KCP(mKCP)

mKCP constructs a TCP like stream tunnel based on a UDP connection. Please make sure firewall rules have been set up correctly. mKCP consumes additional traffic to transfer data with less delay and may consume for traffic than TCP based transport.

mKCP Stream Transport

  • Name: kcp
  • Type: Transport Protocol
  • ID: stream.kcp

seed: string

The encryption seed for traffic obfuscator. Need to be the same on both sides.

mtu: number

Maximum transmission unit. This value is typically between 576 - 1460. It is 1350 by default.

tti: number

Transmission time interval in a millisecond. mKCP will send data at this frequency. Please choose a value between 10 - 100. It is 50 by default.

uplinkCapacity: number

Upload bandwidth capacity. The maximum speed to send data in MB/s. It is 5 by default. Beware it is Byte, not Bit. You can set it to 0 for very low bandwidth.

downlinkCapacity: number

Download bandwidth capacity. The maximum speed to receive data in MB/s. It is 20 by default. Beware it is Byte, not Bit. You can set it to 0 for very low bandwidth.

Tips

uplinkCapacity and downlinkCapacity decide the transfer speed of mKCP. In the client uplink's case, the client's uplinkCapacity determines the speed packets are sent, and the server side's downlinkCapacity determines the speed server receives the traffic. and the lower one will be the effective one. It is recommended to set downlinkCapacity to a relatively large value, like 100, and set uplinkCapacity to the actual network speed. If the speed is insufficient, one may increase the value of uplinkCapacity , until 2 times the actual bandwidth.

congestion: true | false

Whether congestion control is enabled. It is false by default. This will instruct V2Ray to decrease transfer speed if there is too much packet loss.

readBufferSize: number

The read buffer size of a single connection, in MB. It is 2 by default.

writeBufferSize: number

The write buffer size of a single connection, in MB. It is 2 by default.

Tips

readBufferSize and writeBufferSize determine the memory usage of a connection. If transfer speed is the priority, one may set a higher readBufferSize and writeBufferSize, to increase transfer speed at the cost of higher memory usage. If the network speed is less than 20 MB/s, the default value should sufficient. Otherwise, increase readBufferSize and writeBufferSize's and balance the memory usage and transfer speed manually.