UDPv4Transport.Property_t Class Reference

Configurable IPv4/UDP Transport-Plugin properties. More...

Inheritance diagram for UDPv4Transport.Property_t:

Public Member Functions
	Property_t ()

Public Attributes
int	send_socket_buffer_size
	Size in bytes of the send buffer of a socket used for sending.
int	recv_socket_buffer_size
	Size in bytes of the receive buffer of a socket used for receiving.
int	unicast_enabled
	Allows the transport plugin to use unicast for sending and receiving.
int	multicast_enabled
	Allows the transport plugin to use multicast for sending and receiving.
int	multicast_ttl
	Value for the time-to-live parameter for all multicast sends using this plugin.
int	multicast_loopback_disabled
	Prevents the transport plugin from putting multicast packets onto the loopback interface.
int	ignore_loopback_interface
	Prevents the transport plugin from using the IP loopback interface.
int	ignore_nonup_interfaces
	Prevents the transport plugin from using a network interface that is not reported as UP by the operating system.
int	ignore_nonrunning_interfaces
	Prevents the transport plugin from using a network interface that is not reported as RUNNING by the operating system.
int	no_zero_copy
	Prevents the transport plugin from doing a zero copy.
int	send_blocking
	Control blocking behavior of send sockets. CHANGING THIS FROM THE DEFAULT CAN CAUSE SIGNIFICANT PERFORMANCE PROBLEMS.
long	transport_priority_mask
	Set mask for use of transport priority field.
int	transport_priority_mapping_low
	Set low value of output range to IPv4 TOS.
int	transport_priority_mapping_high
	Set high value of output range to IPv4 TOS.
int	send_ping
	Configures whether to send PING messages.
long	interface_poll_period
	Specifies the period in milliseconds to query for changes in the state of all the interfaces.
int	reuse_multicast_receive_resource
	Controls whether or not to reuse multicast receive resources.
int	protocol_overhead_max
	Maximum size in bytes of protocol overhead, including headers.
String	public_address
	Public IP address associated with the transport instantiation.
Public Attributes inherited from Transport.Property_t
final int	classid
	The Transport-Plugin Class ID.
final int	address_bit_count
	Number of bits in a 16-byte address that are used by the transport. Should be between 0 and 128.
final int	properties_bitmap
	A bitmap that defines various properties of the transport to the RTI Connext core.
int	gather_send_buffer_count_max
	Specifies the maximum number of buffers that RTI Connext can pass to the send() method of a transport plugin.
int	message_size_max
	The maximum size of an RTPS message in bytes that can be sent or received by the transport plugin.
final StringSeq	allow_interfaces_list
	A list of strings, each identifying a range of interface addresses or an interface name. If the list is non-empty (i.e., allow_interfaces_list_length > 0), allow the use of only these interfaces. If the list is empty, allow the use of all interfaces.
final StringSeq	deny_interfaces_list
	A list of strings, each identifying a range of interface addresses or an interface name. If the list is non-empty (i.e., deny_interfaces_list_length > 0), deny the use of these interfaces.
final StringSeq	allow_multicast_interfaces_list
	A list of strings, each identifying a range of interface addresses or an interface name. If the list is non-empty (i.e., allow_multicast_interfaces_list_length > 0), allow the use of multicast only on these interfaces; otherwise allow the use of all the allowed interfaces.
final StringSeq	deny_multicast_interfaces_list
	A list of strings, each identifying a range of interface addresses or an interface name. If the list is non-empty (i.e., deny_multicast_interfaces_list_length > 0), deny the use of those interfaces for multicast.

Additional Inherited Members
Static Public Attributes inherited from Transport.Property_t
static final int	NDDS_TRANSPORT_CLASSID_INVALID = -1
	Invalid Transport Class ID.
static final int	NDDS_TRANSPORT_CLASSID_RESERVED_RANGE = 1000
	Transport-Plugin class IDs below this are reserved by RTI.
static final int	NDDS_TRANSPORT_PROPERTY_BIT_BUFFER_ALWAYS_LOANED = 0x2
	Specified zero-copy behavior of transport.
static final int	NDDS_TRANSPORT_PROPERTY_GATHER_SEND_BUFFER_COUNT_MIN = 3
	Minimum number of gather-send buffers that must be supported by a Transport Plugin implementation.
Protected Member Functions inherited from Struct
	Struct ()
abstract void	pull_from_nativeI (long native_status)
abstract void	push_to_nativeI (long native_status)

Detailed Description

Configurable IPv4/UDP Transport-Plugin properties.

The properties in this structure can be modified by the end user to configure the plugin. However, the properties must be set before the plugin is instantiated.

See Also

com.rti.ndds.transport.TransportSupport.set_builtin_transport_property()

Constructor & Destructor Documentation

Property_t

(

)

Create an empty UDPv4Transport property with default values

Member Data Documentation

int send_socket_buffer_size

Size in bytes of the send buffer of a socket used for sending.

On most operating systems, setsockopt() will be called to set the SENDBUF to the value of this parameter.

