Chapter Two Homework
1. What are some typical proficient ends for organisations today?
Scalability, handiness, Performance, Security, Usability, manageableness, adaptability, affordability.
2. What does handiness intend?
It ‘s can be expressed as a per centum uptime per twelvemonth, month, hebdomad, twenty-four hours, or hr compared to the entire clip in that period. It does besides be expressed as a average clip between failure ( MTBF ) and average clip to mend ( MTTR ) .
3. If a web is up for 835 hours in five hebdomads, what is the handiness?
In the hebdomad = 24 ten 7 = 168 hr in one hebdomad
So, 168 ten 5 = 840 hr
So the handiness is 835 / 840 = 0.994 ten 100 = 99.4 %
4. Using the five 9s handiness, what is the down clip in 2nd per four hebdomads?
One hebdomads in 2nd = 60 ten 60 ten 24 ten 7 = 604800 2nd
4 Weeks = 604800 ten 4 = 2419200 2nd
Availability = 1 – 0.99999 = 0.000001 2nd
So the downtime is 0.000001 * 2419200 = 24.192 second.
5. What does the term hot-swapping agencies, and what the grounds for utilizing it?
6. A client requires 99.999 % handiness, how would you transport out care for such a web? Assume that hot-swapping is non possible
7. What are the typical spot error rate BER of a fibre nexus & A ; Cu nexus?
8. If a burden is 115kbps where a package switch needs to convey it over an ISDN circuit ( 128kbps ) , what is the use? How many packages in the waiting line?
Utilization = 115/128 = 0.898 %
Average figure of packages in waiting line = ( 0.898 ) / 1-0.898 ) = 8,804 Packages
9. How do bandwidth and throughput differ?
Bandwidth: is a information carrying capacity of a circuit, normally specified in spots per second
Throughput is the measure of mistake free informations transmitted per unit of clip, normally specified in packages per second
10. How can one better web efficiency?
More the package is larger more the efficiency of the web will be.
11. What are the security menaces if a web device is compromised?
Datas fluxing through the web can be intercepted, analyzed, altered, or deleted, compromising unity and confidentiality.
Additional, related web services, which rely on trust among web devices, can be compromised. For illustration, bad routing informations or wrong hallmark information could be injected into the web.
User watchwords can be compromised and used for farther invasions and possibly to make out and assail other webs.
The constellation of the device can be altered to let connexions that should n’t be allowed or to forbid connexions that should be allowed.
12. What tradeoffs may be necessary in order to better web efficiency?
Implementing good throughput for one application might do hold jobs for another application. The cause of the efficiency of the ( web ) throughput is the package size, so if one application have big package size to do it efficiency the other package for another application may make n’t hold capacity on the web.
13. Redundancy is non one of the web ends, what is meant by redundancy? Explain to what web end is related and why?
Redundancy means adding duplicate links or devices to a web to avoid downtime.
Redundancy is linked to Availability, but redundancy is non a web end, but excess web topologies are going more and more important for many webs design client who want to do certain concern continuity after a major mistake or catastrophe.