Vortex Lite Configuration Guide

Introduction

This guide describes the various configuration elements and attributes available for Vortex Lite. The configuration items should be added to an XML file and then the LITE_URI environment variable should be set to point to the path of that XML file with the “file://” URI prefix.

The lite.xml file supplied with Vortex Lite contains the following:

<Lite>
  <Domain>
    <Id>0</Id>
  </Domain>
  <DDSI2E>
    <General>
      <NetworkInterfaceAddress>AUTO</NetworkInterfaceAddress>
      <AllowMulticast>true</AllowMulticast>
      <EnableMulticastLoopback>true</EnableMulticastLoopback>
    </General>
    <Compatibility>
      <StandardsConformance>lax</StandardsConformance>
    </Compatibility>
    <Tracing>
      <Verbosity>warning</Verbosity>
    </Tracing>
  </DDSI2E>
</Lite>

The tags in the XML file should be nested in the same way as they are in the table of contents in this configuration guide. The nesting and numbering of the tags in the contents of this guide allows you to see which elements are the parent or children of one another. For example, if you wanted to find a description of the NetworkInterfaceAddress attribute, you would first navigate to it’s parent, the General element (2.4*), and inside that you would find a heading for the child NetworkInterfaceAddress attribute (2.4.9*) along with a description and valid values. Some attributes may state that they are required and if so these elements must be present when the parent element is included in the XML file.

If you wanted to add a new element, say to enable security, you would navigate to the Security element of the guide (2.8*). This has a child element called SecurityProfile (2.8.1*) which should be nested within the Security element. Each element lists a number of occurences, this states how many times this element can appear in your XML file. The SecurityProfile element has three attributes, Name (2.8.1.3*), which is required, and Cipher (2.8.1.1*) and CipherKey (2.8.1.2*) which are optional. Attributes are added within the parent element tag in the format name=”value”. Adding these new elements and attributes would result in the following XML:

<Lite>
  <Domain>
    <Id>0</Id>
  </Domain>
  <DDSI2E>
      <General>
          <NetworkInterfaceAddress>AUTO</NetworkInterfaceAddress>
          <AllowMulticast>true</AllowMulticast>
          <EnableMulticastLoopback>true</EnableMulticastLoopback>
      </General>
      <Compatibility>
          <StandardsConformance>lax</StandardsConformance>
      </Compatibility>
      <Tracing>
          <Verbosity>warning</Verbosity>
      </Tracing>
      <Security>
          <SecurityProfile Name="GlobalProfile" Cipher="blowfish" CipherKey="00000000000000000000000000000000"/>
      </Security>
  </DDSI2E>
</Lite>

*Section numbers correct at time of writing, but may become outdated as sections of this guide are generated from the xml descriptors to ensure the implementation, tooling and documentation descriptions are consistent.

2   DDSI2E

The root element of a DDSI2E networking service configuration.

  • Full path: DDSI2E
  • Occurrences min-max: 1-1

2.1   Channels

This element is used to group a set of channels. The channels are independent data paths through DDSI2E and by using separate threads and setting their priorities appropriately, channels can be used to map transport priorities to operating system scheduler priorities, ensuring system-wide end-to-end priority preservation.

This element is used to group a set of channels. The channels are independent data paths through DDSI2E and by using separate threads and setting their priorities appropriately, channels can be used to map transport priorities to operating system scheduler priorities, ensuring system-wide end-to-end priority preservation.

  • Full path: DDSI2E/Channels
  • Occurrences min-max: 0-1

2.1.1   Channel

This element defines a channel.

  • Full path: DDSI2E/Channels/Channel
  • Occurrences min-max: 0-42
  • Child elements: AuxiliaryBandwidthLimit, DataBandwidthLimit, DiffServField, QueueSize, Resolution
  • Required attributes: Name
  • Optional attributes: TransportPriority
2.1.1.1   Name

This attribute specifies name of this channel. The name should uniquely identify the channel.

  • Full path: DDSI2E/Channels/Channel/Name
  • Format: string
  • Default value: n/a
  • Required: true
2.1.1.2   TransportPriority

This attribute sets the transport priority threshold for the channel. Each DCPS data writer has a “transport_priority” QoS and this QoS is used to select a channel for use by this writer. The selected channel is the one with the largest threshold not greater than the writer’s transport priority, and if no such channel exists, the channel with the lowest threshold.

  • Full path: DDSI2E/Channels/Channel/TransportPriority
  • Format: integer
  • Default value: 0
  • Required: false
2.1.1.3   AuxiliaryBandwidthLimit

This element specifies the maximum transmit rate of auxiliary traffic on this channel (e.g. retransmits, heartbeats, etc). Bandwidth limiting uses a leaky bucket scheme. The default value “inf” means DDSI2E imposes no limitation, the underlying operating system and hardware will likely limit the maimum transmit rate. The unit must be specified explicitly. Recognised units: X*b/s, *X*bps for bits/s or *X*B/s, *X*Bps for bytes/s; where *X is an optional prefix: k for 10 3, Ki for 2 10, M for 10 6, Mi for 2 20, G for 10 9, Gi for 2 30.

  • Full path: DDSI2E/Channels/Channel/AuxiliaryBandwidthLimit
  • Format: string
  • Default value: inf
  • Occurrences min-max: 0-1
2.1.1.4   DataBandwidthLimit

This element specifies the maximum transmit rate of new samples and directly related data, for this channel. Bandwidth limiting uses a leaky bucket scheme. The default value “inf” means DDSI2E imposes no limitation, the underlying operating system and hardware will likely limit the maimum transmit rate.

The unit must be specified explicitly. Recognised units: X*b/s, *X*bps for bits/s or *X*B/s, *X*Bps for bytes/s; where *X is an optional prefix: k for 10 3, Ki for 2 10, M for 10 6, Mi for 2 20, G for 10 9, Gi for 2 30.

  • Full path: DDSI2E/Channels/Channel/DataBandwidthLimit
  • Format: string
  • Default value: inf
  • Occurrences min-max: 0-1
2.1.1.5   DiffServField

This element describes the DiffServ setting the channel will apply to the networking messages. This parameter determines the value of the diffserv field of the IP version 4 packets sent on this channel which allows QoS setting to be applied to the network traffic send on this channel.

