ION-DTN

= Release Notes for ION 3.6.1 = January 31, 2018 %%%%%%%%%%% = GENERAL = %%%%%%%%%%% The ION (interplanetary overlay network) software is a suite of communication protocol implementations designed to support mission operation communications across an end-to-end interplanetary network, which might include on-board (flight) subnets, in-situ planetary or lunar networks, proximity links, deep space links, and terrestrial internets. Included in the ION software distribution are the following packages: - ici (interplanetary communication infrastructure), a set of libraries that provide flight-software-compatible support for functions on which the other packages rely, such as dynamic memory management, non-volatile storage management, and inter-task communication via shared memory. The ici libraries are designed to make the porting of IPN software to multiple operating systems - Linux, VxWorks, Solaris, etc. - as easy as possible. Ici now includes zco (zero-copy object), a library that minimizes the copying of application data as it is encapsulated in multiple layers of protocol structure while traversing the protocol stack. - bp (bundle protocol), an implementation of the Delay-Tolerant Networking (DTN) architecture's Bundle Protocol. - ltp (licklider transmission protocol), a DTN convergence layer protocol for reliable transmission over links characterized by long or highly variable delay. - dgr (datagram retransmission), an alternative implementation of ltp that is designed for use over the Internet protocol stack. dgr implements congestion control and is designed for relatively high performance. - bssp (bundle streaming service protocol), a DTN convergence layer protocol for reliable transmission of streaming data. - ams - an implementation of the CCSDS Asynchronous Message Service. - cfdp - a class-1 (Unacknowledged) implementation of the CCSDS File Delivery Protocol. - bss - a Bundle Streaming Service (BSS) for disruption-tolerant reliable data streaming. BSS supports real-time streaming applications by passing the bundle payloads to the associated application for immediate display of the most recent data while storing all bundle payloads received into a database for user-directed playback. - dtpc (delay-tolerant payload conditioning), an application framework providing TCP-like support for end-to-end retransmission and data delivery in transmission order without duplication or omission. Features included: - cgr - Contract graph routing: a method of dynamic routing designed for space based applications of ION, but still usable for terrestrial applications. It computes routes using scheduled communication and deals with time-varying network topology. - brs - Bundle relay service: provides interconnectivity between networks that do not allow servers (those behind NAT for example). For more information, check man brsscla and man brsccla. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.6.1 = %%%%%%%%%%%%%%%%%%%%%%%%%% ION version 3.6.1 includes the following changes: - A new Android development kit for ION-based applications is now available. It's large, so it's provided in a separate file. - A new installer for the Windows port of ION is also now available, likewise in a separate file. - A "deadly embrace" in tcpcli was causing nodes to lock up during heavy continuous bidirectional file transfer. That is now fixed. - The erasure-coded link service adapter from University of Bologna has been updated, now including proactive fragmentation for improved performance. - The "bpsec" bundle security system has been renamed "sbsp" (Streamlined Bundle Security Protocol) to align with specifications that are being standardized by the Consultative Committee for Space Data Systems (CCSDS). - Asynchronous Message Service and Bundle Streaming Service have been added to the RTEMs port. - Contact Graph Routing in the Bundle Protocol has been updated to align with the new Schedule-Aware Bundle Routing (SABR) specification that is being standardized by CCSDS. - The delay-tolerant key administration system in the "contrib" directory has been updated with a model for optimizing the configuration of an aggregate key authority, plus scripts for testing various key authority configurations. - The ION Design Guide has finally been updated. - Loopback transmission has been restored to the TCPCL convergence-layer adapter. No changes to operational interfaces or APIs this time. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.6.0b= %%%%%%%%%%%%%%%%%%%%%%%%%% Version 3.6.0b is an interim release aimed at improving the ability of ION to tolerate continuous heavy relay traffic at the DTN gateway for the International Space Station. The changes made to accomplish this are mostly invisible, but they include the deployment of a new "ltpdeliv" daemon (for data acquisition rate control) and resolution of a particularly subtle race condition. In addition, this version includes the following upgrades: - A new "ionunlock" utility has been added, for unfreezing an ION node that has gotten locked up due to some thread having been destroyed while still the owner of the ION system mutex. - In the "contrib" directory, the build for DTKA has been modified to fit into the ION 3.6 environment. - Also in the "contrib" directory, dtnperf has been tweaked to build properly in the ION 3.6 environment and ECLSA has been updated in a number of ways. - The ION implementation of Asynchronous Management Protocol has been upgraded in many ways, including optional support for data storage in MySQL. - Most regression test failures for ION running in recent versions of Mac OS X have been addressed. ION now once again runs in this environment, though there still may be a few rough edges. - The build and test environment for Windows has been greatly improved. Version 3.6.1 will focus on some more visible enhancements to ION but will of course retain all of these upgrades as well. --- A note on Windows operating environments --- Building ION on Windows requires at a minimum the MinGW-w64 [http://mingw-w64.org/] compiler package, and most likely a utilities package to provide a shell. For this release, testing was done with the following configurations: - 32-bit Windows ION is built with i686-4.9.3-release-posix-dwarf-rt_v4-rev1.7z - 64-bit Windows ION is built with x86_64-7.1.0-release-win32-seh-rt_v5-rev1.7z Both system variants use the MinGW-MSYS utiltites bundle MSYS-20111123. During testing of 3.6.0b the current set of instructions for installation and operation of ION on Windows was found to be partially outdated and in need of revision. In particular, running the built-in validation tests requires additional setup steps beyond the basic ION deployment. Revised documentation will be provided in release 3.6.1. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.6.