1.) Explain the cirumstances under which a token-ring netwrok is more effective than an Ethernet network.
A token ring is very effective under high sustained load, as no collisionscan occur and each slot may be used to carry a message, providing highthroughput. A token ring is less effective when the load is light (tokenprocessing takes longer than bus access, so any one packet can take longerto reach its destination), or sporadic.
http://www.arl.wustl.edu/~fredk/Courses/cs422/sp00/Answers
2.) Although security issues were not mentioned in this chapter, every network owner must consider them. Knowing that open networks all data to pass to every node, describe the posssible security concerns of open network achitectures. include the implicatiions of passing logon procedures, user IDs, and passwords openly on the network.
Content located on the Network may be the property of another person.
All information, data, text, software, music, sound, images, sketches, diagrams, photographs, graphics, renderings, CAD files, video, messages or any other materials whatsoever (collectively, "Content"), however posted to, maintained on, or transmitted via the Network, is the sole responsibility and property of the person from which such Content originated (the “Author”). This means that the Author, and not the Network or AFH, is entirely responsible for all Content that he or she uploads, posts, or transmits via the Network. In the event any Content is deemed illegal under applicable law, we will cooperate fully with applicable authorities in removing such Content and identifying its Author.
This type of network architecture are openly vulnerable for the possible malicious intrusions like worms, viruses and other malicious programs. Malicious person entering a network to damaged the entire system can easily passed causing great unfavourable effect. Passing logon procedure can be now favourable to the someone whose will is to destruct, they can now easily alter and use open information for their own purpose that against to the rights of the people all over the network.
The development of highly sophisticated computer technology causes the network security experts to create a more secure and safety measures for the private information but as this open network be implemented the whole system must be publicly accessed and the information security are wholly responsibility of someone who is the owner.
3. )Remembering the discussion of deadlocks, if you were designing a networked system, how would you manage the treat of deadlocks in your network? Consider all of the following: prevention, detection, avoidance, and recovery.
Prevention -
The importance of computer networking to achieve resource sharing and data sharing is widely recognized. Local networking to achieve high performance and reliability is inevitable for the future. As cost of logic and memory decreases, the cost of communications resources become increasingly significant and these resources must be increasingly shared. This heightens the possibility of deadlocks due to this sharing.
- their must be a mutual exclusive access in the network.
- their must be a condition for holding non-sharable resources.
- any request for certain files inn the network must be allocated, but it cannot request another resources unless it releases the resource that it holds.
- before requesting resources, we first check wheter they arre available or not to prevent hold and wait state.
Avoidance-
A token ring is very effective under high sustained load, as no collisionscan occur and each slot may be used to carry a message, providing highthroughput. A token ring is less effective when the load is light (tokenprocessing takes longer than bus access, so any one packet can take longerto reach its destination), or sporadic.
http://www.arl.wustl.edu/~fredk/Courses/cs422/sp00/Answers
2.) Although security issues were not mentioned in this chapter, every network owner must consider them. Knowing that open networks all data to pass to every node, describe the posssible security concerns of open network achitectures. include the implicatiions of passing logon procedures, user IDs, and passwords openly on the network.
Content located on the Network may be the property of another person.
All information, data, text, software, music, sound, images, sketches, diagrams, photographs, graphics, renderings, CAD files, video, messages or any other materials whatsoever (collectively, "Content"), however posted to, maintained on, or transmitted via the Network, is the sole responsibility and property of the person from which such Content originated (the “Author”). This means that the Author, and not the Network or AFH, is entirely responsible for all Content that he or she uploads, posts, or transmits via the Network. In the event any Content is deemed illegal under applicable law, we will cooperate fully with applicable authorities in removing such Content and identifying its Author.
This type of network architecture are openly vulnerable for the possible malicious intrusions like worms, viruses and other malicious programs. Malicious person entering a network to damaged the entire system can easily passed causing great unfavourable effect. Passing logon procedure can be now favourable to the someone whose will is to destruct, they can now easily alter and use open information for their own purpose that against to the rights of the people all over the network.
The development of highly sophisticated computer technology causes the network security experts to create a more secure and safety measures for the private information but as this open network be implemented the whole system must be publicly accessed and the information security are wholly responsibility of someone who is the owner.
3. )Remembering the discussion of deadlocks, if you were designing a networked system, how would you manage the treat of deadlocks in your network? Consider all of the following: prevention, detection, avoidance, and recovery.
Prevention -
The importance of computer networking to achieve resource sharing and data sharing is widely recognized. Local networking to achieve high performance and reliability is inevitable for the future. As cost of logic and memory decreases, the cost of communications resources become increasingly significant and these resources must be increasingly shared. This heightens the possibility of deadlocks due to this sharing.
