In computer networks, delay refers to the time it takes for a bit of data to travel from one designated point to another. Different types of delays can affect the performance and quality of service in a network. Here are the primary types of network delays:
Propagation Delay:
- The time taken for a signal or packet to travel from the sender to the receiver through a medium (e.g., copper wire, fiber optic, air).
- It’s determined by the distance between the sender and receiver and the speed of the signal propagation in the transmission medium.
Transmission Delay:
- The time required to push all the packet’s bits into the link, i.e., the time taken to load the packet onto the transmission medium.
- It depends on the packet’s size and the bandwidth (data rate) of the link.
Processing Delay:
- Time taken by routers to process the packet header, check for bit-level errors, and determine the packet’s destination.
- Can also involve time taken for other operations such as applying security measures or transformation on the packet.
Queuing Delay:
- Time a packet spends waiting in a queue until it can be processed or transmitted.
- Queuing delay varies depending on the level of congestion in the network. In heavily loaded networks, this delay can be significant.
Serialization Delay:
- Similar to transmission delay, it’s the time taken to convert a packet from parallel to serial format for transmission. Often relevant for high-speed interfaces.
Nodal Delay:
- The total delay incurred at a single node (typically a router). It’s the sum of the processing, queuing, and transmission delays at that node.
End-to-End Delay:
- The total time taken for a packet to travel from the source to the destination. It’s the cumulative sum of all individual delays (propagation, transmission, processing, and queuing) experienced as the packet traverses the network.
Jitter:
- Not a “delay” in the strictest sense, but it’s related. Jitter refers to the variability in packet delay in networks, i.e., how much packet delay varies over time.
Understanding and managing these delays is crucial for network designers and administrators, especially in real-time applications like VoIP or streaming, where timely packet delivery is essential.
Key terms in plain language
Open a term for a concise explanation of language used on this page.
Fiber Internet
Internet delivered through strands of glass using light. Fiber commonly supports high capacity, low latency, and strong upload performance, but availability must be confirmed for the exact address.
Bandwidth
The amount of data a connection can carry in a given time, usually measured in Mbps or Gbps. More bandwidth supports more users, devices, and simultaneous applications.
VoIP
Voice over Internet Protocol carries phone calls over an IP network instead of a traditional analog phone line. Call quality depends on network stability, latency, and traffic management.
Cybersecurity
The practices and controls used to protect identities, devices, networks, applications, and data from unauthorized access, disruption, or manipulation.
Zero Trust
A security model that does not automatically trust a user or device because of its location. Access is continuously verified and limited to what is necessary.
SASE
Secure Access Service Edge combines networking and security capabilities in a cloud-delivered architecture so users and locations can receive consistent policy wherever they connect.