JXTA in a Nutshell

Chapter 18. The JXTA Standard Transport Bindings Specification

TCP/IP Transport Binding

The following section describes the transport binding for the JXTA protocols over TCP/IP. The document describes the message wire format of JXTA endpoint messages over a TCP/IP socket connection.

TCP/IP Wire Format

This section defines the TCP/IP message wire format. Each TCP/IP message is composed of:

• Header

• Body

Header

The format of the header is:

Type

Src IP

Src Port

Size

Option

Unused

The header fields are as follows:

Type

One byte. The byte info is used to either unicast or multicast the request.

• 1 = This is a propagate message.

• 2 = This is a unicast message.

• 3 = This for ACK (unused).

• 4 = This is for NACK (unused).

Src IP

Four bytes. (IP addresses are in the IPv4 format.)

Src Port

Two bytes (network byte order representation). The port is present since each peer may decide to bind its transport service to a specific port number. The TCP binding does not require that a specific port be used.

Size

Four-byte body, not counting the header (network byte order representation).

Option

One-byte option. These options are intended to be used to specify the kind of socket connection (uni- or bidirectional) in use:

• HANDCHECK = 1 not implemented yet (bidirectional)

• NONBLOCKING = 2 (unidirectional transfer)

Unused

Four bytes.

Body

The format of the body is described in Chapter 16 and is represented as a byte array.

Connection States

The TCP/IP binding is stateless and does not require any states to be maintained. ...