# //CycloneDDS
Children: [Domain](#cycloneddsdomain)


CycloneDDS configuration


## //CycloneDDS/Domain
Attributes: [Id](#cycloneddsdomainid)

Children: [Compatibility](#cycloneddsdomaincompatibility), [Discovery](#cycloneddsdomaindiscovery), [General](#cycloneddsdomaingeneral), [Internal](#cycloneddsdomaininternal), [Partitioning](#cycloneddsdomainpartitioning), [SSL](#cycloneddsdomainssl), [Sizing](#cycloneddsdomainsizing), [TCP](#cycloneddsdomaintcp), [ThreadPool](#cycloneddsdomainthreadpool), [Threads](#cycloneddsdomainthreads), [Tracing](#cycloneddsdomaintracing)


The General element specifying Domain related settings.


## //CycloneDDS/Domain[@Id]
Text

Domain id this configuration applies to, or "any" if it applies to all
domain ids.

The default value is: "any".


### //CycloneDDS/Domain/Compatibility
Children: [AssumeRtiHasPmdEndpoints](#cycloneddsdomaincompatibilityassumertihaspmdendpoints), [ExplicitlyPublishQosSetToDefault](#cycloneddsdomaincompatibilityexplicitlypublishqossettodefault), [ManySocketsMode](#cycloneddsdomaincompatibilitymanysocketsmode), [StandardsConformance](#cycloneddsdomaincompatibilitystandardsconformance)


The Compatibility elements allows specifying various settings related to
compatability with standards and with other DDSI implementations.


#### //CycloneDDS/Domain/Compatibility/AssumeRtiHasPmdEndpoints
Boolean

This option assumes ParticipantMessageData endpoints required by the
liveliness protocol are present in RTI participants even when not
properly advertised by the participant discovery protocol.

The default value is: "false".


#### //CycloneDDS/Domain/Compatibility/ExplicitlyPublishQosSetToDefault
Boolean

This element specifies whether QoS settings set to default values are
explicitly published in the discovery protocol. Implementations are to
use the default value for QoS settings not published, which allows a
significant reduction of the amount of data that needs to be exchanged
for the discovery protocol, but this requires all implementations to
adhere to the default values specified by the specifications.

When interoperability is required with an implementation that does not
follow the specifications in this regard, setting this option to true
will help.

The default value is: "false".


#### //CycloneDDS/Domain/Compatibility/ManySocketsMode
One of: false, true, single, none, many

This option specifies whether a network socket will be created for each
domain participant on a host. The specification seems to assume that each
participant has a unique address, and setting this option will ensure
this to be the case. This is not the defeault.

Disabling it slightly improves performance and reduces network traffic
somewhat. It also causes the set of port numbers needed by Cyclone DDS to
become predictable, which may be useful for firewall and NAT
configuration.

The default value is: "single".


#### //CycloneDDS/Domain/Compatibility/StandardsConformance
One of: lax, strict, pedantic

This element sets the level of standards conformance of this instance of
the Cyclone DDS Service. Stricter conformance typically means less
interoperability with other implementations. Currently three modes are
defined:

* pedantic: very strictly conform to the specification, ultimately for
  compliancy testing, but currently of little value because it adheres even to
  what will most likely turn out to be editing errors in the DDSI standard.
  Arguably, as long as no errata have been published it is the current text
  that is in effect, and that is what pedantic currently does.

* strict: a slightly less strict view of the standard than does pedantic: it
  follows the established behaviour where the standard is obviously in error.

* lax: attempt to provide the smoothest possible interoperability, anticipating
  future revisions of elements in the standard in areas that other
  implementations do not adhere to, even though there is no good reason not to.

The default setting is "lax".

The default value is: "lax".


### //CycloneDDS/Domain/Discovery
Children: [DSGracePeriod](#cycloneddsdomaindiscoverydsgraceperiod), [DefaultMulticastAddress](#cycloneddsdomaindiscoverydefaultmulticastaddress), [EnableTopicDiscovery](#cycloneddsdomaindiscoveryenabletopicdiscovery), [MaxAutoParticipantIndex](#cycloneddsdomaindiscoverymaxautoparticipantindex), [ParticipantIndex](#cycloneddsdomaindiscoveryparticipantindex), [Peers](#cycloneddsdomaindiscoverypeers), [Ports](#cycloneddsdomaindiscoveryports), [SPDPInterval](#cycloneddsdomaindiscoveryspdpinterval), [SPDPMulticastAddress](#cycloneddsdomaindiscoveryspdpmulticastaddress)


The Discovery element allows specifying various parameters related to the
discovery of peers.


#### //CycloneDDS/Domain/Discovery/DSGracePeriod
Number-with-unit

This setting controls for how long endpoints discovered via a Cloud
discovery service will survive after the discovery service disappeared,
allowing reconnect without loss of data when the discovery service
restarts (or another instance takes over).

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "30 s".


#### //CycloneDDS/Domain/Discovery/DefaultMulticastAddress
Text

This element specifies the default multicast address for all traffic
other than participant discovery packets. It defaults to
Discovery/SPDPMulticastAddress.

The default value is: "auto".


#### //CycloneDDS/Domain/Discovery/EnableTopicDiscovery
Boolean

Do not use.

The default value is: "true".


#### //CycloneDDS/Domain/Discovery/MaxAutoParticipantIndex
Integer

This element specifies the maximum DDSI participant index selected by
this instance of the Cyclone DDS service if the
Discovery/ParticipantIndex is "auto".

The default value is: "9".


#### //CycloneDDS/Domain/Discovery/ParticipantIndex
Text

This element specifies the DDSI participant index used by this instance
of the Cyclone DDS service for discovery purposes. Only one such
participant id is used, independent of the number of actual
DomainParticipants on the node. It is either:

* auto: which will attempt to automatically determine an available participant
  index (see also Discovery/MaxAutoParticipantIndex), or

* a non-negative integer less than 120, or

* none:, which causes it to use arbitrary port numbers for unicast sockets
  which entirely removes the constraints on the participant index but makes
  unicast discovery impossible.

The default is auto. The participant index is part of the port number
calculation and if predictable port numbers are needed and fixing the
participant index has no adverse effects, it is recommended that the
second be option be used.

The default value is: "none".


#### //CycloneDDS/Domain/Discovery/Peers
Children: [Group](#cycloneddsdomaindiscoverypeersgroup), [Peer](#cycloneddsdomaindiscoverypeerspeer)


This element statically configures addresses for discovery.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.


##### //CycloneDDS/Domain/Discovery/Peers/Group
Children: [Peer](#cycloneddsdomaindiscoverypeersgrouppeer)


This element statically configures a fault tolerant group of addresses
for discovery. Each member of the group is tried in sequence until one
succeeds.


###### //CycloneDDS/Domain/Discovery/Peers/Group/Peer
Attributes: [Address](#cycloneddsdomaindiscoverypeersgrouppeeraddress)


This element statically configures an addresses for discovery.