Windows platform support for setting the diffserv field is dependent on the OS version.

For Windows versions XP SP2 and 2003 to use the diffserv field the following parameter should be added to the register:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TcpIp\Parameters\DisableUserTOSSetting

The type of this parameter is a DWORD and its value should be set to 0 to allow setting of the diffserv field.

For Windows version 7 or higher a new API (qWAVE) has been introduced. For these platforms the specified diffserv value is mapped to one of the support traffic types. The mapping is as follows: 1-8 background traffic; 9-40 excellent traffic; 41-55 audio/video traffic; 56 voice traffic; 57-63 control traffic. When an application is run without Administrative priveleges then only the diffserv value of 0, 8, 40 or 56 is allowed.

  • Full path: DDSI2E/Channels/Channel/DiffServField
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1
2.1.1.6   QueueSize

This element specifies the number of messages the network queue for this channel can contain. If this queue is full when an application tries to write a sample, the sample will be dropped or the writer suspended, depending on the QoS settings of the writer.

  • Full path: DDSI2E/Channels/Channel/QueueSize
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1
2.1.1.7   Resolution

This element specifies the interval at which the DDSI2E transmit thread for this channel wakes up, and which controls the smallest latency_budget that has an effect. A shorter latency_budget is rounded to 0. The downside of a reducing this setting is that it increases the number of idle wake-ups of the transmit thread when there is no data to 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.

  • Full path: DDSI2E/Channels/Channel/Resolution
  • Format: string
  • Default value: 1s
  • Occurrences min-max: 0-1

2.2   Compatibility

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

  • Full path: DDSI2E/Compatibility
  • Occurrences min-max: 0-1
  • Child elements: AckNackNumbitsEmptySet, ArrivalOfDataAssertsPpAndEpLiveliness, AssumeRtiHasPmdEndpoints, ExplicitlyPublishQosSetToDefault, ManySocketsMode, RespondToRtiInitZeroAckWithInvalidHeartbeat, StandardsConformance

2.2.1   AckNackNumbitsEmptySet

This element governs the representation of an acknowledgement message that does not also negatively-acknowledge some samples. If set to 0, the generated acknowledgements have an invalid form and will be reject by the strict and pedantic conformance modes, but several other implementation require this setting for smooth interoperation.

If set to 1, all acknowledgements sent by DDSI2E adhere the form of acknowledgement messages allowed by the standard, but this causes problems when interoperating with these other implementations. The strict and pedantic standards conformance modes always overrule an AckNackNumbitsEmptySet=0 to prevent the transmitting of invalid messages.

  • Full path: DDSI2E/Compatibility/AckNackNumbitsEmptySet
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1

2.2.2   ArrivalOfDataAssertsPpAndEpLiveliness

This setting is currently ignored (accepted for backwards compatibility).

  • Full path: DDSI2E/Compatibility/ArrivalOfDataAssertsPpAndEpLiveliness
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.2.3   AssumeRtiHasPmdEndpoints

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.

  • Full path: DDSI2E/Compatibility/AssumeRtiHasPmdEndpoints
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.2.4   ExplicitlyPublishQosSetToDefault

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.

  • Full path: DDSI2E/Compatibility/ExplicitlyPublishQosSetToDefault
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.2.5   ManySocketsMode

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 DDSI2E to become predictable, which may be useful for firewall and NAT configuration.

  • Full path: DDSI2E/Compatibility/ManySocketsMode
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.2.6   RespondToRtiInitZeroAckWithInvalidHeartbeat

This element allows a closer mimicking of the behaviour of some other DDSI implementations, albeit at the cost of generating even more invalid messages. Setting it to true ensures a Heartbeat can be sent at any time when a remote node requests one, setting it to false delays it until a valid one can be sent.

The latter is fully compliant with the specification, and no adverse effects have been observed. It is the default.

  • Full path: DDSI2E/Compatibility/RespondToRtiInitZeroAckWithInvalidHeartbeat
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.2.7   StandardsConformance

This element sets the level of standards conformance of this instance of the DDSI2E 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”.

  • Full path: DDSI2E/Compatibility/StandardsConformance
  • Format: enumeration
  • Default value: lax
  • Valid values: lax, strict, pedantic
  • Occurrences min-max: 0-1

2.3   Discovery

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

  • Full path: DDSI2E/Discovery
  • Occurrences min-max: 0-1
  • Child elements: DSClusterLeaseDuration, DomainId, GenerateBuiltinTopics, MaxAutoParticipantIndex, ParticipantIndex, SPDPInterval, SPDPMulticastAddress

2.3.1   DSClusterLeaseDuration

This element specifies the lease duration for entities discovered through a discovery service.

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

  • Full path: DDSI2E/Discovery/DSClusterLeaseDuration
  • Format: string
  • Default value: 300 s
  • Occurrences min-max: 0-1

2.3.2   DomainId

This element allows overriding of the DDS Domain Id that is used for DDSI2E.

  • Full path: DDSI2E/Discovery/DomainId
  • Format: string
  • Default value: default
  • Occurrences min-max: 0-1

2.3.3   GenerateBuiltinTopics

This element controls whether or not DDSI2E generates built-in topics from its discovery. When disabled, it relies on the durability service.

  • Full path: DDSI2E/Discovery/GenerateBuiltinTopics
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.3.4   MaxAutoParticipantIndex

This element specifies the maximum DDSI participant index selected by this instance of the DDSI2E service if the Discovery/ParticipantIndex is “auto”.

  • Full path: DDSI2E/Discovery/MaxAutoParticipantIndex
  • Format: integer
  • Default value: 9
  • Occurrences min-max: 0-1

2.3.5   ParticipantIndex

This element specifies the DDSI participant index used by this instance of the DDSI2E 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.

  • Full path: DDSI2E/Discovery/ParticipantIndex
  • Format: string
  • Default value: auto
  • Occurrences min-max: 0-1

2.3.6   Peers

This element statically configures addresses for discovery.

