1. Introduction to TCP/IP

2. Protocols are a set of rules that govern how computers exchange data over a network
There is two type of protocols:
LAN protocols: defines how communication is carried out over various LAN media
Exp: NetBEUI, IPX/SPX, TCP/IP
WAN protocols: defines how communication is carried out over various WAN media
Exp: SLIP, HDLC,PPP

3. TCP/IP
The Transmission Control Protocol/Internet Protocol (TCP/IP) suite of protocols was developed as a part of the research done by the Defense Advanced Research Projects Agency (DARPA)
It is the protocol of the internet
It is route information from the source to destination by performing the following tasks:
Defining the packet and addressing the scheme
Moving data between link layer and transport layer
Routing the packets to remote hosts
Performing fragmentation and reassembly of packets

4. TCP/IP suite protocols
IP (Internet protocol)
Best effort delivery routing of the packets
Connectionless and unreliable
ICMP ( Internet Control Message Protocol)
Defines an small number of messages used for diagnostic and management purposes
ICMP uses IP to carry out the following function:
Announces network error
Announces network congestion
Assists troubleshooting
Announces timeouts

5. Cont… ARP ( Address Resolution Protocol)
Determine the MAC address for known IP address
Two messages ARP Request and ARP reply
RARP ( Reverse Address Resolution Protocol)
Determine the IP address when MAC address known
Two messages RARP Request and RARP reply

6. Cont... DHCP (Dynamic Host Configuration Protocol)
Provides automatic configuration of IP addresses
DNS (Domain Name System)
Resolves hosts names to their respective IP addresses
SNMP Simple network management protocol
Monitor remote devices

7. Cont… SMTP (Simple mail Transfer protocol)
Transfer mail over internet
NNTP ( Network News Transfer protocol)
Used to setup Bulletin Discussions over internet
FTP ( File Transfer protocol)
Download or upload files over internet
Uses connection oriented protocol (TCP)
TFTP ( Trivial File Transfer protocol)
Copy files from one device to anther
Uses a connectionless protocol (UDP)

8. IP Addressing
Different devices within an internetwork are identified by an IP address
IP address
Uniquely identifies
network to which
host is attached
Network ID
Host ID
Identifies host
uniquely given the
network

9. Cont… The network part has not been allocated a fixed address space
It is 32 bits, dotted-decimal notation, 4 byte
Network Host
0-255

10. Cont… 0.0.0.0 reserved for network addresses
reserved for broadcast address
Numbers assigned to network or host 1-254

11. Subnet Mask
To determine which part from the IP address is network ID and which is Host ID
Anding operation with the IP address to determine the network address

12. Cont…

13. Default Gateway (router)
The network ID of the destination used to check whether the destination is in the same network with the computer or not
Yes, use the ARP to determine the MAC address and forward the frame to it
No, send it to the router (using the ip of the router) and the router looks into the Routing table for the destination network and forwarding the packet to the corresponding interface.

14. IP address classes A 001 to 126 224 – 2 = 16,777,214 B 128 to 191
= 65,534 C
192 to 223
28 -2 = 254 D
224 to 239 E
240 to 254

15. Problems
IPv4 address scheme is limited by its 32 bits problems for the long-term growth of the internet
Class D and class E reserved
Networks , , are reserved for protocol operations
Class A and Class B addresses were gone and goes to individual organizations like HP (3 As) unused IP addresses within these blocks is very large
Class C networks used to entire country in some countries in Asia and Africa because they arrive late to the internet
limited number of hosts
reduce the number of available
globally unique IP address

16. Cont…
The global internet routing table is huge and continues to grow go beyond the capacity of routers

17. Solutions Subnet masking Address allocation for private internet
Hierarchical addressing
Variable-length subnet masks
Route summarization
Classes interdomain routing
Network address translation

18. Subnet addressing
Networks divided into subnets thus saving IP address spaces, reduce broadcasting and use the network address more efficient
Done by reserving bits from host address
Any number of bits can be borrowed as long as two bits remain.
Computers see subnetwork address in 3 parts ( Net,subnet,host )

19. Subnetting a class C network
In a class C network (exp: )
Network address part can’t be change
Reserved bits from host part
Reserving one bit : cannot be use to create subnet because only two numbers are possible 0,1 . 0 reserved for networks while 1 reserved for broadcasting
Minimum two bits for subnetting

20. Cont… With to bits , 4 numbers are possible 00 reserved for network 
Reserved for broadcast
The direct broadcast address for the produced two subnet will be:  

21. Cont... From the remaining 6 bits in the host part  62 hosts
The range of IP addresses in each subnet: to to to to
The default subnet mask for this network will be 

22. In a class C network

23. Cont… See in the notes Subnetting in class C using 3 bits
Class B Subnetting

24. Private addressing
IP can be assigned to devices in private network .But this IPs may conflict with IPs over the internet
Sol1: assigned to them public IP address  exhausting IP address space
Sol2: use IP networks numbers called private internets  must be no internet connectivity

25. Cont… Address Allocation for Private Internets
It is a set of networks that will never be assigned to any organization as a registered network number

26. IPv6 Is the successor to the currently used IPv4
Specification completed in 1994
Makes improvements to IPv4 (no revolutionary changes)
significant increase of the IP address to 128 bits (16 bytes)
IPv6 will solve – for the foreseeable future – the problems with IP addressing
IPv4 has a maximum of 232  4 billion addresses
IPv6 has a maximum of 2128 = (232)4  4 billion x 4 billion x 4 billion x 4 billion addresses
improves routing, security and Quality of Service (QoS)

27. Cont…
The 128-bit IPv6 address is written as eight 16-bit integers (using hexadecimal digits for each integer)
Exp:
CEDF:BP76:3245:4464:FACE:2E50:3025:DF12

28. IPv6 Prefix (subnet mask)
IPv4 subnet mask called as address prefix in IPv6 and it used to determine which part of the IP is network ID and which is host ID
Its format: the IP address with a slash (/) followed by the prefix length
Exp: CEDF:BP76:3245:4464:FACE:2E50:3025:DF12 /64
The prefix is a decimal value that indicates the number of high order contiguous bits that is the network portion of the IP address