###### //CycloneDDS/Domain/Discovery/Peers/Group/Peer[@Address]
Text

This element specifies an IP address to which discovery packets must be
sent, in addition to the default multicast address (see also
General/AllowMulticast). Both a hostnames and a numerical IP address is
accepted; the hostname or IP address may be suffixed with :PORT to
explicitly set the port to which it must be sent. Multiple Peers may be
specified.


##### //CycloneDDS/Domain/Discovery/Peers/Peer
Attributes: [Address](#cycloneddsdomaindiscoverypeerspeeraddress)


This element statically configures an addresses for discovery.


##### //CycloneDDS/Domain/Discovery/Peers/Peer[@Address]
Text

This element specifies an IP address to which discovery packets must be
sent, in addition to the default multicast address (see also
General/AllowMulticast). Both a hostnames and a numerical IP address is
accepted; the hostname or IP address may be suffixed with :PORT to
explicitly set the port to which it must be sent. Multiple Peers may be
specified.


#### //CycloneDDS/Domain/Discovery/Ports
Children: [Base](#cycloneddsdomaindiscoveryportsbase), [DomainGain](#cycloneddsdomaindiscoveryportsdomaingain), [MulticastDataOffset](#cycloneddsdomaindiscoveryportsmulticastdataoffset), [MulticastMetaOffset](#cycloneddsdomaindiscoveryportsmulticastmetaoffset), [ParticipantGain](#cycloneddsdomaindiscoveryportsparticipantgain), [UnicastDataOffset](#cycloneddsdomaindiscoveryportsunicastdataoffset), [UnicastMetaOffset](#cycloneddsdomaindiscoveryportsunicastmetaoffset)


The Ports element allows specifying various parameters related to the
port numbers used for discovery. These all have default values specified
by the DDSI 2.1 specification and rarely need to be changed.


##### //CycloneDDS/Domain/Discovery/Ports/Base
Integer

This element specifies the base port number (refer to the DDSI 2.1
specification, section 9.6.1, constant PB).

The default value is: "7400".


##### //CycloneDDS/Domain/Discovery/Ports/DomainGain
Integer

This element specifies the domain gain, relating domain ids to sets of
port numbers (refer to the DDSI 2.1 specification, section 9.6.1,
constant DG).

The default value is: "250".


##### //CycloneDDS/Domain/Discovery/Ports/MulticastDataOffset
Integer

This element specifies the port number for multicast meta traffic (refer
to the DDSI 2.1 specification, section 9.6.1, constant d2).

The default value is: "1".


##### //CycloneDDS/Domain/Discovery/Ports/MulticastMetaOffset
Integer

This element specifies the port number for multicast meta traffic (refer
to the DDSI 2.1 specification, section 9.6.1, constant d0).

The default value is: "0".


##### //CycloneDDS/Domain/Discovery/Ports/ParticipantGain
Integer

This element specifies the participant gain, relating p0, articipant
index to sets of port numbers (refer to the DDSI 2.1 specification,
section 9.6.1, constant PG).

The default value is: "2".


##### //CycloneDDS/Domain/Discovery/Ports/UnicastDataOffset
Integer

This element specifies the port number for unicast meta traffic (refer to
the DDSI 2.1 specification, section 9.6.1, constant d3).

The default value is: "11".


##### //CycloneDDS/Domain/Discovery/Ports/UnicastMetaOffset
Integer

This element specifies the port number for unicast meta traffic (refer to
the DDSI 2.1 specification, section 9.6.1, constant d1).

The default value is: "10".


#### //CycloneDDS/Domain/Discovery/SPDPInterval
Number-with-unit

This element specifies the interval between spontaneous transmissions of
participant discovery packets.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "30 s".


#### //CycloneDDS/Domain/Discovery/SPDPMulticastAddress
Text

This element specifies the multicast address that is used as the
destination for the participant discovery packets. In IPv4 mode the
default is the (standardised) 239.255.0.1, in IPv6 mode it becomes
ff02::ffff:239.255.0.1, which is a non-standardised link-local multicast
address.

The default value is: "239.255.0.1".


### //CycloneDDS/Domain/General
Children: [AllowMulticast](#cycloneddsdomaingeneralallowmulticast), [DontRoute](#cycloneddsdomaingeneraldontroute), [EnableMulticastLoopback](#cycloneddsdomaingeneralenablemulticastloopback), [ExternalNetworkAddress](#cycloneddsdomaingeneralexternalnetworkaddress), [ExternalNetworkMask](#cycloneddsdomaingeneralexternalnetworkmask), [FragmentSize](#cycloneddsdomaingeneralfragmentsize), [MaxMessageSize](#cycloneddsdomaingeneralmaxmessagesize), [MulticastRecvNetworkInterfaceAddresses](#cycloneddsdomaingeneralmulticastrecvnetworkinterfaceaddresses), [MulticastTimeToLive](#cycloneddsdomaingeneralmulticasttimetolive), [NetworkInterfaceAddress](#cycloneddsdomaingeneralnetworkinterfaceaddress), [PreferMulticast](#cycloneddsdomaingeneralprefermulticast), [Transport](#cycloneddsdomaingeneraltransport), [UseIPv6](#cycloneddsdomaingeneraluseipv6)


The General element specifies overall Cyclone DDS service settings.


#### //CycloneDDS/Domain/General/AllowMulticast
One of:
* Keyword: default
* Comma-separated list of: false, spdp, asm, ssm, true

This element controls whether Cyclone DDS uses multicasts for data
traffic.

It is a comma-separated list of some of the following keywords: "spdp",
"asm", "ssm", or either of "false" or "true", or "default".

* spdp: enables the use of ASM (any-source multicast) for participant
  discovery, joining the multicast group on the discovery socket, transmitting
  SPDP messages to this group, but never advertising nor using any multicast
  address in any discovery message, thus forcing unicast communications for all
  endpoint discovery and user data.

* asm: enables the use of ASM for all traffic, including receiving SPDP but not
  transmitting SPDP messages via multicast

* ssm: enables the use of SSM (source-specific multicast) for all non-SPDP
  traffic (if supported)

When set to "false" all multicasting is disabled. The default, "true"
enables full use of multicasts. Listening for multicasts can be
controlled by General/MulticastRecvNetworkInterfaceAddresses.

"default" maps on spdp if the network is a WiFi network, on true if it is
a wired network

The default value is: "default".


#### //CycloneDDS/Domain/General/DontRoute
Boolean

This element allows setting the SO_DONTROUTE option for outgoing packets,
to bypass the local routing tables. This is generally useful only when
the routing tables cannot be trusted, which is highly unusual.

The default value is: "false".


#### //CycloneDDS/Domain/General/EnableMulticastLoopback
Boolean

This element specifies whether Cyclone DDS allows IP multicast packets to
be visible to all DDSI participants in the same node, including itself.
It must be "true" for intra-node multicast communications, but if a node
runs only a single Cyclone DDS service and does not host any other
DDSI-capable programs, it should be set to "false" for improved
performance.

The default value is: "true".


