MANAGEMENT OF CISCO INTERNETWORK
Introduction
With the advancement in modern technology in the area of microelectronics and computing there is the attendant need to share information, making information and communication the hallmark of the digital age. This development has necessitated the need to interconnect various networked electronic devices in a manner that would permit exchange of information and sharing other resources. These networked devices are mainly computers and other similar technological gadgets that make information processing possible. At the heart of this need is Cisco Systems which designs technologies and manufactures devices that enable the interconnection of networked devices for the purpose of sharing resources. Some of the devices manufactured by Cisco Systems include Switches and Routers while another technology is the Internet Operating System (IOS).
1. Cisco Technologies, Routers and Switches
The interconnection of devices in order to share resources is implemented using different architectures and depending on the scale of the network. A network model can either be client-server model where there is a dedicated controller of the network or peer-to-peer model where all the computers are the same. Based on size of network, a network can be a Personal Area Network (PAN), a Local Area Network (LAN), a Metropolitan Area Network (MAN) or a Wide Area Network (WAN) (Stallings, 2009, 214). The most used of the networks is the LAN which is implemented mainly in buildings to interconnect the resources therein. A LAN consists basically of the computers and other devices to be interconnected, the physical medium for the connection such as a cable and a device to which all the other devices connect through.
A switch is a device that makes the interconnection of devices on a network possible by breaking up collision domains. The switch manages the system resources efficiently using intelligent frame forwarding as network data units are forwarded to the port it is destined for instead of broadcasting to all the ports. This reduces the network overhead and efficiently manages bandwidth. Cisco has a number of switch models that perform this function in a network. Some of these are the Cisco Catalyst 4900, 3750, 2960 and 2940 Series (Cisco, 2005, 4).
A router is another network device that is used to interconnect networks together, routing packets from one network to another (Habraken, 1999, 2). Routers break up broadcast domains making it possible to segment the set of devices that will hear a broadcast on the network. Routers carry out packet switching using logical addresses, determine the best path to networks enabling internetwork communication and also filter packets using access lists. Cisco is a major manufacturer of high quality routers with the Cisco 850, 1800, 2800 and 3800 Series routers (Cisco, 2007, 5).
The Cisco Internet Operating System (IOS) is a proprietary kernel that runs on Cisco routers and switches providing the services offered by the devices (Lammle, 2007, 173) by efficiently managing the resources of the hardware.
2. Accessing and Using Routers and Switches
a. Accessing and using Routers and Switches
Cisco routers and switches are connected using standard Registered Jack – 45 (RJ-45) port and plugs, the console port using RS232 connectors and E1 connection for routers. Computers are connected to switches using Unshielded Twisted Pair (UTP) cables terminated with RJ-45 plugs while routers are connected using E1 cables for the WAN connection.
b. Connecting to the router
Connection can be established with a Cisco router through a number of methods. The connection can be made through a console port which is an RJ-45 module, through the Telnet program or through an auxiliary port. Interaction with the device IOS is through a command line interface (CLI) that enables configuration and management of the devices possible.
3. Wide Area Networking (WAN)
With the increasing importance of LANs to businesses and organizations, there was the need to make the availability of network connection extensible to cover a wider geographical space. The LAN however has a limitation in the geographical span of the coverage of the network to small buildings mostly 100 metres length. Wide Area Networks (WANs) make possible the connection of networks between two locations that are geographically far apart using wireless technology and different protocols.
4. IP Addressing, Multicasting and IPv6
IP Addressing
IP addressing entails assigning a unique identifier to a host for the purpose of identification on a network without which the device cannot communicate over the network. An IP address is a logical address which is assigned to hosts either statically by a network administrator or dynamically by a Dynamic Host Configuration Protocol (DHCP) server. IPv4 is the first IP address version that was developed and used to facilitate communication over a network.
The structure of the IPv4 addresses is such that they are 32 bits long and are grouped into 4 groups of 8 bits each, separated by a dot (Tanenbaum and Wetherall, 2011, 487). Each of the group of 8 bits is referred to as an octet thus making an IPv4 address composed of four octets separated by a dot. An example IPv4 address is 172.84.40.2.
The implication of the original 32-bit IPv4 address architecture meant that the Internet could support only 232 (or 4,294,967,296) possible IPv4 addresses. The about 4.3 billion addresses were soon exhausted due to inadequate planning of networks. IPv6 address is the new IP addressing scheme meant to replace the exhausted IPv4 addressing scheme. Three types of IPv4 addresses are defined by the internet standards – the unicast address, multicast address and broadcast address. An IPv4 unicast address identifies a single host on the network such that packets meant for the unicast address is delivered to the single host. IPv4 multicast address is a typical example of one-to-many communication where any packet addressed to a multicast address is delivered to all the hosts that are addressed by that multicast address.
IPv4 broadcast addressing is used also for one-to-many communication within a subnetwork. Packets destined for a broadcast address are sent to all the hosts connected to that subnetwork. IPv4 address are broken down into classes A to E based on the number of bits used to define the network and the number of bits used to define hosts as each address consists of a network part and the host part.