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #103: Made pthread_t variable access abstract for POSIX task signal management. - SourceForge Bug #104: Fixed segmentation fault in the ipnd neighbor discovery task that caused a crash when a beaconing node that it has been listening to abruptly terminates. - SourceForge Bug #106: Fix a bug using lseek on Windows machines when trying to transfer large files (over 2GB in size). - SourceForge Bug #107: Updated to a new convergence layer management system. (See ION interface changes in version 3.6.0 note below for more information). - SourceForge Bug #110: Fix flow control to reserve ZCO before allocating SDR heapspace. - SourceForge Bug #112: Added include directories needed to successfully build acsadmin on Windows. - SourceForge Bug #115: Fix a bug in bpadmin that caused a segmentation fault and subsequent lock up if "s outduct" was entered without any parameters. - SourceForge Feature Request #56: Added a TTL option to bpsendfile so the user can specify a TTL longer than 300 seconds if needed. - SourceForge Feature Request #58: LTP performance enhancements. - SourceForge Feature Request #59: Added ECLSA an implementation of erasure coding under LTP. - SourceForge Feature Request #60: Enabled custodial retransmission when using the UDP convergence-layer adapter by adding an optional retransmission timeout interval (RTT) that defaults to 0. - SourceForge Feature Request #63: Added an option to allow automatic discard of status messages for a CFDP transfer in a recipient does not want to process them. - Added a new system to disable tests that you do not want to run when using the runtests script. --- ION interface changes in version 3.6.0 --- In ION version 3.6.0 we introduce a new degree of indirection between routing (next-hop bundle-layer endpoint selection) and forwarding (next-hop convergence-layer endpoint selection). This new capability, named "convergence layer management" (CLM), provides a number of important benefits. Unfortunately, in order to realize those benefits we had to revise some ION interfaces more drastically than we usually do in moving to a new version. Please be aware of the following significant changes as you adjust your test and deployment environments to utilize ION 3.6.0. -- API changes None of the "public" application programming interfaces in ION are affected by the introduction of CLM, but the Bundle Protocol private internal API has changed in some significant ways; these changes particularly affect the implementation of convergence-layer adapters. Most important of these is a change to the function prototype for bpDequeue; see the comments in the bpP.h header file. -- Behavioral changes BP flow control is now exerted at node granularity, in a new daemon process named "bpclm", rather than at outduct granularity. One effect of this change is that the data rates declared in the contact plan now are enforced for all convergence-layer protocols, not just LTP. Another is that the plan for bundle egress to a given neighboring node may now comprise multiple convergence-layer outducts, not just one; the ipnadmin and dtn2admin utilities don't support this option, but new commands implemented in the bpadmin utility do. -- Configuration changes Several changes in ION 3.6.0 may affect your configuration files. There are no longer any "promiscuous" outducts. The "*" command-line argument to udpclo is no longer valid: you need a separate udpclo task, allocated to an explicit socket expression (<ip_address> [:<port_number>]), for each neighbor to which you will transmit bundle by UDP. This change affects "outduct" commands passed to bpadmin and also "plan" commands passed to ipnadmin and dtn2admin. There is a similar impact on the DGR convergence-layer adapter: the dgrcla daemon no longer exists, having been replaced by dgrcli and dgrclo daemons; see the man pages for these new daemon programs. There are no longer any "plan rules" that override default egress plan directives. User-written outduct selection functions may be inserted at compile time to achieve the objectives of plan rules (and much more), but at this time no such functions are delivered with ION 3.6.0. The operation of the dtn2admin utility has been expanded, conceptually enabling the declaration of egress plans for sets of nodes whose EIDs conform to any wild-carded EID string regardless of URL scheme, without any sensitivity to trailing "/" characters or "demux" strings. Enabling this expansion, though, it is now necessary to include scheme name and ":" (in addition to the scheme-specific part of the EID) when declaring, editing, or deleting a plan. Finally, the TCP convergence-layer protocol implementation has been significantly revised: it now enables bundle to be transmitted to a neighboring node over a TCP connection that was established by that node, i.e., not declared a priori in local outduct commands. That is, it is no longer necessary to declare outducts for all neighboring nodes to which you want to be able to send bundles by tcpcl. However, these revisions are fairly complex and were time-consuming to debug; tcpcl loopback introduces a whole additional layer of complexity, particularly in fault handling, so at least for now tcpcl loopback is not supported in ION 3.6.0. Everything one might want to demonstrate or test using tcpcl loopback can be more cleanly and convincingly accomplished using two nodes exercising tcpcl on the same machine, so we don't see removal of this limitation as urgent. - NOTE for MacOS X users: At this time, ION 3.6.0 will NOT run on any recent version of MacOS. Our tests on MacOS 10.11 show failures in the semaphore locking system that we have not yet fully diagnosed. No work-around is available. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.5.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #94: Warnings printed at compile time on 64-bit Windows were fixed. - SourceForge Bug #98: Fixed bug in the dtn2 directive lookup function that ignored egress plans and rules citing CL protocols of classes that don't match the protocol class indicated by the bundle's required quality of service for plans that cite the "forwarding" directive. - SourceForge Feature Request #48: Improved the portability of Alarms and enabled them to be used in flight code as they no longer spawn new threads but instead are implemented as events in the RFX timeline that are clocked out by rfxclock at 1-second granularity. - The BP security and Asynchronous Management Protocol (bpsec) replaced the previous BP security mechanism bsp. - Added opportunistic contact graph routing (ocgr) based on predicted contacts. This system is still experimental but is ready for others to experiment with. - Fixes for bugs in AMS uncovered in IPAS demonstration environment development. - Added tcpcl-ack-resilience-test. - Fixed issue-265-bpdriver-ttl-option test by adding support for BSD netcat. - NOTE for MacOS X users: At this time, ON 3.5.0 will NOT run on any recent version of MacOS. Our tests on MacOS 10.11 show failures in the semaphore locking system that we have not yet fully diagnosed. No work-around is available. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.4.1 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #60: The ION killm script no longer fails to clean up shared memory allocations from the current user when their username is longer than 10 characters. - SourceForge Bug #89: The ION TCPCL has been updated to implement bundle acknowledgments, which are listed as an optional feature in the TCPCL specification (RFC 7242). Bundle acknowledgments can help improve reliability of TCPCL transmissions by alleviating issues that can occur during a window after a disconnection but before a timeout. During this time the CLO may finish its send() call without error and trigger BP to delete the bundle before the timeout fires and it is discovered the transmission did not succeed and can no longer be retransmitted. - SourceForge Bug #91: The ION autoconf configuration has been streamlined by merging the libipnfw and libdtn2fw libraries directly into libbp. This should improve portability and alleviate any build issues that some users reported having in ION v3.4.0. - SourceForge Feature Request #50: ION now supports an abstract "bulk" storage type for zero-copy objects. This allows FPGAs to receive inbound data into bulk storage and invoke ION data acquisition logic that will encapsulate the bulk storage objects in ZCOs for LTP and BP processing. