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RTI Connext .Net APIs
Version 5.1.0
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QoS related to the reliable writer protocol defined in RTPS. More...
#include <managed_infrastructure.h>
Public Attributes | |
| System::Int32 | low_watermark |
| When the number of unacknowledged samples in the current send window of a reliable writer meets or falls below this threshold, the ::DDS::StatusKind::RELIABLE_WRITER_CACHE_CHANGED_STATUS is considered to have changed. | |
| System::Int32 | high_watermark |
| When the number of unacknowledged samples in the current send window of a reliable writer meets or exceeds this threshold, the ::DDS::StatusKind::RELIABLE_WRITER_CACHE_CHANGED_STATUS is considered to have changed. | |
| Duration_t | heartbeat_period |
| The period at which to send heartbeats. | |
| Duration_t | fast_heartbeat_period |
| An alternative heartbeat period used when a reliable writer needs to flush its unacknowledged samples more quickly. | |
| Duration_t | late_joiner_heartbeat_period |
| An alternative heartbeat period used when a reliable reader joins late and needs to be caught up on cached samples of a reliable writer more quickly than the normal heartbeat rate. | |
| Duration_t | virtual_heartbeat_period |
| The period at which to send virtual heartbeats. Virtual heartbeats inform the reliable reader about the range of samples currently present, for each virtual GUID, in the reliable writer's queue. | |
| System::Int32 | samples_per_virtual_heartbeat |
| The number of samples that a reliable writer has to publish before sending a virtual heartbeat. | |
| System::Int32 | max_heartbeat_retries |
| The maximum number of periodic heartbeat retries before marking a remote reader as inactive. | |
| System::Int32 | heartbeats_per_max_samples |
| The number of heartbeats per current send window. | |
| Duration_t | min_nack_response_delay |
| The minimum delay to respond to a NACK. | |
| Duration_t | max_nack_response_delay |
| The maximum delay to respond to a nack. | |
| Duration_t | nack_suppression_duration |
| The duration for ignoring consecutive NACKs that may trigger redundant repairs. | |
| System::Int32 | max_bytes_per_nack_response |
| The maximum total message size when resending dropped samples. | |
| Duration_t | disable_positive_acks_min_sample_keep_duration |
| The minimum duration a sample is queued for ACK-disabled readers. | |
| Duration_t | disable_positive_acks_max_sample_keep_duration |
| The maximum duration a sample is queued for ACK-disabled readers. | |
| System::Int32 | disable_positive_acks_decrease_sample_keep_duration_factor |
| Controls rate of contraction of dynamic sample keep duration. | |
| System::Int32 | disable_positive_acks_increase_sample_keep_duration_factor |
| Controls rate of growth of dynamic sample keep duration. | |
| System::Int32 | min_send_window_size |
| Minimum size of send window of unacknowledged samples. | |
| System::Int32 | max_send_window_size |
| Maximum size of send window of unacknowledged samples. | |
| Duration_t | send_window_update_period |
| Period in which send window may be dynamically changed. | |
| System::Int32 | send_window_increase_factor |
| Increases send window size by this percentage when reacting dynamically to network conditions. | |
| System::Int32 | send_window_decrease_factor |
| Decreases send window size by this percentage when reacting dynamically to network conditions. | |
| System::Int32 | multicast_resend_threshold |
| The minimum number of requesting readers needed to trigger a multicast resend. | |
Properties | |
| System::Boolean | inactivate_nonprogressing_readers [get, set] |
| Whether to treat remote readers as inactive when their NACKs do not progress. | |
| System::Boolean | disable_positive_acks_enable_adaptive_sample_keep_duration [get, set] |
| Enables dynamic adjustment of sample keep duration in response to congestion. | |
| System::Boolean | enable_multicast_periodic_heartbeat [get, set] |
| Whether periodic heartbeat messages are sent over multicast. | |
QoS related to the reliable writer protocol defined in RTPS.
It is used to configure a reliable writer according to RTPS protocol.
The reliability protocol settings are applied to batches instead of individual data samples when batching is enabled.
| System::Int32 DDS::RtpsReliableWriterProtocol_t::low_watermark |
When the number of unacknowledged samples in the current send window of a reliable writer meets or falls below this threshold, the ::DDS::StatusKind::RELIABLE_WRITER_CACHE_CHANGED_STATUS is considered to have changed.