#### //CycloneDDS/Domain/General/ExternalNetworkAddress
Text

This element allows explicitly overruling the network address Cyclone DDS
advertises in the discovery protocol, which by default is the address of
the preferred network interface (General/NetworkInterfaceAddress), to
allow Cyclone DDS to communicate across a Network Address Translation
(NAT) device.

The default value is: "auto".


#### //CycloneDDS/Domain/General/ExternalNetworkMask
Text

This element specifies the network mask of the external network address.
This element is relevant only when an external network address
(General/ExternalNetworkAddress) is explicitly configured. In this case
locators received via the discovery protocol that are within the same
external subnet (as defined by this mask) will be translated to an
internal address by replacing the network portion of the external address
with the corresponding portion of the preferred network interface
address. This option is IPv4-only.

The default value is: "0.0.0.0".


#### //CycloneDDS/Domain/General/FragmentSize
Number-with-unit

This element specifies the size of DDSI sample fragments generated by
Cyclone DDS. Samples larger than FragmentSize are fragmented into
fragments of FragmentSize bytes each, except the last one, which may be
smaller. The DDSI spec mandates a minimum fragment size of 1025 bytes,
but Cyclone DDS will do whatever size is requested, accepting fragments
of which the size is at least the minimum of 1025 and FragmentSize.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "1280 B".


#### //CycloneDDS/Domain/General/MaxMessageSize
Number-with-unit

This element specifies the maximum size of the UDP payload that Cyclone
DDS will generate. Cyclone DDS will try to maintain this limit within the
bounds of the DDSI specification, which means that in some cases
(especially for very low values of MaxMessageSize) larger payloads may
sporadically be observed (currently up to 1192 B).

On some networks it may be necessary to set this item to keep the
packetsize below the MTU to prevent IP fragmentation. In those cases, it
is generally advisable to also consider reducing Internal/FragmentSize.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "4096 B".


#### //CycloneDDS/Domain/General/MulticastRecvNetworkInterfaceAddresses
Text

This element specifies on which network interfaces Cyclone DDS listens to
multicasts. The following options are available:

* all: listen for multicasts on all multicast-capable interfaces; or

* any: listen for multicasts on the operating system default interface; or

* preferred: listen for multicasts on the preferred interface
  (General/NetworkInterfaceAddress); or

* none: does not listen for multicasts on any interface; or

* a comma-separated list of network addresses: configures Cyclone DDS to listen
  for multicasts on all of the listed addresses.

If Cyclone DDS is in IPv6 mode and the address of the preferred network
interface is a link-local address, "all" is treated as a synonym for
"preferred" and a comma-separated list is treated as "preferred" if it
contains the preferred interface and as "none" if not.

The default value is: "preferred".


#### //CycloneDDS/Domain/General/MulticastTimeToLive
Integer

This element specifies the time-to-live setting for outgoing multicast
packets.

The default value is: "32".


#### //CycloneDDS/Domain/General/NetworkInterfaceAddress
Text

This element specifies the preferred network interface for use by Cyclone
DDS. The preferred network interface determines the IP address that
Cyclone DDS advertises in the discovery protocol (but see also
General/ExternalNetworkAddress), and is also the only interface over
which multicasts are transmitted. The interface can be identified by its
IP address, network interface name or network portion of the address. If
the value "auto" is entered here, Cyclone DDS will select what it
considers the most suitable interface.

The default value is: "auto".


#### //CycloneDDS/Domain/General/PreferMulticast
Boolean

When false (default) Cyclone DDS uses unicast for data whenever there a
single unicast suffices. Setting this to true makes it prefer
multicasting data, falling back to unicast only when no multicast address
is available.

The default value is: "false".


#### //CycloneDDS/Domain/General/Transport
One of: default, udp, udp6, tcp, tcp6, raweth

This element allows selecting the transport to be used (udp, udp6, tcp,
tcp6, raweth)

The default value is: "default".


#### //CycloneDDS/Domain/General/UseIPv6
One of: false, true, default

Deprecated (use Transport instead)

The default value is: "default".


### //CycloneDDS/Domain/Internal
Children: [AccelerateRexmitBlockSize](#cycloneddsdomaininternalacceleraterexmitblocksize), [AssumeMulticastCapable](#cycloneddsdomaininternalassumemulticastcapable), [AutoReschedNackDelay](#cycloneddsdomaininternalautoreschednackdelay), [BuiltinEndpointSet](#cycloneddsdomaininternalbuiltinendpointset), [ControlTopic](#cycloneddsdomaininternalcontroltopic), [DDSI2DirectMaxThreads](#cycloneddsdomaininternalddsi2directmaxthreads), [DefragReliableMaxSamples](#cycloneddsdomaininternaldefragreliablemaxsamples), [DefragUnreliableMaxSamples](#cycloneddsdomaininternaldefragunreliablemaxsamples), [DeliveryQueueMaxSamples](#cycloneddsdomaininternaldeliveryqueuemaxsamples), [EnableExpensiveChecks](#cycloneddsdomaininternalenableexpensivechecks), [GenerateKeyhash](#cycloneddsdomaininternalgeneratekeyhash), [HeartbeatInterval](#cycloneddsdomaininternalheartbeatinterval), [LateAckMode](#cycloneddsdomaininternallateackmode), [LeaseDuration](#cycloneddsdomaininternalleaseduration), [LivelinessMonitoring](#cycloneddsdomaininternallivelinessmonitoring), [MaxParticipants](#cycloneddsdomaininternalmaxparticipants), [MaxQueuedRexmitBytes](#cycloneddsdomaininternalmaxqueuedrexmitbytes), [MaxQueuedRexmitMessages](#cycloneddsdomaininternalmaxqueuedrexmitmessages), [MaxSampleSize](#cycloneddsdomaininternalmaxsamplesize), [MeasureHbToAckLatency](#cycloneddsdomaininternalmeasurehbtoacklatency), [MinimumSocketReceiveBufferSize](#cycloneddsdomaininternalminimumsocketreceivebuffersize), [MinimumSocketSendBufferSize](#cycloneddsdomaininternalminimumsocketsendbuffersize), [MonitorPort](#cycloneddsdomaininternalmonitorport), [MultipleReceiveThreads](#cycloneddsdomaininternalmultiplereceivethreads), [NackDelay](#cycloneddsdomaininternalnackdelay), [PreEmptiveAckDelay](#cycloneddsdomaininternalpreemptiveackdelay), [PrimaryReorderMaxSamples](#cycloneddsdomaininternalprimaryreordermaxsamples), [PrioritizeRetransmit](#cycloneddsdomaininternalprioritizeretransmit), [RediscoveryBlacklistDuration](#cycloneddsdomaininternalrediscoveryblacklistduration), [RetransmitMerging](#cycloneddsdomaininternalretransmitmerging), [RetransmitMergingPeriod](#cycloneddsdomaininternalretransmitmergingperiod), [RetryOnRejectBestEffort](#cycloneddsdomaininternalretryonrejectbesteffort), [SPDPResponseMaxDelay](#cycloneddsdomaininternalspdpresponsemaxdelay), [ScheduleTimeRounding](#cycloneddsdomaininternalscheduletimerounding), [SecondaryReorderMaxSamples](#cycloneddsdomaininternalsecondaryreordermaxsamples), [SendAsync](#cycloneddsdomaininternalsendasync), [SquashParticipants](#cycloneddsdomaininternalsquashparticipants), [SynchronousDeliveryLatencyBound](#cycloneddsdomaininternalsynchronousdeliverylatencybound), [SynchronousDeliveryPriorityThreshold](#cycloneddsdomaininternalsynchronousdeliveryprioritythreshold), [Test](#cycloneddsdomaininternaltest), [UnicastResponseToSPDPMessages](#cycloneddsdomaininternalunicastresponsetospdpmessages), [UseMulticastIfMreqn](#cycloneddsdomaininternalusemulticastifmreqn), [Watermarks](#cycloneddsdomaininternalwatermarks), [WriteBatch](#cycloneddsdomaininternalwritebatch), [WriterLingerDuration](#cycloneddsdomaininternalwriterlingerduration)


