The IETF created the Transport Services (taps) working group in 2014. It has a mandate to mitigate ossification at the transport protocol layer.
Changes to a protocol must be tolerated by all on-path intermediaries; if wide Internet deployment of the change is desired, then this extends to a large portion of intermediaries on the Internet. A middlebox must tolerate widely-used protocols as they were being used at the time of its deployment, but is liable not to tolerate new protocols or changes to extant ones, effectively creating a vicious cycle as novel wire images cannot gain wide enough deployment to make middleboxes tolerate the new wire image across the entire Internet. Even all participants tolerating the protocol is no guarantee of use: in the absence of a negotiation or discovery mechanism, the endpoints may default to a protocol that is considered more reliable.
Beyond middleboxes, ossification can also be caused by insufficient flexibility within the endpoint's implementation. Operating system kernels are slow to change and deploy, and protocols implemented in hardware can also inappropriately fix protocol details. A widely-used application programming interface (API) that makes assumptions about the operation of underlying protocols can hinder the deployment of protocols that do not share those assumptions.
Active use of extension points is required if they are not to ossify. Reducing the number of extension points, documenting invariants that protocol participants can rely on as opposed to incidental details that must not be relied upon, and prompt detection of issues in deployed systems can assist in ensuring active use. However, even active use may only exercise a narrow portion of the protocol and ossification can still occur in the parts that remain invariant in practice despite theoretical variability. "Greasing" an extension point, where some implementations indicate support for non-existent extensions, can ensure that actually-existent-but-unrecognised extensions are tolerated (cf. chaos engineering). HTTP headers are an example of an extension point that has successfully avoided significant ossification, as participants will generally ignore unrecognised headers.
A new protocol may be designed to mimic the wire image of an existing ossified protocol; alternatively, a new protocol may be encapsulated within an existing, tolerated protocol. A disadvantage of encapsulation is that there is typically overhead and redundant work (e.g., outer checksums made redundant by inner integrity checks).
With sufficient effort and coordination, ossification can be directly reversed. A flag day, where protocol participants make changes in concert, can break the vicious cycle and establish active use. This approach was used to deploy EDNS, which had formerly not been tolerated by servers.
Ammar 2018, p. 57-58. - Ammar, Mostafa (January 2018). "Ex Uno Pluria: The Service-Infrastructure Cycle, Ossification, and the Fragmentation of the Internet". ACM SIGCOMM Comput. Commun. Rev. doi:10.1145/3211852.3211861. S2CID 12169344. https://doi.org/10.1145%2F3211852.3211861
Ammar 2018, p. 59. - Ammar, Mostafa (January 2018). "Ex Uno Pluria: The Service-Infrastructure Cycle, Ossification, and the Fragmentation of the Internet". ACM SIGCOMM Comput. Commun. Rev. doi:10.1145/3211852.3211861. S2CID 12169344. https://doi.org/10.1145%2F3211852.3211861
Raiciu et al. 2012, p. 1. - Raiciu, Costin; Paasch, Christoph; Barre, Sebastien; Ford, Alan; Honda, Michio; Duchene, Fabien; Bonaventure, Olivier; Handley, Mark (2012). How Hard Can It Be? Designing and Implementing a Deployable Multipath TCP. 9th USENIX Symposium on Networked Systems Design and Implementation (NSDI 12). https://www.usenix.org/conference/nsdi12/technical-sessions/presentation/raiciu
"Transport Services (taps) – Group history". IETF. https://datatracker.ietf.org/wg/taps/history/
"Transport Services – charter-ietf-taps-02". IETF. https://datatracker.ietf.org/doc/charter-ietf-taps/
Trammell & Kuehlewind 2019, p. 2. - Trammell, Brian; Kuehlewind, Mirja (April 2019). The Wire Image of a Network Protocol. doi:10.17487/RFC8546. RFC 8546. https://datatracker.ietf.org/doc/html/rfc8546
