Lossless and FIFO delivery of multicast messages, using negative acks. E.g. when receiving P:1, P:3, P:4, a receiver asks P for retransmission of message 2.



Configuration Example


     <pbcast.NAKACK gc_lag="50"


Configuration Parameters


discard_delivered_msgsShould messages delivered to application be discarded
enable_xmit_time_statsIf true, retransmissions stats will be captured. Default is false
exponential_backoffThe first value (in milliseconds) to use in the exponential backoff. Enabled if greater than 0. Default is 0
gc_lagGarbage collection lag
idGive the protocol a different ID if needed so we can have multiple instances of it in the same stack
levelSets the logger level (see javadocs)
log_discard_msgsdiscards warnings about promiscuous traffic
log_not_found_msgsIf true, trashes warnings about retransmission messages not found in the xmit_table (used for testing)
max_msg_batch_sizeMax number of messages to be removed from a NakReceiverWindow. This property might get removed anytime, so don't use it !
max_rebroadcast_timeoutTimeout to rebroadcast messages. Default is 2000 msec
max_xmit_buf_sizeIf value is > 0, the retransmit buffer is bounded. If value <= 0 unbounded buffers are used. Default is 0
nameGive the protocol a different name if needed so we can have multiple instances of it in the same stack
print_stability_history_on_failed_xmitShould stability history be printed if we fail in retransmission. Default is false
retransmit_timeoutsTimeout before requesting retransmissions. Default is 600, 1200, 2400, 4800
statsDetermines whether to collect statistics (and expose them via JMX). Default is true
use_mcast_xmitRetransmit messages using multicast rather than unicast
use_mcast_xmit_reqUse a multicast to request retransmission of missing messages. Default is false
use_range_based_retransmitterWhether to use the old retransmitter which retransmits individual messages or the new one which uses ranges of retransmitted messages. Default is true. Note that this property will be removed in 3.0; it is only used to switch back to the old (and proven) retransmitter mechanism if issues occur
use_stats_for_retransmissionUse statistics gathered from actual retransmission times to compute new retransmission times. Default is false
xmit_from_random_memberAsk a random member for retransmission of a missing message. Default is false
xmit_history_max_sizeSize of retransmission history. Default is 50 entries


See also Protocol Configuration Common Parameters.



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