The Internal elements deal with a variety of settings that evolving and
that are not necessarily fully supported. For the vast majority of the
Internal settings, the functionality per-se is supported, but the right
to change the way the options control the functionality is reserved. This
includes renaming or moving options.


#### //CycloneDDS/Domain/Internal/AccelerateRexmitBlockSize
Integer

Proxy readers that are assumed to sill be retrieving historical data get
this many samples retransmitted when they NACK something, even if some of
these samples have sequence numbers outside the set covered by the NACK.

The default value is: "0".


#### //CycloneDDS/Domain/Internal/AssumeMulticastCapable
Text

This element controls which network interfaces are assumed to be capable
of multicasting even when the interface flags returned by the operating
system state it is not (this provides a workaround for some platforms).
It is a comma-separated lists of patterns (with ? and * wildcards)
against which the interface names are matched.

The default value is: "".


#### //CycloneDDS/Domain/Internal/AutoReschedNackDelay
Number-with-unit

This setting controls the interval with which a reader will continue
NACK'ing missing samples in the absence of a response from the writer, as
a protection mechanism against writers incorrectly stopping the sending
of HEARTBEAT messages.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "1 s".


#### //CycloneDDS/Domain/Internal/BuiltinEndpointSet
One of: full, writers, minimal

This element controls which participants will have which built-in
endpoints for the discovery and liveliness protocols. Valid values are:

* full: all participants have all endpoints;

* writers: all participants have the writers, but just one has the readers;

* minimal: only one participant has built-in endpoints.

The default is writers, as this is thought to be compliant and reasonably
efficient. Minimal may or may not be compliant but is most efficient, and
full is inefficient but certain to be compliant. See also
Internal/ConservativeBuiltinReaderStartup.

The default value is: "writers".


#### //CycloneDDS/Domain/Internal/ControlTopic

The ControlTopic element allows configured whether Cyclone DDS provides a
special control interface via a predefined topic or not.


#### //CycloneDDS/Domain/Internal/DDSI2DirectMaxThreads
Integer

This element sets the maximum number of extra threads for an
experimental, undocumented and unsupported direct mode.

The default value is: "1".


#### //CycloneDDS/Domain/Internal/DefragReliableMaxSamples
Integer

This element sets the maximum number of samples that can be defragmented
simultaneously for a reliable writer. This has to be large enough to
handle retransmissions of historical data in addition to new samples.

The default value is: "16".


#### //CycloneDDS/Domain/Internal/DefragUnreliableMaxSamples
Integer

This element sets the maximum number of samples that can be defragmented
simultaneously for a best-effort writers.

The default value is: "4".


#### //CycloneDDS/Domain/Internal/DeliveryQueueMaxSamples
Integer

This element controls the Maximum size of a delivery queue, expressed in
samples. Once a delivery queue is full, incoming samples destined for
that queue are dropped until space becomes available again.

The default value is: "256".


#### //CycloneDDS/Domain/Internal/EnableExpensiveChecks
One of:
* Comma-separated list of: whc, rhc, all
* Or empty

This element enables expensive checks in builds with assertions enabled
and is ignored otherwise. Recognised categories are:

* whc: writer history cache checking

* rhc: reader history cache checking



In addition, there is the keyword all that enables all checks.

The default value is: "".


#### //CycloneDDS/Domain/Internal/GenerateKeyhash
Boolean

When true, include keyhashes in outgoing data for topics with keys.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/HeartbeatInterval
Attributes: [max](#cycloneddsdomaininternalheartbeatintervalmax), [min](#cycloneddsdomaininternalheartbeatintervalmin), [minsched](#cycloneddsdomaininternalheartbeatintervalminsched)

Number-with-unit

This elemnents allows configuring the base interval for sending writer
heartbeats and the bounds within it can vary.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "100 ms".


#### //CycloneDDS/Domain/Internal/HeartbeatInterval[@max]
Number-with-unit

This attribute sets the maximum interval for periodic heartbeats.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "8 s".


#### //CycloneDDS/Domain/Internal/HeartbeatInterval[@min]
Number-with-unit

This attribute sets the minimum interval that must have passed since the
most recent heartbeat from a writer, before another asynchronous (not
directly related to writing) will be sent.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "5 ms".


#### //CycloneDDS/Domain/Internal/HeartbeatInterval[@minsched]
Number-with-unit

This attribute sets the minimum interval for periodic heartbeats. Other
events may still cause heartbeats to go out.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "20 ms".


#### //CycloneDDS/Domain/Internal/LateAckMode
Boolean

Ack a sample only when it has been delivered, instead of when committed
to delivering it.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/LeaseDuration
Number-with-unit

This setting controls the default participant lease duration.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "10 s".


#### //CycloneDDS/Domain/Internal/LivelinessMonitoring
Attributes: [Interval](#cycloneddsdomaininternallivelinessmonitoringinterval), [StackTraces](#cycloneddsdomaininternallivelinessmonitoringstacktraces)

Boolean

This element controls whether or not implementation should internally
monitor its own liveliness. If liveliness monitoring is enabled, stack
traces can be dumped automatically when some thread appears to have
stopped making progress.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/LivelinessMonitoring[@Interval]
Number-with-unit

This element controls the interval at which to check whether threads have
been making progress.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "1s".


#### //CycloneDDS/Domain/Internal/LivelinessMonitoring[@StackTraces]
Boolean

This element controls whether or not to write stack traces to the Cyclone
DDS trace when a thread fails to make progress (on select platforms
only).

The default value is: "true".


#### //CycloneDDS/Domain/Internal/MaxParticipants
Integer

This elements configures the maximum number of DCPS domain participants
this Cyclone DDS instance is willing to service. 0 is unlimited.

The default value is: "0".


#### //CycloneDDS/Domain/Internal/MaxQueuedRexmitBytes
Number-with-unit

This setting limits the maximum number of bytes queued for
retransmission. The default value of 0 is unlimited unless an
AuxiliaryBandwidthLimit has been set, in which case it becomes NackDelay
* AuxiliaryBandwidthLimit. It must be large enough to contain the largest
sample that may need to be retransmitted.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "50 kB".