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.4.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #61: Fixed bug in using FreeBSD semaphores that could cause unexpected behavior and lockoups under FreeBSD. - SourceForge Bug #74: Fixed bug where semaphore IDs were only properly reclaimed on certain RTEMS operating systems (VxWorks, POSIX). This could cause ION to exhaust the pool of semaphore IDs and create outduct lockups. ION now properly reuses obsolete semaphore IDs under Windows and SVRr4. - SourceForge Bug #79: Fixed bug where removing and re-adding an outduct could cause a bundle transmission failure. - SourceForge Bug #81: Fixed bug where ION child processes could become zombie processes. The sm_TaskSpawn() function in ION now properly forces child processes to be re-parented by the "init" process which periodically reaps the zombie processes. - SourceForge Bug #83: Fixed bug where ION would presume bi-directional BAB were enabled when BAB was only specified as unidirectional in a configuration. This would cause the non-BAB bundles to be declared inauthentic despite no BAB rule being specified in that direction. - SourceForge Bug #84: Fixed bug where continuously sending BCB-enabled bundles could cause erroneous generation of truncated bundles in the source node. This was due to the Linux file system was having trouble keeping up with the rate of temporary file creation when BCB's ARC4 ciphersuite used a temporary file for ciphertext. ION now does the crypto in place, overwriting the contents of the payload ZCO. - SourceForge Bug #85: Fixed bug where the number of rules that were entered into ionsecrc would not match the number of messages when cleared in ionsecadmin. - SourceForge Bug #86: Fixed bug that caused LTP block reassembly to be very CPU-intensive when the block was transmitted in small segments. This could cause delays in processing the block that would incur the expiration of the senders ack timer and ultimately result in session cancellation. ION now receives the block directly into the correct location in a temporary acquisition file and wraps the delivery ZCO around that file. - SourceForge Bug #87: Fixed bug where BSSP block acknowledgments were sent via TCP rather than UDP, which could result in the volume of TCP BSSP acknowledgment traffic becoming so heavy that the sending BSSP UDP congestion loss would increase to the point of degrading visual quality. - SourceForge Bug #88: Fixed a bug where the CFDP UTO ZCO request could become interrupted by moving the "attendant" structure into the BP volatile database to keep it stable. - SourceForge Feature Request #29: The ION testing subsystem has been updated to begin tests immediately after subsystem initialization. Previously ION used hard timeouts to wait for subsystem initialization which could be overly-aggressive timings on slower systems or overly-conservative on fast systems. - SourceForge Feature Request #33: The ION CGR implementation now supports probabilistic contacts. These are opportunistic contacts with probabilities less than 1.0. ION now accepts contacts with probabilities less than 1.0 and will forward multiple copies of a bundle through different discovered contacts until the bundle's computed net delivery probability exceeds a hard-coded threshold value. - SourceForge Feature Request #34: ION now supports proactive bundle bundle fragmentation in LTPCLO. - SourceForge Feature Request #35: ION now properly blocks and unblocks non-LTP links in a contact plan. Previously, ION only explicitly blocked and unblocked links operating LTP. - SourceForge Feature Request #37: The ION CFDP implementation has been updated per new CCSDS CFDP specification revisions. CFDP now uses a managed configuration parameter obtained via a Management Information Base (MIB) as its checksum type. Previously, this value was hard coded into the EOF PDU layout. - Fixed several miscellaneous bugs with IP Neighbor Discovery. - ION now only attempts to rebuild the ION.pdf design document if all required tools are detected. - New and updated tools are now available in the ION contrib subdirectory: - Updates have been applied to DTNPerf, and tool for testing DTN performance testing. - Added BPTAP, a tool that enables BP to act like Ethernet underlying IP. - Added Delay Tolerant Key Administration (DTKA), a tool enabling trustworthy delay-tolerant distribution of public keys. NOTE: DTKA is not built by default. See /contrib/dtka/README.txt for special instructions on building the DTKA tool. Public API changes: - bp.h: the new function bp_memo is added. It was previously exposed only in the BP private API. - zco.h: the new functions zco_revise, zco_create_obj_ref, and zco_destroy_obj_ref are added. Operational interface changes: - cfdpadmin (cfdprc): - Added support for explicitly adding remote entities and specifying their UT-layer endpoints. - ipnadmin (ipnrc): - "groups" have been renamed "exits" to avoid a terminology clash with multicast "groups". However, the older "group" terminology is still accepted by ipnadmin for backward compatibility. BUILD NOTE: Substantial changes have been made in this version as to how ION is built. As a result, some platforms (particularly older Linux platforms) may encounter linker warnings when building ION 3.4.0. These issues will be resolved in the next release, but in the meantime an alternate Makefile has been provided that may resolve this issue on affected platforms. If you encounter any linker warnings, try the following procedure to build from this alternate Makefile: 1.) cd <top of ION directory> 2.) cp Makefile.am.alt Makefile.am 3.) autoreconf -fi (requires libtool and autoconf to be installed) 4.) ./configure 5.) make %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.3.1 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #37: The ION tutorial has been updated. - SourceForge Bug #73: Fixed two bugs introduced by the dynamic generation of LTP reports. See the SourceForge Bug #47 entry and the ltprc(5) man page for details on dynamic LTP report generation. 1.) The computation of the segment loss rate (errors per segment) was incorrect and now uses the following corrected formula: segmentLossRate = 1.0 - ((1.0 - maxber) ** (maxSegmentSize * 8)) 2.) The retransmission limit on the number of times any single report or checkpoint may be retransmitted is now computed dynamically as a function of segment loss rate rather than a static number. - SourceForge Bug #74: Obsolete IPCs are now properly reclaimed when running under Windows and SVr4. - ION now tracks the release of semaphores in winion's array of IPC handles as well as the semaphore tables themselves. - Previously, the release of obsolete semaphores was not tracked by the winion daemon, which could be easily saturated given low semaphore limits and recently-expanded semaphore usage in ION (CGR, ionStartAttendant). - SourceForge Feature Request #40: The bping ION application has been ported to Windows. A dtnperf port for Windows is slated for a later release. - SourceForge Feature Request #42: ION now resolves host names when socket connections are made rather than resolving them all on ION startup. - Fixed a memory leak in CFDP that could occur when TargetFFS is defined. - Several fixes have been applied in response to the successful completion of CCSDS BP interoperability testing. - Delay Tolerant Payload Conditioning (DTPC) has been updated for conformance the specification. - The CGR algorithm has been updated to omit downstream contacts that end before initial contact on route. - ION no longer requires pdfjam to build man pages into the ION documentation. