Classification-of-a-Routing-algorithm2a.pdf

Classification of a Routing algorithm Adaptive Routing algorithm  An adaptive routing algorithm is also known as dynamic routing algorithm.  This algorithm makes the routing decisions based on the topology and network traffic.  The main parameters related to this a...

Classification of a Routing algorithm Adaptive Routing algorithm  An adaptive routing algorithm is also known as dynamic routing algorithm.  This algorithm makes the routing decisions based on the topology and network traffic.  The main parameters related to this algorithm are hop count, distance and estimated transit time. An adaptive routing algorithm can be classified into three parts:  Centralized algorithm:  It is also known as global routing algorithm as it computes the least cost path between source and destination by using complete and global knowledge about the network.  This algorithm takes the connectivity between the nodes and link cost as input, and this information is obtained before actually performing any calculation. Link state algorithm is referred to as a centralized algorithm since it is aware of the cost of each link in the network.  Isolation algorithm:  It is an algorithm that obtains the routing information by using local information rather than gathering information from other nodes.  Distributed algorithm: It is also known as decentralized algorithm as it computes the leastcost path between source and destination in an iterative and distributed manner.  In the decentralized algorithm, no node has the knowledge about the cost of all the network links. In the beginning, a node contains the information only about its own directly attached links and through an iterative process of calculation computes the least-cost path to the destination.  A Distance vector algorithm is a decentralized algorithm as it never knows the complete path from source to the destination, instead it knows the direction through which the packet is to be forwarded along with the least cost path. Non-Adaptive Routing algorithm  Non Adaptive routing algorithm is also known as a static routing algorithm.  When booting up the network, the routing information stores to the routers.  Non Adaptive routing algorithms do not take the routing decision based on the network topology or network traffic. The Non-Adaptive Routing algorithm is of two types:  Flooding:  In case of flooding, every incoming packet is sent to all the outgoing links except the one from it has been reached. The disadvantage of flooding is that node may contain several copies of a particular packet.  Random walks:  In case of random walks, a packet sent by the node to one of its neighbors randomly. An advantage of using random walks is that it uses the alternative routes very efficiently. Differences b/w Adaptive and Non-Adaptive Routing Algorithm RIP Protocol  RIP stands for Routing Information Protocol. RIP is an intra-domain routing protocol used within an autonomous system.  Intra-domain means routing the packets in a defined domain, for example, web browsing within an institutional area.  To understand the RIP protocol, our main focus is to know the structure of the packet, how many fields it contains, and how these fields determine the routing table. Understanding the structure of the packet (RIP)  RIP is based on the distance vector-based strategy, so we consider the entire structure as a graph where nodes are the routers, and the links are the networks.  In a routing table, the first column is the destination, or we can say that it is a network address.  The cost metric is the number of hops to reach the destination. The number of hops available in a network would be the cost. The hop count is the number of networks required to reach the destination.  In RIP, infinity is defined as 16, which means that the RIP is useful for smaller networks or small autonomous systems. The maximum number of hops that RIP can contain is 15 hops, i.e., it should not have more than 15 hops as 16 is infinity. How is hop count determined?  when the router 1 forwards the packet to the router 2 then it will count as 1 hop count. Similarly, when the router 2 forwards the packet to the router 3 then it will count as 2 hop count, and when the router 3 forwards the packet to router 4, it will count as 3 hop count. In the same way,  RIP can support maximum upto 15 hops, which means that the 16 routers can be configured in a RIP.  If there are 8 routers in a network where Router 1 wants to send the data to Router 3. If the network is configured with RIP, it will choose the route which has the least number of hops. There are three routes in the above network, i.e., Route 1, Route 2, and Route 3. The Route 2 contains the least number of hops, i.e., 2 where Route 1 contains 3 hops, and Route 3 contains 4 hops, so RIP will choose Route 2.  Suppose R1 wants to send the data to R4. There are two possible routes to send data from r1 to r2. As both the routes contain the same number of hops, i.e., 3, so RIP will send the data to both the routes simultaneously. This way, it manages the load balancing, and data reach the destination a bit faster. The following are the disadvantages of RIP:  In RIP, the route is chosen based on the hop count metric. If another route of better bandwidth is available, then that route would not be chosen. The following are the advantages of a RIP protocol:  It is easy to configure  It has less complexity  The CPU utilization is less. Dynamic Host Configuration Protocol (DHCP)  is a client/server protocol that automatically provides an Internet Protocol (IP) host with its IP address and other related configuration information such as the subnet mask and default gateway Why use DHCP  Every device on a TCP/IP-based network must have a unique unicast IP address to access the network and its resources.  