This value is measured in units of samples, except with batching configurations where it is measured in units of batches.
The value must be greater than or equal to zero and strictly less than high_watermark.
The high and low watermarks are used for switching between the regular and fast heartbeat rates (DDS::RtpsReliableWriterProtocol_t::heartbeat_period and DDS::RtpsReliableWriterProtocol_t::fast_heartbeat_period, respectively). When the number of unacknowledged samples in the queue of a reliable DDS::DataWriter meets or exceeds high_watermark, the ::DDS::StatusKind::RELIABLE_WRITER_CACHE_CHANGED_STATUS is changed, and the DataWriter will start heartbeating at fast_heartbeat_rate. When the number of samples meets or falls below low_watermark, ::DDS::StatusKind::RELIABLE_WRITER_CACHE_CHANGED_STATUS is changed, and the heartbeat rate will return to the "normal" rate (heartbeat_rate).
[default] 0
[range] [0, 100 million], < high_watermark
| System::Int32 DDS::RtpsReliableWriterProtocol_t::high_watermark |
When the number of unacknowledged samples in the current send window of a reliable writer meets or exceeds this threshold, the ::DDS::StatusKind::RELIABLE_WRITER_CACHE_CHANGED_STATUS is considered to have changed.
This value is measured in units of samples, except with batching configurations where it is measured in units of batches.
The value must be strictly greater than low_watermark and less than or equal to a maximum that depends on the container QoS policy:
In DDS::DomainParticipantQos::discovery_config:
For DDS::DiscoveryConfigQosPolicy::publication_writer
high_watermark<= DDS::AllocationSettings_t::max_count in DDS::DomainParticipantResourceLimitsQosPolicy::local_writer_allocation
For DDS::DiscoveryConfigQosPolicy::subscription_writer
high_watermark<= DDS::AllocationSettings_t::max_count in DDS::DomainParticipantResourceLimitsQosPolicy::local_reader_allocation
In DDS::DataWriterQos::protocol:
For DDS::DataWriterProtocolQosPolicy::rtps_reliable_writer,
high_watermark<=DDS::ResourceLimitsQosPolicy::max_samples if batching is disabled. Otherwise,
high_watermark<=DDS::DataWriterResourceLimitsQosPolicy::max_batches high_watermark<=DDS::RtpsReliableWriterProtocol_t::max_send_window_size
[default] 1
[range] [1, 100 million] or DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED, > low_watermark <= maximum which depends on the container policy
| Duration_t DDS::RtpsReliableWriterProtocol_t::heartbeat_period |
The period at which to send heartbeats.
A reliable writer will send periodic heartbeats at this rate.
[default] 3 seconds
[range] [1 nanosec,1 year], >= DDS::RtpsReliableWriterProtocol_t::fast_heartbeat_period, >= DDS::RtpsReliableWriterProtocol_t::late_joiner_heartbeat_period
| Duration_t DDS::RtpsReliableWriterProtocol_t::fast_heartbeat_period |
An alternative heartbeat period used when a reliable writer needs to flush its unacknowledged samples more quickly.
This heartbeat period will be used when the number of unacknowledged samples in the cache of a reliable writer meets or exceeds the writer's high watermark and has not subsequently dropped to the low watermark. The normal period will be used at all other times.
This period must not be slower (i.e. must be of the same or shorter duration) than the normal heartbeat period.
[default] 3 seconds
[range] [1 nanosec,1 year], <= DDS::RtpsReliableWriterProtocol_t::heartbeat_period
| Duration_t DDS::RtpsReliableWriterProtocol_t::late_joiner_heartbeat_period |
An alternative heartbeat period used when a reliable reader joins late and needs to be caught up on cached samples of a reliable writer more quickly than the normal heartbeat rate.
This heartbeat period will be used when a reliable reader joins after a reliable writer with non-volatile durability has begun publishing samples. Once the reliable reader has received all cached samples, it will be serviced at the same rate as other reliable readers.
This period must not be slower (i.e. must be of the same or shorter duration) than the normal heartbeat period.
