What is point-to-point (P2P)?

Point-to-point (P2P) is a direct connection between two devices, where traffic travels over a dedicated channel only between these two nodes.

Short phrasing for the interview:

A point-to-point connection is a communication channel that directly connects two devices with no intermediate nodes.

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#Main characteristics of P2P

#1. Only two devices participate in the channel

There are no switches, hubs, or routers (unless they are the endpoints themselves).

For example:

• PC ↔ PC
• Router ↔ router
• Switch ↔ switch
• Antenna ↔ antenna

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#2. The channel is dedicated

Unlike "point-to-multipoint", the P2P channel is used by only two devices, so:

• there are no collisions,
• there is no competition for bandwidth,
• performance is predictable.

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#3. Simple routing logic

A packet always goes in one of two directions: there or back.

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#Where P2P connections are used

#1. In wired networks

• an Ethernet connection between two devices over a cable
• a direct connection between two switches (uplink)
• a connection between two routers in a WAN channel

Example: Two provider routers connected by a fiber-optic line - a classic point-to-point.

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#2. In wireless networks

Often used in outdoor Wi-Fi systems:

• two directional antennas create a P2P radio bridge between buildings
• it provides high speed over long distances

Example: Connecting two offices via a Wi-Fi "bridge".

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#3. In telephony and older transmission channels

The P2P principle was used:

• in leased lines,
• in PPP/HDLC channels (WAN protocols).

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#P2P vs Point-to-Multipoint (PTMP)

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#Example of a precise interview answer

Point-to-point is a type of connection in which two devices are connected directly over a dedicated channel. Traffic travels only between these two nodes, which provides low latency, no competition for the channel, and simple routing. Examples: a connection between two routers in a WAN, a radio bridge between buildings, a direct Ethernet connection between two devices.

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#Cheat sheet

• P2P = two devices ↔ a direct channel.
• No third nodes.
• A clean, predictable channel with no collisions.
• Used in WAN, radio bridges, uplinks.
• The opposite is point-to-multipoint.