Transmission delay refers to the time a computer needs to push a packet’s bits into a wire during network-based packet switching. Also known as “store-and-forward delay” and “packetization delay,” it is the delay that the data rate of the link causes.
Transmission delay has all to do with a packet’s length but not the distance between two nodes. As such, it is proportional to a packet’s length in bits. While we have defined the term, what we know now remains a bit too technical still, doesn’t it? Don’t fret, just read on.
Read More about a “Transmission Delay”
To clear some cobwebs, let’s tackle the definition bit by bit.
What Terms Should You Know about to Understand What a Transmission Delay Is?
Here are some terms you need to comprehend:
- Packet: It is a formatted unit of data that a packet-switched network carries. It contains control information and user data.
- Packet switching: It is a method of grouping data into packets for transmission over a digital network.
- Control information: It gives the data necessary (header and metadata) to deliver a payload.
- Payload: Also known as “user data,” it is the actual intended message. For malware, the payload is the part that performs the malicious action.
- Header: It is supplemental data placed at the start of a block stored on or transmitted through a device.
- Metadata: It provides information about the payload but not its content, typically used for discovery and identification.
- Bit: It is the most basic unit of information in computing and digital communications. It’s a contracted form of “binary digit.” It represents a logical state with one of two possible values—0 or 1 (that can stand for, say, “yes” or “no).
- Wire: It refers to the cable used to connect devices to a network.
- Data rate: It is the amount of data transmitted over a network within a specified time.
- Packet length: It is the number of bytes a packet has. The minimum size of an IP packet is 21 bytes (20 bytes for the header and 1 byte of data). The maximum size is 65,535 bytes.
- Node: It is a redistribution point or communication endpoint. In a physical network node, it is an electronic device attached to a network capable of creating, receiving, or transmitting information over a communication channel.
So, to simplify, a transmission delay is the time it takes for a computer to push information to a device connected to it. It is computed using this formula:
DT = N/R seconds
DT is the transmission delay, N is the number of bits that require transmission, and R is the transmission rate in bits per second (bps).
What Are the Other Types of Delays in Computing Apart from Transmission Delay?
Three types of delays occur in computing. We already defined the first (transmission delay) above. We’ll tackle the other two below.
End-to-end delay is the time it takes to send a packet across a network from the source to the destination. It is also known as “one-way delay (OWD),” as it only goes in one direction.
Network delay indicates the latency (a delay measurement) for a bit to travel across a telecommunication network from one communication endpoint to another.
What Factors Affect Transmission Delay?
At least four factors affect transmission delay, which we discussed in greater detail below.
- Active session volume: A wired network processes packets using the first in, first out (FIFO) method. That said, the more packets there are to process, the longer the transmission delay is.
- Link transmission capacity: The bigger the transmission capacity of a wire, the shorter the transmission delay. That’s why when you upgrade your Internet access plan from 10Mbps Ethernet to 100Mbps Fast Ethernet, you’re ideally reducing the transmission delay by a factor of 10. You thus get faster Internet speed.
- Medium access control (MAC) access delay: Shared transmission links are suitable for the MAC protocol, which controls the access of nodes to a shared medium. The kind of MAC protocol influences this delay.
- Context switch in the operating system (OS): Sending or receiving packets takes a finite amount of time. Every computer has a maximum packet transmission speed. Ironically, the higher the access speed, the greater the delay. The computer’s processing speed must match that of the transmission.
We hope this post gave you a chance to understand what a transmission delay is and how it affects how fast you can access a network-connected device.