This value must be greater than or equal to com.rti.ndds.transport.Transport.Property_t.message_size_max. The maximum value is operating system-dependent.

int recv_socket_buffer_size

Size in bytes of the receive buffer of a socket used for receiving.

On most operating systems, setsockopt() will be called to set the RECVBUF to the value of this parameter.

This value must be greater than or equal to com.rti.ndds.transport.Transport.Property_t.message_size_max. The maximum value is operating system-dependent.

int unicast_enabled

Allows the transport plugin to use unicast for sending and receiving.

This value turns unicast UDP on (if set to 1) or off (if set to 0) for this plugin. By default, it will be turned on (1). Also by default, the plugin will use all the allowed network interfaces that it finds up and running when the plugin is instanced.

int multicast_enabled

Allows the transport plugin to use multicast for sending and receiving.

This value turns multicast UDP on (if set to 1) or off (if set to 0) for this plugin. By default, it will be turned on (1) for those platforms that support multicast. Also by default, the plugin will use the all network interfaces allowed for multicast that it finds up and running when the plugin is instanced.

int multicast_ttl

Value for the time-to-live parameter for all multicast sends using this plugin.

This value is used to set the TTL of multicast packets sent by this transport plugin.

See Also

NDDS_TRANSPORT_UDPV4_MULTICAST_TTL_DEFAULT

int multicast_loopback_disabled

Prevents the transport plugin from putting multicast packets onto the loopback interface.

If multicast loopback is disabled (this value is set to 1), then when sending multicast packets, RTI Connext will not put a copy of the packets on the loopback interface. This prevents applications on the same node (including itself) from receiving those packets.

This value is set to 0 by default, meaning multicast loopback is enabled.

Disabling multicast loopback (setting this value to 1) may result in minor performance gains when using multicast.

[NOTE: Windows CE systems do not support multicast loopback. This field is ignored for Windows CE targets.]

int ignore_loopback_interface

Prevents the transport plugin from using the IP loopback interface.

Currently three values are allowed:

• 0: Forces local traffic to be sent over loopback, even if a more efficient transport (such as shared memory) is installed (in which case traffic will be sent over both transports).

• 1: Disables local traffic via this plugin. The IP loopback interface is not used, even if no NICs are discovered. This is useful when you want applications running on the same node to use a more efficient plugin (such as shared memory) instead of the IP loopback.

• -1: Automatic. Lets RTI Connext decide between the above two choices.

The current "automatic" (-1) RTI Connext policy is as follows:

• If a shared memory transport plugin is available for local traffic and there is a locator on the initial peers list that can use shared memory, the effective value is 1 (i.e., disable UPV4 local traffic).

• Otherwise, the effective value is 0 (i.e., use UDPv4 for local traffic also).

[default] -1 Automatic RTI Connext policy based on availability of the shared memory transport.

int ignore_nonup_interfaces

Prevents the transport plugin from using a network interface that is not reported as UP by the operating system.

The transport checks the flags reported by the operating system for each network interface upon initialization. An interface which is not reported as UP will not be used. This property allows the user to configure the transport to start using even the interfaces which were not reported as UP.

Two values are allowed:

• 0: Allow the use of interfaces which were not reported as UP.

• 1: Do not use interfaces which were not reported as UP.

[default] 1

int ignore_nonrunning_interfaces

Prevents the transport plugin from using a network interface that is not reported as RUNNING by the operating system.

The transport checks the flags reported by the operating system for each network interface upon initialization. An interface which is not reported as UP will not be used. This property allows the same check to be extended to the IFF_RUNNING flag implemented by some operating systems. The RUNNING flag is defined to mean that "all resources are allocated", and may be off if there is no link detected, e.g., the network cable is unplugged.

Two values are allowed:

• 0: Do not check the RUNNING flag when enumerating interfaces, just make sure the interface is UP.

• 1: Check the flag when enumerating interfaces, and ignore those that are not reported as RUNNING. This can be used on some operating systems to cause the transport to ignore interfaces that are enabled but not connected to the network.

[default] 0 (i.e., do not check RUNNING flag)

int no_zero_copy

Prevents the transport plugin from doing a zero copy.

By default, this plugin will use the zero copy on OSs that offer it. While this is good for performance, it may sometime tax the OS resources in a manner that cannot be overcome by the application.

The best example is if the hardware/device driver lends the buffer to the application itself. If the application does not return the loaned buffers soon enough, the node may error or malfunction. In case you cannot reconfigure the H/W, device driver, or the OS to allow the zero copy feature to work for your application, you may have no choice but to turn off zero copy use.

By default this is set to 0, so RTI Connext will use the zero-copy API if offered by the OS.

int send_blocking

Control blocking behavior of send sockets. CHANGING THIS FROM THE DEFAULT CAN CAUSE SIGNIFICANT PERFORMANCE PROBLEMS.

Currently two values are defined:

• NDDS_TRANSPORT_UDPV4_BLOCKING_ALWAYS: Sockets are blocking (default socket options for Operating System).

• NDDS_TRANSPORT_UDPV4_BLOCKING_NEVER: Sockets are modified to make them non-blocking. THIS IS NOT A SUPPORTED CONFIGURATION AND MAY CAUSE SIGNIFICANT PERFORMANCE PROBLEMS.

