Ultra Messaging® Configuration Guide
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4.16. Transport Acceleration Options

Transport Acceleration Options enable Datagram Bypass Layer (DBL) acceleration in conjunction with DBL-enabled Myricom® 10-Gigabit Ethernet NICs for Linux and Microsoft® Windows®. DBL is a kernel-bypass technology that accelerates sending and receiving UDP traffic. DBL does not support fragmentation and reassembly, so you must avoid sending messages larger than the MTU configured on the DBL interface.

DBL acceleration is available for the following Ultra Messaging® transport types.

LBT-RM (UDP-based reliable multicast)
LBT-RU (UDP-based reliable unicast)
Multicast Immediate Messaging
Multicast Topic Resolution

Note: Transport Acceleration is not supported on the HP NonStop® platform.

To enable DBL Transport Acceleration,

Install the Myricom 10-Gigabit Ethernet NIC.
Install the DBL shared library.
Update your search path to include the location of the DBL shared library.
Include the appropriate Transport Acceleration Options in your Ultra Messaging Configuration File.

Note: We recommend setting transport_datagram_max_size to a value at least 28 bytes smaller than the configured MTU.

4.16.1. dbl_lbtrm_acceleration (context)

Flag indicating if DBL acceleration is enabled for LBT-RM transports.

Scope:	context
Type:	int
When to Set:	Can only be set during object initialization.
Version:	This option was implemented in LBM 4.0.

Value	Description
1	DBL acceleration is enabled for LBT-RM.
0	DBL acceleration is not enabled for LBT-RM. Default for all.

4.16.2. dbl_lbtru_acceleration (context)

Flag indicating if DBL acceleration is enabled for LBT-RU transports.

Scope:	context
Type:	int
When to Set:	Can only be set during object initialization.
Version:	This option was implemented in LBM 4.0.

Value	Description
1	DBL acceleration is enabled for LBT-RU.
0	DBL acceleration is not enabled for LBT-RU. Default for all.

4.16.3. dbl_mim_acceleration (context)

Flag indicating if DBL acceleration is enabled for multicast immediate messaging (MIM).

Scope:	context
Type:	int
When to Set:	Can only be set during object initialization.
Version:	This option was implemented in LBM 4.0.

Value	Description
1	DBL acceleration is enabled for MIM.
0	DBL acceleration is not enabled for MIM. Default for all.

4.16.4. dbl_resolver_acceleration (context)

Flag indicating if DBL acceleration is enabled for topic resolution.

Scope:	context
Type:	int
When to Set:	Can only be set during object initialization.
Version:	This option was implemented in LBM 4.0.

Value	Description
1	DBL acceleration is enabled for topic resolution.
0	DBL acceleration is not enabled for topic resolution. Default for all.

4.16.5. resolver_ud_acceleration (context)

Flag indicating if Accelerated Multicast is enabled for Topic Resolution. Accelerated Multicast requires InfiniBand or 10 Gigabit Ethernet hardware and the purchase and installation of the Ultra Messaging Accelerated Multicast Module. See your Ultra Messaging representative for licensing specifics. UD Acceleration relies on the network hardware supporting loopback which InfiniBand does, but current ConnectX and ConnectX2 10 Gigabit Ethernet hardware does not. Future 10gbe hardware should support loopback.

InfiniBand users should enable this option.
10 Gigabit Ethernet users should have this option disabled (default) for current generation hardware.

Check your hardware configuration to determine if this option needs to be changed.

Scope:	context
Type:	int
When to Set:	Can only be set during object initialization.
Version:	This option was implemented in LBM 5.2.

Value	Description
1	Accelerated Topic Resolution is enabled.
0	Accelerated Topic Resolution is not enabled. Default for all.

4.16.6. ud_acceleration (context)

Flag indicating if Accelerated Multicast is enabled for LBT-RM. Accelerated Multicast requires InfiniBand or 10 Gigabit Ethernet hardware and the purchase and installation of the Ultra Messaging Accelerated Multicast Module. See your Ultra Messaging representative for licensing specifics.

Scope:	context
Type:	int
When to Set:	Can only be set during object initialization.
Version:	This option was implemented in LBM 4.1.

Value	Description
1	Accelerated Multicast is enabled.
0	Accelerated Multicast is not enabled. Default for all.

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