To achieve high reliability# with network traffics, we need to address the following issues:
- Fault Tolerance
- Scalability (don’t degrade the performance at the same time)
- Quality of Service (QoS)#
- Network Security#
Network Reliability
- TRS2251 Chapter 1: Introduction to OSI Model and Internetworking
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Quality of Service (QoS)
QoS is the ability of a network to provide improved service to selected network traffic over various underlying technologies. The increasing need for real-time traffics such as video streaming and VoIP has made QoS as an important requirement for a #reliable network. It decreases the Network Congestion# and the effect on the quality of the critical packets especially low delay and low jitter. QoS can potentially filter out malicious low prioritised packets (from unknown type or origin) as a policing mechanism, but it is still vulnerable to DDoS and concealed traffic.
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Packet Switching
Packets could share the same circuit, therefore adding redundancy, that is adding more circuits into it to increase Network Reliability# could also increase its overall throughput.
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Internet Service Provider (ISP)
There is a hierarchy for ISP: Tier 1 (the highest), Tier 2 and Tier 3 (the lowest). Tier 1 ISPs, such as AT&T, and NTT, provides free of charge traffic exchange between Tier 1 networks. Tier 2 ISPs usually provide regional Internet services to the users, for example Telekom Malaysia (TM). Tier 3 ISPs, for instance, Unifi, Maxis, Celcom etc., provide local Internet services. Network traffic that is destined for Tier 2 and/or Tier 3 doesn’t need to travel to a central point for distribution, therefore increase the scalability# of the Internet.
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Circuit Switching
Though redundant circuits are possible with Circuit Switching, only one user could be in the circuit which the circuits are separated for each call, and only one path could be selected per call.