Data Communications & NetworksCOMP.6104Case Study PresentationBrad Boyce

Topics Covered

Introduction Topology Connection Media Subnets Transport/Network/Routing Protocols Backbone Technology Wireless LAN Security Network Diagram Final Recommendation

Introduction

I have been hired to oversee the network upgrade for ADTECH, a software development company with sites based in Auckland, Wellington and Christchurch.

Objectives of this upgrade include:

Establish a WAN link between the three sites Upgrade the existing LAN and backbones for the three sites Provide wireless connectivity to the board room and staff room at the

Wellington site Maintain best practice.

Topology

The network topology refers to the logical layout in which devices are connected to each other.

An appropriate topology will be selected for the LANs, Backbone and WAN.

LAN topology defines how devices connect to the backbone. Backbone - distribution layer connects LANs to the core layer of the

backbone. Backbone - core layer connects the distribution layer to the WAN. WAN provides a connection between the three sites.

LAN Topology

Devices on the ADTECH LANs will use a STAR topology, with each device connecting to a central distribution device.

Backbone Topology

The central switches of the LANs will themselves collect to an upper level of switches, also using a star topology.

These switches collectively create the distribution layer of the backbone.

This is a switched backbone topology.

Backbone Topology

A switched backbone at the distribution layer provides: Reduced costs Easier management Greater speeds(Fitzgerald & Dennis, 2009)

Backbone Topology

The distribution layer switches connect to routers, collectively forming a core layer of the backbone.

The routers at the core layer use network layer addresses (IP) to move messages around.

This means messages can stay within their own LAN unless addressed outside of it.

This is a routed backbone topology.

WAN Topology

The routers on the core layer of the backbone connect to a central router known as the core router. There is one core router at each of the three ADTECH sites.

A fibre-optic line will be leased to connect the core routers at each site, in a bus topology from Auckland to Wellington to Christchurch.

Connection Media

Most LANs use Category 5 or 5e cables, which contain four pairs of wires.

New installations tend to use the newer category 6 Ethernet cable, which supports Gigabit speeds. (Wells, n.d.) This is the recommendation for our LANs.

Wireless access in the Wellington office will be supplied using IEEE 802.11ac Wi-Fi technology.

Backwards compatibility for 802.11b/g and n will be incorporated into the hardware.

The WAN will used a leased fibre-optic connection.

Subnets

Splitting up the networks at each site can drastically reduce network traffic, as messages can stay within the same subnet unless addressed outside of it (the same principle behind the routed backbone).

This is usually done logically – for example a network could be split into different subnets by department, or by floor.

The ADTECH network has 225 workstations in Wellington, 200 in Auckland, and 50 in Christchurch.

A single subnet could technically be used at each site (254 hosts max.), however the recommendation would be to split each sites network by floor. 3 subnets in Wellington 2 subnets in Auckland 1 subnet in Christchurch

Transport/Network/Routing Protocols

Several packet-switched protocols were considered for this project; X.25, Asynchronous Transfer Mode (ATM), Frame Relay and Ethernet Services.

As the majority of our network uses Ethernet connection media, Ethernet services is the most appropriate service protocol to use as it will require no translation.

Ethernet services therefore provide much faster speeds, as well as error correction, and greater compatibility. (Fitzgerald & Dennis, 2009)

Transport/Network/Routing Protocols

Routing protocols considered include Routing Information Protocol (RIP) and Open Shortest Path First (OSPF).

The RIP routing protocol is a distance-vector protocol that only considers the number of hops from source to destination when making routing decisions. Suitable for smaller networks.

OSPF is a Link State protocol that not only considers number of hops, but also circuit speed, and network congestion. More comprehensive protocol than RIP Recommended for ADTECH network

Backbone Technology

As mentioned, Routed backbone at core layer Switched backbone at distribution layer

Fibre optic connection between the three sites will be leased from another company, e.g. FX Networks who operate a 500 GB/s fibre optic backbone in New Zealand (shared virtually between subscribers).

Wireless LAN Security

Three options considered for securing the wireless LANs in the Wellington office:

Wired Equivalent Privacy (WEP) Wi-Fi Protected Access (WPA) Wi-Fi Protected Access II (WPA2)

Of the three encryption protocols, WPA2 is the newest and offers the the greatest protection. Utilizes Advanced Encryption Standard (AES) to encrypt pre-shared keys (PSK).WPA2 offers an Enterprise version which allows each user to have their own password. (Horowitz, 2009)WPA2-AES Enterprise is the preferred security protocol for the ADTECH wireless LAN.

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Final Recommendation

Star LAN topology Switched distribution layer backbone Routed core layer backbone Bus WAN topology Category 6 LAN cabling 802.11ac WiFi with backwards compatibility Leased fibre-optic WAN Separate subnets per floor in each building Ethernet services and OSPF routing protocol WPA2-AES Enterprise wireless security protocol

References

Fitzgerald, J., & Dennis, A. (2009). Business Data Communications and Networking (10th ed.). USA: John Wiley & Sons Inc.Horowitz, M. (2009, September 8). The Best Security for Wireless Networks . Retrieved from eSecurity Planet: http://www.esecurityplanet.com/views/article.php/3837976/The-Best-Security-for-Wireless-Networks.htmRtrifunovski. (2014, February 1). Image - Patrick Star.png - MoBrosStudios Wiki:. Retrieved from wikia.com: http://mobrosstudios.wikia.com/wiki/File:Patrick_Star.png