2:15:35:02:C3

Reverse Address Resolution The process of finding out the IP address of a host given a hardware address is called Reverse Address Resolution Reverse address resolution is needed by diskless workstations when booting.

RARP conversation HEY - Everyone please listen! My Ethernet address is 22:BC:66:17:01:75. Does anyone know my IP address ? not me Hi Green! Your IP address is

ICMP Internet Control Message Protocol ICMP is a protocol used for exchanging control messages. ICMP uses IP to deliver messages. ICMP messages are usually generated and processed by the IP software, not the user process.

UDP User Datagram Protocol UDP is a transport-layer protocol  communication between processes UDP uses IP to deliver datagrams to the right host.

Ports UDP/IP uses an abstract destination point called a protocol port. Ports are identified by a positive integer. Operating systems provide some mechanism that processes use to specify a port.

Ports Host A Host B Process

UDP Datagram Delivery Connectionless Unreliable Minimal Source PortDestination Port LengthChecksum Data UDP Datagram Format

TCP Transmission Control Protocol TCP is an alternative transport layer protocol supported by TCP/IP. TCP provides:  Connection-oriented  Reliable  Full-duplex  Byte-Stream

TCP frame structure