Protocol ossification: Difference between revisions

Revision as of 11:58, 14 March 2020

Revision as of 11:59, 14 March 2020

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'''Protocol ossification''' is a progressive reduction in the flexibility of [[network protocol]] design caused by the presence of [[middlebox]]es in the network which cannot easily be removed or upgraded to allow protocol changes. An example of this is the presence of [[firewall]] and [[carrier grade NAT]] middleboxes in the [[Internet]], where over-cautious checking of protocol fields has prevented the use of those fields for future protocol expansion, breaking the [[end-to-end principle]] of the Internet architecture.<ref>{{Cite journal|last=Papastergiou|first=Giorgos|last2=Fairhurst|first2=Gorry|last3=Ros|first3=David|last4=Brunstrom|first4=Anna|last5=Grinnemo|first5=Karl-Johan|last6=Hurtig|first6=Per|last7=Khademi|first7=Naeem|last8=Tuxen|first8=Michael|last9=Welzl|first9=Michael|last10=Damjanovic|first10=Dragana|last11=Mangiante|first11=Simone|date=2017|title=De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives|url=http://ieeexplore.ieee.org/document/7738442/|journal=IEEE Communications Surveys & Tutorials|volume=19|issue=1|pages=619–639|doi=10.1109/COMST.2016.2626780|issn=1553-877X|url=https://aura.abdn.ac.uk/bitstream/handle/2164/8317/De_ossifying_the_internet_transport_layer.pdf}}</ref>

For example, protocol ossification initially prevented the adoption of [[TLS 1.3]], a problem which was fixed by introducinga [[workaround]] which introduced elements into the TLS 1.3 handshake which appeared (falsely) to middleboxes to be a TLS 1.2 handshake.<ref>{{Cite web|url=https://blog.cloudflare.com/why-tls-1-3-isnt-in-browsers-yet/|title=Why TLS 1.3 isn't in browsers yet|date=2017-12-26|website=The Cloudflare Blog|language=en|access-date=2020-03-14}}</ref>

Protocol ossification can be avoided by the use of [[encryption]] or [[tunnelling]] to hide the structure of new protocol extensions from older middleboxes.<ref name=LWN>{{Cite web|url=https://lwn.net/Articles/745590/|title=QUIC as a solution to protocol ossification|website=lwn.net|access-date=2020-03-14|first=Jonathan|last=Corbet|date=January 29, 2018}}</ref> [[QUIC]] is an examples of a protocol which uses encryption to avoid middleboxes.<ref>{{Cite web|url=https://blog.cloudflare.com/the-road-to-quic/|title=The Road to QUIC|date=2018-07-26|website=The Cloudflare Blog|language=en|access-date=2020-03-14}}</ref>