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.3.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #47: ION's LTP implementation now computes limits on "report" segment generation dynamically, based on block size, segment size, and anticipated bit error rate. This enables LTP to "try harder" to complete block transmission when rates of data loss are high. See the notes below on configuration interface changes. - SourceForge Bug #54: Fixed bug that could cause multithreaded applications under VxWorks to refuse bundles with the error message: "Can't receive: not owner of endpoint." For this purpose, a thread that will only send (never receive) bundles can use a BpSAP created by calling bp_open_source rather than bp_open; in this circumstance, sending and receiving threads may use different bpSAPs tagged with the same endpoint ID. IMPORTANT: see the notes below on application interface changes! - SourceForge Bug #62: Fixed several miscellaneous implementation bugs in the Contact Graph Routing (CGR) engine dealing with Earliest Transmission Opportunities (ETO) and Overbooking management (OB). - SourceForge Bug #63: Removed restrictions on possible CBHE node and service numbers. MAX_CBHE_NODE_NBR may now be any unsigned long number (2^64-1). MAX_CBHE_SERVICE_NBR may now be any unsigned int number (2^32-1). - SourceForge Bug #65: Removed duct-level support for LTP "green" transmission. "Green" transmission is now selected on a bundle-by-bundle basis via the bundle's extended class of service options. - SourceForge Bug #67: Updated the Previous Hop Node extension block (PHN) implementation to be compliant with the specification in RFC 6259. The sending node's EID is now represented by two distinct NULL-terminated strings (Scheme Name and SSP) rather than one NULL-terminated EID. - SourceForge Bug #68: Fixed bug where the sockets of links utilizing STCP could prematurely close if the other side did not respond for several hours. ION now respects the EHOSTUNREACH errno value and periodically attempts to reconnect rather than closes the socket. - SourceForge Bug #70: Fixed bug with ION's uClibC macros that caused ION compilation to fail in environments that use uClibC. - SourceForge Feature Request #13: Optimizations have been made to improve ION's reactive forwarding implementation: - When a bundle is reforwarded due to expiration of its xmitOverdue timer ION now considers the possibility that forwarding the bundle back to the node it received the bundle from may now actually be the optimal route. - ION now sends Custody Refused signals back to the sending nodes when forwarding the bundle is not possible, even when custody transfer was not requested. This enables a mechanism for backtracking the bundle through the network when forward progress through a route is blocked. - SourceForge Feature Request #19: ION now supports Bundle-in-Bundle Encapsulation (bibe) per the draft-irtf-burleigh-bibe Internet Draft. Bundle-in-Bundle Encapsulation enables the Streamlined Bundle Security Protocol (SBSP), which omits security destinations from the security extension blocks, to function in cross-domain solutions by encapsulating bundles whose destination is the selected security destination. - SourceForge Feature Request #29: Optimizations have been applied to the ION test suite to reduce the amount of time needed to initialize each test. - SourceForge Feature Request #31: ION's public API is now more "const-correct" which enables better interopability with C++ interfaces. - SourceForge Feature Request #32: zero-copy-object space allocation has been enhanced to enable bidirectional flow control on convergence-layer protocols that back-propagate blocking on buffer space requests. - SourceForge Feature Request #33: ION now supports probabilistic contacts. These are contacts with probabilities less than 1.0 that could potentially be handled by the CGR algorithms to enable the possibility for more efficient routing decisions to be made by the CGR engine. - ION now supports the Streamlined Bundle Security Protocol (SBSP) in place of the Bundle Security Protocol defined in RFC 6257. For details, see https://datatracker.ietf.org/doc/draft-birrane-dtn-sbsp/. - Fixes have been applied to the ION.pdf construction procedure to enable proper formatting of the appended man pages. - Man page creation can now be disabled. Man pages are still built by default. To disable man page creation, use "./configure --disable-manpages". **Configuration interface changes** Because buffer space for "zero-copy objects" in ION has been split into separate pools for inbound and outbound data, the ionrc command for managing "occupancy" has been split into two commands, "inbound" and "outbound". See the ionrc(5) man page for details. Migrating ION from standard Bundle Security Protocol to the new Streamlined Bundle Security Protocol has entailed changing some of the ionsecrc commands: "bsppibrule" is replaced by "bspbibrule", and "bsppcbrule" is replaced by "bspbcbrule". See the ionsecrc(5) man page for details. Limits on retransmission in LTP are now computed dynamically to account for differences in bundle size, segment size, and bit error rate. For this purpose, the default value for maximum bit error rate at a given LTP engine is hard-coded to be 10^-6 (one uncorrected flipped bit per million). This value can be overridden by the new ltprc command for managing "maxber"; see the ltprc(5) man page for details. **Application programming interface changes** Again because of the splitting of ZCO buffer space into two pools, many of the zco library function prototypes have been changed: in most cases, an additional ZcoAcct parameter (ZcoInbound or ZcoOutbound) has been added. Also: - A new zco_status function has been added, to print a brief report of the buffer status. - New zco_extent_too_large and zco_get_aggregate_length functions have been added to aid in resource management. - Other new functions include zco_acct, zco_header_text, and zco_trailer_text. - Passing a negative value of extent length to zco_create or zco_append_extent indicates that (a) the actual extent length is the additive inverse of the value provided and (b) it is asserted that this length does not violate the configured limits on ZCO buffer space occupancy. See the zco(3) man page for details of these changes. Leveraging these upgrades to enable more flexible resource management, the ionCreateZco and ionAppendZcoExtent function prototypes have been modified and the ion function library now includes several new functions that provide better control of "blocking" behavior in ZCO buffer space allocation: ionStartAttendant, ionPauseAttendant, ionResumeAttendant, ionStopAttendant, ionRequestZcoSpace, ionShred. See the ion(3) man page for details of these changes. NOTE: The changes made to address SourceForge Bug #54 (described above) have the potential to BREAK APPLICATIONS! If your application code currently makes any use of the bundle address that is returned when bp_send() is called, then YOU MUST MAKE BOTH OF THE FOLLOWING CHANGES IN YOUR CODE: 1.) Use bp_open_source() with the "detain" flag set to 1 INSTEAD OF bp_open() to obtain the BpSAP handle that you pass to bp_send(). 