#### //CycloneDDS/Domain/Internal/MaxQueuedRexmitMessages
Integer

This settings limits the maximum number of samples queued for
retransmission.

The default value is: "200".


#### //CycloneDDS/Domain/Internal/MaxSampleSize
Number-with-unit

This setting controls the maximum (CDR) serialised size of samples that
Cyclone DDS will forward in either direction. Samples larger than this
are discarded with a warning.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "2147483647 B".


#### //CycloneDDS/Domain/Internal/MeasureHbToAckLatency
Boolean

This element enables heartbeat-to-ack latency among Cyclone DDS services
by prepending timestamps to Heartbeat and AckNack messages and
calculating round trip times. This is non-standard behaviour. The
measured latencies are quite noisy and are currently not used anywhere.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/MinimumSocketReceiveBufferSize
Number-with-unit

This setting controls the minimum size of socket receive buffers. The
operating system provides some size receive buffer upon creation of the
socket, this option can be used to increase the size of the buffer beyond
that initially provided by the operating system. If the buffer size
cannot be increased to the specified size, an error is reported.

The default setting is the word "default", which means Cyclone DDS will
attempt to increase the buffer size to 1MB, but will silently accept a
smaller buffer should that attempt fail.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "default".


#### //CycloneDDS/Domain/Internal/MinimumSocketSendBufferSize
Number-with-unit

This setting controls the minimum size of socket send buffers. This
setting can only increase the size of the send buffer, if the operating
system by default creates a larger buffer, it is left unchanged.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "64 KiB".


#### //CycloneDDS/Domain/Internal/MonitorPort
Integer

This element allows configuring a service that dumps a text description
of part the internal state to TCP clients. By default (-1), this is
disabled; specifying 0 means a kernel-allocated port is used; a positive
number is used as the TCP port number.

The default value is: "-1".


#### //CycloneDDS/Domain/Internal/MultipleReceiveThreads
Attributes: [maxretries](#cycloneddsdomaininternalmultiplereceivethreadsmaxretries)

Boolean

This element controls whether all traffic is handled by a single receive
thread or whether multiple receive threads may be used to improve
latency. Currently multiple receive threads are only used for
connectionless transport (e.g., UDP) and ManySocketsMode not set to
single (the default).

The default value is: "true".


#### //CycloneDDS/Domain/Internal/MultipleReceiveThreads[@maxretries]
Integer

Receive threads dedicated to a single socket can only be triggered for
termination by sending a packet. Reception of any packet will do, so
termination failure due to packet loss is exceedingly unlikely, but to
eliminate all risks, it will retry as many times as specified by this
attribute before aborting.

The default value is: "4294967295".


#### //CycloneDDS/Domain/Internal/NackDelay
Number-with-unit

This setting controls the delay between receipt of a HEARTBEAT indicating
missing samples and a NACK (ignored when the HEARTBEAT requires an
answer). However, no NACK is sent if a NACK had been scheduled already
for a response earlier than the delay requests: then that NACK will
incorporate the latest information.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "10 ms".


#### //CycloneDDS/Domain/Internal/PreEmptiveAckDelay
Number-with-unit

This setting controls the delay between the discovering a remote writer
and sending a pre-emptive AckNack to discover the range of data
available.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "10 ms".


#### //CycloneDDS/Domain/Internal/PrimaryReorderMaxSamples
Integer

This element sets the maximum size in samples of a primary re-order
administration. Each proxy writer has one primary re-order administration
to buffer the packet flow in case some packets arrive out of order. Old
samples are forwarded to secondary re-order administrations associated
with readers in need of historical data.

The default value is: "128".


#### //CycloneDDS/Domain/Internal/PrioritizeRetransmit
Boolean

This element controls whether retransmits are prioritized over new data,
speeding up recovery.

The default value is: "true".


#### //CycloneDDS/Domain/Internal/RediscoveryBlacklistDuration
Attributes: [enforce](#cycloneddsdomaininternalrediscoveryblacklistdurationenforce)

Number-with-unit

This element controls for how long a remote participant that was
previously deleted will remain on a blacklist to prevent rediscovery,
giving the software on a node time to perform any cleanup actions it
needs to do. To some extent this delay is required internally by Cyclone
DDS, but in the default configuration with the 'enforce' attribute set to
false, Cyclone DDS will reallow rediscovery as soon as it has cleared its
internal administration. Setting it to too small a value may result in
the entry being pruned from the blacklist before Cyclone DDS is ready, it
is therefore recommended to set it to at least several seconds.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "10s".


#### //CycloneDDS/Domain/Internal/RediscoveryBlacklistDuration[@enforce]
Boolean

This attribute controls whether the configured time during which recently
deleted participants will not be rediscovered (i.e., "black listed") is
enforced and following complete removal of the participant in Cyclone
DDS, or whether it can be rediscovered earlier provided all traces of
that participant have been removed already.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/RetransmitMerging
One of: never, adaptive, always

This elements controls the addressing and timing of retransmits. Possible
values are:

* never: retransmit only to the NACK-ing reader;

* adaptive: attempt to combine retransmits needed for reliability, but send
  historical (transient-local) data to the requesting reader only;

* always: do not distinguish between different causes, always try to merge.

The default is never. See also Internal/RetransmitMergingPeriod.

The default value is: "never".


#### //CycloneDDS/Domain/Internal/RetransmitMergingPeriod
Number-with-unit

This setting determines the size of the time window in which a NACK of
some sample is ignored because a retransmit of that sample has been
multicasted too recently. This setting has no effect on unicasted
retransmits.

See also Internal/RetransmitMerging.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "5 ms".


#### //CycloneDDS/Domain/Internal/RetryOnRejectBestEffort
Boolean

Whether or not to locally retry pushing a received best-effort sample
into the reader caches when resource limits are reached.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/SPDPResponseMaxDelay
Number-with-unit

Maximum pseudo-random delay in milliseconds between discovering a remote
participant and responding to it.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "0 ms".


#### //CycloneDDS/Domain/Internal/ScheduleTimeRounding
Number-with-unit

This setting allows the timing of scheduled events to be rounded up so
that more events can be handled in a single cycle of the event queue. The
default is 0 and causes no rounding at all, i.e. are scheduled exactly,
whereas a value of 10ms would mean that events are rounded up to the
nearest 10 milliseconds.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "0 ms".


#### //CycloneDDS/Domain/Internal/SecondaryReorderMaxSamples
Integer

This element sets the maximum size in samples of a secondary re-order
administration. The secondary re-order administration is per reader in
need of historical data.

The default value is: "128".


#### //CycloneDDS/Domain/Internal/SendAsync
Boolean

This element controls whether the actual sending of packets occurs on the
same thread that prepares them, or is done asynchronously by another
thread.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/SquashParticipants
Boolean

This element controls whether Cyclone DDS advertises all the domain
participants it serves in DDSI (when set to false), or rather only one
domain participant (the one corresponding to the Cyclone DDS process;
when set to true). In the latter case Cyclone DDS becomes the virtual
owner of all readers and writers of all domain participants, dramatically
reducing discovery traffic (a similar effect can be obtained by setting
Internal/BuiltinEndpointSet to "minimal" but with less loss of
information).