  • Full path: DDSI2E/Discovery/Peers
  • Occurrences min-max: 0-1
2.3.6.1   Group

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

  • Full path: DDSI2E/Discovery/Peers/Group
  • Occurrences min-max: 0-*
2.3.6.1.1   Peer

This element statically configures an addresses for discovery.

  • Full path: DDSI2E/Discovery/Peers/Group/Peer
  • Occurrences min-max: 0-*
  • Required attributes: Address
2.3.6.1.1.1   Address

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.

  • Full path: DDSI2E/Discovery/Peers/Group/Peer/Address
  • Format: string
  • Default value: n/a
  • Required: true

2.3.7   Ports

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.

  • Full path: DDSI2E/Discovery/Ports
  • Occurrences min-max: 0-1
  • Child elements: Base, DomainGain, MulticastDataOffset, MulticastMetaOffset, ParticipantGain, UnicastDataOffset, UnicastMetaOffset
2.3.7.1   Base

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

  • Full path: DDSI2E/Discovery/Ports/Base
  • Format: integer
  • Default value: 7400
  • Occurrences min-max: 0-1
2.3.7.2   DomainGain

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).

  • Full path: DDSI2E/Discovery/Ports/DomainGain
  • Format: integer
  • Default value: 250
  • Occurrences min-max: 0-1
2.3.7.3   MulticastDataOffset

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

  • Full path: DDSI2E/Discovery/Ports/MulticastDataOffset
  • Format: integer
  • Default value: 1
  • Occurrences min-max: 0-1
2.3.7.4   MulticastMetaOffset

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

  • Full path: DDSI2E/Discovery/Ports/MulticastMetaOffset
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1
2.3.7.5   ParticipantGain

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).

  • Full path: DDSI2E/Discovery/Ports/ParticipantGain
  • Format: integer
  • Default value: 2
  • Occurrences min-max: 0-1
2.3.7.6   UnicastDataOffset

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

  • Full path: DDSI2E/Discovery/Ports/UnicastDataOffset
  • Format: integer
  • Default value: 11
  • Occurrences min-max: 0-1
2.3.7.7   UnicastMetaOffset

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

  • Full path: DDSI2E/Discovery/Ports/UnicastMetaOffset
  • Format: integer
  • Default value: 10
  • Occurrences min-max: 0-1

2.3.8   SPDPInterval

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.

  • Full path: DDSI2E/Discovery/SPDPInterval
  • Format: string
  • Default value: 30 s
  • Occurrences min-max: 0-1

2.3.9   SPDPMulticastAddress

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.

  • Full path: DDSI2E/Discovery/SPDPMulticastAddress
  • Format: string
  • Default value: 239.255.0.1
  • Occurrences min-max: 0-1

2.4   General

The General element specifies overall DDSI2E settings.

  • Full path: DDSI2E/General
  • Occurrences min-max: 0-1
  • Child elements: AllowMulticast, EnableLoopback, DontRoute, EnableMulticastLoopback, ExternalNetworkAddress, ExternalNetworkMask, MulticastRecvNetworkInterfaceAddresses, MulticastTimeToLive, NetworkInterfaceAddress, StartupModeCoversTransient, StartupModeDuration, UseIPv6

2.4.1   AllowMulticast

This element controls whether DDSI2E 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”.

  • spdp: enables the use of ASM (any-source multicast) for participant discovery
  • asm: enables the use of ASM for all traffic (including SPDP)
  • 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.

  • Full path: DDSI2E/General/AllowMulticast
  • Format: string
  • Default value: true
  • Occurrences min-max: 0-1

2.4.2   EnableLoopback

This element specifies whether DDSI packets are visible to all DDSI participants in the same process. It must be \”true\” for intra-process communications, i.e. a reader and writer communicating in the same address space. If enabled and using multicast then EnableMulticastLoopback must also be enabled.

  • Full path: DDSI2E/General/EnableLoopback
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.4.3   DontRoute

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.

  • Full path: DDSI2E/General/DontRoute
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.4.4   EnableMulticastLoopback

This element specifies whether DDSI2E 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 DDSI2E service and does not host any other DDSI-capable programs, it should be set to “false” for improved performance.

  • Full path: DDSI2E/General/EnableMulticastLoopback
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.4.5   ExternalNetworkAddress

This element allows explicitly overruling the network address DDSI2E advertises in the discovery protocol, which by default is the address of the preferred network interface (General/NetworkInterfaceAddress), to allow DDSI2E to communicate across a Network Address Translation (NAT) device.

  • Full path: DDSI2E/General/ExternalNetworkAddress
  • Format: string
  • Default value: auto
  • Occurrences min-max: 0-1

2.4.6   ExternalNetworkMask

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.

  • Full path: DDSI2E/General/ExternalNetworkMask
  • Format: string
  • Default value: 0.0.0.0
  • Occurrences min-max: 0-1

2.4.7   MulticastRecvNetworkInterfaceAddresses

This element specifies on which network interfaces DDSI2E 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 DDSI2E to listen for multicasts on all of the listed addresses.

If DDSI2E 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.

  • Full path: DDSI2E/General/MulticastRecvNetworkInterfaceAddresses
  • Format: string
  • Default value: preferred
  • Occurrences min-max: 0-1

2.4.8   MulticastTimeToLive

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

  • Full path: DDSI2E/General/MulticastTimeToLive
  • Format: integer
  • Default value: 32
  • Occurrences min-max: 0-1

2.4.9   NetworkInterfaceAddress

This element specifies the preferred network interface for use by DDSI2E. The preferred network interface determines the IP address that DDSI2E 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, DDSI2E will select what it considers the most suitable interface.

  • Full path: DDSI2E/General/NetworkInterfaceAddress
  • Format: string
  • Default value: auto
  • Occurrences min-max: 0-1

2.4.10   StartupModeCoversTransient

This element configures whether startup-mode should also cover transient and persistent data, for configurations where the durability service does not take care of it. Configurations without defined merge policies best leave this enabled.