- their must be a mutual exclusive access in the network.
- their must be a condition for holding non-sharable resources.
- any request for certain files inn the network must be allocated, but it cannot request another resources unless it releases the resource that it holds.
- before requesting resources, we first check wheter they arre available or not to prevent hold and wait state.
Avoidance-
In an apparatus having a network including successive stages of cross-point switches which collectively interconnect a plurality of nodes external to said network, wherein at least one message is carried between one of the nodes and one of the cross-point switches over a route through said network, a method for preventing routing deadlocks from occurring in the network which comprises the steps of: creating a graphical representation of the network; searching for the existence of cycles within the graphical representation; partitioning the graphical representation into at a first subgraph and a second subgraph if cycles exist in the graphical representation; searching for the existence of edges directed from the first subgraph to the second subgraph; and removing the edges directed from the first subgraph to the second subgraph. Preferably the step of partitioning the network into at a first subgraph and a second subgraph is performed such that the first subgraph and the second subgraph have an equal number of vertices, a number of directed edges from the first subgraph to the second subgraph is minimized so as to minimize the number of routes prohibited, and a set of partition constraints are satisfied. The method is recursively applied to the first subgraph and then the second subgraph, thereby removing all of the deadlock prone cycles in the network while minimizing the number of routes prohibited due to remove edges.
Detection -
The problem of detecting process deadlocks is common to transaction oriented computer systems which allow data sharing. Several good algorithms exist for detecting process deadlocks in a single location facility. However, the deadlock detection problem becomes more complex in a geographically distributed computer network due to the fact that all the information needed to detect a deadlock is not necessarily available in a single node, and communications may lead to synchronization problems in getting an accurate view of the network state.
Two algorithms are then presented for detecting deadlocks in a computer network which allows processes to wait for access to a portion of a database, or a message from another process. The first algorithm presented is based on the premise that there is one control node in the network, and this node has primary responsibility for detecting process deadlocks. The second, and recommended, algorithm distributes the responsibility for detecting deadlocks among the nodes in which the involved processes and resources reside. Thus a failure of any single node has limited effect upon the other node in the network.
Recovery-
Routing algorithms used in wormhole switched networks must all provide a solution to the deadlock problem. If the routing algorithm allows deadlock cycles to form, then it must provide a deadlock recovery mechanism. Because deadlocks are anomalies that occur while routing, the deadlock recovery mechanism should not allocate any expensive hardware resources for the sake of handling such a rare event. Rather, it should only dedicate a minimal set of required resources to the recovery process in order to engage most of the hardware resources to the task of routing normal packets. This paper proposes a new deadlock recovery mechanism to be used with the True Fully Adaptive Routing algorithm. The new deadlock recovery mechanism takes advantage of the concept behind wormhole switching. The scheme is efficient in terms of hardware requirements, causes fewer deadlocks and can compete with other expensive deadlock recovery schemes.
4.)Assuming you had sufficient funds to upgrade only one component for a system with which you are familiar, explain which component you would choose to upgrade to improve overall performance, and why?
A wireless Ethernet bridge, because it converts a wired Ethernet device for use on a wireless computer network. Wireless Ethernet bridges and USB adapters are both sometimes called wireless media adapters as they enable devices for WiFi utilizing Ethernet or USB physical media. Wireless Ethernet bridges support game consoles, digital video recorders and other Ethernet-based consumer devices as well as ordinary computers.
True network bridge devices like the WET54G do not require device driver software installation in order to function, simplifying installation. Instead, network settings for the WET54G can be made through a browser-based administrative interface.
Like USB adapters, wireless Ethernet bridges can draw their power from the main cable connected to the host device. Ethernet bridges require a specialized Power over Ethernet (PoE) converter to make this work, however, whereas this functionality is automatic with USB. Without a PoE add-on, wireless Ethernet bridges need a separate power cord.
Wirelss Ethernet bridges commonly feature LED lights. The WET54G, for example, displays lights for power, Ethernet and Wi-Fi status.
True network bridge devices like the WET54G do not require device driver software installation in order to function, simplifying installation. Instead, network settings for the WET54G can be made through a browser-based administrative interface.
Like USB adapters, wireless Ethernet bridges can draw their power from the main cable connected to the host device. Ethernet bridges require a specialized Power over Ethernet (PoE) converter to make this work, however, whereas this functionality is automatic with USB. Without a PoE add-on, wireless Ethernet bridges need a separate power cord.
Wirelss Ethernet bridges commonly feature LED lights. The WET54G, for example, displays lights for power, Ethernet and Wi-Fi status.
