Network Speed and Congestion Management

Network Speed

• Networks operate at predefined speeds (e.g., 1000 base T gigabit network at 1 Gbps).
• Traffic cannot exceed the predefined speed (1 Gbps for a gigabit network).
• Congestion occurs when multiple connections to the same destination exceed this speed.

Congestion and Bottleneck

• Congestion happens when traffic exceeds network capacity.
• Buffers in switches/routers are small and overflow leads to packet loss.
• Solutions include increasing network speed/size or reducing traffic.
• Bottlenecks can be challenging to diagnose—could be CPU, storage, or network-speed related.

Example of Bottleneck Analysis

• Web transaction response time can indicate bottlenecks.
• Example: Database server causing delay (1500-1750 ms), improved by configuration changes.

Measuring Network Usage

• Bandwidth Percentage: Measures network usage over time.
• Throughput: Amount of data moved through the network in a given time.
• Monitoring tools include switches, SNMP, and NetFlow.

Latency

• Delay between request and response.
• Measurement requires tools at each network link for accurate latency capture.

Packet Loss and Corruption

• Ideal network scenario: no packet loss.
• Packet loss can occur due to network outages or contention.
• Corrupted data is identified and discarded, requiring retransmission.

Impact on Applications

• Voice over IP and live video streams are sensitive to delays.
• Packet loss leads to disruptions like delays, clicking noises, or stream stutter.

Jitter

• Measure of time between packet frames.
• High jitter indicates irregular packet receipt, affecting real-time applications.
• Consistent jitter ensures smooth operation of phone calls and live streams.