2.) Call bp_release() as soon as possible (for example, immediately after passing the new bundles address to bp_track()) to end the detention of any bundle created by passing that detaining BpSAP handle to any invocation of bp_send(). If you need to receive bundles as well as send them, then the BpSAP handle that you pass to bp_receive() must be a different handle that is obtained by calling bp_open() in the usual way. **Operational changes** An additional daemon task named "bptransit" has been added to standard ION operations. bptransit is responsible for presenting to the forwarding daemon(s) bundles that were received from other nodes (i.e., that reside in Inbound ZCO space) and are destined for yet other nodes; in doing so, it migrates these bundles from Inbound buffer space to Outbound buffer space on the same prioritized basis as the insertion of locally sourced outbound bundles. Management of the bptransit daemon is automatic. See the bptransit(1) man page for details. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.2.2 = %%%%%%%%%%%%%%%%%%%%%%%%%% - SourceForge Bug #32: Improved Windows support - MinGW makefiles now build a wider array of ION applications. - ION-based applications can now be developed in Visual Studio via the new "winimplib.bat" batch script which creates import libraries suitable for linking ION DLLs. - See "BuildingIONonWindowsForUseWithVisualStudio.pdf" for documentation on how to build ION-based applications in Visual Studio. - SourceForge Bug #49: ION now sends a "Depleted Storage" custody refusal signal back to the current custodian when an ION node lacks sufficient ZCO space to contain a bundle. - SourceForge Bug #50: ION now behaves more consistently across platforms when ionadmin is unable to open its designated configuration file. - The ionadmin application now considers being unable to open its configuration file to be a serious error and will stop the ION initialization routines at this point. This gives clearer and more immediate feedback to the user that an error was encountered that they must resolve to resume normal ION operation. - Previously, ionadmin would load a default configuration if it was unable to open its configuration file EXCEPT under vxWorks 6.3 PowerPC where ionadmin would cease with a "can't open SDR config file" message. - SourceForge Bug #51: The "ionconfig" man page has been updated. Some examples of entries that were obsolete are as follows: - The pathName parameter should not be encased in quotes. Previously, the example showed a pathName that was encased in quotes. - The default config flag is 13, which corresponds to SDR_IN_DRAM | SDR_REVERSIBLE | SDR_BOUNDED Previously, the documentation gave an incorrect default config flag of 1. - The default wmKey is 65281. Previously, this was reported to be 65537. - SourceForge Bug #52: The "bping" application has been updated for better compatibility under VxWorks. This was made possible by adding an option to run bping as a lightweight task with positional runtime arguments. - SourceForge Bug #53: Fixed bug in command argument parsing in the "bprecvfile" application under VxWorks. Previously the "a1" argument was reused for both the "EID" and "maxFiles" fields. - SourceForge Bug #55: Fixed bugs in the "bpcancel" application. - The bpcancel application now prints a message when it is unable to cancel the transmission of a bundle. - The man page for the bpcancel application has been updated to clarify that the application attempts to cancel the transmission of a specified bundle rather than destroy the specified bundle. - Note that it is not always possible to cancel the transmission of a bundle for which multiple internal copies exist due to being transmitted at different times or to different nodes. - SourceForge Bug #56: ION now builds properly under OSX 10.9.5. - SourceForge Bug #57: ION now has PARTIAL support for FreeBSD. - ION now builds properly under FreeBSD 10. - IMPORTANT NOTE: Several key ION applications have not yet been updated to run properly in a FreeBSD environment. These applications will be updated in a later ION release. These updates may also become available in the short term in the form of an official ION patch. - SourceForge Bug #59: Fixed bug in the "dtpcadmin" application where it failed to accept a valid parameter of zero in the "maxRtx", "aggrSizeLimit", and "aggrTimeLimit" fields. - SourceForge Feature Request #18: The "cgrfetch" application now has an option to list all valid outducts. This should simplify usage by making it easier to identify an outduct to run the application against. - SourceForge Feature Request #20: ION has been updated to better support the CFS environment. CFS can now leverage many standalone ION executables via an alternative API where the application's "main()" is replaced with a callable function. - SourceForge Feature Request #21: ION now allows users to adjust the maximum block size that LTP will receive directly into the SDR heap rather than a temporary file. This allows users to ensure that a bundle's receive- generate-forward chain can be handled entirely in memory. This often improves efficiency by alleviating the need to write to a disk medium. - SourceForge Feature Request #22: ION now has an option to support handling database reversibility mechanisms in memory rather than files. - SourceForge Feature Request #23: As a performance optimization, ION now has better documented support for using pointer de-references rather than memcpy() when executing read-only database operations. - SourceForge Feature Request #24: ION's mechanisms to prevent resource leaks when ION is killed and restarted rather than shut down cleanly have been modified to support the CFS environment. Note that this problem occurs most commonly when transaction reversibility is disabled because task termination locks the datastore until all tasks are killed. If utilizing a file on disk for transaction reversibility would be too slow, consider utilizing the new functionality to support database reversibility mechanisms in memory (SourceForge Feature Request #22) rather than disabling transaction reversibility entirely. - SourceForge Feature Request #26: The CFDP implementation has been updated to conform to the proposed CFDP V1 specification. Further updates will be required when the specification revisions are completed and approved by CCSDS. - The interface changes are as follows: The function prototypes for the CFDP functions cfdp_put() and cfdp_preview() have changed to accommodate proposed updates to the CFDP specification. File offsets and lengths in all CFDP function calls are now of type uvast (rather than unsigned int), because CFDP can now be used to send files larger than 4 GB. See the cfdp(3) man page for details. - The cfdptest test program has been updated to enable specification of closure latency and segment metadata. See the cfdptest(1) man page for details. - SourceForge Feature Request #27: ION now provides support for the DTN Metadata Extension Block as specified in RFC 6258. - SourceForge Feature Request #29: The ION test suite has been revamped to dynamically detect when ION applications are initialized rather than wait preset amounts of time for them to initialize. This provides faster execution of the test suite when applications initialize faster than these preset times and more reliable execution of the test suite when applications initialize slower than the preset times. - The "DTNperf" application now builds properly under sparc architectures. DTNperf is an external utility that is included with ION in "/contrib". - Several compilation issues with the "icinm.h" header file implementation have been resolved. - Improvements have been made to the TCPCLO. - The receiveBundles() thread