SXP Developer Guide


SXP (Scalable-Group Tag eXchange Protocol) project is an effort to enhance OpenDaylight platform with IP-SGT (IP Address to Source Group Tag) bindings that can be learned from connected SXP-aware network nodes. The current implementation supports SXP protocol version 4 according to the Smith, Kandula - SXP IETF draft and grouping of peers and creating filters based on ACL/Prefix-list syntax for filtering outbound and inbound IP-SGT bindings. All protocol legacy versions 1-3 are supported as well. Additionally, version 4 adds bidirectional connection type as an extension of a unidirectional one.

SXP Architecture

The SXP Server manages all connected clients in separate threads and a common SXP protocol agreement is used between connected peers. Each SXP network peer is modelled with its pertaining class, e.g., SXP Server represents the SXP Speaker, SXP Listener the Client. The server program creates the ServerSocket object on a specified port and waits until a client starts up and requests connect on the IP address and port of the server. The client program opens a Socket that is connected to the server running on the specified host IP address and port.

The SXP Listener maintains connection with its speaker peer. From an opened channel pipeline, all incoming SXP messages are processed by various handlers. Message must be decoded, parsed and validated.

The SXP Speaker is a counterpart to the SXP Listener. It maintains a connection with its listener peer and sends composed messages.

The SXP Binding Handler extracts the IP-SGT binding from a message and pulls it into the SXP-Database. If an error is detected during the IP-SGT extraction, an appropriate error code and sub-code is selected and an error message is sent back to the connected peer. All transitive messages are routed directly to the output queue of SXP Binding Dispatcher.

The SXP Binding Dispatcher represents a selector that will decides how many data from the SXP-database will be sent and when. It is responsible for message content composition based on maximum message length.

The SXP Binding Filters handles filtering of outgoing and incoming IP-SGT bindings according to BGP filtering using ACL and Prefix List syntax for specifying filter or based on Peer-sequence length.

The SXP Domains feature provides isolation of SXP peers and bindings learned between them, also exchange of Bindings is possible across SXP-Domains by ACL, Prefix List or Peer-Sequence filters

Key APIs and Interfaces

As this project is fairly small, it provides only few features that install and provide all APIs and implementations for this project.

  • sxp-api
  • spx-core
  • sxp-controller
  • sxp-cluster-route
  • sxp-karaf
  • sxp-robot
  • sxp-system-tests


Contains data holders and entities


Main logic and core features


RPC request handling


Performs managing of SXP devices in cluster environment


Defines Karaf4 dependencies


Contains JRobot libraries used in CSIT Robot tests


Contains REST client used for testing purposes