USB4 Protocol Tunneling is similar to Alt Mode but doesn't require a DP or PCIe controller. USB4 Protocol Tunneling creates a USB-C tunnel through which DisplayPort or PCIe data can be sent. Conceptually, Protocol Tunneling creates a 'pipe' with one protocol and uses it to send data in another protocol. If both devices can speak and understand the same protocol, a connection can be established. When devices talk to one another, they do so using a protocol. When a device is connected to a USB4 port, USB PD negotiates a 'contract' to deliver power, safely supplying up to 100 W (5A/20V). USB4 dynamically allocates bandwidth to video and data based on actual needs.ġ00 Watt Charging: All USB4 devices support USB Power Delivery. Video and Data Bandwidth Optimization: USB 3.2 allocated fixed bandwidth to data or video or, in DP Alt Mode, gave 100% to video. DisplayPort and Thunderbolt 3 are also supported via Alt Mode.īackward compatibility with USB 3.2, USB 2.0 and Thunderbolt 3: USB4 maintains compatibility with previous versions of the USB specification and, thanks to its Thunderbolt 3 foundation, supports TB3 Alt Mode too. Multiple Data and Display Protocols: USB4 supports USB 3.2, PCIe and DisplayPort 1.4a through a technique called protocol tunneling. They can optionally support 40 Gbps (4.8 GB/sec) if they use the shorter 0.8 meter Gen 3 cable. Up to 40Gbps Data Transfer Rate: USB4 devices are required to support 20 Gbps (2.4 GB/sec). The USB4 protocol requires a USB-C to USB-C cable. USB 4 (officially 'USB4' without the space) is an important update, not only for the new capabilities it offers but because it helps to resolve the confusion over USB 3.x naming and, for the most part, it gives users a predictable and consistent experience.

Usb 2 vs usb 3 for mice