...Default gateway From Wikipedia, the free encyclopedia In computer networking, a gateway is a node (a router) on a TCP/IP network that serves as an access point to another network. A default gateway is the node on the computer network that the network software uses when an IP address does not match any other routes in the routing table. In home computing configurations, an ISP often provides a physical device which both connects local hardware to the Internet and serves as a gateway. Such devices include DSL modems and cable modems. In organizational systems a gateway is a node that routes the traffic from a workstation to another network segment. The default gateway commonly connects the internal networks and the outside network (Internet). In such a situation, the gateway node could also act as a proxy server and a firewall. The gateway is also associated with both a router, which uses headers and forwarding tables to determine where packets are sent, and a switch, which provides the actual path for the packet in and out of the gateway. In other words, a default gateway provides an entry point and an exit point in a network. Contents [hide] * 1 Example1 * 2 Example2 * 3 See also * 4 External links | [edit] Example1 An office network consists of six hosts and a router is given as: Hosts addresses: * 192.168.4.3 * 192.168.4.4 * 192.168.4.5 * 192.168.4.6 * 192.168.4.7 * 192.168.4.8 Router (this side) address: * 192.168.4.1 The network...
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...Impact of MAC Layer on the Performance of ODMRP, Fisheye, AODV and DSR, Routing Protocols in Mobile Ad hoc Networks A. Sravani, G. Srinu, and A.Venkataramana Abstract— Mobile Ad hoc Network is an emerging area. Its standards are defined by IETF. MANET is a self generated, self organized and self handled network consisting of collection of independent nodes. MANETs Presents several desirable properties like dynamic topology, Easy of deployment and robustness, which are qualify them as an attractive topic for the research community. Providing QoS routing is a major issue in MANETs. Media Access Control layer plays crucial role in Ad hoc networks. Several routing protocols have already been proposed for MANETs. This paper describes the impact of MAC layer protocols like 802.11 and CSMA on the various routing protocols like AODV, DSR, ODMRP and Fisheye. Numbers of simulation scenarios were carried out by using Glomosim-2.03. The QoS parameters used are Throughput, Delay and PDR. Simulation results found that AODV performs better in 802.11 and CSMA, DSR and ODMRP performs better in only under 802.11. Keywords— MANET, AODV, DSR, FSR, GloMoSim, ODMRP I. INTRODUCTION Wireless communication networks are basically two types as shown in Fig.1. One is infrastructure based and other one is infrastructure less. Infrastructure based is cellular communications whereas infrastructure less is ad hoc networks. Fig.1 Classification of wireless communication networks A. Cellular...
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...By: Dick Gilbert Routers A router is a network layer device responsible for routing traffic between subnetwork that make up a data internetwork . A subnetwork is defined as a collection of network resources that can be reached without needing to go through a router. A internetwork a collection of two or more subnetworks connected using routers. The role of a router is pretty simple. It receives packets transmitted by end stations and routes them through the internetwork to the right subnetwork. Routers can also perform more advanced functions if the network layer protocol supports those functions. Most of them have the ability to fragment packets. Routers also provide some congestion control capablilties .Routers can be fairly sophisticated packet filters. Some people sometimes mistake routing for bridging. Routing is also a network layer function. Routers operate on packets and choices based on the network layer address. Bridging is a data link layer function. Bridges operate on frames and make filtering and forwarding choices based on the media access control address. Packets ride within frames and are the transmission unit used to get a message from one end station to another anywhere in the internetwork. If two end stations are in the same subnetwork , the packet will be placed in a frame by the transmitter and sent across the subnetwork to the...
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...Fall 2006, Syracuse University Lecture Notes for CIS/CSE 758: Internet Security Routing Protocols (1) Introduction Static routing versus dynamic routing Static routing Fixes routes at boot time Useful only for simplest cases Dynamic routing Table initialized at boot time Values inserted/updated by protocols that propagate route information Necessary in large internets Routing with partial information The routing table in a given router contains partial information about possible destinations For the unknown destinations, forward them to the default router. Potential problem: some destinations might be unreachable. Original Internet and the problem if the core routers are allowed to have default routes. Core routing architecture with single backbone. Assumes a centralized set of routers that know all possible destinations in an internet. Non-core routers use the core routers as their default routers. Work best for internets that have a single, centrally managed backbone. Inappropriate for multiple backbones. Disadvantage Central bottleneck for all traffic Not every site could have a core router connected to the backbone: how do they get routing information? No shortcut route possible: non-core routers always forward their traffic to the default routers even though another core router provides a better route. This is because the noncore routers do not know which one is better without full knowledge of all possible destinations...
