Computer Networks and Data Comuncation-LEC3.pdf
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Addressing &&Subnet MAC address (Media Access Control) is a globally unique identifier assigned to network devices it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format. The first 3...
Addressing &&Subnet MAC address (Media Access Control) is a globally unique identifier assigned to network devices it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format. The first 3-bytes are ID number of the manufacturer, which is assigned by an Internet standards body. The second 3-bytes are serial number assigned by the manufacturer. IP Addressing An IP, or Internet Protocol address, is a unique set of numbers assigned to each device connected to a network, like the Internet. It’s like an address for your computer, phone, or any other device, allowing them to communicate with each other. When you visit a website, your device uses the IP address to find and connect to the website’s server. Every IP address consists of two parts, one identifying the network and one identifying the node. There are two versions of IP: IPv4 and IPv6 Internet Protocol (IP V4) Uniquely identify each device on an IP network layer. Some times we called it the logical address Every host (computer, networking device, peripheral) must have a unique address at the same network The IP address 32 bit divided into 4 octets each octet 8 bit IPv4 addresses IPv4 addresses consist of two things: the network address and the host address. It stands for Internet Protocol version four. IPv4 addresses are 32-bit integers that have to be expressed in Decimal Notation. It is represented by 4 numbers separated by dots in the range of 0-255, which have to be converted to 0 and 1, to be understood by Computers. For Example, An IPv4 Address can be written as 189.123.123.90. IPv6 Address IPv6 is based on IPv4 and stands for Internet Protocol version 6. It was first introduced in December 1995 by Internet Engineering Task Force. IP version 6 is the new version of Internet Protocol, which is way better than IP version 4 in terms of complexity and efficiency. IPv6 is written as a group of 8 hexadecimal numbers separated by colon (:). It can be written as 128 bits of 0s and 1s. IPv6 Address Format IPv6 Address Format is a 128-bit IP Address, which is written in a group of 8 hexadecimal numbers separated by colon (:). Type of IP IPv4 IPv6 1-It is a 32 bit binary 1-technology in the IP was invented because the available number number usually It became a few large number of users on the represented as 4 network decimal values, each 2-uses a 128-bit representing 8 bits, in gives about 79Octellion any the range 0 to 255 79,000,000,000,000,000,000,000,000,000 (known as octets) 3-Hexadecimal system is used instead of the binary system separated by decimal 4-In eight separate boxes box consists of four points. numbers and letters Example: 192.168.1.2 5-example 3FFE: 0B00: 0800: 0002: 0000: 0000: 0000: 000C Benefits of IPv6 over IPv4 Larger Address Space: IPv6 has a greater address space than IPv4, which is required for expanding the IP Connected Devices. IPv6 has 128 bit IP Address rather and IPv4 has a 32-bit Address. Improved Security: IPv6 has some improved security which is built in with it. IPv6 offers security like Data Authentication, Data Encryption, etc. Here, an Internet Connection is more Secure. Simplified Header Format: As compared to IPv4, IPv6 has a simpler and more effective header Structure, which is more cost-effective and also increases the speed of Internet Connection. Prioritize: IPv6 contains stronger and more reliable support for QoS features, which helps in increasing traffic over websites and increases audio and video quality on pages. Improved Support for Mobile Devices: IPv6 has increased and better support for Mobile Devices. It helps in making quick connections over other Mobile Devices and in a safer way than IPv4. How IP is represented ? IP components An IP address can be further divided into two parts: Network address: Identifies the network to which a device belongs (like a city in a physical address). Host address: Uniquely identifies a specific device within the network (like a street address and house number). Address Classes Address Classes Class A : it uses first octet for network addresses and last three octets for host addressing , begin with 0xxx, or 1 to 126 decimal. Class B : it uses first two octets for network addresses and last two for host addressing ,begin with 10xx, or 128 to 191 decimal. Class C : it uses first three octets for network addresses and last one for host addressing ,begin with 110x, or 192 to 223 decimal. Class D : it provides flat IP addressing scheme in contrast to hierarchical structure for above three, begin with 1110, or 224 to 239 decimal. Class E : It is used as experimental, begin with 1111, or 240 to 254 decimal. Addresses beginning with 01111111, or 127 decimal, are reserved for loopback and for internal testing on a local machine. [You can test this: you should always be able to ping 127.0.0.1, which points to yourself] Class D addresses are reserved for multicasting. Class E addresses are reserved for future use. They should not be used for host addresses. Now we can see how the Class determines, by default, which part of the IP address belongs to the network (N) and which part belongs to the node (H). Class A : N. H. H. H