no longer terminates prematurely under some circumstances when a connection is broken. - The sending rate is no longer artifically capped at 1 bundle/sec. - The "ionscript" application has been updated to support dtpcadmin configuration files. - ION's collection of man pages was previously included in "ION.pdf" but is now available as a separate document, "ION-manpages.pdf". %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.2.1 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Feature Request #8: Improvements have been made in how ION infers the node number of the sending node. ION now implements the Previous Hop Insertion Block (here called Previous Hop Node, phn) extension block, which contains the identifying singleton endpoint of the sending node. Previously, ION utilized mechanisms for inferring the node number from convergence-layer EIDs, which could generate false information, especially when multiple nodes were resident on the same machine. - Feature Request #14: The stream of "watch" characters that ION generates when significant bundle events occur can now be redirected in a manner similar to the way log messages may be redirected. - Feature Request #15: Per specification, ION's LTP implementation now supports LTP Authentication as described in RFC 5327. - Feature Request #16: In preparation for the deployment of delay-tolerant security key administration (DTKA), ION now includes several new features dealing with public/private key management in the ION security database. DTKA itself has been prototyped but is still pending approval for open source release. - Feature Request #17: A significant overhaul of the Bundle Streaming Service (BSS) has been implemented to resolve a fundamental incompatibility with implementing BSS with multicast. The new BSS forwarding implementation (BSSP) resides at the convergence layer directly under BP so BSS channel acknowledgments can be disambiguated. Previously, the BSS forwarder design relied on BP custody transfer to control BSS data forwarding over reliable and unreliable channels, which was incompatible with multicast because custody transfer can't distinguish among the multiple identical copies of a bundle that are forwarded at a multicast branch point. - Bug #21: The interface for the internal smlist "deletion" callback has been modified to be more consistent with the interfaces for the "lyst" and "sdrlist" modules. The API now accepts the address of the element to delete rather than its content. - Bug #24: Fixed an error in the implementation of previously-released bugfix where source or destination CFDP entity IDs could become malformed when their entityNbrLengths differ. - Bug #30: Applied various updates to LTP notices to be more compliant with the RFC 5326 specification. - LtpExportSessionStart notice is now delivered properly. - Reception claims in on-the-wire segments now have offsets that are relative to the report segment lower bound rather than relative to the start of the block. - Bug #33: LTP Green segment traffic is no longer terminated prematurely when a partly-red partly-green block is sent. - As a Receiver: Previously, closure of an import session (on reception of report-ACK) could incorrectly suppress the processing of subsequently received Green segments for the same session. - As a Sender: Previously, processing of an "all-received" Report segment could incorrectly closes the export session, which should not occur until the EOB has also been sent. - Bug #34: The Service Data Aggregation (SDA) in LTP has been updated to be compliant with the latest specifications. The SDA now properly passes the client ID to the client data unit length determination callback. - Bug #36: Fixed specific compilation problems with dtnperf under the Scientific Linux 5.5 (gcc 4.1.2) operating system. - Bug #39: Per specification, ION's LTP implementation now rejects LTP segments that do not contain the proper version number identifier (0b0000). Previously, ION would process segments regardless of version number. - Bug #40: Per specification, ION's LTP implementation now rejects LTP blocks with a session number of 0, as the specifications requires session numbers chosen by LTP senders to be in the range [1, 2^32-1]. Previously, ION would process such blocks with a cancel segment code 3. - Bug #41: Added checks in the AMS TCP connection pool implementation to help detect and guard against data corruption. - Bug #42: Improvements have been made to the rate control implementation of BP to better handle cases where the available residual capacity on the channel to a neighboring node is overstated. - Bug #43: Per specification, ION's LTP implementation now marks bundles as "malformed" when there are gaps in the sequence of green data segments. Previously, ION inserted fill data to saturate the gaps, which could result in the delivery of a damaged bundle. - Bug #44: Various man pages have been updated to be more compliant with the man page specification. - Bug #45: Added/updated man pages for various parts of the AMS subsystem. - Bug #46: Fixed bug in ionscript where a bss/ipn mutual exclusion error was presented when creating a monolithic configuration file and not specifying existing bss and ipn configuration files as input. Ionscript now properly outputs a monolithic configuration file that contains neither a BSS nor an IPN subsection. - Bug #48: Fixed a contact graph routing bug when recomputing routes wherein ION could exclude the potentially-optimal route from consideration if it is the initial contact on any remaining route. Due to the recent inclusion of CGR Payload Classes, it is no longer correct to exclude such routes from consideration. - Patch #5: The Delay Tolerant Network Management Protocol (DTNMP) reference implementation has been updated to the version that was used for testing and demonstration earlier in the year. - ION no longer requires libexpat by default in order to build. Expat is still required in order to use XML configuration files for AMS. To build against libexpat, use "./configure --with-expat". %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.2.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Issue #364: Added support for Delay Tolerant Payload Conditioning (DTPC). - DTPC adds (optional) end-to-end functionality similar to terrestrial transport-layer protocols on top of the Bundle Protocol. - DTPC offers the following additional enhancements: - Application data record aggregation into large ADUs. This reduces the BP overhead by preventing the proliferation of large numbers of small bundles. - Elision of redundant application data records. This optimizes the utilization of low-capacity communication links. - Feature Request #5: Several bugfixes and performance enhancements have been applied to the DCCP convergence layer. - Proper handling for the SIGPIPE signal. - Usage of keepalives (rather than terminating idle connections) and improved retry capability with an exponential backoff. - CCID and Transmission Queue Length are now configurable within ION. - Support added for the 0.0.0.0 (any) IP address. - Various other refinements to standardize the DCCP CL with the other ION convergence layers. - Feature Request #9: Added support for the DTN Network Monitoring reference implementation (DTNMP). DTNMP is an API added to ION that is used to produce and monitor BP, LTP, and ICI instrumentation data. - Feature Request #11: ION now provides the TTL of each received bundle in order to accomodate a CCSDS Blue Book service requirement. - Feature Request #12: Added support for DTNperf. DTNperf