Arkko et al. 2023, 3. Further Work. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Papastergiou et al. 2017, p. 619. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Papastergiou et al. 2017, p. 620. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Edeline & Donnet 2019, p. 171. - Edeline, Korian; Donnet, Benoit (2019). A Bottom-Up Investigation of the Transport-Layer Ossification. 2019 Network Traffic Measurement and Analysis Conference (TMA). doi:10.23919/TMA.2019.8784690. https://doi.org/10.23919%2FTMA.2019.8784690
Edeline & Donnet 2019, p. 173-175. - Edeline, Korian; Donnet, Benoit (2019). A Bottom-Up Investigation of the Transport-Layer Ossification. 2019 Network Traffic Measurement and Analysis Conference (TMA). doi:10.23919/TMA.2019.8784690. https://doi.org/10.23919%2FTMA.2019.8784690
Edeline & Donnet 2019, p. 169. - Edeline, Korian; Donnet, Benoit (2019). A Bottom-Up Investigation of the Transport-Layer Ossification. 2019 Network Traffic Measurement and Analysis Conference (TMA). doi:10.23919/TMA.2019.8784690. https://doi.org/10.23919%2FTMA.2019.8784690
Honda et al. 2011, p. 1. - Honda, Michio; Nishida, Yoshifumi; Raiciu, Costin; Greenhalgh, Adam; Handley, Mark; Tokuda, Hideyuki (2011). Is It Still Possible to Extend TCP?. 2011 ACM SIGCOMM Conference on Internet Measurement. doi:10.1145/2068816.2068834. https://doi.org/10.1145%2F2068816.2068834
Edeline & Donnet 2019, p. 169. - Edeline, Korian; Donnet, Benoit (2019). A Bottom-Up Investigation of the Transport-Layer Ossification. 2019 Network Traffic Measurement and Analysis Conference (TMA). doi:10.23919/TMA.2019.8784690. https://doi.org/10.23919%2FTMA.2019.8784690
Papastergiou et al. 2017, p. 620. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Papastergiou et al. 2017, p. 621. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Papastergiou et al. 2017, p. 621. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Corbet 2015. - Corbet, Jonathan (8 December 2015). "Checksum offloads and protocol ossification". LWN.net. https://lwn.net/Articles/667059/
Papastergiou et al. 2017, p. 620. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Hardie 2019, p. 7-8. - Hardie, Ted, ed. (April 2019). Transport Protocol Path Signals. doi:10.17487/RFC8558. RFC 8558. https://datatracker.ietf.org/doc/html/rfc8558
Fairhurst & Perkins 2021, 7. Conclusions. - Fairhurst, Gorry; Perkins, Colin (July 2021). Considerations around Transport Header Confidentiality, Network Operations, and the Evolution of Internet Transport Protocols. doi:10.17487/RFC9065. RFC 9065. https://datatracker.ietf.org/doc/html/rfc9065
Fairhurst & Perkins 2021, 2. Current Uses of Transport Headers within the Network. - Fairhurst, Gorry; Perkins, Colin (July 2021). Considerations around Transport Header Confidentiality, Network Operations, and the Evolution of Internet Transport Protocols. doi:10.17487/RFC9065. RFC 9065. https://datatracker.ietf.org/doc/html/rfc9065
Fairhurst & Perkins 2021, 3. Research, Development, and Deployment. - Fairhurst, Gorry; Perkins, Colin (July 2021). Considerations around Transport Header Confidentiality, Network Operations, and the Evolution of Internet Transport Protocols. doi:10.17487/RFC9065. RFC 9065. https://datatracker.ietf.org/doc/html/rfc9065
Fairhurst & Perkins 2021, 7. Conclusions. - Fairhurst, Gorry; Perkins, Colin (July 2021). Considerations around Transport Header Confidentiality, Network Operations, and the Evolution of Internet Transport Protocols. doi:10.17487/RFC9065. RFC 9065. https://datatracker.ietf.org/doc/html/rfc9065
Arkko et al. 2023, 2.1. Intentional Distribution. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Arkko et al. 2023, 2.2. Control of the Distribution of Information. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Arkko et al. 2023, 2.3. Protecting Information and Authentication. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Arkko et al. 2023, 2.5. Limiting Impact of Information. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Arkko et al. 2023, 2.4. Minimize Information. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Arkko et al. 2023, 2.6. Minimum Set of Entities. - Arkko, Jari; Hardie, Ted; Pauly, Tommy; Kühlewind, Mirja (July 2023). Considerations on Application - Network Collaboration Using Path Signals. doi:10.17487/RFC9419. RFC 9419. https://datatracker.ietf.org/doc/html/rfc9419
Thomson & Pauly 2021, 3. Active Use. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Thomson & Pauly 2021, 4. Complementary Techniques. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Thomson & Pauly 2021, 3.1. Dependency Is Better. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Trammell & Kuehlewind 2019, p. 7. - Trammell, Brian; Kuehlewind, Mirja (April 2019). The Wire Image of a Network Protocol. doi:10.17487/RFC8546. RFC 8546. https://datatracker.ietf.org/doc/html/rfc8546