[default] 3 seconds
[range] [1 nanosec,1 year], <= DDS::RtpsReliableWriterProtocol_t::heartbeat_period
| Duration_t DDS::RtpsReliableWriterProtocol_t::virtual_heartbeat_period |
The period at which to send virtual heartbeats. Virtual heartbeats inform the reliable reader about the range of samples currently present, for each virtual GUID, in the reliable writer's queue.
A reliable writer will send periodic virtual heartbeats at this rate.
[default] DDS::Duration_t::DURATION_AUTO. If DDS::PresentationQosPolicy::access_scope is set to ::DDS::PresentationQosPolicyAccessScopeKind::GROUP_PRESENTATION_QOS, this value is set to DDS::RtpsReliableWriterProtocol_t::heartbeat_period. Otherwise, the value is set to DDS::Duration_t::DURATION_INFINITE.
[range] > 1 nanosec, DDS::Duration_t::DURATION_INFINITE, or DDS::Duration_t::DURATION_AUTO
| System::Int32 DDS::RtpsReliableWriterProtocol_t::samples_per_virtual_heartbeat |
The number of samples that a reliable writer has to publish before sending a virtual heartbeat.
[default] DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
[range] [1,1000000], DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
| System::Int32 DDS::RtpsReliableWriterProtocol_t::max_heartbeat_retries |
The maximum number of periodic heartbeat retries before marking a remote reader as inactive.
When a remote reader has not acked all the samples the reliable writer has in its queue, and max_heartbeat_retries number of periodic heartbeats has been sent without receiving any ack/nack back, the remote reader will be marked as inactive (not alive) and be ignored until it resumes sending ack/nack.
Note that piggyback heartbeats do NOT count towards this value.
[default] 10
[range] [1, 1 million] or DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
| System::Int32 DDS::RtpsReliableWriterProtocol_t::heartbeats_per_max_samples |
The number of heartbeats per current send window.
A piggyback heartbeat is sent every [(current send window size/heartbeats_per_max_samples)] number of samples written
If set to zero, no piggyback heartbeat will be sent.
If current send window size is DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED, 100 million is assumed as the value in the calculation.
[default] 8
[range] [0, 100 million]
heartbeats_per_max_samples<= DDS::ResourceLimitsQosPolicy::max_samples if batching is disabled. Otherwise:
heartbeats_per_max_samples<= DDS::DataWriterResourceLimitsQosPolicy::max_batches
heartbeats_per_max_samples<= DDS::RtpsReliableWriterProtocol_t::max_send_window_size
| Duration_t DDS::RtpsReliableWriterProtocol_t::min_nack_response_delay |
The minimum delay to respond to a NACK.
When a reliable writer receives a NACK from a remote reader, the writer can choose to delay a while before it sends repair samples or a heartbeat. This sets the value of the minimum delay.
[default] 0 seconds
[range] [0,1 day], <= max_nack_response_delay
| Duration_t DDS::RtpsReliableWriterProtocol_t::max_nack_response_delay |
The maximum delay to respond to a nack.
This set the value of maximum delay between receiving a NACK and sending repair samples or a heartbeat.
[default] The default value depends on the container policy:
For DDS::DiscoveryConfigQosPolicy : 0 seconds
For DDS::DataWriterProtocolQosPolicy : 0.2 seconds
[range] [0,1 day], >= min_nack_response_delay
| Duration_t DDS::RtpsReliableWriterProtocol_t::nack_suppression_duration |
The duration for ignoring consecutive NACKs that may trigger redundant repairs.
A reliable writer may receive consecutive NACKs within a short duration from a remote reader that will trigger the sending of redundant repair messages.
This specifies the duration during which consecutive NACKs are ignored to prevent redundant repairs from being sent.
[default] 0 seconds
[range] [0,1 day],
| System::Int32 DDS::RtpsReliableWriterProtocol_t::max_bytes_per_nack_response |
The maximum total message size when resending dropped samples.
As part of the reliable communication protocol, data writers send heartbeat (HB) messages to their data readers. Each HB message contains the sequence number of the most recent sample sent by the data writer.
In response, a data reader sends an acknowledgement (ACK) message, indicating what sequence numbers it did not receive, if any. If the data reader is missing some samples, the data writer will send them again.
max_bytes_per_nack_response determines the maximum size of the message sent by the data writer in response to an ACK. This message may contain multiple samples.