is a utility provided in ION's "contrib" directory that can be used to invoke performance testing between BP nodes. - Bug #22: Improved support for the Extended Class Of Service block (ECOS). ION now uses the "best effort" / "streaming" flag in ECOS to decide between UDP and TCP transmission. - Bug #24: Fixed a bug in CFDP where the destination entity ID could become malformed when the length of the compressed destination entity ID was smaller than the length of the compressed source entity ID. - Bug #25: Updated ION to be conformant with several new build warnings introduced in GCC 4.8. - Bug #26: Increased the default stack size for the tcpcli and tcpclo processes to prevent crashes under RTEMS and VxWorks. - Bug #27: Fixed a memory leak that could arise when sending anonymous bundles (bundles with a source EID of "dtn:none") while BSP was enabled. - Bug #28: Fixed bug where reforwarded bundles were sometimes not being properly purged from the forwarding queue. - Bug #29: Fixed bug where the ltp_get_notice() operation could return a bad value in its "data" value if the operation was interrupted. ltp_get_notice() now properly sets the "data" to zero if interrupted. - Bug #29: Errors in production of notices in LTP have been corrected. - An option to limit the length of checkpoint and report serial numbers in LTP has been added. The default limit is 2 bytes. - Added generalized service data aggregation to LTP. - Added controls to help understand and debug CGR routing decisions. - The CGR routing engine can now dynamically log diagnostic trace messages by enabling its "trace" flag. - A new "cgrfetch" utility can used to invoke the creation of JSON input files that describe the CGR routes that were considered. These JSON input files can be used in conjunction with the CGR Viewer web application to produced PDF files that provides illustrated graphs for all considered routes. See /contrib/cgr-viewer/Readme.md for more information. - Added man pages for the Asynchronous Message Service (AMS) subsystem. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.1.3 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Feature Request #6: LTP screening is now disabled (rather than enabled) by default. This should eliminate one often mystifying source of apparent connectivity loss. - Bug #23: Updated build configuration to fix build problems due to problems linking various pthread libraries when using bleeding-edge automake tools. - Bug #20: Child process of fork() was unable to write to log file if exec() failed. - Bug #19: Lifetime expiration of fragmentary bundles could cause a crash. - Bug #18: A cosmetic fix -- an informative log message has been added to explain an alarming message issued by the ACS system. - Bug #17: Various "admin" utility program function were broken when the new restart capability was added. - Bug #16: Errors in the generation of LTP checkpoint serial numbers have been fixed. In particular, no more duplicate checkpoint serial numbers. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.1.2 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Bug #13: Migrated admission control facilities into the ZCO subsystem so that they can be used outside of the BP subsystem. - Bug #14: Fixed bug where CFDP headers could be stripped by the ZCO subsystem. - Bug #15: Fixed various bugs that could affect ION's stability. - Fixed possible deadlock if the bpcp/bpcpd were terminated via a signal while in the middle of an SDR transaction. - Fixed bug in the outducts of several convergence layers and forwarder daemons that could cause them to not shut down properly due to an unintended interaction between the erasure of a taskVar semaphore with their internal looping constructs. - Feature Request #1: Implemented "payload classes" to enable more sophisticated contact graph routing functionality. Extended CGR to compute routes on a per-payload-class basis that respects the maximum bundle size that can be sent along each route. The current payload classes are as follows: - Payloads up to 1024 bytes (1 KB) - Payloads between 1024 bytes (1 KB) and 1048576 bytes (1 MB) - Payloads between 1048576 bytes (1 MB) and 1073741824 bytes (1 GB) - Payloads larger than 1073741824 bytes (1 GB) - Feature Request #4: Updated SDNV decoder and corresponding APIs to support up to 64-bit SDNV's on 32-bit systems, allowing for a wider space of possible IPN values. - Added uClibc support for ION. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.1.1 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Bug #9: Fixed several bugs in the TCP convergence layer. - TCPCLO would not reconnect to its neighbor if the neighbor was unreachable on startup. Fixed by instituting a default keepalive (currently 15 seconds). - Fixed a TCPCL interoperability bug when an external implementation uses full-duplex TCP connections where the tcpclo would fail to receive bundles from this implementation if the TCP connection had ever been previously lost. - Capped the maximum TCP reconnection timeout to 1 hour down from 24 hours. - Bug #11: Fixed bug with transaction reversibility enabled where unpredictable behavior could occur when a transaction reversal was forced and the state of the SDR and working memory were out of sync. ION now reinitializes working memory from the SDR to ensure data consistency. - Bug #12: Fixed a bug in the red-black tree data structure used in LTP by which sm_rbt_destroy() didn't release the tree's mutex to the OS which could ultimately lead to consumption of all semaphores on the system and crash the node. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.1.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Began transitioning to the SourceForge issue tracker for code management. SourceForge-originated issues are designated as "Bugs" or "Feature Requests". - Bug #1: Fixed bug where the contact graph routing engine would prefer a multi-hop route to the source over the "no-hop" loopback connection. - Bug #2: Fixed bug in contact graph routing engine where erroneous routes could be selected if route caching was enabled and any "downstream" contact on a route had an end time earlier than the end time of the first contact on the route. - Bug #3: Updated code and configurations to always use the dotted-string representation of the sender's IP address rather than hostname. This was done to mitigate problems that can arise due to aliasing and multihoming. - Bug #7: Fixed bug where ionadmin would duplicate all currently-added contacts and ranges that were added in the ION configuration files before starting ION with the 's' command. - Bug #8: Fixed bug where bundles that expired while in the limbo queue were not properly deallocated. - Bug #10: Updated the ionstart/ionscript/killm scripts with support for the following ION administrative modules: - Bundle streaming service (BSS) - Interplanetary multicast (IMC) - Aggregate custody signals (ACS) - Feature Request #2: Added support for bundle age extension blocks to help accomodate platforms that may not be able to provide a stable clock. For more information on the bundle age extension, refer to internet draft draft-irtf-dtnrg-bundle-age-block-01 - Feature Request #3: Added support for bundle multicast. - Issue #195: Finished replacement of pthreads-based semaphore "unwedge" function with simpler platform-specific equivalents, begun in ION 2.4.0. - Issue #306: Implemented several improvements to congestion forecasting. - Improved the accuracy of the forecast of maximum storage occupancy by incorporating estimations based on the rate of data being transmitted in and out of the internal data heaps. - ION now raises an alarm if expected peak volume of data is larger than ION's allocated file storage size. - Added new utility called "ionwarn" that is used for computing congestion forecast at an ION node based on contact plan. - Issue #311: Added a Bundle Streaming Service (BSS) regression test that does not require the use of "xterm". - Issue #339: Fixed bug in aggregate custody signals implementation that prevented successful completion of regression tests on some platforms. - Issue #349: Optimized the LTP engine to achieve faster data rates by by substituting red-black trees and hash tables for linked lists where appropriate. