ZMQ_MCAST_LOOP removed

Multicast loopback is not a real multicast, rather a kernel-space
simulation. Moreover, it tends to be rather unreliable and lossy.
Removing the option will force users to use transports better
suited for the job, such as inproc or ipc.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

3 files changed, 2 insertions, 37 deletions

diff --git a/doc/zmq_getsockopt.txt b/doc/zmq_getsockopt.txt
index c93fc7f..eef4b1f 100644
--- a/doc/zmq_getsockopt.txt
+++ b/doc/zmq_getsockopt.txt
@@ -187,23 +187,6 @@ Default value:: -1
 Applicable socket types:: all, when using multicast transports
 
 
-ZMQ_MCAST_LOOP: Control multicast loop-back
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The 'ZMQ_MCAST_LOOP' option controls whether data sent via multicast
-transports can also be received by the sending host via loop-back.  A value of
-zero indicates that the loop-back functionality is disabled, while the default
-value of 1 indicates that the loop-back functionality is enabled.  Leaving
-multicast loop-back enabled when it is not required can have a negative impact
-on performance. Where possible, disable 'ZMQ_MCAST_LOOP' in production
-environments.
-
-[horizontal]
-Option value type:: int64_t
-Option value unit:: boolean
-Default value:: 1
-Applicable socket types:: all, when using multicast transports
-
-
 ZMQ_SNDBUF: Retrieve kernel transmit buffer size
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The 'ZMQ_SNDBUF' option shall retrieve the underlying kernel transmit buffer
diff --git a/doc/zmq_pgm.txt b/doc/zmq_pgm.txt
index d9bce5a..91b1678 100644
--- a/doc/zmq_pgm.txt
+++ b/doc/zmq_pgm.txt
@@ -23,9 +23,8 @@ UDP datagrams (the 'epgm' transport).
 The 'pgm' and 'epgm' transports can only be used with the 'ZMQ_PUB' and
 'ZMQ_SUB' socket types.
 
-Further, PGM sockets are rate limited by default and incur a performance
-penalty when used over a loop-back interface. For details, refer to the
-'ZMQ_RATE', 'ZMQ_RECOVERY_IVL' and 'ZMQ_MCAST_LOOP' options documented in
+Further, PGM sockets are rate limited by default. For details, refer to the
+'ZMQ_RATE', and 'ZMQ_RECOVERY_IVL' options documented in
 linkzmq:zmq_setsockopt[3].
 
 CAUTION: The 'pgm' transport implementation requires access to raw IP sockets.
diff --git a/doc/zmq_setsockopt.txt b/doc/zmq_setsockopt.txt
index 6c7046e..9387116 100644
--- a/doc/zmq_setsockopt.txt
+++ b/doc/zmq_setsockopt.txt
@@ -197,23 +197,6 @@ Default value:: -1
 Applicable socket types:: all, when using multicast transports
 
 
-ZMQ_MCAST_LOOP: Control multicast loop-back
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The 'ZMQ_MCAST_LOOP' option shall control whether data sent via multicast
-transports using the specified 'socket' can also be received by the sending
-host via loop-back. A value of zero disables the loop-back functionality, while
-the default value of 1 enables the loop-back functionality. Leaving multicast
-loop-back enabled when it is not required can have a negative impact on
-performance. Where possible, disable 'ZMQ_MCAST_LOOP' in production
-environments.
-
-[horizontal]
-Option value type:: int64_t
-Option value unit:: boolean
-Default value:: 1
-Applicable socket types:: all, when using multicast transports
-
-
 ZMQ_SNDBUF: Set kernel transmit buffer size
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The 'ZMQ_SNDBUF' option shall set the underlying kernel transmit buffer size