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...SECURITY ISSUES AND PROCEDURES OF COMMUNICATION NETWORKS Student’s Name Institutional Affiliation Currently prompt evolution in computer communications linked to terminal-based, multi-operator systems, and in computer networks. Almost all these arrangements interconnect process, keep important data that is consider reserved or patented by their possessors and managers, or that should be protected from illegal access as a requisite of the law. Additionally, telecommunication systems, connected terminals, communication processors, and computers should be safeguarded from invaders who may strive to modify programs or files in the system, or to interrupt the facilities offered. The above threats are existent, as it is not challenging to interrupt communications in telecommunication systems, and the probability of connecting illegitimate terminals or computers into the scheme with the aim of “managing" the usual terminal-computer network, or making the system inaccessible to others. The security of such systems against the several dangers encompasses identification, and verification of the individuality, organized right to use to computers and their databases, and shelter of the information being carried in the telecommunication system. Related to every threat is various conceptual, along with technical challenges and a diversity of solutions. Local area network (LAN) refers to an assembly of PCs and other devices spread over a reasonably limited area and linked by a communications...
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...(IJCSIS) International Journal of Computer Science and Information Security, Vol. 4, No. 1 & 2, 2009 A Survey of Attacks, Security Mechanisms and Challenges in Wireless Sensor Networks Dr. G. Padmavathi, Mrs. D. Shanmugapriya, Prof and Head, Dept. of Computer Science, Avinashilingam University for Women, Coimbatore, India, ganapathi.padmavathi@gmail.com Lecturer, Dept. of Information Technology, Avinashilingam University for Women, Coimbatore, India, ds_priyaa@rediffmail.com Abstract—Wireless Sensor networks (WSN) is an emerging technology and have great potential to be employed in critical situations like battlefields and commercial applications such as building, traffic surveillance, habitat monitoring and smart homes and many more scenarios. One of the major challenges wireless sensor networks face today is security. While the deployment of sensor nodes in an unattended environment makes the networks vulnerable to a variety of potential attacks, the inherent power and memory limitations of sensor nodes makes conventional security solutions unfeasible. The sensing technology combined with processing power and wireless communication makes it profitable for being exploited in great quantity in future. The wireless communication technology also acquires various types of security threats. This paper discusses a wide variety of attacks in WSN and their classification mechanisms and different securities available to handle them including...
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...Course Project Author Note This assignment is being submitted on September 5, 2013, for N235/CET2629 Section 02 Cisco Networking Fundamentals and Routing course. Course Project Assuming that the router (R1) connecting the NOC to the outside world is configured with an IP address of 154.78.0.1 is directly linked to router (R2) with IP address 154.78.0.244 complete the following: Explain the steps required to configure router R1 and R2 to use Frame relay your explanation should include the commands used. Frame relay is fairly simple to configure. Remember that by default, Cisco uses High-level Data Link Control (HDLC) as a serial link encapsulation. This is a proprietary encapsulation and can only be used if you’re connecting two Cisco routers with a point-to-point link. Frame relay allows you to connect multiple vendors’ routers because of the frame relay standards created. The configuration of each router is very simple and looks something like this: R1 Router>enable Router#config t Router(config)#hostname R1 R1(config)# interface serial 0 R1(config-if)#ip address 154.78.0.1 255.255.0.0 R1(config-if)#no shutdown R1(config-if)#exit R1(config)#exit R1# R2 Router>enable Router#config t Router(config)#hostname R2 R2(config)#interface serial 0 R2(config-if)#ip address 154.78.0.244/255.255.0.0 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#exit R2# The two routers can now communicate point to point. If a company had large streams...
