rfc8931v3.txt | rfc8931.txt | |||
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skipping to change at line 425 ¶ | skipping to change at line 425 ¶ | |||
to end as smaller fragment Sequences 13 and 14 in Section 6.2. | to end as smaller fragment Sequences 13 and 14 in Section 6.2. | |||
The first fragment is recognized by a Sequence of 0; it carries its | The first fragment is recognized by a Sequence of 0; it carries its | |||
Fragment_Size and the Datagram_Size of the compressed packet before | Fragment_Size and the Datagram_Size of the compressed packet before | |||
it is fragmented, whereas the other fragments carry their | it is fragmented, whereas the other fragments carry their | |||
Fragment_Size and Fragment_Offset. The last fragment for a datagram | Fragment_Size and Fragment_Offset. The last fragment for a datagram | |||
is recognized when its Fragment_Offset and its Fragment_Size add up | is recognized when its Fragment_Offset and its Fragment_Size add up | |||
to the stored Datagram_Size of the packet identified by the sender | to the stored Datagram_Size of the packet identified by the sender | |||
link-layer address and the Datagram_Tag. | link-layer address and the Datagram_Tag. | |||
1 2 3 | 1 2 3 | |||
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |||
|1 1 1 0 1 0 0|E| Datagram_Tag | | |1 1 1 0 1 0 0|E| Datagram_Tag | | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |||
|X| Sequence| Fragment_Size | Fragment_Offset | | |X| Sequence| Fragment_Size | Fragment_Offset | | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |||
X set == Ack-Request | X set == Ack-Request | |||
Figure 1: RFRAG Dispatch Type and Header | Figure 1: RFRAG Dispatch Type and Header | |||
skipping to change at line 872 ¶ | skipping to change at line 872 ¶ | |||
in the reassembling endpoint and on intermediate nodes. There is no | in the reassembling endpoint and on intermediate nodes. There is no | |||
new parameter as echoing ECN is always on. These parameters | new parameter as echoing ECN is always on. These parameters | |||
typically include the reassembly timeout at the reassembling | typically include the reassembly timeout at the reassembling | |||
endpoint, an inactivity cleanup timer on the intermediate nodes, and | endpoint, an inactivity cleanup timer on the intermediate nodes, and | |||
the number of messages that can be processed in parallel in all | the number of messages that can be processed in parallel in all | |||
nodes. | nodes. | |||
The configuration settings introduced by this specification only | The configuration settings introduced by this specification only | |||
apply to the fragmenting endpoint, which is in full control of the | apply to the fragmenting endpoint, which is in full control of the | |||
transmission. LLNs vary a lot in size (there can be thousands of | transmission. LLNs vary a lot in size (there can be thousands of | |||
nodes in a mesh), in speed (from 10 Kbps to several Mbps at the | nodes in a mesh), in speed (from 10 Kbps to several Mbps at the PHY | |||
Physical Layer (PHY) layer), in traffic density, and in optimizations | layer), in traffic density, and in optimizations that are desired | |||
that are desired (e.g., the selection of a Routing Protocol for LLNs | (e.g., the selection of a Routing Protocol for LLNs (RPL) [RFC6550] | |||
(RPL) [RFC6550] Objective Function [RFC6552] impacts the shape of the | Objective Function [RFC6552] impacts the shape of the routing graph). | |||
routing graph). | ||||
For that reason, only very generic guidance can be given on the | For that reason, only very generic guidance can be given on the | |||
settings of the fragmenting endpoint and on whether complex | settings of the fragmenting endpoint and on whether complex | |||
algorithms are needed to perform congestion control or to estimate | algorithms are needed to perform congestion control or to estimate | |||
the round-trip time. To cover the most complex use cases, this | the round-trip time. To cover the most complex use cases, this | |||
specification enables the fragmenting endpoint to vary the fragment | specification enables the fragmenting endpoint to vary the fragment | |||
size, the window size, and the inter-frame gap based on the number of | size, the window size, and the inter-frame gap based on the number of | |||
losses, the observed variations of the round-trip time, and the | losses, the observed variations of the round-trip time, and the | |||
setting of the ECN bit. | setting of the ECN bit. | |||
skipping to change at line 1498 ¶ | skipping to change at line 1497 ¶ | |||
is to manage the number of fragments present in the network; this is | is to manage the number of fragments present in the network; this is | |||
achieved by reducing the number of outstanding fragments over a | achieved by reducing the number of outstanding fragments over a | |||
congested path by throttling the sources. | congested path by throttling the sources. | |||
Acknowledgments | Acknowledgments | |||
The author wishes to thank Michel Veillette, Dario Tedeschi, Laurent | The author wishes to thank Michel Veillette, Dario Tedeschi, Laurent | |||
Toutain, Carles Gomez Montenegro, Thomas Watteyne, and Michael | Toutain, Carles Gomez Montenegro, Thomas Watteyne, and Michael | |||
Richardson for their in-depth reviews and comments. Also, many | Richardson for their in-depth reviews and comments. Also, many | |||
thanks to Roman Danyliw, Peter Yee, Colin Perkins, Tirumaleswar | thanks to Roman Danyliw, Peter Yee, Colin Perkins, Tirumaleswar | |||
Reddy.K, Eric Vyncke, Warren Kumari, Magnus Westerlund, Erik | Reddy.K, Éric Vyncke, Warren Kumari, Magnus Westerlund, Erik | |||
Nordmark, and especially Benjamin Kaduk and Mirja Kuehlewind for | Nordmark, and especially Benjamin Kaduk and Mirja Kühlewind for their | |||
their careful reviews and help during the IETF Last Call and IESG | careful reviews and help during the IETF Last Call and IESG review | |||
review process. Thanks to Jonathan Hui, Jay Werb, Christos Polyzois, | process. Thanks to Jonathan Hui, Jay Werb, Christos Polyzois, | |||
Soumitri Kolavennu, Pat Kinney, Margaret Wasserman, Richard Kelsey, | Soumitri Kolavennu, Pat Kinney, Margaret Wasserman, Richard Kelsey, | |||
Carsten Bormann, and Harry Courtice for their various contributions | Carsten Bormann, and Harry Courtice for their various contributions | |||
in the long process that lead to this document. | in the long process that lead to this document. | |||
Author's Address | Author's Address | |||
Pascal Thubert (editor) | Pascal Thubert (editor) | |||
Cisco Systems, Inc. | Cisco Systems, Inc. | |||
Building D | Building D | |||
45 Allee des Ormes - BP1200 | 45 Allee des Ormes - BP1200 | |||
End of changes. 3 change blocks. | ||||
10 lines changed or deleted | 9 lines changed or added | |||
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