  • Full path: DDSI2E/General/StartupModeCoversTransient
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.4.11   StartupModeDuration

This element specifies how long the DDSI2E remains in its “startup” mode. While in “startup” mode all volatile reliable data published on the local node is retained as-if it were transient-local data, allowing existing readers on remote nodes to obtain the data even though discovering them takes some time. Best-effort data by definition need not arrive, and transient and persistent data are covered by the durability service.

Once the system is stable, DDSI2E keeps track of the existence of remote readers whether or not matching writers exist locally, avoiding this discovery delay and ensuring this is merely a node startup issue.

Setting General/StartupModeDuration to 0s will disable it.

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

  • Full path: DDSI2E/General/StartupModeDuration
  • Format: string
  • Default value: 2 s
  • Occurrences min-max: 0-1

2.4.12   UseIPv6

This element can be used to DDSI2E use IPv6 instead of IPv4. This is currently an either/or switch.

  • Full path: DDSI2E/General/UseIPv6
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5   Internal

The Internal elements deal with a variety of settings that are still evolving.

  • Full path: DDSI2E/Internal
  • Occurrences min-max: 0-1
  • Child elements: AccelerateRexmitBlockSize, AggressiveKeepLast1Whc, AssumeMulticastCapable, AuxiliaryBandwidthLimit, BuiltinEndpointSet, ConservativeBuiltinReaderStartup, DDSI2DirectMaxThreads, DefragReliableMaxSamples, DefragUnreliableMaxSamples, DeliveryQueueMaxSamples, ForwardAllMessages, FragmentSize, GenerateKeyhash, LateAckMode, LeaseDuration, LegacyFragmentation, MaxMessageSize, LogStackTraces, MaxParticipants, MaxQueuedRexmitBytes, MaxQueuedRexmitMessages, MaxSampleSize, MeasureHbToAckLatency, MinimumSocketReceiveBufferSize, MinimumSocketSendBufferSize, NackDelay, PreEmptiveAckDelay, PrimaryReorderMaxSamples, RetransmitMerging, RetransmitMergingPeriod, RetryOnRejectBestEffort, RetryOnRejectDuration, SPDPResponseMaxDelay, ScheduleTimeRounding, SecondaryReorderMaxSamples, SquashParticipants, SuppressSPDPMulticast, SynchronousDeliveryLatencyBound, SynchronousDeliveryPriorityThreshold, UnicastResponseToSPDPMessages, WriteBatch, WriterLingerDuration

2.5.1   AccelerateRexmitBlockSize

Internal 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.

  • Full path: DDSI2E/Internal/AccelerateRexmitBlockSize
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1

2.5.2   AggressiveKeepLast1Whc

Internal This element controls whether to drop a reliable sample from a DDSI2E WHC before all readers have acknowledged it as soon as a later sample becomes available. It only affects DCPS data writers with a history QoS setting of KEEP_LAST with depth 1.

  • Full path: DDSI2E/Internal/AggressiveKeepLast1Whc
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.3   AssumeMulticastCapable

Internal 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.

  • Full path: DDSI2E/Internal/AssumeMulticastCapable
  • Format: string
  • Occurrences min-max: 0-1

2.5.4   AuxiliaryBandwidthLimit

Internal This element specifies the maximum transmit rate of auxiliary traffic not bound to a specific channel, such as discovery traffic, as well as auxiliary traffic related to a certain channel if that channel has elected to share this global AuxiliaryBandwidthLimit. Bandwidth limiting uses a leaky bucket scheme. The default value “inf” means DDSI2E imposes no limitation, the underlying operating system and hardware will likely limit the maimum transmit rate.

The unit must be specified explicitly. Recognised units: X*b/s, *X*bps for bits/s or *X*B/s, *X*Bps for bytes/s; where *X is an optional prefix: k for 10 3, Ki for 2 10, M for 10 6, Mi for 2 20, G for 10 9, Gi for 2 30.

  • Full path: DDSI2E/Internal/AuxiliaryBandwidthLimit
  • Format: string
  • Default value: inf
  • Occurrences min-max: 0-1

2.5.5   BuiltinEndpointSet

Internal 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.

  • Full path: DDSI2E/Internal/BuiltinEndpointSet
  • Format: enumeration
  • Default value: writers
  • Valid values: full, writers, minimal
  • Occurrences min-max: 0-1

2.5.6   ConservativeBuiltinReaderStartup

Internal This element forces all DDSI2E built-in discovery-related readers to request all historical data, instead of just one for each “topic”. There is no indication that any of the current DDSI implementations requires changing of this setting, but it is conceivable that an implementation might track which participants have been informed of the existence of endpoints and which have not been, refusing communication with those that have “can’t” know.

Should it be necessary to hide DDSI2E’s shared discovery behaviour, set this to true and Internal/BuiltinEndpointSet to full.

  • Full path: DDSI2E/Internal/ConservativeBuiltinReaderStartup
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.7   DDSI2DirectMaxThreads

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

  • Full path: DDSI2E/Internal/DDSI2DirectMaxThreads
  • Format: integer
  • Default value: 1
  • Occurrences min-max: 0-1

2.5.8   DefragReliableMaxSamples

Internal 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.

  • Full path: DDSI2E/Internal/DefragReliableMaxSamples
  • Format: integer
  • Default value: 16
  • Occurrences min-max: 0-1

2.5.9   DefragUnreliableMaxSamples

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

  • Full path: DDSI2E/Internal/DefragUnreliableMaxSamples
  • Format: integer
  • Default value: 4
  • Occurrences min-max: 0-1

2.5.10   DeliveryQueueMaxSamples

Internal 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.

  • Full path: DDSI2E/Internal/DeliveryQueueMaxSamples
  • Format: integer
  • Default value: 256
  • Occurrences min-max: 0-1

2.5.11   ForwardAllMessages

Internal Forward all messages from a writer, rather than trying to forward each sample only once. The default of trying to forward each sample only once filters out duplicates for writers in multiple partitions under nearly all circumstances, but may still publish the odd duplicate. Note: the current implementation also can lose in contrived test cases, that publish more than 2**32 samples using a single data writer in conjunction with carefully controlled management of the writer history via cooperating local readers.

