What is a Router Essay Example

What is a Router? Paper The computer is comprised of an overall system architecture eased on the designers needs and design constraints much like the network. Specific comparisons are that the signal and data busses comprise the physical network with the Operating System analogous to the router and route-policy systems in the network. As the network is equipped with ports in locations necessary for user and device access, the computer is equipped with interfaces and interface devices that enhance the ability of users to interact with the computer mouse, keyboard, monitor, etc. 2. Given the existing configuration a total link-weight of 22 between Network A doe) and Network B (Sandy) is errantly in place. Given the option to adding an additional link with a weighting of IS to the architecture the link could he added between Network C and Network 8 to arrive at a total link weighting to 20, or the link could be directly implemented between Networks A and d, The exact location for improving the interconnectedness between the networks should be determined by studying the communication flow between Networks A and B as well as Network C and B. A CDC is a WAN service that is specifically optimized for the distribution of either static or streaming content to Internet users. There are two functions that preferential a CDC from most traditional public IP-based networks namely the function to look at the source of a connection request and determine the best resource to assign to the data request based on geographic localization and server utilization Mannerly that the closest server With the lightest loading will be the proper device to route a connection request to. We will write a custom essay sample on What is a Router? specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on What is a Router? specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on What is a Router? specifically for you FOR ONLY $16.38 $13.9/page Hire Writer More directly a CDC attempts to optimize traffic flows to the most local answer possible rather than following strict hierarchical routing rules. The challenge for the CDC architect is to constantly review source requests and to place data sources in the right areas s traffic patterns grow and change. 4. The end points of the service are defined as the physical hand off between the WAN provider and the client network equipment (router or switch), A. Metrics that may be applicable to the end to end service connection between client endpoints are: i. Availability based on reliability, contracted throughput, and error rate. Ii. Quality of service as measured by droppedlost packets or frames as a percentage to overall traffic presented to the WAN. Iii. Specific So measurements by protocol -? for example traffic may be contracted for a higher availability than ESMTP traffic. In the case of an ATM WAN where ATM So metrics are used the granularity can be very finely defined to jitter (maintenance of a strict time relationships between ATM cells), cell loss, and differentiation of traffic contracts between Constant Bit Rate and Unassigned Bit Rate streams. The simplest metrics that are representative of overall system delay are components that affect the network specifically: traffic loading and any data loss that might be caused by discarded frames on a WAN, the physical distance between the source and sink (a rule Of thumb is Aims delay per 100 miles Of injection distance), capacity of the embedded switches and routers on the WAN network if they are overloaded at any one point then frame discard and loss are directly impacted as TCP attempts to resend the frames which are then seen by the user as an increase in latency on the link. At the server end metrics that contribute to overall delay can include the quality of connectivity been the server and the network, the capacity of the server to fulfill data requests based on the type of data the users are requesting (streaming versus static content, or short bank type ATM transaction messages), disk resources and verbal user traffic demands on the server(s). 6, Before Firewall: uses uses Gee Switch Router alms POS CO-48 Total Latency: moms (PC to Server) Servers 1 ms uses 1 souse Gee switch Router User PCs B. After Firewall: 1 souse Gee Switch uses Router alms POS COCO Inns Router uses Gee Switch uses Total Latency: 2. Ms (PC to Server) uses User PCs Fastest Switch Security Firewall 7. High-quality (phone company-grade) voice calls: Guaranteed service Required because the calls are very sensitive to dropped data in order to retain legibility and identity Of the calling party A. Voice over IP (Poi): Predictable arrive Given the user expectations and the nature of public IP networks, the POI connection needs to be predictable, but does not require the end-end guarantee of a traditional phone call. B. FTP File Transfers: Best Effort Best effort is adequate to provide the connection between user and source with TCP ensuring delivery off all data frames C. Audio File Downloads: Best Effort As with FTP, this is a non real-time application that can make use of TCP to ensure delivery over a variable time. D. Video on demand: Guaranteed Service Required to ensure that the video data stream maintains a fixed loss and titer tolerance across a heterogeneous network to avoid loss of video signal or unsatisfactory picture quality. E. Server access: Best effort As with other non time sensitive applications, Server access can be accomplished over a best effort service that best accommodates the variable bandwidth and user demands for the data link, 8, perform-nuance Boundaries and Thresholds A. The MS (network Management System) could be programmed to route specific traffic types over different routes depending on So needs if a specific threshold was exceeded, In this case, time-sensitive traffic could take the most direct route that could purport the sub-moms requirement while less important traffic could take longer-delay routes. B. Setting up a monitor package to trap packet throughput between the user and their local router Or Ethernet switch port will allow the network administrator to ensure that any one user does not use more network resources than they are allotted. Chapter 2 Exercises: I. Why is requirements analysis important to network architecture and design? Give three reasons. A: Analysis provides a number of widely researched data points that help to filter out specific user or group needs that may not be reflective of the organization as a whole. Specifically, three reasons for performing requirements analysis are: To develop a more objective, organization-wide view of system requirements and services needed. To ensure the interconnection architecture (how meshed the network is and where the interconnect points are) matches the information flow within and between groups in the organization Network capacity planning and link sizing. 