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...NI-LIMIT 11 NI-LIMIT COMPUTER NETWORK SYSTEM PROPOSAL [Type the document subtitle] [Type the author name] TABLE OF CONTENTS ACKNOWLEDGEMENTS My fellow group members would like to thank our dear lecturer Mrs. Noris Ismail for doing her lecturing job professionally which broadened our knowledge greatly about networking and enabled us to come up with such a detailed proposal for network infrastructure and mixing it with several other ideas to finally make a final report on it. I would also want to thank my fellow group members for the effort and dedication they put in to complete the task of coming up with the report and the final proposal. Chapter one: Company profile NI-Limits Sdn Bhd NI-Limits Sdn Bhd is a digital design & web management company that provides stateof-the-art service through a mixed team of local and foreign professionals with the mission of delivering unparallel service and support to both Malaysian and International markets. NI-Limits Sdn Bhd is a Malaysian based company resulting from a merger of several independent web development agencies (Pixel Media, Webb Designs and Quartz Interactive) and international freelancers that have been in business since 1997. Mark Smalley and Nigel Webb formed Pixel Media in Sarawak, Malaysia in 1997. As a team of independent freelancers working together, they developed online marketing material to clients throughout Asia. The company primarily dealt with Oil and Gas related companies that were...
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...Semester Two Journal and Study Guide CISCO SYSTEMS NETWORKING Academy CCNA 2 Chapter 1 WANs and Routers One major characteristic of a wide-area network (WAN) is that the network operates beyond the local LAN's geographic scope. It uses the services of carriers, such as regional Bell operating companies (RBOCs), Sprint, and MCI. WANs use serial connections of various types to access bandwidth over wide-area geographies. By definition, the WAN connects devices that are separated by wide areas. WAN devices include the following: • • • • • • Routers, which offer many services, including internetworking and WAN interface ports Switches, which connect to WAN bandwidth for voice, data, and video communication Modems, which interface voice-grade services and channel service units/digital service units Channel service units/data service units (CSUs/DSUs) that interface T1/E1 services and Terminal Adapters/Network Termination 1 (TA/NT1s) TA/NT1s that interface Integrated Services Digital Network (ISDN) services Communication servers, which concentrate on dial-in and dial-out user communication Concept Questions 1. A WAN is used to interconnect local-area networks (LANs) that are typically separated by a large geographic area. A WAN operates at the OSI reference model physical and data link layers. The WAN provides for the exchange of data packets/frames between routers/bridges and the LANs that they support. Draw a WAN that includes three LANs. 1 of 116 CCNA 2 Chapter 1 WANs and...
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...selecting internetworking devices at the core, access, and distribution layer in a computer network When designing a network there are many different important criteria for selecting internetworking devices for router the number ports need for your business. The processing speed and amount of memory do you need for your business. If you need LAN or WAN support availability and quality of technical support and documentation of training and vendor. For switch and bridges you have to look at number of MAC address can learn, support of port security, support for cut through switching and support for adaptive cut through switching. Don’t forget amount of memory. The router network layer protocols supported, routing protocols support, support for multicast, support for advanced queuing switching and other optimization. These are all important of selecting internetworking. You have to look at the business and customers that you are support then you use these internetwork criteria to make your decisions. Priscilla Oppenheimer (2012). Top-Down Networking Design. (Special Edition for Strayer University) Boston, MA, Pearson Learning Solutions Describe the key criteria involved in selecting WAN technologies and WAN providers. Discuss which criteria is the most important from your perspective and state why. When selecting WAN technologies and WAN provider this will vary from company to company one of the most important factors would be the cost. This would also include business...
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... The default gateway often connects a local network to the Internet, although internal gateways for local networks also exist. In simple words the Gateway (normally associated with a router ) is an entry and an exit point for network traffic. A depiction below shows a SOHO and how the wireless router acts as a gateway for all the devices connected. In big enterprises, the device playing the part of a gateway could also act as a proxy server and a firewall. In most cases the gateway is a router, which use headers and forwarding tables to determine where packets are sent. Configuring the Router as a Gateway Login to the router’s web interface (refer to router guide) , and click on the “Setup Tab” and proceed to the “Advanced Routing option” Use the instructions as given below : If the Router is directly connected to the DSL/Cable modem, select the default option of Gateway. In this example , we will attempt to configure the router as a gateway . Our assumption would be that the customer only has one wireless router connecting to the Cable/DSL modem. Click on Save Settings and verify that the devices connected to the router’s LAN interfaces can access the internet (as depicted below). 1 2 References References Wikipedia June 25 2011, http://www.wikipedia.org Compnetworking June 26 2011 , http://compnetworking.about.com Webopedia June 26 2011, http://www.webopedia.com Cisco-Linksys June 26 2011,...