Without DHCP, IP addresses for new computers or computers that are moved from one subnet to another must be configured manually.  IP addresses for computers that are removed from the network must be manually reclaimed.  entire process is automated and managed centrally. The DHCP server maintains a pool of IP addresses and leases an address to any DHCPenabled client when it starts up on the network. Because the IP addresses are dynamic (leased) rather than static (permanently assigned), addresses no longer in use are automatically returned to the pool for reallocation. Benefits of DHCP  Reliable IP address configuration DHCP minimizes configuration errors caused by manual IP address configuration, such as typographical errors, or address conflicts caused by the assignment of an IP address to more than one computer at the same time ❑ Reduced network administration Centralized and automated TCP/IP configuration. The ability to define TCP/IP configurations from a central location The ability to assign a full range of additional TCP/IP configuration values by means of DHCP options. The efficient handling of IP address changes for clients that must be updated frequently PROXY SERVER  proxy server refers to a server that acts as an intermediary between the request made by clients, and a particular server for some services or requests for some resources  The basic purpose of Proxy servers is to protect the direct connection of Internet clients and internet resources  The proxy server also prevents the identification of the client’s IP address when the client makes any request is made to any other servers. Types of Proxy Server  Reverse Proxy Server reverse proxy server to listen to the request made by the client and redirect to the particular web server which is present on different servers. Web Proxy Server  Web Proxy forwards the HTTP requests, only URL is passed instead of a path. The request is sent to a particular the proxy server responds. Examples, Apache, HAP Proxy. Anonymous Proxy Server  This type of proxy server does not make an original IP address instead these servers are detectable still provides rational anonymity to the client device. Highly Anonymity Proxy  This proxy server does not allow the original IP address and it as a proxy server to be detected. Transparent Proxy  This type of proxy server is unable to provide any anonymity to the client, instead, the original IP address can be easily detected using this proxy. CGI Proxy  CGI proxy server was developed to make the websites more accessible. It accepts the requests to target URLs using a web form and after processing its result will be returned to the web browser Suffix Proxy  Suffix proxy server basically appends the name of the proxy to the URL.  This type of proxy doesn’t preserve any higher level of anonymity. It is used for bypassing the web filters.  It is easy to use and can be easily implemented but is used less due to the more number of web filter present in it. allows a user to access web content by appending the name of the proxy server to the URL of the requested content (e.g. "en.wikipedia.org.SuffixProxy.com"). I2P Anonymous Proxy  It uses encryption to hide all The Invisible Internet Project (I2P) is a fully encrypted the communications at private network layer. It protects your activity and various levels. location. Every day people use the network to connect with people without worry of being tracked  This encrypted data is then or their data being collected. In some cases people relayed through various rely on the network when they need to be discrete or network routers present at are doing sensitive work. different locations and thus I2P is a fully distributed proxy.  This software is free of cost and open source to use, It also resists the censorship. DNS Proxy  DNS proxy take requests in the form of DNS queries and forward them to the Domain server where it can also be cached, moreover flow of request can also be redirected. How Does The Proxy Server Operate  Every computer has its unique IP address which it uses to communicate with another node.  proxy server has its IP address that your computer knows. When a web request is sent, your request goes to the proxy server first.  The Proxy sends a request on your behalf to the internet and then collect the data and make it available to you.  proxy can change your IP address,  the webserver will be unable to fetch your location in the world. It protects data from getting hacked.  Moreover, it can block some web pages Disadvantages of Proxy Server  Proxy Server Risks Free installation does not invest much in backend hardware or encryption. It will result in performance issues and potential data security issues. If you install a “free” proxy server, treat very carefully, some of those might steal your credit card numbers. ❑ Browsing history log The proxy server stores your original IP address and web request information is possibly unencrypted form and saved locally. Always check if your proxy server logs and saves that data – and what kind of retention or law enforcement cooperation policies they follow while saving data. ❑ No encryption No encryption means you are sending your requests as plain text. Anyone will be able to pull usernames and passwords and account information easily Take the quiz