2. Categorize each of the following requirements as core (fundamental), feature, or informational. A, Network must support Fast Ethernet and Gee interfaces for all devices on the network. i. This is a fundamental requirement. This defines the base technology and technical capabilities and constraints that the network must provide to end users. B. Network backbone should be upgradeable in capacity to Gob/s within 2 years of deployment. i. This is a feature. This requirements speaks to a technology enhancement (Gobs Ethernet) that is not currently available but which is actively in development by the relevant industry standards organizations. His was not a requirement set forth as part of the overall system design but avgas offered by the hardware vendors, then this would be an informational requirement. C. Finance department requires firewall retention for their server. i. This is fundamental. This requirement may have been discovered via requirements analysis or it may have just been a fixed design point specified by the relevant group. D. Existing network consists of Scabies Ethernet and EDDIE segments. i. This is informational. The fundamental requirement for the new newborn to support BassettGee has already been set. This is merely informational to the designer, possibly implying some reuse of facilities (copper or fiber) from the existing network. E. Newborn personnel would like to be able to bill users for network service. i. This has tuft answers: If the requirements analysis drew out that the network had to directly recoup its costs and operational expenses, or that billing was a requirement to support transient users then this would be a fundamental requirement. IF the billing option was merely a desire by the IT etwork support group and was not a requirement identified throughout the organization ,then this would be classed as a feature given that a complete network accounting and billing system implies much more infrastructure than just the physical and logical interconnectivity the network provider* Network core must not enervate or terminate any user traffic. i. As may be logically inferred from the Statement this is a fundamental design requirement Of the network. G. Network must support digital video traffic from remote video cameras and may additionally support sound from these cameras. i. As With item (P) above, part of this statement is a fundamental requirement (the need for digital video traffic support) and part is feature-driven (the desire to have audio along With the video). Please note that this requirement does NOT specify the technology used to deliver the requirement in other words, the fundamental requirement or the network to support Bassett and Gee does not imply that the digital video must run over Ethernet. In this case, the digital video is a fundamental requirement, but the methodology to provide the digital video may be a feature of a manufacturer to do so over Ethernet, or may be on a completely separate and parallel nonvoter infrastructure to the Ethernet backbone. 3. Categorize each of the following requirements as user, application, device, or network. A Database servers must run Brand EX. software. i. This is a straightforward user requirement based on factors external to the network requirements analysis. Reasons for this may be embedded base of developed applications based on the EX. software, business relationships, or other, no- technical reasons. 8. Teleconferencing requires at least Kbpss capacity. i. This can be a combination of two factors -? application and device. Since there is no additional information provided here for the Kbpss stated requirement it will be the analysts job to determine if the bandwidth figure is based on the device needs of the teleconferencing equipment or is there an associated application that defines a frame rate or resolution that is satisfied with the cookbooks stated need. As with all other areas of the requirements analysis, the person doing the data gathering and analysis must separate the device and application needs from the pre-conceived needs that the users may hold. This is one of the fundamental jobs expected in doing a thorough analysis separation Of the imagined need from the actual requirement. C. Users must be able to submit print jobs up to MOB in size. i. This is an application requirement. Presumably with data gathering the architect will come to quantify the application that is generating such large print files and accommodate them in the overall design. Properly answering his application requirement speaks to the needs to understand information flows (where are the users versus the print-server or printing system and what impact does that have on the network architecture from bandwidth needed between user, server and print system and where is it most efficient to place the printing system. D. Each access network should be able to serve up to 200 users. i. This is a network requirement. The type of users and applications are not stated here, 50 the current information only supplies a design need for network capacity per access network. 4. Give an example of a requirement as it lows from user to application to device to network. Show how it becomes more technical at each component. User: must have assetsGee connectivity Application: Requires Spooks-sustained throughput Requires access to servers located in two separate areas of company. Network: Must support TCP, FTP and NAPS along faith firewall in front Of each application server and RADIUS user authentication. SUMP required to monitor and control network attached devices. 