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...selecting internetworking devices at the core, access, and distribution layer in a computer network When designing a network there are many different important criteria for selecting internetworking devices for router the number ports need for your business. The processing speed and amount of memory do you need for your business. If you need LAN or WAN support availability and quality of technical support and documentation of training and vendor. For switch and bridges you have to look at number of MAC address can learn, support of port security, support for cut through switching and support for adaptive cut through switching. Don’t forget amount of memory. The router network layer protocols supported, routing protocols support, support for multicast, support for advanced queuing switching and other optimization. These are all important of selecting internetworking. You have to look at the business and customers that you are support then you use these internetwork criteria to make your decisions. Priscilla Oppenheimer (2012). Top-Down Networking Design. (Special Edition for Strayer University) Boston, MA, Pearson Learning Solutions Describe the key criteria involved in selecting WAN technologies and WAN providers. Discuss which criteria is the most important from your perspective and state why. When selecting WAN technologies and WAN provider this will vary from company to company one of the most important factors would be the cost. This would also include business...
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...(Online) : 2278-1021 International Journal of Advanced Research in Computer and Communication Engineering Vol. 2, Issue 6, June 2013 Implementation and Evaluation of Wireless Mesh Networks on MANET Routing Protocols Shashi Bhushan1,Anil Saroliya2 ,Vijander Singh3 Research Scholar, Computer Science, Amity University, Jaipur, India 1 Assistant Professor, Computer Science, Amity University, Jaipur, India 2 Senior Lecturer, Computer Science, Amity University, Jaipur, India 3 Abstract—Wireless Mesh Network (WMN) is a kind of network which is made up of Mesh router and Mesh clients where Mesh router having lesser mobility and form the heart of WMNs. In this paper, Wireless Mesh Network over MANET implemented using routing protocols such as AODV, DSR. In this work NS-2.34 simulator is used for simulations. Various measurements and calculations were figure out in this work like throughput, Average end-end delay, PDR, NRL and Routing packets in Random way point mobility model. WMN have features such as self configuration, self healing and low cost of equipment. This work specifically aims to study the performance of routing protocols in a wireless mesh network, where static mesh routers and mobile clients participate together to implement networks functionality such as routing and packet forwarding in different mobility scenarios Keywords- Ad hoc Network, Routing Protocols, Wireless Mesh Network, Performance, Throughput, PDR, NRL and Routing packets in Random way point mobility model...
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...that carries an active route to 19. In this manner, there is hop count of 2. Multi hop routing includes sending the information through multiple stops rather than sending it using a one long pathway. 2.3. Routing Protocols Bearing the fact that it is imperative for a packet to hop multiple times to reach the final destination, a routing protocol is used. The routing protocol has two major purposes : • selection of routes for various source-destination pairs and • delivery of messages to the correct destination The second purpose is in abstract direct and utilises a variety of data structures called routing tables. This project deals with finding and selecting routes and delivering the packets to the intended destination. 2.3.1. Path Cost Hop count is the developed metric that is used to calculate the best path between the source and the destination. However, another entity called the cost, can be used to determine the lowest distance path between source and the destination. Most routing protocols rely on shortest path or least cost routing, however a single...
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...American International University–Bangladesh Continuing Education Center (CEC) 02 8816173 Ext 406 www.cec.aiub.edu CCNA Routing and Switching Course Outline CCENT Introduction to Networks Routing & Switching Essentials Scaling Networks Connecting Networks CCNA CCNA 1 – Introduction to Networks This course introduces the architecture, structure, functions, components, and models of the Internet and other computer networks. The principles and structure of IP addressing and the fundamentals of Ethernet concepts, media, and operations are introduced to provide a foundation for the curriculum. By the end of the course, students will be able to build simple LANs, perform basic configurations for routers and switches, and implement IP addressing schemes. Chapter 1 2 3 4 5 6 7 8 9 10 11 Topic Exploring the Network Configuring a Network Operating System Network Protocols and Communications Network Access Ethernet Network Layer Transport Layer IP Addressing Subnetting IP Networks Application Layer It’s a Network Students who complete Introduction to Networks will be able to perform the following functions: Understand and describe the devices and services used to support communications in data networks and the Internet Understand and describe the role of protocol layers in data networks Understand and describe the importance of addressing and naming schemes at various layers of data networks in IPv4 and IPv6 environments Design, calculate, and apply subnet...
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