[default] NDDS_TRANSPORT_UDPV4_BLOCKING_ALWAYS.

long transport_priority_mask

Set mask for use of transport priority field.

This is used in conjunction with com.rti.ndds.transport.UDPv4Transport.Property_t.transport_priority_mapping_low and com.rti.ndds.transport.UDPv4Transport.Property_t.transport_priority_mapping_high to define the mapping from DDS transport priority (see TRANSPORT_PRIORITY) to the IPv4 TOS field. Defines a contiguous region of bits in the 32-bit transport priority value that is used to generate values for the IPv4 TOS field on an outgoing socket.

For example, the value 0x0000ff00 causes bits 9-16 (8 bits) to be used in the mapping. The value will be scaled from the mask range (0x0000 - 0xff00 in this case) to the range specified by low and high.

If the mask is set to zero, then the transport will not set IPv4 TOS for send sockets.

[default] 0.

int transport_priority_mapping_low

Set low value of output range to IPv4 TOS.

This is used in conjunction with com.rti.ndds.transport.UDPv4Transport.Property_t.transport_priority_mask and com.rti.ndds.transport.UDPv4Transport.Property_t.transport_priority_mapping_high to define the mapping from DDS transport priority to the IPv4 TOS field. Defines the low value of the output range for scaling.

Note that IPv4 TOS is generally an 8-bit value.

[default] 0.

int transport_priority_mapping_high

Set high value of output range to IPv4 TOS.

This is used in conjunction with com.rti.ndds.transport.UDPv4Transport.Property_t.transport_priority_mask and com.rti.ndds.transport.UDPv4Transport.Property_t.transport_priority_mapping_low to define the mapping from DDS transport priority to the IPv4 TOS field. Defines the high value of the output range for scaling.

Note that IPv4 TOS is generally an 8-bit value.

[default] 0xff.

int send_ping

Configures whether to send PING messages.

This property specifies whether to send a PING message before commencing the discovery process. On certain operating systems or with certain switches the initital UDP packet, configuring the ARP table, was unfortunately dropped. To avoid dropping the initial RTPS discovery sample, a PING message is sent to preconfigure the ARP table in those environments.

[default] 1 (enabled)

long interface_poll_period

Specifies the period in milliseconds to query for changes in the state of all the interfaces.

The value of this property is ignored if ignore_non_interfaces is 1. If ignore_nonup_interfaces is 0 then the UDPv4 transport creates a new thread to query the status of the interfaces. This property specifies the polling period in milliseconds for performing this query.

[default] 500 milliseconds.

int reuse_multicast_receive_resource

Controls whether or not to reuse multicast receive resources.

Setting this to 0 (FALSE) prevents multicast crosstalk by uniquely configuring a port and creating a receive thread for each multicast group address.

[default] 0.

int protocol_overhead_max

Maximum size in bytes of protocol overhead, including headers.

This value is the maximum size, in bytes, of protocol-related overhead. Normally, the overhead accounts for UDP and IP headers. The default value is set to accommodate the most common UDP/IP header size.

Note that when com.rti.ndds.transport.Transport.Property_t.message_size_max plus this overhead is larger than the UDPv4 maximum message size (65535 bytes), the middleware will automatically reduce the effective message_size_max, to 65535 minus this overhead.

[default] 28.

See Also

com.rti.ndds.transport.Transport.Property_t.message_size_max

String public_address

Public IP address associated with the transport instantiation.

Setting the public IP address is only necessary to support communication over WAN that involves Network Address Translation (NAT).

Typically, the address is the public address of the IP NAT router that provides access to the WAN.

By default, the com.rti.dds.domain.DomainParticipant creating the transport will announce the IP addresses obtained from the NICs to other DomainParticipants in the system.

When this property is set, the DomainParticipant will announce the IP address corresponding to the property value instead of the LAN IP addresses associated with the NICs.

Note 1: Setting this property is necessary, but is not a sufficient condition for sending and receiving data over the WAN. You must also configure the IP NAT router to allow UDP traffic and to map the public IP address specified by this property to the DomainParticipant's private LAN IP address. This is typically done with one of the following mechanisms:

• Port Forwarding: You must map the private ports used to receive discovery and user data traffic to the corresponding public ports (see com.rti.dds.infrastructure.RtpsWellKnownPorts_t). Public and private ports must be the same since the transport does not allow you to change the mapping.

• 1:1 NAT: You must add a 1:1 NAT entry that maps the public IP address specified in this property to the private LAN IP address of the DomainParticipant.

Note 2: By setting this property, the com.rti.dds.domain.DomainParticipant only announces its public IP address to other DomainParticipants. Therefore, communication with DomainParticipants within the LAN that are running on different nodes will not work unless the NAT router is configured to enable NAT reflection (hairpin NAT).

There is another way to achieve simultaneous communication with DomainParticipants running in the LAN and WAN, that does not require hairpin NAT. This way uses a gateway application such as RTI Routing Service to provide access to the WAN.

WAN communication using RTI Routing Service

[default] null (the transport uses the IP addresses obtained from the NICs)