Assessment Item 3

Assignment 3

The advantages and disadvantages of cut-through architecture are as follows,

Advantage

Cut-through architecture lets the data frame enter into and exit from thecut-through switch at almost same time. The cut-through switches forwards data without storing it in contrast with traditional store-and-forward switches. Those switchesstores the whole frame for a minimum time to examine various fields of the data frame. This process reduces the overall network throughput. The cut-through architecture is free from this drawback. It helps in improving the network throughput by allowingswitches to pass data frames faster.

Disadvantage

As the cut-through architecture does not examine the data frames only forwards it, there is a potential risk of forwardingerroneous data frames. The store-and-forward device can identify a corrupted data frame by performing cyclic checksum and can take corrective measures. However, in cut through architecture, the time is the first concern. So, the data frames get forwarded even before calculation of cyclic checksum. So, if it can detect the error, there will be no chance to correct it. Although the network throughput is improved by cut through technology the network integrity is hampered if it forwards too many erroneous data frames.(Cisco, 2014)

The common RAID or Redundant Array of Independent Disks techniques are,

RAID-0

In RAID 0 technique data is broken down intosmaller fragments and stored into different disks. The associated technique is called striping. No data redundancy is present in this technique. If one disks fails, the fragments stored in that disk will be lost. The advantage is data can be read from or written into multiple disks at the same time in a much faster way.

RAID-1

InRAID 1 technique at least two disks store same data. Addition of this data redundancy increases the level of fault tolerance unlike RAID 0. If one disk is crashed, there will be another one or more having the same data. This technique is called disk mirroring.

RAID-3

In RAID 3 technique multiple disks store stripped data. Along with information about error-checking. The error checking information are stored into some different disks. To recover data from some damage the error checking information are needed.

RAID-5

RAID 5 techniques breaks the data into stripes and same copies of the stripped data are stored across at least three disks. Here also error checking code like parity information are present with data. However, those information are not stored into some other disks, those are stored with data itself. Though the redundancy level is higher, still it is more reliable and popular RAID technique. (Godse & Godse , 2006)

Metro Ethernet is a popular Ethernet technology for last few years. It uses standard Ethernet connection to interconnect different businesses with one another by using a point-to-point connection. A company can connect to the Internet Service Provider by using a point-to-point metro connection. The traffic is shared between only the ISP and the company. On the other hand, many such companies are connected to the ISP in the same way. So, from ISP’s standing point it has multiple point to point metro Ethernet connections for multiple companies. (Halabi & Halabi, 2003)

Packet switched networks does not create a physical path or circuit for all packets of a transmission. As the name suggests, a virtual circuit packet-switched network creates a logical connection for transmitting all packets through a network. Prior to transmitting a large amount of data, it is broken down into packets. A temporary data transmission path is determined across the networks and all routers through the path are informed. The packets are transferred through the same path, routers just stores and forwards those, do not decide paths. After the completion of data transmission the path is obsolete. Here, the data is transmitted via a logical circuit or channel unlike circuit switching where physical transmission channels like telephone line were used. (White, 2012)

Internet is a complex interconnection of different types of networks, routers, communications channels and protocols. Routers are used to decide the route of a packet across the networks. A router receives a data packet, checks its IP address, determines the path and again encapsulate the packet. Wide area networks follows several routing techniques.

Mostly wide area networks uses store-and-forward method for routing. Each router receives packets, queues those in memory, calculates the address and forwards those. At a time a router can receive multiple packets from different sources.

Routing tables are used for keep tracking the status of neighbor router. The routing tables are updated periodically. Packets are forwarded after consulting the routing tables. (Forouzan, 2006)

CLECs or Competitive Local Exchange carriers were developed for better accommodation of already delivered services. In USA, cable services were already provided by telephone service providers for domestic purposes. So, there was a running and efficient cable and telephone network. It was a good idea to use the existing telephone network and cable services for data communication services. Major Cable TV companies like Comcast, Cox Communications and several small or medium companies were already serving the major parts of the country. Presently CLECs like WTI Communications, XO Communications, Granite LLC, TelCentris, Windstream Tele, Pacific, Birch Communications, World Communications Incorporated, Integra Telecom, BullsEye Telecom, Airespring, etc. are functioning in USA. (Goleniewski, 2002)

NAT stands for Network Address Translation. Mainly NAT is used for IP masquerading technique. IP masquerading can hide entire IP address space of private network behind a single IP address of public network. So, it is basically an address translation methodology for IP addresses.

NAT helps is assigning a common global IP address for all packets coming from the private network associated with it. For outer world, those packets seems to be coming from a single IP address. When packets are received for that IP address NAT again checks those packets and translates the IP address back to the different IP addresses of the private network. This translation is invisible from outside.

The basic NAT provides only one-to-one IP address translation. This type of NAT can change onlyo the IP addresses and IP header checksum.

The popular type of NAT is One-to-many NAT. It translates one private IP address space into a single global IP address. (Forouzan, 2006)

There are several advantages and disadvantages of ATM or Asynchronous Transfer Mode.

Advantages

• ATM has high speed data transfer rates for several classes of service. It can operate on different kind of network topologies and media.
• ATM supportsdifferent application with varied bandwidths and transmission speeds.
• High speed Cell switching is used in conjunction with ATM for routing.
• It has shorter delays and high bandwidths.
• Customers can choose different plans and pricings from wide range of ATM service classes.
• It is extremely versatile in carrying packet data, voice, and multimedia data.
• ATM solutions are expensive. The cost of the equipment is relatively high because of supporting cell switching.
• Installing and maintain ATM networks are complex and costly.
• Compatible resources like hardware and software are not easily available.

Disadvantages

(Forouzan, 2006)

Some examples of systems that uses biometric techniques are given below,

1. Different ATM manufacturing companies uses biometrics to enhance the security of the ATM machines. Most of those uses fingerprints or retina scan for verification and validation.
2. Fingerprints are used for authentication for ages even before the idea of biometrics. Security systems implements fingerprint checks for authentication. Those are seen to uses in banking sectors etc.
3. Eye scanning is another popular biometric technique used in various system and industries. There are several forms of eye scanning, like Retinal scans which is a popular low cost biometric solution. Another form is Irish scanning which is not so common and costly solution. Devices like Laptops etc. uses this retina scanning methods for securing user accounts and access to the system.
4. Another kind of biometric is Ear scanning. It is a relatively new but promising field of biometric research. England possess the largest database of Ear scans.
5. Digitized voice is another form of cost effective biometric solution. The pattern of digitized voice is used for matching. The closest match is sufficient for validation and authentication.

(Vacca, 2007)

Ciampa, M. (2011). Security+ Guide to Network Security Fundamentals. Cengage Learning.

Cisco. (2014). Cut-Through and Store-and-Forward Ethernet Switching for Low-Latency Environments. Retrieved from Cisco: http://www.cisco.com/c/en/us/products/collateral/switches/nexus-5020-switch/white_paper_c11-465436.html

Forouzan, A. B. (2006). Data Communications & Networking. McGraw-Hill.

Godse , D. A., & Godse , A. P. (2006). Computer Organisation and Architecture. Technical Publications.

Goleniewski, L. (2002). Telecommunications Essentials: The Complete Global Source for Communications Fundamentals, Data Networking and the Internet, and Next-generation Networks. Addison-Wesley Professional.

Halabi, S., & Halabi, B. (2003). Metro Ethernet. Cisco Press.

Vacca, J. R. (2007). Biometric Technologies and Verification Systems. Butterworth-Heinemann.

White, C. (2012). Data Communications and Computer Networks: A Business User’s Approach. Cengage Learning.