Thomson & Pauly 2021, 3.3. Falsifying Active Use. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Thomson & Pauly 2021, 3.4. Examples of Active Use. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Papastergiou et al. 2017, p. 623. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Papastergiou et al. 2017, p. 623-4. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Papastergiou et al. 2017, p. 630. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Corbet 2016. - Corbet, Jonathan (20 June 2016). "Transport-level protocols in user space". LWN.net. https://lwn.net/Articles/691887/
Papastergiou et al. 2017, p. 629. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Thomson & Pauly 2021, 3.5. Restoring Active Use. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Thomson & Pauly 2021, A.5. TCP. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Edeline & Donnet 2019, p. 175-176. - Edeline, Korian; Donnet, Benoit (2019). A Bottom-Up Investigation of the Transport-Layer Ossification. 2019 Network Traffic Measurement and Analysis Conference (TMA). doi:10.23919/TMA.2019.8784690. https://doi.org/10.23919%2FTMA.2019.8784690
Raiciu et al. 2012, p. 1. - Raiciu, Costin; Paasch, Christoph; Barre, Sebastien; Ford, Alan; Honda, Michio; Duchene, Fabien; Bonaventure, Olivier; Handley, Mark (2012). How Hard Can It Be? Designing and Implementing a Deployable Multipath TCP. 9th USENIX Symposium on Networked Systems Design and Implementation (NSDI 12). https://www.usenix.org/conference/nsdi12/technical-sessions/presentation/raiciu
Hesmans et al. 2013, p. 1. - Hesmans, Benjamin; Duchene, Fabien; Paasch, Christoph; Detal, Gregory; Bonaventure, Olivier (2013). Are TCP extensions middlebox-proof?. HotMiddlebox '13. CiteSeerX 10.1.1.679.6364. doi:10.1145/2535828.2535830. https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.679.6364
Rybczyńska 2020. - Rybczyńska, Marta (13 March 2020). "A QUIC look at HTTP/3". LWN.net. https://lwn.net/Articles/814522/
Thomson & Pauly 2021, A.5. TCP. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Papastergiou et al. 2017, p. 620. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
Papastergiou et al. 2017, p. 627. - Papastergiou, Giorgos; Fairhurst, Gorry; Ros, David; Brunstrom, Anna; Grinnemo, Karl-Johan; Hurtig, Per; Khademi, Naeem; Tüxen, Michael; Welzl, Michael; Damjanovic, Dragana; Mangiante, Simone (2017). "De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives". IEEE Communications Surveys & Tutorials. 19: 619–639. doi:10.1109/COMST.2016.2626780. hdl:2164/8317. S2CID 1846371. https://doi.org/10.1109%2FCOMST.2016.2626780
McQuistin, Perkins & Fayed 2016, p. 1. - McQuistin, Stephen; Perkins, Colin; Fayed, Marwan (July 2016). Implementing Real-Time Transport Services over an Ossified Network. 2016 Applied Networking Research Workshop. doi:10.1145/2959424.2959443. hdl:1893/26111. https://doi.org/10.1145%2F2959424.2959443
Sullivan 2017. - Sullivan, Nick (2017-12-26). "Why TLS 1.3 isn't in browsers yet". The Cloudflare Blog. Retrieved 2020-03-14. https://blog.cloudflare.com/why-tls-1-3-isnt-in-browsers-yet/
Corbet 2018. - Corbet, Jonathan (29 January 2018). "QUIC as a solution to protocol ossification". LWN.net. https://lwn.net/Articles/745590/
Trammell & Kuehlewind 2019, p. 2. - Trammell, Brian; Kuehlewind, Mirja (April 2019). The Wire Image of a Network Protocol. doi:10.17487/RFC8546. RFC 8546. https://datatracker.ietf.org/doc/html/rfc8546
Thomson & Pauly 2021, 3.3. Falsifying Active Use. - Thomson, Martin; Pauly, Tommy (December 2021). Long-Term Viability of Protocol Extension Mechanisms. doi:10.17487/RFC9170. RFC 9170. https://datatracker.ietf.org/doc/html/rfc9170
Thomson 2021, 2. Fixed Properties of All QUIC Versions. - Thomson, Martin (May 2021). Version-Independent Properties of QUIC. doi:10.17487/RFC8999. RFC 8999. https://datatracker.ietf.org/doc/html/rfc8999
Corbet 2018. - Corbet, Jonathan (29 January 2018). "QUIC as a solution to protocol ossification". LWN.net. https://lwn.net/Articles/745590/
Kühlewind & Trammell 2022, 2. The Necessity of Fallback. - Kühlewind, Mirja; Trammell, Brian (September 2022). Applicability of the QUIC Transport Protocol. doi:10.17487/RFC9308. RFC 9308. https://datatracker.ietf.org/doc/html/rfc9308