default namespace = "https://cdds.io/config" namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0" grammar { start = [ a:documentation [ xml:lang="en" """ CycloneDDS configuration""" ] ] element CycloneDDS { [ a:documentation [ xml:lang="en" """

The General element specifying Domain related settings.

""" ] ] element Domain { [ a:documentation [ xml:lang="en" """

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

The default value is: "any".

""" ] ] attribute Id { text }? & [ a:documentation [ xml:lang="en" """

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

""" ] ] element Compatibility { [ a:documentation [ xml:lang="en" """

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".

""" ] ] element AssumeRtiHasPmdEndpoints { xsd:boolean }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element ExplicitlyPublishQosSetToDefault { xsd:boolean }? & [ a:documentation [ xml:lang="en" """

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 default.

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".

""" ] ] element ManySocketsMode { ("false"|"true"|"single"|"none"|"many") }? & [ a:documentation [ xml:lang="en" """

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:

The default value is: "lax".

""" ] ] element StandardsConformance { ("lax"|"strict"|"pedantic") }? }? & [ a:documentation [ xml:lang="en" """

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

""" ] ] element Discovery { [ a:documentation [ xml:lang="en" """

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".

""" ] ] element DSGracePeriod { duration_inf }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element DefaultMulticastAddress { text }? & [ a:documentation [ xml:lang="en" """

An override for the domain id, to be used in discovery and for determining the port number mapping. This allows creating multiple domains in a single process while making them appear as a single domain on the network. The value "default" disables the override.

The default value is: "default".

""" ] ] element ExternalDomainId { text }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element MaxAutoParticipantIndex { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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:

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".

""" ] ] element ParticipantIndex { text }? & [ a:documentation [ xml:lang="en" """

This element statically configures addresses for discovery.

""" ] ] element Peers { [ a:documentation [ xml:lang="en" """

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

""" ] ] element Group { [ a:documentation [ xml:lang="en" """

This element statically configures an addresses for discovery.

""" ] ] element Peer { [ a:documentation [ xml:lang="en" """

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.

The default value is: "".

""" ] ] attribute Address { text } }* }* & [ a:documentation [ xml:lang="en" """

This element statically configures an addresses for discovery.

""" ] ] element Peer { [ a:documentation [ xml:lang="en" """

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.

The default value is: "".

""" ] ] attribute Address { text } }* }? & [ a:documentation [ xml:lang="en" """

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.

""" ] ] element Ports { [ a:documentation [ xml:lang="en" """

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".

""" ] ] element Base { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element DomainGain { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "1".

""" ] ] element MulticastDataOffset { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element MulticastMetaOffset { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "2".

""" ] ] element ParticipantGain { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "11".

""" ] ] element UnicastDataOffset { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element UnicastMetaOffset { xsd:integer }? }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element SPDPInterval { duration }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element SPDPMulticastAddress { text }? & [ a:documentation [ xml:lang="en" """

String extension for domain id that remote participants must match to be discovered.

The default value is: "".

""" ] ] element Tag { text }? }? & [ a:documentation [ xml:lang="en" """

The General element specifies overall Cyclone DDS service settings.

""" ] ] element General { [ a:documentation [ xml:lang="en" """

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".

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".

""" ] ] element AllowMulticast { xsd:token { pattern = "default|((false|spdp|asm|ssm|true)(,(false|spdp|asm|ssm|true))*)" } }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element DontRoute { xsd:boolean }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element EnableMulticastLoopback { xsd:boolean }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element ExternalNetworkAddress { text }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element ExternalNetworkMask { text }? & [ a:documentation [ xml:lang="en" """

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 (210 bytes), MB & MiB (220 bytes), GB & GiB (230 bytes).

The default value is: "1344 B".

""" ] ] element FragmentSize { memsize }? & [ a:documentation [ xml:lang="en" """

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 (210 bytes), MB & MiB (220 bytes), GB & GiB (230 bytes).

The default value is: "4096 B".

""" ] ] element MaxMessageSize { memsize }? & [ a:documentation [ xml:lang="en" """

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

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".

""" ] ] element MulticastRecvNetworkInterfaceAddresses { text }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "32".

""" ] ] element MulticastTimeToLive { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element NetworkInterfaceAddress { text }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element PreferMulticast { xsd:boolean }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "default".

""" ] ] element Transport { ("default"|"udp"|"udp6"|"tcp"|"tcp6"|"raweth") }? & [ a:documentation [ xml:lang="en" """

Deprecated (use Transport instead)

The default value is: "default".

""" ] ] element UseIPv6 { ("false"|"true"|"default") }? }? & [ a:documentation [ xml:lang="en" """

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.

""" ] ] element Internal { [ a:documentation [ xml:lang="en" """

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".

""" ] ] element AccelerateRexmitBlockSize { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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: "".

""" ] ] element AssumeMulticastCapable { text }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element AutoReschedNackDelay { duration_inf }? & [ a:documentation [ xml:lang="en" """

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

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".

""" ] ] element BuiltinEndpointSet { ("full"|"writers"|"minimal") }? & [ a:documentation [ xml:lang="en" """

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

""" ] ] element ControlTopic { empty }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "1".

""" ] ] element DDSI2DirectMaxThreads { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element DefragReliableMaxSamples { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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

The default value is: "4".

""" ] ] element DefragUnreliableMaxSamples { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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".

""" ] ] element DeliveryQueueMaxSamples { xsd:integer }? & [ a:documentation [ xml:lang="en" """

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