If max_bytes_per_nack_response is larger than the maximum message size supported by the underlying transport, RTI Connext will send multiple messages. If the total size of all samples that need to be resent is larger than max_bytes_per_nack_response, the remaining samples will be resent the next time an ACK arrives.
[default] 131072
[range] [0, 1 GB]
| Duration_t DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_min_sample_keep_duration |
The minimum duration a sample is queued for ACK-disabled readers.
When positive ACKs are disabled for a data writer (DDS::DataWriterProtocolQosPolicy::disable_positive_acks = true) or a data reader (DDS::DataReaderProtocolQosPolicy::disable_positive_acks = true), a sample is available from the data writer's queue for at least this duration, after which the sample may be considered to be acknowledged.
[default] 1 millisecond
[range] [0,1 year], <= DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_max_sample_keep_duration
| Duration_t DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_max_sample_keep_duration |
The maximum duration a sample is queued for ACK-disabled readers.
When positive ACKs are disabled for a data writer (DDS::DataWriterProtocolQosPolicy::disable_positive_acks = true) or a data reader (DDS::DataReaderProtocolQosPolicy::disable_positive_acks = true), a sample is available from the data writer's queue for at most this duration, after which the sample is considered to be acknowledged.
[default] 1 second
[range] [0,1 year], >= DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_min_sample_keep_duration
| System::Int32 DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_decrease_sample_keep_duration_factor |
Controls rate of contraction of dynamic sample keep duration.
Used when DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_enable_adaptive_sample_keep_duration = true.
When the adaptive algorithm determines that the keep duration should be decreased, this factor (a percentage) is multiplied with the current keep duration to get the new shorter keep duration. For example, if the current keep duration is 20 milliseconds, using the default factor of 95% would result in a new keep duration of 19 milliseconds.
[default] 95
[range] <= 100
| System::Int32 DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_increase_sample_keep_duration_factor |
Controls rate of growth of dynamic sample keep duration.
Used when DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_enable_adaptive_sample_keep_duration = true.
When the adaptive algorithm determines that the keep duration should be increased, this factor (a percentage) is multiplied with the current keep duration to get the new longer keep duration. For example, if the current keep duration is 20 milliseconds, using the default factor of 150% would result in a new keep duration of 30 milliseconds.
[default] 150
[range] >= 100
| System::Int32 DDS::RtpsReliableWriterProtocol_t::min_send_window_size |
Minimum size of send window of unacknowledged samples.
A DDS::DataWriter has a limit on the number of unacknowledged samples in-flight at a time. This send window can be configured to have a minimum size (this field) and a maximum size (max_send_window_size). The send window can dynamically change, between the min and max sizes, to throttle the effective send rate in response to changing network congestion, as measured by negative acknowledgements received.
[default] DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
[range] > 0, <= max_send_window_size, or DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
| System::Int32 DDS::RtpsReliableWriterProtocol_t::max_send_window_size |
Maximum size of send window of unacknowledged samples.
A DDS::DataWriter has a limit on the number of unacknowledged samples in-flight at a time. This send window can be configured to have a minimum size (min_send_window_size) and a maximum size (this field). The send window can dynamically change, between the min and max sizes, to throttle the effective send rate in response to changing network congestion, as measured by negative acknowledgements received.
When both min_send_window_size and max_send_window_size are DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED, then either DDS::ResourceLimitsQosPolicy::max_samples (for non-batching) or DDS::DataWriterResourceLimitsQosPolicy::max_batches (for batching) serves as the effective max_send_window_size. When DDS::ResourceLimitsQosPolicy::max_samples (for non-batching) or DDS::DataWriterResourceLimitsQosPolicy::max_batches (for batching) is less than max_send_window_size, then it serves as the effective max_send_window_size. If it is also less than min_send_window_size, then effectively both min and max send window sizes are equal to max_samples or max_batches.
In addition, the low and high watermarks are scaled down linearly to stay within the current send window size, and the full reliable queue status is set when the send window is full.
[default] DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
[range] > 0, >= min_send_window_size, or DDS::ResourceLimitsQosPolicy::LENGTH_UNLIMITED
| Duration_t DDS::RtpsReliableWriterProtocol_t::send_window_update_period |
Period in which send window may be dynamically changed.
The DDS::DataWriter's send window will dynamically change, between the min and max send window sizes, to throttle the effective send rate in response to changing network congestion, as measured by negative acknowledgements received.
