Multicast Resolver Network Options

The image below shows a simplified relationship between the primary multicast resolver network options.

See Topic Resolution Overview for general information on Topic Resolution.

Reference  <-

resolver_multicast_address (context)  <-

Multicast address (or domain name of the multicast address) used for Topic Resolution.

This option automatically sets the values for resolver_multicast_incoming_address (context) and resolver_multicast_outgoing_address (context) as evidenced by the default values for all three options, which are the same.

See also UDP-Based Topic Resolution Details.

Scope:	context
Type:	struct in_addr
Default value:	224.9.10.11
When to Set:	Can only be set during object initialization.

resolver_multicast_incoming_address (context)  <-

Incoming multicast address (or domain name of the multicast address) used for finer control of Topic Resolution.

This value may be set to 0.0.0.0 (INADDR_ANY), to switch off listening to topic resolution messages. This means that queries from receivers or advertisements from sources will not be handled.

See also resolver_multicast_outgoing_address (context).

Scope:	context
Type:	struct in_addr
Default value:	224.9.10.11
When to Set:	Can only be set during object initialization.

resolver_multicast_incoming_port (context)  <-

Incoming multicast port used for finer control of Topic Resolution.

See also resolver_multicast_outgoing_port (context).

See Port Assignments for more information about configuring ports.

Scope:	context
Type:	lbm_uint16_t
Default value:	12965
Byte order:	Network
When to Set:	Can only be set during object initialization.

resolver_multicast_interface (context)  <-

Specifies which network interface UM sends/receives all multicast traffic (Topic Resolution, LBT-RM, Multicast Immediate Messaging).

You can specify full IP address of interface, or just network part (see Specifying Interfaces for details).

Default is set to default_interface (context), if specified. Otherwise, it is set to the default multicast interface as determined by UM (the first multicast-capable, non-loopback interface).

Note: if specifying an interface name in an XML-format file, see Interface Device Names and XML.

Scope:	context
Type:	lbm_ipv4_address_mask_t
Default value:	0.0.0.0
When to Set:	Can only be set during object initialization.

resolver_multicast_outgoing_address (context)  <-

Outgoing multicast address (or domain name of the multicast address) used for finer control of Topic Resolution.

See also resolver_multicast_incoming_address (context).

Scope:	context
Type:	struct in_addr
Default value:	224.9.10.11
When to Set:	Can only be set during object initialization.

resolver_multicast_outgoing_port (context)  <-

Outgoing multicast port used for finer control of Topic Resolution.

See also resolver_multicast_incoming_port (context).

See Port Assignments for more information about configuring ports.

Scope:	context
Type:	lbm_uint16_t
Default value:	12965
Byte order:	Network
When to Set:	Can only be set during object initialization.

resolver_multicast_port (context)  <-

Multicast port used for Topic Resolution.

This option automatically sets the values for resolver_multicast_incoming_port (context) and resolver_multicast_outgoing_port (context) as evidenced by the default values for all three options, which are the same.

See Port Assignments for more information about configuring ports.

Scope:	context
Type:	lbm_uint16_t
Default value:	12965
Byte order:	Network
When to Set:	Can only be set during object initialization.

resolver_multicast_receiver_socket_buffer (context)  <-

Value used to set the SO_RCVBUF socket option for the topic resolution receiving socket.

In some cases the OS will not allow all of this value to be used.

A value of 0 instructs UM to use the default OS values. See Socket Buffer Sizes for platform-dependent information. See also our white paper Topics in High Performance Messaging for background and guidelines on UDP buffer sizing.

Scope:	context
Type:	lbm_ulong_t
Units:	bytes
Default value:	8388608 (8MB)
When to Set:	Can only be set during object initialization.

resolver_multicast_ttl (context)  <-

The IP TTL (hop count) to use for a Topic Resolution packet.

A value of 1 confines the packet to the local network (but may also cause high CPU usage on some routers). Also controls TTL on LBT-RM packets.

Scope:	context
Type:	lbm_uint8_t
Default value:	16
When to Set:	Can only be set during object initialization.