5. Which Of the following customer requirements could be categorized as misconstruction? As rate-critical? As real-time? As none of these? Give reasons for each choice. A. Processing telemetry data from a space shuttle launch and providing that data to mission control during launch (Customer: NASA). i. This fulfills all three requirements as defined above. It can be assumed from the information provided here that the telemetry information is (literally) mission critical since it is being collected and disseminated real-time during the launch versus being analyzed post-launch, The information is rate critical because the activity is happening in real time and the need is to monitor conditions as they occur during the launch. And finally it is real time since the action related to the tat (Shuttle launch) is intrinsically required as the launch occurs there may be postulation data analysis and processing but that would come under a different set to requirements tort analysis and network support. B. Processing requests from automated teller machines throughout a city, (Customer: Bank) i, The data is mission-critical to the Bank because it is core to their business needs during the day, The network needs to be very reliable and not provide a single point of failure path normally ATM networks for Banks use a network topology where the ATM machines in a small geographical area are spread out on different recruits taking different physical routes so that any one network failure will not incapacitate all the Tams (and the Banks ability to conduct business) in a specific area of town . There is no erratically nature to this traffic since the inquiry response messages that are sent between the ATM and the Banks hosts are relatively short and large-bandwidth connections will not improve transaction-processing times. Tee requirement is also not real- time since the Bank computers are operating on a inquiry esponse model and do not have to interact with the customers in real-time (as we define real-time). C Processing requires for Web pages from your servers. (Customer: Internet Service Provider) i. Without knowing the nature of the web pages we Will make the assumption that this is not a mission. Critical application since the public Internet is being used for server access. This assumption is based on the highly non-deterministic nature and reliability of the public Internet versus a private network, Again, the rate-critical nature is not applicable because no streaming application (video being served on a web page from the corporate server), was defined so we may assume these are static web pages. Ghastly, since the public Internet is the media, there is no real-time component possible so we can summarize that this application does not require any of the specified customer requirements. 6. Give an example of a mission-critical application tort each of these three environments: government, military, commercial. Why would each application be considered mission-critical? A Government: The fire department is a mission critical government applications The requirement is to monitor in real-time all the fire alarm sensors throughout a cubby and then to dispatch the closest fire-fighting equipment to that location. Reliability, real-time and mission critical are all factors in this application need. 8. Military: Actions during a military engagement are mission critical the need is to have real-time access to data from many different sources in order to provide relevant command information to the army. C. Commercial: Commodity trading floor. The mission critical nature here is that the brokerage houses need to have extremely accurate, realties information Of actions in money markets and trading floors in order to make real-time decisions for their business needs and the needs of their clients. A loss of communication here could mean huge financial losses or business failure for the brokerage house. 7. Section 2. 5. 1 describes several types of delay (real-time, interactive. Burst, interactive bulk, and asynchronous). Give an example of applications or traffic types that have each type of delay. A. Real-Time: These can either be a traditional real-time source such as a camera or broadcaster using a local or wide-area network for content distribution (01 ERECT/s local channels are one example). Another example is in the fly-by-wire networks found in most modern airliners -? the pilot inputs to the controls are acted on in real time by the flight computer and passed over copper and fiber networks within the airlines to move control surfaces and control the engines, Not only is this real time, but also it is a duplex path where the effects the flight control movements have on the airliner must be passed back to the pilot in real time B. Interactive-Bulk: A commercial example of this would be in the ATM example referenced earlier. The key factor in this delay model is that the network is not providing the relevant time delay factor in getting a response to input -rather is the processing of he input commands or instructions that is the source of the predominance of the delay. The user inputs a request (get money) and the commands travel the network and cause a large number Of actions to occur at the host end (validating password, adequate money in the account, and then authorizing payment back to the ATM). In most networks, the ratio Of delay between the network and the host processing time is usually an order of magnitude or more. C. Interactive Burst: A delay factor that is characteristic Of a high network latency and a low processing latency For example, any application with minimal host processing mime would fall into this category most directly a telnet or terminal connection to a device over a network. The vast amount of delay that the user sees is from the network component since most actions in this application require little to no host processing time and the delay is chiefly a factor of network throughput and delay characteristics. D. Asynchronous: Here there is no connection between the newborn latency and the host-processing time. Messages are created and sent without regard to time synchronization between sender and receiver. One modern application would be Instant Messaging (AIM, Yahoo IM, etc. , where the network is applying a variable latency to embedded hosts (the IM servers) that have a variable processing time. From the user view each person can type messages back and forth to the receiver without having to wait for a response to the last message. 