Open Fabrics Enterprise Distribution (OFED)
		    RDMA CM in OFED 3.18 Release Notes
			  
			   June 2015


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Table of Contents
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1. Overview
2. New Features
3. Known Issues

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1. Overview
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The RDMA CM is a communication manager used to setup reliable, connected
and unreliable datagram data transfers.  It provides an RDMA transport
neutral interface for establishing connections.  The API concepts are
based on sockets, but adapted for queue pair (QP) based semantics:
communication must be over a specific RDMA device, and data transfers
are message based.

The RDMA CM can control both the QP and communication management
(connection setup / teardown) portions of an RDMA API, or only
the communication management piece.  It works in conjunction with the verbs
API defined by the libibverbs library.  The libibverbs library provides the
underlying interfaces needed to send and receive data.

The RDMA CM can operate asynchronously or synchronously.  The mode of
operation is controlled by the user.

The RDMA CM also provides the rsocket implementation.
Rsockets is a protocol over RDMA that supports a socket-level API
for applications.  Rsocket APIs are intended to match the behavior
of corresponding socket calls.  A preload library is included as part of
the RDMA CM package, which allows many socket based applications to run
unmodified over rsockets.

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2. New Features
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for OFED 3.18

Enhancements to the librdmacm release 1.0.21, versus the 1.0.18 release,
mostly centered around bug fixes.  Notable feature enhancements include
the following.

* There were several updates and bug fixes to the rsockets code based
  on more extensive testing and use cases.  Rsockets now supports the
  use of native InfiniBand addressing.

* The RDMA CM was updated to support XRC QPs.

* The rsocket preload library allows for fine grained interception of
  socket calls.

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3. Known Issues
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The RDMA CM relies on the operating system's network configuration tables to
map IP addresses to RDMA devices.  Incorrectly configured network
configurations can result in the RDMA CM being unable to locate the correct
RDMA device.

If you experience problems using the RDMA CM, you may want to check the
following:

   * Verify that you have IP connectivity over the RDMA devices.  For example,
     ping between iWarp or IPoIB devices.

   * Ensure that IP network addresses assigned to RDMA devices do not
     overlap with IP network addresses assigned to standard Ethernet devices.

   * For multicast issues, either bind directly to a specific RDMA device, or
     configure the IP routing tables to route multicast traffic over an RDMA
     device's IP address.