Unit 45 Wide Area Networking Technologies

Introduction

Aim

To provide learners with an understanding of Wide Area Network (WAN) technologies and the delivery of a wide range of networked services across a WAN infrastructure.

Unit abstract

WANs such as the internet have become a part of everyday life with many commercial, educational and governmental organisations having ownership or access to a WAN infrastructure. Many home and small business users broadband/ADSL (Asymmetric Digital Subscriber Line) connections are part of a WAN infrastructure supplied by their Internet Service Provider, where in many cases, the WAN precedes the direct connection to the internet. The impact of a WAN across an organisation includes the up-skilling of staff, changes to the physical environment and changes to commercial procedures. It also requires changes to the access, security and ownership of the data which passes across the WAN. In this unit learners will understand that consideration must be given to not only the physical WAN but the organizational culture as a whole. Learners will understand the importance of considering how WAN devices communicate and ‘learn’ about other devices and the changing topology. They will also explore communication speed and traffic management issues relating to the Quality of Service (QoS) of data delivery.

Learning outcomes

1 Understand the impact of WAN technologies

WAN technologies: eg dial-up, ADSL (Asymmetric Digital Subscriber Line) and all derivatives, broadband, frame relay, ISDN (Integrated Services Digital Network), MPLS (Multiprotocol Layer Switching), interior routing protocols, exterior routing, static routing; WAN hardware: eg routers, layer 2 aggregators, servers, cabling systems, modems, transceivers, satellite uplinks, 3G, 4G, VPN concentrators
Traffic intensive services: quality of service management eg DSCP (Differentiated Service Code Point), IP precedence, queues, base rules, congestion management; quality of service need eg Voice over IP, video streaming, audio streaming;
WAN security: eg MD5 hash (Message Digest algorithm 5), broadcast reduction, filters, traffic rules, firewalls, access control lists, directed updates, tunnelling
Trust: trust of intermediary system; trust of remote systems; trust of networks on WAN

2 Be able to design WAN infrastructures

Devices: expected average number of devices on system; anticipated participation
Bandwidth: expected average load; anticipated peak load; cost constraint
Users: quality expectations, concept of system growth
Applications: security requirements, quality of service needs, redundancy
Communications: suited to devices, suited to users, supportive of quality of service
Scalable: eg able to support network growth, able to support addition of communication devices, able to cope with bandwidth use and trend change
Security: network access, protocol management, peer authentication, tunneling across untrusted domains
Technology: network design, routing table reduction, protocol management

3 Be able to implement WAN infrastructures

Devices: eg installation of communication devices allocation of networks, communication device configuration
Services: DNS (Domain Name Service), email, web, video, application Specialised configuration: eg routing protocol, interfaces, network address allocation, security features, security ACLs, MD5 authentication, tunnel creation
Traffic management:system monitoring, traffic intensive, traffic precedence
Connectivity: suitable bandwidth, communication infrastructure, throughput
Testing: local systems able to inter-communication; security; bandwidth

4 Be able to manage WAN infrastructures

WAN performance: network monitoring tools, user access, traffic analysis, bandwidth monitoring, checking configuration, checking rules
Resolve WAN issues: using troubleshooting methodology; prove resolution