  • Full path: DDSI2E/Internal/ForwardAllMessages
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.12   FragmentSize

Internal This element specifies the size of DDSI sample fragments generated by DDSI2E. 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 DDSI2E 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/FragmentSize
  • Format: string
  • Default value: 1280 B
  • Occurrences min-max: 0-1

2.5.13   GenerateKeyhash

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

  • Full path: DDSI2E/Internal/GenerateKeyhash
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.5.14   LateAckMode

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

  • Full path: DDSI2E/Internal/LateAckMode
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.15   LeaseDuration

Internal This setting controls the default participant lease duration.

  • Full path: DDSI2E/Internal/LeaseDuration
  • Format: string
  • Default value: 10 s
  • Occurrences min-max: 0-1

2.5.16   LegacyFragmentation

Internal This option enables a backwards-compatible, non-compliant setting and interpretation of the control flags in fragmented data messages. To be enabled only when requiring interoperability between compliant and non-compliant versions of DDSI2E for large messages.

  • Full path: DDSI2E/Internal/LegacyFragmentation
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.17   MaxMessageSize

Internal This element specifies the maximum size of the UDP payload that DDSI2E will generate. DDSI2E 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/MaxMessageSize
  • Format: string
  • Default value: 4096 B
  • Occurrences min-max: 0-1

2.5.18   LogStackTraces

This element controls whether or not to write stack traces to the DDSI2 trace when a thread fails to make progress (on select platforms only).

  • Full path: DDSI2E/Internal/LogStackTraces
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.19   MaxParticipants

Internal This elements configures the maximum number of DCPS domain participants this DDSI2E instance is willing to service. 0 is unlimited.

  • Full path: DDSI2E/Internal/MaxParticipants
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1

2.5.20   MaxQueuedRexmitBytes

Internal 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/MaxQueuedRexmitBytes
  • Format: string
  • Default value: 0 B
  • Occurrences min-max: 0-1

2.5.21   MaxQueuedRexmitMessages

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

  • Full path: DDSI2E/Internal/MaxQueuedRexmitMessages
  • Format: integer
  • Default value: 200
  • Occurrences min-max: 0-1

2.5.22   MaxSampleSize

Internal This setting controls the maximum (CDR) serialised size of samples that DDSI2E 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/MaxSampleSize
  • Format: string
  • Default value: 2147483647 B
  • Occurrences min-max: 0-1

2.5.23   MeasureHbToAckLatency

Internal This element enables heartbeat-to-ack latency among DDSI2E 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.

  • Full path: DDSI2E/Internal/MeasureHbToAckLatency
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.24   MinimumSocketReceiveBufferSize

Internal 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 DDSI2E 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/MinimumSocketReceiveBufferSize
  • Format: string
  • Default value: default
  • Occurrences min-max: 0-1

2.5.25   MinimumSocketSendBufferSize

Internal 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/MinimumSocketSendBufferSize
  • Format: string
  • Default value: 64 KiB
  • Occurrences min-max: 0-1

2.5.26   NackDelay

Internal 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.

  • Full path: DDSI2E/Internal/NackDelay
  • Format: string
  • Default value: 10 ms
  • Occurrences min-max: 0-1

2.5.27   PreEmptiveAckDelay

Internal 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.

  • Full path: DDSI2E/Internal/PreEmptiveAckDelay
  • Format: string
  • Default value: 10 ms
  • Occurrences min-max: 0-1

2.5.28   PrimaryReorderMaxSamples

Internal 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.

  • Full path: DDSI2E/Internal/PrimaryReorderMaxSamples
  • Format: integer
  • Default value: 64
  • Occurrences min-max: 0-1

2.5.29   RetransmitMerging

Internal 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 adaptive. See also Internal/RetransmitMergingPeriod.

  • Full path: DDSI2E/Internal/RetransmitMerging
  • Format: enumeration
  • Default value: adaptive
  • Valid values: never, adaptive, always
  • Occurrences min-max: 0-1

2.5.30   RetransmitMergingPeriod

Internal 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.

  • Full path: DDSI2E/Internal/RetransmitMergingPeriod
  • Format: string
  • Default value: 5 ms
  • Occurrences min-max: 0-1

2.5.31   RetryOnRejectBestEffort

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

  • Full path: DDSI2E/Internal/RetryOnRejectBestEffort
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.32   RetryOnRejectDuration

Internal How long to keep locally retrying pushing a received sample into the reader caches when resource limits are reached. Default is dependent on Internal/LateAckMode: if the latter is false, it is 80% of Internal/ResponsivenessTimeout, otherwise it is 0.

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

  • Full path: DDSI2E/Internal/RetryOnRejectDuration
  • Format: string
  • Default value: default
  • Occurrences min-max: 0-1

2.5.33   SPDPResponseMaxDelay

Internal 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.

  • Full path: DDSI2E/Internal/SPDPResponseMaxDelay
  • Format: string
  • Default value: 0 ms
  • Occurrences min-max: 0-1

2.5.34   ScheduleTimeRounding

Internal 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.

  • Full path: DDSI2E/Internal/ScheduleTimeRounding
  • Format: string
  • Default value: 0 ms
  • Occurrences min-max: 0-1

2.5.35   SecondaryReorderMaxSamples

Internal 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.

  • Full path: DDSI2E/Internal/SecondaryReorderMaxSamples
  • Format: integer
  • Default value: 16
  • Occurrences min-max: 0-1

2.5.36   SquashParticipants

Internal This element controls whether DDSI2E advertises all the domain participants it serves in DDSI (when set to false), or rather only one domain participant (the one corresponding to the DDSI2E process; when set to true). In the latter case DDSI2E becomes the virtual owner of all readers and writers of all domain participants, dramatically reducing discovery traffic.

  • Full path: DDSI2E/Internal/SquashParticipants
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.37   SuppressSPDPMulticast

Internal The element controls whether the mandatory multicasting of the participant discovery packets occurs. Completely disabling multicasting requires this element be set to true, and generally requires explicitly listing peers to ping for unicast discovery.

See also General/AllowMulticast.

  • Full path: DDSI2E/Internal/SuppressSPDPMulticast
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.38   SynchronousDeliveryLatencyBound

Internal 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.