Class B : N.N.H.H Class C : N.N.N.H Classification of IP Address An IP Address is basically classified into two types: Private IP Address Public IP Address What is a Private IP Address? The Private IP Address of a system is the IP address that is used to communicate within the same network. Using private IP data or information can be sent or received within the same network. The router basically assigns these types of addresses to the device. Unique private IP Addresses are provided to each and every device that is present on the network. These things make Private IP Addresses more secure than Public IP Addresses What is a Public IP Address? The Public IP Address of a system is the IP address that is used to communicate outside the network. A public IP address is basically assigned by the ISP (Internet Service Provider). Public IP Address is basically of two types: Dynamic IP Address: Dynamic IP Addresses are addresses that change over time. After establishing a connection of a smartphone or computer with the Internet, ISP provides an IP Address to the device, these random addresses are called Dynamic IP Address. Static IP Address: Static Addresses are those addresses that do not change with time. These are stated as permanent internet addresses. Mostly these are used by the DNS (Domain Name System) Servers. IP ADDRESS RANGES Private IP Addresses (Local IP) PUBLIC IP ADDRESSES (REAL IP) ❖ How to assign IP address to device Manually Automatic APIPA Manually Automatic DHCP Server used to assign dynamically the IP Configuration including (Host IP, Subnet mask, Default Gateway, DNS server IP and the Lease Time) APIPA APIPA (Automatic Private IP Address ) If no DHCP server is available the APIPA is used Auto configuration IP address used to let LAN users talk to Each other if the DHCP fails Can not be Routed Rang : 169.254.0.0 To 169.254.255.255 RESERVED ADDRESS Network address: - reserved - can not be assigned to any device - used for routing by the router Class A:10.0.0.0 Class B: 172.16.0.0 Class C:192. 168.1.0 RESERVED ADDRESS Loop back Address - Loopback address: It is used just for testing -the TCP/IP Protocol Suit 127.0.0.1 example test NIC Default Gateway The default gateway is the internal IP (LAN)address of your router. It is needed for a device to get a packet out to the internet (WAN). DELIVERY OF IP PACKETS subnet 1-A subnet is a logical grouping of connected network devices. 2- Nodes on a subnet tend to be located in close physical proximity to each other on a LAN. 3-Network designers employ subnets as a way to partition networks into logical segments for greater ease of administration. 4-When subnets are properly implemented, both the performance and security of network can be improved. 5-In internet protocol (IP) networking, devices on a subnet share contiguous ranges of IP address numbers. A subnet, or subnetwork, is a network inside a network. Subnets make networks more efficient. Through subnetting, network traffic can travel a shorter distance without passing through unnecessary routers to reach its destination. Uses of Subnetting Subnetting helps in organizing the network in an efficient way which helps in expanding the technology for large firms and companies. Subnetting is used for specific staffing structures to reduce traffic and maintain order and efficiency. Subnetting divides domains of the broadcast so that traffic is routed efficiently, which helps in improving network performance. Subnetting is used in increasing network security. Subnet mask The subnet mask, a 32-bit number like the IP address, plays a critical role in subnetting. It define which bits in the IP address belong to the network portion (subnet) and which belong to the host portion. Subnet Mask Bits: A 1 in the subnet mask corresponds to the network (subnet) bits in the IP address. Host Mask Bits: A 0 in the subnet mask corresponds to the host bits in the IP address Default subnet masks Class A =/8 : 255.0.0.0 11111111.00000000.00000000.00000000 Class B =/16 : 255.255.0.0 11111111.11111111.00000000.00000000 Class C =/24: 255.255.255.0 11111111.11111111.11111111.00000000 How does subnetting work ?ٍ If we have a network ID : 192.168.1.0 with a subnet mask : 255.255.255.0 Let’s present that in binary: Network ID : 11000000. 10101000.00000001.00000000 Subnet mask: 11111111.11111111.11111111.00000000 ▪ To do a subnetting for this network we focus on the octet that used for host which every bit in it equal to zero. ▪ As we see if the bits are equal to 1 in the subnet mask that means the corresponding bit in the Ip is used for the network and if it equal to 0 that means the corresponding bit in the IP used for host. ▪ And the ones should be in sequence without zeros among them. ▪ Therefore, to do a subnetting we flip we flip a 0 or more into a 1 from the last octet Example 192.168.5.0/24 5 subnet 2^n-2 >= 5 ➔ n is the number of bits will be network in the last octet in the subnet mask We used (-2) for the future growth (2 networks for reserve) n=3 Subnet mask = 11111111.11111111.11111111.111 00000 In decimal =255.255.255.244 Network Firs, last , network , broadcast IP Subnet Example2 Subnet Example2 Solution Section3 ❖ ARP (ADDRESS RESOLUTION PROTOCOL) ARP operation Section3 Write subnet mask and network, broadcast IP, first and last IP for the following 192.168.1.0/24 2 subnet 192.168.2.0/24 4 subnet 192.168.3.0/24 13 subnet Thanks! Any questions?