The default value is: "false".


#### //CycloneDDS/Domain/Internal/SynchronousDeliveryLatencyBound
Number-with-unit

This element controls whether samples sent by a writer with QoS settings
transport_priority >= SynchronousDeliveryPriorityThreshold and a
latency_budget at most this element's value will be delivered
synchronously from the "recv" thread, all others will be delivered
asynchronously through delivery queues. This reduces latency at the
expense of aggregate bandwidth.

Valid values are finite durations with an explicit unit or the keyword
'inf' for infinity. Recognised units: ns, us, ms, s, min, hr, day.

The default value is: "inf".


#### //CycloneDDS/Domain/Internal/SynchronousDeliveryPriorityThreshold
Integer

This element controls whether samples sent by a writer with QoS settings
latency_budget <= SynchronousDeliveryLatencyBound and transport_priority
greater than or equal to this element's value will be delivered
synchronously from the "recv" thread, all others will be delivered
asynchronously through delivery queues. This reduces latency at the
expense of aggregate bandwidth.

The default value is: "0".


#### //CycloneDDS/Domain/Internal/Test
Children: [XmitLossiness](#cycloneddsdomaininternaltestxmitlossiness)


Testing options.


##### //CycloneDDS/Domain/Internal/Test/XmitLossiness
Integer

This element controls the fraction of outgoing packets to drop, specified
as samples per thousand.

The default value is: "0".


#### //CycloneDDS/Domain/Internal/UnicastResponseToSPDPMessages
Boolean

This element controls whether the response to a newly discovered
participant is sent as a unicasted SPDP packet, instead of rescheduling
the periodic multicasted one. There is no known benefit to setting this
to false.

The default value is: "true".


#### //CycloneDDS/Domain/Internal/UseMulticastIfMreqn
Integer

Do not use.

The default value is: "0".


#### //CycloneDDS/Domain/Internal/Watermarks
Children: [WhcAdaptive](#cycloneddsdomaininternalwatermarkswhcadaptive), [WhcHigh](#cycloneddsdomaininternalwatermarkswhchigh), [WhcHighInit](#cycloneddsdomaininternalwatermarkswhchighinit), [WhcLow](#cycloneddsdomaininternalwatermarkswhclow)


Watermarks for flow-control.


##### //CycloneDDS/Domain/Internal/Watermarks/WhcAdaptive
Boolean

This element controls whether Cyclone DDS will adapt the high-water mark
to current traffic conditions, based on retransmit requests and transmit
pressure.

The default value is: "true".


##### //CycloneDDS/Domain/Internal/Watermarks/WhcHigh
Number-with-unit

This element sets the maximum allowed high-water mark for the Cyclone DDS
WHCs, expressed in bytes. A writer is suspended when the WHC reaches this
size.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "100 kB".


##### //CycloneDDS/Domain/Internal/Watermarks/WhcHighInit
Number-with-unit

This element sets the initial level of the high-water mark for the
Cyclone DDS WHCs, expressed in bytes.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "30 kB".


##### //CycloneDDS/Domain/Internal/Watermarks/WhcLow
Number-with-unit

This element sets the low-water mark for the Cyclone DDS WHCs, expressed
in bytes. A suspended writer resumes transmitting when its Cyclone DDS
WHC shrinks to this size.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "1 kB".


#### //CycloneDDS/Domain/Internal/WriteBatch
Boolean

This element enables the batching of write operations. By default each
write operation writes through the write cache and out onto the
transport. Enabling write batching causes multiple small write operations
to be aggregated within the write cache into a single larger write. This
gives greater throughput at the expense of latency. Currently there is no
mechanism for the write cache to automatically flush itself, so that if
write batching is enabled, the application may havee to use the
dds_write_flush function to ensure thta all samples are written.

The default value is: "false".


#### //CycloneDDS/Domain/Internal/WriterLingerDuration
Number-with-unit

This setting controls the maximum duration for which actual deletion of a
reliable writer with unacknowledged data in its history will be postponed
to provide proper reliable transmission.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "1 s".


### //CycloneDDS/Domain/Partitioning
Children: [IgnoredPartitions](#cycloneddsdomainpartitioningignoredpartitions), [NetworkPartitions](#cycloneddsdomainpartitioningnetworkpartitions), [PartitionMappings](#cycloneddsdomainpartitioningpartitionmappings)


The Partitioning element specifies Cyclone DDS network partitions and how
DCPS partition/topic combinations are mapped onto the network partitions.


#### //CycloneDDS/Domain/Partitioning/IgnoredPartitions
Children: [IgnoredPartition](#cycloneddsdomainpartitioningignoredpartitionsignoredpartition)


The IgnoredPartitions element specifies DCPS partition/topic combinations
that are not distributed over the network.


##### //CycloneDDS/Domain/Partitioning/IgnoredPartitions/IgnoredPartition
Attributes: [DCPSPartitionTopic](#cycloneddsdomainpartitioningignoredpartitionsignoredpartitiondcpspartitiontopic)


This element can be used to prevent certain combinations of DCPS
partition and topic from being transmitted over the network. Cyclone DDS
will complete ignore readers and writers for which all DCPS partitions as
well as their topic is ignored, not even creating DDSI readers and
writers to mirror the DCPS ones.


##### //CycloneDDS/Domain/Partitioning/IgnoredPartitions/IgnoredPartition[@DCPSPartitionTopic]
Text

This attribute specifies a partition and a topic expression, separated by
a single '.', that are used to determine if a given partition and topic
will be ignored or not. The expressions may use the usual wildcards '*'
and '?'. Cyclone DDS will consider an wildcard DCPS partition to match an
expression iff there exists a string that satisfies both expressions.


#### //CycloneDDS/Domain/Partitioning/NetworkPartitions
Children: [NetworkPartition](#cycloneddsdomainpartitioningnetworkpartitionsnetworkpartition)


The NetworkPartitions element specifies the Cyclone DDS network
partitions.


##### //CycloneDDS/Domain/Partitioning/NetworkPartitions/NetworkPartition
Attributes: [Address](#cycloneddsdomainpartitioningnetworkpartitionsnetworkpartitionaddress), [Connected](#cycloneddsdomainpartitioningnetworkpartitionsnetworkpartitionconnected), [Name](#cycloneddsdomainpartitioningnetworkpartitionsnetworkpartitionname)


This element defines a Cyclone DDS network partition.


##### //CycloneDDS/Domain/Partitioning/NetworkPartitions/NetworkPartition[@Address]
Text

This attribute specifies the multicast addresses associated with the
network partition as a comma-separated list. Readers matching this
network partition (cf. Partitioning/PartitionMappings) will listen for
multicasts on all of these addresses and advertise them in the discovery
protocol. The writers will select the most suitable address from the
addresses advertised by the readers.