  • Full path: DDSI2E/Internal/SynchronousDeliveryLatencyBound
  • Format: string
  • Default value: inf
  • Occurrences min-max: 0-1

2.5.39   SynchronousDeliveryPriorityThreshold

Internal 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.

  • Full path: DDSI2E/Internal/SynchronousDeliveryPriorityThreshold
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1

2.5.40   Test

Internal Testing options.

The unit must be specified explicitly.

  • Full path: DDSI2E/Internal/Test
  • Occurrences min-max: 0-1
  • Child elements: XmitLossiness
2.5.40.1   XmitLossiness

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

  • Full path: DDSI2E/Internal/Test/XmitLossiness
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1

2.5.41   UnicastResponseToSPDPMessages

Internal 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.

  • Full path: DDSI2E/Internal/UnicastResponseToSPDPMessages
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.5.42   Watermarks

Internal Watermarks for flow-control.

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

  • Full path: DDSI2E/Internal/Watermarks
  • Occurrences min-max: 0-1
  • Child elements: WhcHigh, WhcLow
2.5.42.1   WhcHigh

Internal This element sets the high-water mark for the DDSI2E 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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Internal/Watermarks/WhcHigh
  • Format: string
  • Default value: 100 kB
  • Occurrences min-max: 0-1
2.5.42.2   WhcLow

Internal This element sets the low-water mark for the DDSI2E WHCs, expressed in bytes. A suspended writer resumes transmitting when its DDSI2E WHC shrinks to this size.

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

  • Full path: DDSI2E/Internal/Watermarks/WhcLow
  • Format: string
  • Default value: 1 kB
  • Occurrences min-max: 0-1

2.5.43   WriteBatch

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.

  • Full path: DDSI2E/Internal/WriteBatch
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.5.44   WriterLingerDuration

Internal 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.

  • Full path: DDSI2E/Internal/WriterLingerDuration
  • Format: string
  • Default value: 1 s
  • Occurrences min-max: 0-1

2.6   Partitioning

The Partitioning element specifies DDSI2E network partitions and how DCPS partition/topic combinations are mapped onto the network partitions.

  • Full path: DDSI2E/Partitioning
  • Occurrences min-max: 0-1

2.6.1   IgnoredPartitions

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

  • Full path: DDSI2E/Partitioning/IgnoredPartitions
  • Occurrences min-max: 0-*
2.6.1.1   IgnoredPartition

This element can be used to prevent certain combinations of DCPS partition and topic from being transmitted over the network. DDSI2E 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.

  • Full path: DDSI2E/Partitioning/IgnoredPartitions/IgnoredPartition
  • Occurrences min-max: 0-*
  • Required attributes: DCPSPartitionTopic
2.6.1.1.1   DCPSPartitionTopic

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 ‘?’. DDSI2E will consider an wildcard DCPS partition to match an expression iff there exists a string that satisfies both expressions.

  • Full path: DDSI2E/Partitioning/IgnoredPartitions/IgnoredPartition/DCPSPartitionTopic
  • Format: string
  • Default value: n/a
  • Required: true

2.6.2   NetworkPartitions

The NetworkPartitions element specifies the DDSI2E network partitions.

  • Full path: DDSI2E/Partitioning/NetworkPartitions
  • Occurrences min-max: 0-*
2.6.2.1   NetworkPartition

This element defines a DDSI2E network partition.

  • Full path: DDSI2E/Partitioning/NetworkPartitions/NetworkPartition
  • Occurrences min-max: 0-*
  • Required attributes: Address, Name
  • Optional attributes: Connected, SecurityProfile
2.6.2.1.1   Address

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.

  • Full path: DDSI2E/Partitioning/NetworkPartitions/NetworkPartition/Address
  • Format: string
  • Default value: n/a
  • Required: true
2.6.2.1.2   Connected

This attribute is a placeholder.

  • Full path: DDSI2E/Partitioning/NetworkPartitions/NetworkPartition/Connected
  • Format: boolean
  • Default value: true
  • Required: false
2.6.2.1.3   Name

This attribute specifies the name of this DDSI2E network partition. Two network partitions cannot have the same name.

  • Full path: DDSI2E/Partitioning/NetworkPartitions/NetworkPartition/Name
  • Format: string
  • Default value: n/a
  • Required: true
2.6.2.1.4   SecurityProfile

This attribute selects the DDSI2E security profile for encrypting the traffic mapped to this DDSI2E network partition. The default “null” means the network partition is unsecured; any other name refers to a security profile defined using the Security/SecurityProfile elements.

  • Full path: DDSI2E/Partitioning/NetworkPartitions/NetworkPartition/SecurityProfile
  • Format: string
  • Default value: null
  • Required: false

2.6.3   PartitionMappings

The PartitionMappings element specifies the mapping from DCPS partition/topic combinations to DDSI2E network partitions.

  • Full path: DDSI2E/Partitioning/PartitionMappings
  • Occurrences min-max: 0-*
2.6.3.1   PartitionMapping

This element defines a mapping from a DCPS partition/topic combination to a DDSI2E network partition. This allows partitioning data flows by using special multicast addresses for part of the data and possibly also encrypting the data flow.

  • Full path: DDSI2E/Partitioning/PartitionMappings/PartitionMapping
  • Occurrences min-max: 0-*
  • Required attributes: DCPSPartitionTopic, NetworkPartition
2.6.3.1.1   DCPSPartitionTopic

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 DDSI2E network partition named by the NetworkPartition attribute in this PartitionMapping element. The expressions may use the usual wildcards ‘*’ and ‘?’. DDSI2E will consider a wildcard DCPS partition to match an expression if there exists a string that satisfies both expressions.

  • Full path: DDSI2E/Partitioning/PartitionMappings/PartitionMapping/DCPSPartitionTopic
  • Format: string
  • Default value: n/a
  • Required: true
2.6.3.1.2   NetworkPartition

This attribute specifies which DDSI2E network partition is to be used for DCPS partition/topic combinations matching the DCPSPartitionTopic attribute within this PartitionMapping element.