Based on the first octet of the IPv4 address, the addresses are classified as follows; Class A: 1 -126, Class B: 128 -191 (127 is reserved for loopback interfaces), Class C: 192 -223, Class D: 224 -239 and Class E: 240 -255.
In class A addresses, the first octet is used to define the network while the remaining three are used for hosts making class A networks suitable for very few networks with large number of hosts each. Class B networks support moderate sized networks with moderate number of hosts as the first two octets are used for network addressing and the other two octets are used for host addressing. Class C networks employ the first three octets for defining the network and the last octet for defining hosts thus making them suitable for large number of networks with few hosts each.
IPv6
IPV6 was developed as a response to the limitation of the predecessor IPv4 which made use of 32 bits in groups of 8 bits each as the addressing scheme for devices on a network. With the 32 bits length of the IPv4, just approximately 4.3 billion devices can be uniquely addressed as obtained from calculating 232. This number became a limitation as the size of the internet grew exponentially.
IPv6 addresses are four times the size of the 32-bit length IPv4 addresses, making them 128 bits in length. This implies that we can have an estimated 3.40 X 1038 (2128) unique addresses in this scheme. This is a very large number of addresses and will be difficult to exhaust in the nearest future if it can even ever be exhausted. IPv6 addresses are composed of a group of eight four-character hexadecimal numbers which are separated by colons and are each 16 bits long (Forouzan, 2011, 387). The structure of an IPv6 address is such that the network prefix is represented by the first 48 bits, the subnet ID which is used for defining subnets is represented by the next 16 bits while the interface identifier takes the last 64 bits of the 128 bits length of the address (RFC-4921, n.d.). Using this structure there is no need to define subnets explicitly since there is an implicit part for the subnet ID in the IP address structure. An example of IPv6 is FE40:0000:AE30:348E:2D82:0000:DA94:A93E.
Figure 4.2: IPv6 packet
Three types of address are supported in IPv6. They are the unicast, multicast and broadcast addresses.
IPv6 unicast addresses only a single interface such that packets meant for a unicast address are delivered to a single interface. The multicast addresses identify multiple interfaces in a manner that the packets destined for the multicast address are delivered to all the interfaces that are identified by the multicast address. This arrangement represents a one-to-many communication. IPv6 anycast address also identifies multiple interfaces like the multicast address. The only difference from multicast is that packets addressed to anycast address are delivered to the nearest interface that is identified by the anycast address. This is an example of a one-to-one-of-many communication.
5. Cisco Network Security
Securing the console is achieved by setting passwords to prevent unauthorized access to the administrative interface of the network device. The methods used to authenticate a user from the console include RADIUS, TACACS+, console password and local user database.
6. Conclusion
The digital age is still driven by the need to share information and communicate over internetworks. The interconnection of devices to make sharing information and resources possible is achieved using a number of network devices and technologies. Different Cisco devices and technology are available to implement networks and internetworks at different scales and across different geographical span. Apart from managing the movement of data packets within LANs and across networks, they also provide a suite of techniques to implement security measures on the networks.
Works Cited
Cisco (2007). “Cisco Router Guide For teleworkers, small offices, small to medium-sized businesses, and enterprise branch and head offices”. PDF. Retrieved on 25th July, 2016 from ftp://ftp.abcdata.com.pl/Cisco/DataSheets/cisco_router_guide-v4.pdf
Joe Habraken (1999). "Practical Cisco Routers". PDF. Retrieved on 23rd July, 2016 from ftp://ftp.tomsk.gov.ru/pub/books/Cisco/QUE%20-20Practical%20Cisco%20Routers.pdf
‘RFC 4291 - IP Version 6 Addressing Architecture’. Web. Accessed on 25th July, 2016 from http://tools.ietf.org/html/rfc4291
Forouzan, Behrouz. "Data Communications and Networking (4th ed.)". New York: McGraw-Hill, 2007. Print.
Tanenbaum, Andrew & Wetherall, David. “Computer Networks (5th ed.)” Boston, MA: Pearson Education, Inc., 2011. Print.
Stallings, W. "Business Data Communications", 6th Ed., Pearson Prentice Hall: New Jersey, 2009.
Cisco (2005). “Cisco Catalyst Switch Guide: Scalable, Intelligent LAN switching for Campus, Branch, and Data Center Networks of all sizes” PDF. Retrieved on 26th July 2016 from http://www.productsandservices.bt.com/btbusiness/btbusinessProducts/pdfs/cisco_catalyst_switch_guide.pdf
Lammle, Todd. "CCNA: Cisco Certified Network Associate Study Guide (6th ed.)" Indianapolis, IN: Wiley Publishing Inc., 2007. Print.
Harris, Joe. "Cisco Network Security: little Black book". PDF. Retrieved on 24th July 2016 from http://www.e-reading.club/bookreader.php/142068/Harris__Cisco_Network_Security_Little_Black_Book.pdf