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.0.2 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Issue #280: Fixed a deadlock scenario when using "ionstart" to start two nodes nodes in parallel. - Issue #349: Applied some optimizations to the LTP engine to help it operate at data rates that can exceed 80Mbps. - Issue #357: Fixed compilation issues that prevented ION from building properly on some kfreebsd systems. - Issue #358: Fixed a bug in computing the CFDP inactivity deadline. Updated the "cfdprc" man page to expose the parameters for configuring the CFDP inactivity timeout interval. - Issue #360: Updated the MinGW port of ION to supply definitions for various required macros that are no longer supplied by newer versions of MinGW. - Issue #361: Fixed compilation issues that prevented ION from building properly on some debian-unstable systems. - Issue #362: Fixed a bug where transplantation of man pages into ION.pdf could fail if an obsolete version of man was used, causing compilation to fail. ION now detects if the required "-l" option for man is supported, and does not attempt to transplant the man pages if the option is not found. - Issue #363: Fixed several memory leaks where SDR heap space was allocated but not freed. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.0.1 = %%%%%%%%%%%%%%%%%%%%%%%%%% - *Issue #347: Included a test exercizing the fix for the TCPCL reconnection bug that was made available in ion-open-source v3.0.0. - Issue #348: Refreshed the MinGW and RTEMS ports of ION to build properly. - Issue #352: BPCP, an rcp-like remote copy utility that transfers files via CFDP, is a new utility now included with ION. It is built and installed by default and has an interface similar to rcp, with support for local to remote, remote to local, and remote to remote transfers in recursive and non-recursive modes. - Issue #353: Scrubbed various test configurations in the test suite that produced superfluous messages regarding the bundle security database not being initialized properly. - Issue #354: Slightly changed the behavior of "make retest", a directive that reruns tests that failed on the previous test run. Previously "make retest" would re-run the entire test suite if issued immediately following a completely sucessful test run. "make retest" now returns SUCCESS immediately if issued following a completely successful test run, a behavior more amenable to automated testing. - Issue #355: Updated the ION build process to be compatible with the latest versions of autotools, particularly automake v1.12. - Issue #356: Enhanced the bptrace application with file-sending capabilities. - ION has now been ported to the "bionic" libc implementation, the first step toward porting ION to the Android operating system. - Starting from this release the ION manual "ION.pdf" will be distributed with an appendix containing up-to-date man pages for all ION applications. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 3.0.0 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Issue #242: Removed unnecessary recursion from the CGR implementation to help protect against overflows from incorrect configurations. - Issue #262: ION is now wired with a rudimentary instrumentation framework for insight into run-time status, including bundle processing statistics and node state metrics. This is in preparation for standardized network management. - Issue #302: Implemented red-black trees as an alternative data structure to linked lists for some performance-sensitive applications. Migrated the BP timeline to use red-black trees. - Issue #304: Optimized CGR route computation by developing a new algorithm that employs Dijkstra's Algorithm. - Issue #308: Several updates to ION's Payload Integrity Blocks (PIB) and Payload Confidentiality Blocks (PCB): - Bundle Security Protocol (BSP) utilities now support PIB and PCB. - PIB and PCB extension block code has been added. - Roughly 40 new test cases for PIB, PCB, and BAB combinations have been introduced. - Issue #311: Bundle Streaming Service (BSS) support has been added to ION. BSS passes "real-time" bundle payloads to an application callback while also storing the bundle payloads to a database for user-directed playback. - Issue #314: Standardized spelling of the word "semaphore" throughout the ION codebase. - Issue #322: Improved reliability for custodial retransmissions when the next custodian is a neighbor by making the following tweaks in libbpP.c: - Changed the bpDequeue "stewardship accepted" flag to a custodial timeout interval value (in seconds) that is computed by the CL output daemon, based on CL-specific knowledge, in the event that the CL protocol is not reliable and therefore can't accept stewardship of the bundle. - Added the same custodial timeout interval value to bpHandleXmitSuccess, to trigger reforwarding of the bundle even when stewardship has been taken and CL transmission has been nominally successful and reliable, in the event that the CL transmission ultimately (unexpectedly) does not succeed. - Issue #325: Fixed a bug that could cause ION to crash when sending bundles for which the destination endpoint is not a singleton. - Issue #329: ION now supports sending (rather than just receiving) fragmented bundles. (NOTE: this entailed several changes to the ZCO API.) - Issue #339: Aggregate Custody Signals (ACS) have been added to ION. - ACS is a technology that combines information from various separate custody signals into a single bundle, which has the potential to save "ack channel" bandwidth. - For more information on ACS, see the following document: <http://bioserve.colorado.edu/bp-acs/draft-kuzminsky-aggregate-custody-signals-02.txt> - Issue #342: Changed several invocations of lyst_create() to lyst_create_using(), to ensure that ION's private memory management is always used. - Issue #343: Fixed bugs in LTP that could cause crashes at high data loss rates - Fixed mechanisms for preventing resurrection of closed Import sessions. - Fixed issue where the same report number could become assigned to two different reports, resulting in link service daemons crashing. - Issue #344: Added a "-t <ttl>" command line parameter to set the time-to-live for bundles sent from the bpsource application. Previously bundles were hard-coded with lifetimes of 300 seconds, which is now the default if the TTL is not explicitly specified. - Issue #345: The ION Deployment Guide is now bundled with ION. It provides FAQ-style documentation for helping new users familiarize themselves with ION. - Issue #347: Fixed bug in re-establishing connectivity via TCPCL when a node shuts down and then restarts. %%%%%%%%%%%%%%%%%%%%%%%%%% = NOTES ON RELEASE 2.5.3 = %%%%%%%%%%%%%%%%%%%%%%%%%% - Issue #271: Various autotools changes to update how CFDP is built. - Issue #288: Fixed bug in CFDP implementation where performing a proxy "puts" operation without supplying a flo