draft-ietf-tsvwg-rfc6040update-shim-11.txt   draft-ietf-tsvwg-rfc6040update-shim-12.txt 
Transport Area Working Group B. Briscoe Transport Area Working Group B. Briscoe
Internet-Draft Independent Internet-Draft Independent
Updates: 6040, 2661, 2784, 3931, 4380, November 15, 2020 Updates: 6040, 2661, 2784, 3931, 4380, November 15, 2020
7450 (if approved) 7450 (if approved)
Intended status: Standards Track Intended status: Standards Track
Expires: May 19, 2021 Expires: May 19, 2021
Propagating Explicit Congestion Notification Across IP Tunnel Headers Propagating Explicit Congestion Notification Across IP Tunnel Headers
Separated by a Shim Separated by a Shim
draft-ietf-tsvwg-rfc6040update-shim-11 draft-ietf-tsvwg-rfc6040update-shim-12
Abstract Abstract
RFC 6040 on "Tunnelling of Explicit Congestion Notification" made the RFC 6040 on "Tunnelling of Explicit Congestion Notification" made the
rules for propagation of ECN consistent for all forms of IP in IP rules for propagation of ECN consistent for all forms of IP in IP
tunnel. This specification updates RFC 6040 to clarify that its tunnel. This specification updates RFC 6040 to clarify that its
scope includes tunnels where two IP headers are separated by at least scope includes tunnels where two IP headers are separated by at least
one shim header that is not sufficient on its own for wide area one shim header that is not sufficient on its own for wide area
packet forwarding. It surveys widely deployed IP tunnelling packet forwarding. It surveys widely deployed IP tunnelling
protocols that use such shim header(s) and updates the specifications protocols that use such shim header(s) and updates the specifications
skipping to change at page 7, line 29 skipping to change at page 7, line 29
If a tunnel ingress fragments a packet, it MUST set the outer ECN If a tunnel ingress fragments a packet, it MUST set the outer ECN
field of all the fragments to the same value as it would have set if field of all the fragments to the same value as it would have set if
it had not fragmented the packet. it had not fragmented the packet.
During reassembly of outer fragments [I-D.ietf-intarea-tunnels], if During reassembly of outer fragments [I-D.ietf-intarea-tunnels], if
the ECN fields of the outer headers being reassembled into a single the ECN fields of the outer headers being reassembled into a single
packet consist of a mixture of Not-ECT and other ECN codepoints, the packet consist of a mixture of Not-ECT and other ECN codepoints, the
packet MUST be discarded. packet MUST be discarded.
As a tunnel egress reassembles sets of outer fragments Section 5.3 of [RFC3168] defines the process that a tunnel egress
[I-D.ietf-intarea-tunnels] into packets, it MUST comply with the follows to reassemble sets of outer fragments
reassembly requirements in Section 5.3 of [RFC3168]. [I-D.ietf-intarea-tunnels] into packets.
6. IP-in-IP Tunnels with Tightly Coupled Shim Headers 6. IP-in-IP Tunnels with Tightly Coupled Shim Headers
There follows a list of specifications of encapsulations with tightly There follows a list of specifications of encapsulations with tightly
coupled shim header(s), in rough chronological order. The list is coupled shim header(s), in rough chronological order. The list is
confined to standards track or widely deployed protocols. The list confined to standards track or widely deployed protocols. The list
is not necessarily exhaustive so, for the avoidance of doubt, the is not necessarily exhaustive so, for the avoidance of doubt, the
scope of RFC 6040 is defined in Section 3 and is not limited to this scope of RFC 6040 is defined in Section 3 and is not limited to this
list. list.
 End of changes. 2 change blocks. 
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