IP Addressing Data Communication Quiz by Ravinder Nath Rajotiya - November 13, 2019November 13, 20190 Share on Facebook Share Send email Mail Print Print Table of Contents Toggle IP AddressingIPv4 HeaderClasses of IP AddressesIP Address TypesSubnet MaskHow to find the network ID:VLSM CalculationClassless inter domain routingGateways/RoutersIP Addressing Quiz IP Addressing IP addressing is the role of the layer-3 ‘Network Layer’ in OSI Model or Layer-2 ‘Internet layer’ in TCP/IP model. IPv4 Header The IP header is used to support two key operations, routing and fragmentation. Routing is the mechanism that allows traffic from a given network to be forwarded to other networks, since the data link layer represents a single network for which network boundaries exist. Fragmentation refers to the breaking down of data into manageable blocks that can be transmitted over the network. Figure-1: IPv4 Header Classes of IP Addresses The IPv4 addresses are classified into following five categories: Figure-2: IP Address Classes Class A for instance consist of 126 potential networks, each of which can support 254. Class B for instance consist of 64534 potential networks, each of which can support 64534. Class C address ranges allow for a much more balanced network that scales well to Ethernet networks, supplying just over 2 million potential networks, with each network capable of supporting around 256 addresses, of which 254 are assignable to hosts. Class D is a range reserved for multicast, to a group, which require the member association to groups. Class E is reserved for experimental purposes. IP Address Types Figure-3: IP Address Types As the public IP in IPv4 are limited and cannot take care of the increasing demand of addresses an adhoc arrangement was made allowing few private IP to be reused within the enterprise. However for outbound traffic a IP address translation be performed before data can reach the intended destination. Other special addresses include : a diagnostic range denoted by the 127.0.0.0 network address the first address 0.0.0.0 represents any network the last address 255.255.255.255 represents a broadcast address for the IPv4 (0.0.0.0) network, however the scope of any broadcast in IP is restricted to the boundaries of the local area network from which the broadcast is generated. Subnet Mask Application of the subnet mask to a given IP address enables: identification of the network to which the host belongs. identify the broadcast address for the network Indicate the number of hosts that can be supported as part of the network range. Such information provides the basis for effective network address planning. How to find the network ID: network address = (IP Address) . (Subnet Mask) Let number of bits in Host address = n Total number of hosts = 2n Number of usage address = 2n – 2 Example: bits in subnet mask 24 therefore number of bits for hosts = 32-24 = 8 Total number of hosts = 28 = 256 Number of usage address = 28 – 2 = 254 VLSM Calculation As a means of resolving the limitations of default subnet masks, the concept of variable length subnet masks are introduced, which enable a default subnet mask to be broken down into multiple sub-networks, which may be of a fixed length (a.k.a. fixed length subnet masks or FLSM) or of a variable length known commonly by the term VLSM. The implementation of such subnet masks consists of taking a default class based network and dividing the network through manipulation of the subnet mask. To divide a network of 100 systems into 4 sub-groups: 25 hosts in each sub-group; each subgroup would need 5-bit host address leaving 27 bit network subnet mask Figure-4: VLSM Classless inter domain routing Classless inter-domain routing was initially introduced as a solution to handle problems that were occurring as a result of the rapid growth of the Internet. The primary concerns were to the imminent exhaustion of the class B address space commonly adopted by mid-sized organizations for whom class C was inadequate and where class A was too vast, and management of the 65534 host addresses could be achieved through VLSM. Figure-5: CIDR The solution given involves transitioning to a classless addressing system in which classful boundaries were replaced with address prefixes. It uses the slash ‘/’ notation for subnet mask. The result of CIDR has had far reaching effects and is understood to have effectively slowed the overall exhaustion rate of the IPv4 address space. Gateways/Routers Internet is a network of network and i generally referred as a public network, where communication often is among different network. Figure-6: Gateway In the case where the intended network is different from the originating network, the packet must be forwarded to a gateway via which the packet is able to reach it’s intended destination. In all networks, the gateway is a device that is capable of handling packets and making decisions as to how packets should be routed, in order to reach their intended destination. Where networks are divided by a physical gateway, the interface IP address (in the same network or sub-network) via which that gateway can be reached is considered to be the gateway address. IP Addressing Quiz Welcome to your IPv4 Addressing 1. In Huawei Devices, when NAPT uses a dynamic address pool, addresses in the pool can be used repeatedly. That is, one IP address can be mapped to multiple intranet IP addresses TRUE FALSE 2. The last option field (option) of an IPv4 packet is a length-variable and optional field. What is the maximum length of this field? 40B 60B 20B 10B 3. A Company applies for a class C IP address for subnetting . It has six branches and the largest branch should have 26 host. What would be an appropriate subnet mask for the largest branch ? 255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 4. The broadcast address of the subnet 192.168.1.0/25 is 192.168.1.128 TRUE FALSE 5. For multiple paths to the same destination network, the router needs to compare cost values of the paths. If the cost value are the same the router selects the path based on the preference value TRUE FALSE 6. Which of the following IPv4 addresses can be directly used by a host to access the internet ? 192.168.1.1/24 10.255.255.254/24 172.16.255.254/24 172.32.1.1/24 7. According to the figure, which of the following statements is true? The IP address mask of host A is different from that of host B, therefore Host A & B cannot communicate with each other Host A can successfully ping Host B The broadcast address of Host A and Host B are the same Host A and B can communicate with rach other only when the IP address of Host A and Host B have same masks 8. Which of the following IP addresses can be used by another host to communicate with the host whose ip address is 200.200.200.201/30 without the need to forward traffic through a router? 200.200.200.1 200.200.200.200 200.200.200.202 200.200.200.203 9. A network administrator has been assigned the IP address segment 192.168.176.0/25, from which he/she must allocate a subnet to support 20 users in the marketing department. Which IP subnet best supports this requirements 192.168.176.0/25 192.168.176.0/30 192.168.176.48/29 192.168.176.96/27 10. Which of the following fields is not included in the format of the network - layer packet header ? Source IPv4 Address Destination IPv4 Address TTL Sequence Number 11. As Shown in the figure, host A and host B cannot communicate with each other? TRUE FALSE 12. As shown in Figure, Host A and Host B cannot communicate with each other? TRUE FALSE 13. Which of the following addresses cannot be used as the IPv4 address of a host Class A address Class B address Class C address Class D address 14. Which of the following cannot be the length of an IPv4 packet header 20B 32B 60B 64B Time's up Share on Facebook Share Send email Mail Print Print