##### //CycloneDDS/Domain/Partitioning/NetworkPartitions/NetworkPartition[@Connected]
Boolean

This attribute is a placeholder.

The default value is: "true".


##### //CycloneDDS/Domain/Partitioning/NetworkPartitions/NetworkPartition[@Name]
Text

This attribute specifies the name of this Cyclone DDS network partition.
Two network partitions cannot have the same name.


#### //CycloneDDS/Domain/Partitioning/PartitionMappings
Children: [PartitionMapping](#cycloneddsdomainpartitioningpartitionmappingspartitionmapping)


The PartitionMappings element specifies the mapping from DCPS
partition/topic combinations to Cyclone DDS network partitions.


##### //CycloneDDS/Domain/Partitioning/PartitionMappings/PartitionMapping
Attributes: [DCPSPartitionTopic](#cycloneddsdomainpartitioningpartitionmappingspartitionmappingdcpspartitiontopic), [NetworkPartition](#cycloneddsdomainpartitioningpartitionmappingspartitionmappingnetworkpartition)


This element defines a mapping from a DCPS partition/topic combination to
a Cyclone DDS network partition. This allows partitioning data flows by
using special multicast addresses for part of the data and possibly also
encrypting the data flow.


##### //CycloneDDS/Domain/Partitioning/PartitionMappings/PartitionMapping[@DCPSPartitionTopic]
Text

This attribute specifies a partition and a topic expression, separated by
a single '.', that are used to determine if a given partition and topic
maps to the Cyclone DDS network partition named by the NetworkPartition
attribute in this PartitionMapping element. The expressions may use the
usual wildcards '*' and '?'. Cyclone DDS will consider a wildcard DCPS
partition to match an expression if there exists a string that satisfies
both expressions.


##### //CycloneDDS/Domain/Partitioning/PartitionMappings/PartitionMapping[@NetworkPartition]
Text

This attribute specifies which Cyclone DDS network partition is to be
used for DCPS partition/topic combinations matching the
DCPSPartitionTopic attribute within this PartitionMapping element.


### //CycloneDDS/Domain/SSL
Children: [CertificateVerification](#cycloneddsdomainsslcertificateverification), [Ciphers](#cycloneddsdomainsslciphers), [Enable](#cycloneddsdomainsslenable), [EntropyFile](#cycloneddsdomainsslentropyfile), [KeyPassphrase](#cycloneddsdomainsslkeypassphrase), [KeystoreFile](#cycloneddsdomainsslkeystorefile), [MinimumTLSVersion](#cycloneddsdomainsslminimumtlsversion), [SelfSignedCertificates](#cycloneddsdomainsslselfsignedcertificates), [VerifyClient](#cycloneddsdomainsslverifyclient)


The SSL element allows specifying various parameters related to using
SSL/TLS for DDSI over TCP.


#### //CycloneDDS/Domain/SSL/CertificateVerification
Boolean

If disabled this allows SSL connections to occur even if an X509
certificate fails verification.

The default value is: "true".


#### //CycloneDDS/Domain/SSL/Ciphers
Text

The set of ciphers used by SSL/TLS

The default value is: "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH".


#### //CycloneDDS/Domain/SSL/Enable
Boolean

This enables SSL/TLS for TCP.

The default value is: "false".


#### //CycloneDDS/Domain/SSL/EntropyFile
Text

The SSL/TLS random entropy file name.

The default value is: "".


#### //CycloneDDS/Domain/SSL/KeyPassphrase
Text

The SSL/TLS key pass phrase for encrypted keys.

The default value is: "secret".


#### //CycloneDDS/Domain/SSL/KeystoreFile
Text

The SSL/TLS key and certificate store file name. The keystore must be in
PEM format.

The default value is: "keystore".


#### //CycloneDDS/Domain/SSL/MinimumTLSVersion
Text

The minimum TLS version that may be negotiated, valid values are 1.2 and
1.3.

The default value is: "1.3".


#### //CycloneDDS/Domain/SSL/SelfSignedCertificates
Boolean

This enables the use of self signed X509 certificates.

The default value is: "false".


#### //CycloneDDS/Domain/SSL/VerifyClient
Boolean

This enables an SSL server checking the X509 certificate of a connecting
client.

The default value is: "true".


### //CycloneDDS/Domain/Sizing
Children: [ReceiveBufferChunkSize](#cycloneddsdomainsizingreceivebufferchunksize), [ReceiveBufferSize](#cycloneddsdomainsizingreceivebuffersize)


The Sizing element specifies a variety of configuration settings dealing
with expected system sizes, buffer sizes, &c.


#### //CycloneDDS/Domain/Sizing/ReceiveBufferChunkSize
Number-with-unit

This element specifies the size of one allocation unit in the receive
buffer. Must be greater than the maximum packet size by a modest amount
(too large packets are dropped). Each allocation is shrunk immediately
after processing a message, or freed straightaway.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "128 KiB".


#### //CycloneDDS/Domain/Sizing/ReceiveBufferSize
Number-with-unit

This element sets the size of a single receive buffer. Many receive
buffers may be needed. The minimum workable size a little bit larger than
Sizing/ReceiveBufferChunkSize, and the value used is taken as the
configured value and the actual minimum workable size.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "1 MiB".


### //CycloneDDS/Domain/TCP
Children: [AlwaysUsePeeraddrForUnicast](#cycloneddsdomaintcpalwaysusepeeraddrforunicast), [Enable](#cycloneddsdomaintcpenable), [NoDelay](#cycloneddsdomaintcpnodelay), [Port](#cycloneddsdomaintcpport), [ReadTimeout](#cycloneddsdomaintcpreadtimeout), [WriteTimeout](#cycloneddsdomaintcpwritetimeout)


The TCP element allows specifying various parameters related to running
DDSI over TCP.


#### //CycloneDDS/Domain/TCP/AlwaysUsePeeraddrForUnicast
Boolean

Setting this to true means the unicast addresses in SPDP packets will be
ignored and the peer address from the TCP connection will be used
instead. This may help work around incorrectly advertised addresses when
using TCP.

The default value is: "false".


#### //CycloneDDS/Domain/TCP/Enable
One of: false, true, default

This element enables the optional TCP transport - deprecated, use
General/Transport instead.

The default value is: "default".


#### //CycloneDDS/Domain/TCP/NoDelay
Boolean

This element enables the TCP_NODELAY socket option, preventing multiple
DDSI messages being sent in the same TCP request. Setting this option
typically optimises latency over throughput.

The default value is: "true".


#### //CycloneDDS/Domain/TCP/Port
Integer

This element specifies the TCP port number on which Cyclone DDS accepts
connections. If the port is set it is used in entity locators, published
with DDSI discovery. Dynamically allocated if zero. Disabled if -1 or not
configured. If disabled other DDSI services will not be able to establish
connections with the service, the service can only communicate by
establishing connections to other services.

The default value is: "-1".


#### //CycloneDDS/Domain/TCP/ReadTimeout
Number-with-unit

This element specifies the timeout for blocking TCP read operations. If
this timeout expires then the connection is closed.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "2 s".


