specs/rendezvous

Rendezvous Service

Scope:

• real-time applications that require rendezvous
• replace ws-star-rendezvous in conjunction with p2p-circuit relays.

Rendezvous Protocol

The rendezvous protocol provides facilities for real-time peer discovery within application specific namespaces. Peers connect to the rendezvous service and register their presence in one or more namespaces; they can subsequently enter rendezvous and receive announcements about peer registrations and unregistrations within their namespaces of interest. Registrations persist until the peer disconnects or explicitly unregisters.

Interaction

Client peer A connects to the rendezvous service R and registers for namespace my-app with a REGISTER message. It subsequently enters rendezvous with a RENDEZVOUS message and waits for REGISTER/UNREGISTER announcements from the service.

A -> R: REGISTER{my-app, {QmA, AddressA}}
A -> R: RENDEZVOUS{my-app}

Client peer B connects, registers and enters rendezvous. The rendezvous service immediately notifies B about the current namespace registrations and emits a register notification to A:

B -> R: REGISTER{my-app, {QmB, AddressB}}
B -> R: RENDEZVOUS{my-app}

R -> B: REGISTER{my-app, {QmA, AddressA}}
R -> A: REGISTER{my-app, {QmB, AddressB}}

A third client C connections and registers:

C -> R: REGISTER{my-app, {QmC, AddressC}}
C -> R: RENDEZVOUS{my-app}

R -> C: REGISTER{my-app, {QmA, AddressA}}
R -> C: REGISTER{my-app, {QmB, AddressB}}
R -> A: REGISTER{my-app, {QmC, AddressC}}
R -> B: REGISTER{my-app, {QmC, AddressC}}

Protobuf

message Message {
  enum MessageType {
    REGISTER = 0;
    UNREGISTER = 1;
    RENDEZVOUS = 2;
  }

  message Peer {
    optional string id = 1;
    repeated bytes addrs = 2;
  }

  message Register {
    optional string ns = 1;
    optional Peer peer = 2;
  }

  message Unregister {
    optional string ns = 1;
    optional Peer peer = 2;
  }

  message Rendezvous {
    optional string ns = 1;
  }

  optional MessageType type = 1;
  repeated Register register = 2;
  repeated Unregister unregister = 3;
  repeated Rendezvous rendezvous = 4;
}