8_ Delay performance is increasingly important in support of user and application requirements. Describe why delay is important for the following applications: A. Voice over P: Unlike the IM example discussed above, Poi requires the same degree of sender-receiver delay consistency that a traditional phone call provides. Prom the users view, their brains are expecting a message to be received and then they can immediately issue a response 3 variable delay factor in this application Will cause users to issue longer back- off timers (they will wait longer periods after the receipt of message before responding. An example Of poor delay performance lies in the satellite and extreme long distance phone calls where the propagation delay based on network length (thousands of miles) creates an extremely long elastic delay that users have to consciously account for. B. Unfettered (real-time) video or audio lullaby: In this application, the interactive component that could be affected by delay is not present, but the effect of a variable delay on the application is seen because of the compression schema used tort these traffic types. With a variable delay a real- time video signal may see some portions of the message arrive out of sequence to the receiver. Since this is compressed material, the receiver has no mechanism to cope with inputs that are not time-sequential and that data is normally thrown out by the receiver. The user(s) see this as video or audio dropouts as material s lost by the viable delay component that the network is introducing. C. Teleconferencing: As with Poi and real-time video, the users are presented with an input signal that does not follow the real-time format they are expecting. Pending on the ability of the equipment on each end of the connection to accommodate this variable delay, users may begin to talk over each other and then back off in order to get the conversation back in sync, or a video conference may be interrupted as the image being received on each end is out of sync with the audio that is presented as part of the teleconference. Based on the following applications locations, develop an applications map using the template provided in Figure 2. 17. A. There is a distributed computing application between all compute servers. B. There is a data storage/access application between all compute servers and the storage servers in Main Engineering. C. There is a data migration application between Main Engineering, External Access Building, and Off-Site Data Archival. Campus LANA Building A Internet External Access Building B Main Engineering Building Application A Application C Off-Site Data Archival Building C Application B 10. Which devices below can be considered generic computing devices? Servers? Specialized devices? A. An ATM machine: A specialized device a single-purpose intelligent terminal designed for one specialized task. B. Laptops running Linux 05: generic computing device. In spite of being loaded with the Linux SO, both the laptop and Linux are Off the shelf, generic general computing devices. C. IBM computing cluster of 128 PCs: This is a server of course, and depending on the SO configuration and network design, they may also be considered specialized devices if the application makes them unsuitable for any general purpose work. D. Sun Enterprise 450 database server: This is a general-purpose server and SO (Solaris), that is running a database application. Depending on how specialized the database is, this may also be a specialized device.. but for our purposes it is merely a general purpose server. E. Desktop PC running Windows 2000: As generic as they can possibly be. I l, Add the following devices to the application map developed in problem 4 A Compute servers are located in buildings A, B, and C (l server each), and S compute servers are located in Main Engineering. 8. Storage Servers are located in Main Engineering (2 servers), External Access Building (I server), and at the Off-site Data Archival location (l server). 12. List the Top 10 applications that you expect to use in your work (or your customers) network or that you currently use in the existing List the actual or estimated performance characteristics for each application and try to place them into groups, You can also try to map them to the application groups listed in Section 25. 2. Credit Verification (LOOT) i. Interactive application ii. TelemetryCommand and Control Application E-Mail i. Asynchronous ii Non-real-time Videoconferencing i. Tell-service application ii. Real-time Distributed server database update (Supermarket code-scanner database update) i. Bulk data transport ii. Interactive-bulk Self-Service Web Sales (Product sales via Corp.. Web site) i. Interactive Bulk ii. Client-servers-access Software downloadupgrade (FTP i. Interactive Bulk ii. Bulk data transport Remote terminal access (telnet) i. Interactive-burst ii. AM Security Camera monitoring i. Real time ii. Tell-service Broadcasting (Television Network programming) i, Real-time ii, Tell-service Airline Reservation (Agent) i. Client Server ii. Interactive Chapter 3 Exercises: 1. Initial conditions for your network project consist of the following categories: type of network project, scope of network project, and architecture/design goals. Develop 3 sets of initial conditions (each containing I element from each category), and give an example network project for each set. A. Condition A: New network; Single Site; Support New Application: This network example is the ideal of any network architect an clean sheet of paper design that can make use of new technologies that are available since any in- place networks were implemented. Additionally, this is a single-site network so o WAN considerations, firewall, or other intrusion detection concerns need to be addressed as new issues. An example Of this would include a new company or new division setting up in an empty building. B. Condition B: Analysis of N.B.,pork problems; distance between sites; improve performance to all or part Of the network. Here we are dealing with a set of criteria where an annual (or first time) review of the infrastructure of the corporate WAN is being taken. In this case, the issues are focusing on performance, cost and technology deployed as the current solution been corporate locations and whether the current answer s still correct in the face of current user and application needs. C. Consolidation; network size; upgrade technologyvendor.