#### //CycloneDDS/Domain/TCP/WriteTimeout
Number-with-unit

This element specifies the timeout for blocking TCP write operations. If
this timeout expires then the connection is closed.

The unit must be specified explicitly. Recognised units: ns, us, ms, s,
min, hr, day.

The default value is: "2 s".


### //CycloneDDS/Domain/ThreadPool
Children: [Enable](#cycloneddsdomainthreadpoolenable), [ThreadMax](#cycloneddsdomainthreadpoolthreadmax), [Threads](#cycloneddsdomainthreadpoolthreads)


The ThreadPool element allows specifying various parameters related to
using a thread pool to send DDSI messages to multiple unicast addresses
(TCP or UDP).


#### //CycloneDDS/Domain/ThreadPool/Enable
Boolean

This element enables the optional thread pool.

The default value is: "false".


#### //CycloneDDS/Domain/ThreadPool/ThreadMax
Integer

This elements configures the maximum number of threads in the thread
pool.

The default value is: "8".


#### //CycloneDDS/Domain/ThreadPool/Threads
Integer

This elements configures the initial number of threads in the thread
pool.

The default value is: "4".


### //CycloneDDS/Domain/Threads
Children: [Thread](#cycloneddsdomainthreadsthread)


This element is used to set thread properties.


#### //CycloneDDS/Domain/Threads/Thread
Attributes: [Name](#cycloneddsdomainthreadsthreadname)

Children: [Scheduling](#cycloneddsdomainthreadsthreadscheduling), [StackSize](#cycloneddsdomainthreadsthreadstacksize)


This element is used to set thread properties.


#### //CycloneDDS/Domain/Threads/Thread[@Name]
Text

The Name of the thread for which properties are being set. The following
threads exist:

* gc: garbage collector thread involved in deleting entities;

* recv: receive thread, taking data from the network and running the protocol
  state machine;

* dq.builtins: delivery thread for DDSI-builtin data, primarily for discovery;

* lease: DDSI liveliness monitoring;

* tev: general timed-event handling, retransmits and discovery;

* xmit.CHAN: transmit thread for channel CHAN;

* dq.CHAN: delivery thread for channel CHAN;

* tev.CHAN: timed-even thread for channel CHAN.


##### //CycloneDDS/Domain/Threads/Thread/Scheduling
Children: [Class](#cycloneddsdomainthreadsthreadschedulingclass), [Priority](#cycloneddsdomainthreadsthreadschedulingpriority)


This element configures the scheduling properties of the thread.


###### //CycloneDDS/Domain/Threads/Thread/Scheduling/Class
One of: realtime, timeshare, default

This element specifies the thread scheduling class (realtime, timeshare
or default). The user may need special privileges from the underlying
operating system to be able to assign some of the privileged scheduling
classes.

The default value is: "default".


###### //CycloneDDS/Domain/Threads/Thread/Scheduling/Priority
Text

This element specifies the thread priority (decimal integer or default).
Only priorities that are supported by the underlying operating system can
be assigned to this element. The user may need special privileges from
the underlying operating system to be able to assign some of the
privileged priorities.

The default value is: "default".


##### //CycloneDDS/Domain/Threads/Thread/StackSize
Number-with-unit

This element configures the stack size for this thread. The default value
default leaves the stack size at the operating system default.

The unit must be specified explicitly. Recognised units: B (bytes), kB &
KiB (2^10 bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB
(2<sup>30</sup> bytes).

The default value is: "default".


### //CycloneDDS/Domain/Tracing
Children: [AppendToFile](#cycloneddsdomaintracingappendtofile), [Category](#cycloneddsdomaintracingcategory), [OutputFile](#cycloneddsdomaintracingoutputfile), [PacketCaptureFile](#cycloneddsdomaintracingpacketcapturefile), [Verbosity](#cycloneddsdomaintracingverbosity)


The Tracing element controls the amount and type of information that is
written into the tracing log by the DDSI service. This is useful to track
the DDSI service during application development.


#### //CycloneDDS/Domain/Tracing/AppendToFile
Boolean

This option specifies whether the output is to be appended to an existing
log file. The default is to create a new log file each time, which is
generally the best option if a detailed log is generated.

The default value is: "false".


#### //CycloneDDS/Domain/Tracing/Category
One of:
* Comma-separated list of: fatal, error, warning, info, config, discovery, data, radmin, timing, traffic, topic, tcp, plist, whc, throttle, rhc, content, trace
* Or empty

This element enables individual logging categories. These are enabled in
addition to those enabled by Tracing/Verbosity. Recognised categories
are:

* fatal: all fatal errors, errors causing immediate termination

* error: failures probably impacting correctness but not necessarily causing
  immediate termination

* warning: abnormal situations that will likely not impact correctness

* config: full dump of the configuration

* info: general informational notices

* discovery: all discovery activity

* data: include data content of samples in traces

* radmin: receive buffer administration

* timing: periodic reporting of CPU loads per thread

* traffic: periodic reporting of total outgoing data

* whc: tracing of writer history cache changes

* tcp: tracing of TCP-specific activity

* topic: tracing of topic definitions

* >i>plist: tracing of discovery parameter list interpretation



In addition, there is the keyword trace that enables all but radmin,
topic, plist and whc.

The categorisation of tracing output is incomplete and hence most of the
verbosity levels and categories are not of much use in the current
release. This is an ongoing process and here we describe the target
situation rather than the current situation. Currently, the most useful
is trace.

The default value is: "".


#### //CycloneDDS/Domain/Tracing/OutputFile
Text

This option specifies where the logging is printed to. Note that stdout
and stderr are treated as special values, representing "standard out" and
"standard error" respectively. No file is created unless logging
categories are enabled using the Tracing/Verbosity or
Tracing/EnabledCategory settings.

The default value is: "cyclonedds.log".


#### //CycloneDDS/Domain/Tracing/PacketCaptureFile
Text

This option specifies the file to which received and sent packets will be
logged in the "pcap" format suitable for analysis using common networking
tools, such as WireShark. IP and UDP headers are ficitious, in particular
the destination address of received packets. The TTL may be used to
distinguish between sent and received packets: it is 255 for sent packets
and 128 for received ones. Currently IPv4 only.

The default value is: "".


#### //CycloneDDS/Domain/Tracing/Verbosity
One of: finest, finer, fine, config, info, warning, severe, none

This element enables standard groups of categories, based on a desired
verbosity level. This is in addition to the categories enabled by the
Tracing/Category setting. Recognised verbosity levels and the categories
they map to are:

* none: no Cyclone DDS log

* severe: error and fatal

* warning: severe + warning

* info: warning + info

* config: info + config

* fine: config + discovery

* finer: fine + traffic and timing

* finest: finer + trace

While none prevents any message from being written to a Cyclone DDS log
file.

The categorisation of tracing output is incomplete and hence most of the
verbosity levels and categories are not of much use in the current
release. This is an ongoing process and here we describe the target
situation rather than the current situation. Currently, the most useful
verbosity levels are config, fine and finest.

The default value is: "none".