The change in send window size happens at this update period, whereupon the send window is either increased or decreased in size according to the increase or decrease factors, respectively.
[default] 3 seconds
[range] > [0,1 year]
| System::Int32 DDS::RtpsReliableWriterProtocol_t::send_window_increase_factor |
Increases send window size by this percentage when reacting dynamically to network conditions.
The DDS::DataWriter's send window will dynamically change, between the min and max send window sizes, to throttle the effective send rate in response to changing network congestion, as measured by negative acknowledgements received.
After an update period during which no negative acknowledgements were received, the send window will be increased by this factor. The factor is treated as a percentage, where a factor of 150 would increase the send window by 150%. The increased send window size will not exceed the max_send_window_size.
[default] 105
[range] > 100
| System::Int32 DDS::RtpsReliableWriterProtocol_t::send_window_decrease_factor |
Decreases send window size by this percentage when reacting dynamically to network conditions.
The DDS::DataWriter's send window will dynamically change, between the min and max send window sizes, to throttle the effective send rate in response to changing network congestion, as measured by negative acknowledgements received.
When increased network congestion causes a negative acknowledgement to be received by a writer, the send window will be decreased by this factor to throttle the effective send rate. The factor is treated as a percentage, where a factor of 80 would decrease the send window to 80% of its previous size. The decreased send window size will not be less than the min_send_window_size.
[default] 70
[range] [0, 100]
| System::Int32 DDS::RtpsReliableWriterProtocol_t::multicast_resend_threshold |
The minimum number of requesting readers needed to trigger a multicast resend.
Given readers with multicast destinations, when a reader NACKs for samples to be resent, the writer can either resend them over unicast or multicast. In order for the writer to resend over multicast, this threshold is the minimum number of readers of the same multicast group that the writer must receive NACKs from within a single response-delay. This allows the writer to coalesce near-simultaneous unicast resends into a multicast resend. Note that a threshold of 1 means that all resends will be sent over multicast, if available.
[default] 2
[range] [>= 1]
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getset |
Whether to treat remote readers as inactive when their NACKs do not progress.
Nominally, a remote reader is marked inactive when a successive number of periodic heartbeats equal or greater than DDS::RtpsReliableWriterProtocol_t::max_heartbeat_retries have been sent without receiving any ack/nacks back.
By setting this true, it changes the conditions of inactivating a remote reader: a reader will be considered inactive when it either does not send any ack/nacks or keeps sending non-progressing nacks for DDS::RtpsReliableWriterProtocol_t::max_heartbeat_retries number of heartbeat periods, where a non-progressing nack is one whose oldest sample requested has not advanced from the oldest sample requested of the previous nack.
[default] false
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getset |
Enables dynamic adjustment of sample keep duration in response to congestion.
For dynamic networks where a static minimum sample keep duration may not provide sufficient performance or reliability, setting DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_enable_adaptive_sample_keep_duration = true, enables the sample keep duration to be dynamically adjusted to adapt to network conditions. The keep duration changes according to the detected level of congestion, which is determined to be proportional to the rate of NACKs received. An adaptive algorithm automatically controls the keep duration to optimize throughput and reliability.
To relieve high congestion, the keep duration is increased to effectively decrease the send rate; this lengthening of the keep duration is controlled by DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_increase_sample_keep_duration_factor. Alternatively, when congestion is low, the keep duration is decreased to effectively increase send rate; this shortening of the keep duration is controlled by DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_decrease_sample_keep_duration_factor.
The lower and upper bounds of the dynamic sample keep duration are set by DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_min_sample_keep_duration and DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_max_sample_keep_duration, respectively.
When DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_enable_adaptive_sample_keep_duration = false, the sample keep duration is set to DDS::RtpsReliableWriterProtocol_t::disable_positive_acks_min_sample_keep_duration .
[default] true
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getset |
Whether periodic heartbeat messages are sent over multicast.
When enabled, if a reader has a multicast destination, then the writer will send its periodic HEARTBEAT messages to that destination. Otherwise, if not enabled or the reader does not have a multicast destination, the writer will send its periodic HEARTBEATs over unicast.
[default] false
RTI Connext .Net APIs Version 5.1.0
Copyright © Mon Feb 3 2014
Real-Time Innovations, Inc