Projects / NRL NORM


NRL NORM is an implementation of NACK-Oriented Reliable Multicast. The NORM protocol is designed to provide end-to-end reliable transport of bulk data objects or streams over generic IP multicast routing and forwarding services. NORM uses a selective, negative acknowledgement (NACK) mechanism for transport reliability and offers additional protocol mechanisms to conduct reliable multicast sessions with limited "a priori" coordination among senders and receivers. The protocol offers a number of features to allow different types of applications or possibly other higher level transport protocols to utilize its service in different ways. The protocol leverages the use of FEC-based repair and other IETF reliable multicast transport (RMT) building blocks in its design.

Operating Systems

Recent releases

  •  28 Nov 2007 13:23

    Release Notes: Numerous bugfixes and code cleanups were done. Some minor enhancements were made.

    •  21 Oct 2007 15:11

      Release Notes: This release fixes a condition where receivers kept state for remote senders "stuck" with CC feedback. It fixes a bug that turned the default TTL value into TOS under certain conditions. NormFile read/write is more persistent. A bug has been fixed that incorrectly reported no repair needed when in fact the last segment was missing. A bug that interfered with proper sender stream advancement under severe conditions has been fixed. FEC codecs have been updated to current versions. The "lowDelay" option has been modified for silent receiver use to allow control of FEC block delay. A "Norm Pre-Coder" (NPC) utility has been added.

      •  15 Aug 2006 22:14

        Release Notes: This release fixes several moderate to major bugs, including divide-by-zero, assertion failures, and incorrect pointer dereferencing. It fixes numerous minor bugs.

        •  17 May 2006 04:05

          Release Notes: Bugs in NormQuantizeGroupSize() and in receiver congestion control tracking functions were fixed. The NormGetGrtt() and NormNodeGetGrtt() functions and the NORM_CC_ACTIVE and NORM_CC_INACTIVE notifications were added. Bugs in ns-2 support were fixed. FEC parity segments were modified to be variable size. SERVER* notifications were renamed to SENDER* for consistancy. Incorrect reporting of nack/suppresed counts in debug statistics were fixed. The activity timeout for the remote sender was fixed.

          •  22 Apr 2006 04:56

            Release Notes: This release includes an implementation of RFC3940 and RFC3941, heavy re-use of code and techniques from MDP, and an implementation of an NS-2 simulation of the protocol.


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