  • Full path: DDSI2E/Partitioning/PartitionMappings/PartitionMapping/NetworkPartition
  • Format: string
  • Default value: n/a
  • Required: true

2.7   SSL

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

  • Full path: DDSI2E/SSL
  • Occurrences min-max: 0-1
  • Child elements: CertificateVerification, Ciphers, Enable, EntropyFile, KeyPassphrase, KeystoreFile, SelfSignedCertificates, VerifyClient

2.7.1   CertificateVerification

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

  • Full path: DDSI2E/SSL/CertificateVerification
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.7.2   Ciphers

The set of ciphers used by SSL/TLS

  • Full path: DDSI2E/SSL/Ciphers
  • Format: string
  • Default value: ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH
  • Occurrences min-max: 0-1

2.7.3   Enable

This enables SSL/TLS for TCP.

  • Full path: DDSI2E/SSL/Enable
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.7.4   EntropyFile

The SSL/TLS random entropy file name.

  • Full path: DDSI2E/SSL/EntropyFile
  • Format: string
  • Occurrences min-max: 0-1

2.7.5   KeyPassphrase

The SSL/TLS key pass phrase for encrypted keys.

  • Full path: DDSI2E/SSL/KeyPassphrase
  • Format: string
  • Default value: secret
  • Occurrences min-max: 0-1

2.7.6   KeystoreFile

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

  • Full path: DDSI2E/SSL/KeystoreFile
  • Format: string
  • Default value: keystore
  • Occurrences min-max: 0-1

2.7.7   SelfSignedCertificates

This enables the use of self signed X509 certificates.

  • Full path: DDSI2E/SSL/SelfSignedCertificates
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.7.8   VerifyClient

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

  • Full path: DDSI2E/SSL/VerifyClient
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.8   Security

The Security element specifies DDSI2E security profiles that can be used to encrypt traffic mapped to DDSI2E network partitions.

  • Full path: DDSI2E/Security
  • Occurrences min-max: 0-1

2.8.1   SecurityProfile

This element defines a DDSI2E security profile.

  • Full path: DDSI2E/Security/SecurityProfile
  • Occurrences min-max: 0-*
  • Required attributes: Name
  • Optional attributes: Cipher, CipherKey
2.8.1.1   Cipher

This attribute specifies the cipher to be used for encrypting traffic over network partitions secured by this security profile. The possible ciphers are:

  • aes128: AES with a 128-bit key;
  • aes192: AES with a 192-bit key;
  • aes256: AES with a 256-bit key;
  • blowfish: the Blowfish cipher with a 128 bit key;
  • null: no encryption;

SHA1 is used on conjunction with all ciphers except “null” to ensure data integrity.

  • Full path: DDSI2E/Security/SecurityProfile/Cipher
  • Format: enumeration
  • Default value: null
  • Valid values: null, blowfish, aes128, aes192, aes256
  • Required: false
2.8.1.2   CipherKey

The CipherKey attribute is used to define the secret key required by the cipher selected using the Cipher attribute. The value can be a URI referencing an external file containing the secret key, or the secret key can be defined in-place as a string value.

The key must be specified as a hexadecimal string with each character representing 4 bits of the key. E.g., 1ABC represents the 16-bit key 0001 1010 1011 1100. The key should not follow a well-known pattern and must exactly match the key length of the selected cipher.

A malformed key will cause the security profile to be marked as invalid, and disable all network partitions secured by the (invalid) security profile to prevent information leaks.

As all DDS applications require read access to the XML configuration file, for security reasons it is recommended to store the secret key in an external file in the file system, referenced by its URI. The file should be protected against read and write access from other users on the host.

  • Full path: DDSI2E/Security/SecurityProfile/CipherKey
  • Format: string
  • Default value: “”
  • Required: false
2.8.1.3   Name

This attribute specifies the name of this DDSI2E security profile. Two security profiles cannot have the same name.

  • Full path: DDSI2E/Security/SecurityProfile/Name
  • Format: string
  • Default value: n/a
  • Required: true

2.9   Sizing

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

  • Full path: DDSI2E/Sizing
  • Occurrences min-max: 0-1
  • Child elements: EndpointsInSystem, NetworkQueueSize, ReceiveBufferChunkSize, ReceiveBufferSize

2.9.1   EndpointsInSystem

This endpoint specifies the expected maximum number of endpoints in the network. Underestimating this number will have a significant performance impact, but will not affect correctness; signficantly overestimating it will cause more memory to be used than necessary.

  • Full path: DDSI2E/Sizing/EndpointsInSystem
  • Format: integer
  • Default value: 200
  • Occurrences min-max: 0-1

2.9.2   NetworkQueueSize

This element specifies the maximum number of samples in the network queue. Write/dispose operations add samples to this queue, the DDSI2E service drains it. Larger values allow large bursts of writes to occur without forcing synchronization between the application and the DDSI2E service, but do introduce the potential for longer latencies and increase the maximum amount of memory potentially occupied by messages in the queue.

  • Full path: DDSI2E/Sizing/NetworkQueueSize
  • Format: integer
  • Default value: 10
  • Occurrences min-max: 0-1

2.9.3   ReceiveBufferChunkSize

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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Sizing/ReceiveBufferChunkSize
  • Format: string
  • Default value: 64 KiB
  • Occurrences min-max: 0-1

2.9.4   ReceiveBufferSize

This element sets the size of a single receive buffer. Many receive buffers may be needed. Their size must be greater than ReceiveBufferChunkSize by a modest amount.

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

  • Full path: DDSI2E/Sizing/ReceiveBufferSize
  • Format: string
  • Default value: 128 KiB
  • Occurrences min-max: 0-1

2.10   TCP

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

  • Full path: DDSI2E/TCP
  • Occurrences min-max: 0-1
  • Child elements: Enable, NoDelay, Port, ReadTimeout, WriteTimeout

2.10.1   Enable

This element enables the optional TCP transport.

  • Full path: DDSI2E/TCP/Enable
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.10.2   NoDelay

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.

  • Full path: DDSI2E/TCP/NoDelay
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1

2.10.3   Port

This element specifies the TCP port number on which DDSI2E 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.

