Definition
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" retransmit_timeout="600,1200,2400,4800" use_mcast_xmit="false"></pbcast>
Configuration Parameters
| Name | Description |
|---|---|
| discard_delivered_msgs | Should messages delivered to application be discarded |
| enable_xmit_time_stats | If true, retransmissions stats will be captured. Default is false |
| exponential_backoff | The first value (in milliseconds) to use in the exponential backoff. Enabled if greater than 0. Default is 0 |
| gc_lag | Garbage collection lag |
| id | Give the protocol a different ID if needed so we can have multiple instances of it in the same stack |
| level | Sets the logger level (see javadocs) |
| log_discard_msgs | discards warnings about promiscuous traffic |
| log_not_found_msgs | If true, trashes warnings about retransmission messages not found in the xmit_table (used for testing) |
| max_msg_batch_size | Max number of messages to be removed from a NakReceiverWindow. This property might get removed anytime, so don't use it ! |
| max_rebroadcast_timeout | Timeout to rebroadcast messages. Default is 2000 msec |
| max_xmit_buf_size | If value is > 0, the retransmit buffer is bounded. If value <= 0 unbounded buffers are used. Default is 0 |
| name | Give the protocol a different name if needed so we can have multiple instances of it in the same stack |
| print_stability_history_on_failed_xmit | Should stability history be printed if we fail in retransmission. Default is false |
| retransmit_timeouts | Timeout before requesting retransmissions. Default is 600, 1200, 2400, 4800 |
| stats | Determines whether to collect statistics (and expose them via JMX). Default is true |
| use_mcast_xmit | Retransmit messages using multicast rather than unicast |
| use_mcast_xmit_req | Use a multicast to request retransmission of missing messages. Default is false |
| use_range_based_retransmitter | Whether 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_retransmission | Use statistics gathered from actual retransmission times to compute new retransmission times. Default is false |
| xmit_from_random_member | Ask a random member for retransmission of a missing message. Default is false |
| xmit_history_max_size | Size of retransmission history. Default is 50 entries |
See also Protocol Configuration Common Parameters.
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