  • Full path: DDSI2E/TCP/Port
  • Format: integer
  • Default value: -1
  • Occurrences min-max: 0-1

2.10.4   ReadTimeout

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.

  • Full path: DDSI2E/TCP/ReadTimeout
  • Format: string
  • Default value: 2 s
  • Occurrences min-max: 0-1

2.10.5   WriteTimeout

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.

  • Full path: DDSI2E/TCP/WriteTimeout
  • Format: string
  • Default value: 2 s
  • Occurrences min-max: 0-1

2.11   ThreadPool

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

  • Full path: DDSI2E/ThreadPool
  • Occurrences min-max: 0-1
  • Child elements: Enable, ThreadMax, Threads

2.11.1   Enable

This element enables the optional thread pool.

  • Full path: DDSI2E/ThreadPool/Enable
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.11.2   ThreadMax

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

  • Full path: DDSI2E/ThreadPool/ThreadMax
  • Format: integer
  • Default value: 8
  • Occurrences min-max: 0-1

2.11.3   Threads

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

  • Full path: DDSI2E/ThreadPool/Threads
  • Format: integer
  • Default value: 4
  • Occurrences min-max: 0-1

2.12   Threads

This element is used to set thread properties.

  • Full path: DDSI2E/Threads
  • Occurrences min-max: 0-1

2.12.1   Thread

This element specifies thread properties, such as scheduling parameters and stack size.

  • Full path: DDSI2E/Threads/Thread
  • Occurrences min-max: 0-1000
  • Child elements: StackSize
  • Required attributes: Name
2.12.1.1   Name

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

  • gc: garbage collector thread involved in deleting entities;
  • main: main thread, primarily handling local discovery;
  • 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.
  • Full path: DDSI2E/Threads/Thread/Name
  • Format: string
  • Default value: n/a
  • Required: true
2.12.1.2   Scheduling

This element configures the scheduling properties of the thread.

  • Full path: DDSI2E/Threads/Thread/Scheduling
  • Occurrences min-max: 0-1
  • Child elements: Class, Priority
2.12.1.2.1   Class

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.

  • Full path: DDSI2E/Threads/Thread/Scheduling/Class
  • Format: enumeration
  • Default value: default
  • Valid values: realtime, timeshare, default
  • Occurrences min-max: 0-1
2.12.1.2.2   Priority

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.

  • Full path: DDSI2E/Threads/Thread/Scheduling/Priority
  • Format: string
  • Default value: default
  • Occurrences min-max: 0-1
2.12.1.3   StackSize

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 20 bytes), GB & GiB (2 30 bytes).

  • Full path: DDSI2E/Threads/Thread/StackSize
  • Format: string
  • Default value: default
  • Occurrences min-max: 0-1

2.13   Tracing

The Tracing element controls the amount and type of information that is written into the tracing log by DDSI2E. This is useful to monitor DDSI2E during application development.

  • Full path: DDSI2E/Tracing
  • Occurrences min-max: 0-1
  • Child elements: AppendToFile, EnableCategory, OutputFile, PacketCaptureFile, Timestamps, Verbosity

2.13.1   AppendToFile

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.

  • Full path: DDSI2E/Tracing/AppendToFile
  • Format: boolean
  • Default value: false
  • Occurrences min-max: 0-1

2.13.2   EnableCategory

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

In addition, there is the keyword trace that enables all but radmin . 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.

  • Full path: DDSI2E/Tracing/EnableCategory
  • Format: string
  • Occurrences min-max: 0-1

2.13.3   OutputFile

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.

  • Full path: DDSI2E/Tracing/OutputFile
  • Format: string
  • Default value: lite.log
  • Occurrences min-max: 0-1

2.13.4   PacketCaptureFile

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.

  • Full path: DDSI2E/Tracing/PacketCaptureFile
  • Format: string
  • Occurrences min-max: 0-1

2.13.5   Timestamps

This option has no effect.

  • Full path: DDSI2E/Tracing/Timestamps
  • Format: boolean
  • Default value: true
  • Occurrences min-max: 0-1
  • Optional attributes: absolute
2.13.5.1   absolute

This attribute specifies whether the timestamps in the log file are absolute or relative to the startup time of the service. Currently not implemented in DDSI2E, all timestamps are absolute.

  • Full path: DDSI2E/Tracing/Timestamps/absolute
  • Format: boolean
  • Default value: true
  • Required: false

2.13.6   Verbosity

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

  • none: no DDSI2E 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 DDSI2 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 and finest.

  • Full path: DDSI2E/Tracing/Verbosity
  • Format: enumeration
  • Default value: none
  • Valid values: finest, finer, fine, config, info, warning, severe, none
  • Occurrences min-max: 0-1

2.14   Watchdog

This element specifies the type of OS scheduling class will be used by the thread that announces its liveliness periodically.

  • Full path: DDSI2E/Watchdog
  • Occurrences min-max: 0-1

2.14.1   Scheduling

This element specifies the type of OS scheduling class will be used by the thread that announces its liveliness periodically.

  • Full path: DDSI2E/Watchdog/Scheduling
  • Occurrences min-max: 0-1
  • Child elements: Class, Priority
2.14.1.1   Class

This element specifies the thread scheduling class that will be used by the watchdog thread. The user may need the appropriate privileges from the underlying operating system to be able to assign some of the privileged scheduling classes.

  • Full path: DDSI2E/Watchdog/Scheduling/Class
  • Format: enumeration
  • Default value: default
  • Valid values: realtime, timeshare, default
  • Occurrences min-max: 0-1
2.14.1.2   Priority

This element specifies the thread priority. 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.

  • Full path: DDSI2E/Watchdog/Scheduling/Priority
  • Format: integer
  • Default value: 0
  • Occurrences min-max: 0-1
  • Optional attributes: priority_kind
2.14.1.2.1   priority_kind

This attribute specifies whether the specified Priority is a relative or absolute priority.

  • Full path: DDSI2E/Watchdog/Scheduling/Priority/priority_kind
  • Format: enumeration
  • Default value: relative
  • Valid values: relative, absolute
  • Required: false

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