draft-ietf-6lo-minimal-fragment-04.txt   draft-ietf-6lo-minimal-fragment-05.txt 
6lo T. Watteyne, Ed. 6lo T. Watteyne, Ed.
Internet-Draft Analog Devices Internet-Draft Analog Devices
Intended status: Informational C. Bormann Intended status: Informational P. Thubert, Ed.
Expires: March 2, 2020 Universitaet Bremen TZI Expires: 29 May 2020 Cisco Systems
P. Thubert C. Bormann
Cisco Universitaet Bremen TZI
August 30, 2019 26 November 2019
6LoWPAN Fragment Forwarding On Forwarding 6LoWPAN Fragments over a Multihop IPv6 Network
draft-ietf-6lo-minimal-fragment-04 draft-ietf-6lo-minimal-fragment-05
Abstract Abstract
This document provides a simple method to forwarding 6LoWPAN This document introduces the capability to forward 6LoWPAN fragments.
fragments. When employing adaptation layer fragmentation in 6LoWPAN, This method reduces the latency and increases end-to-end reliability
it may be beneficial for a forwarder not to have to reassemble each in route-over forwarding. It is the companion to using virtual
packet in its entirety before forwarding it. This has always been reassembly buffers which is a pure implementation technique.
possible with the original fragmentation design of RFC4944. This
method reduces the latency and increases end-to-end reliability in
route-over forwarding. It is the companion to the virtual Reassembly
Buffer which is a pure implementation technique.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on March 2, 2020. This Internet-Draft will expire on 29 May 2020.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Overview of 6LoWPAN Fragmentation . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Limits of Per-Hop Fragmentation and Reassembly . . . . . . . 4 2. Overview of 6LoWPAN Fragmentation . . . . . . . . . . . . . . 3
2.1. Latency . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Limits of Per-Hop Fragmentation and Reassembly . . . . . . . 5
2.2. Memory Management and Reliability . . . . . . . . . . . . 4 3.1. Latency . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Virtual Reassembly Buffer (VRB) Implementation . . . . . . . 5 3.2. Memory Management and Reliability . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 4. Forwarding Fragments . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. Virtual Reassembly Buffer (VRB) Implementation . . . . . . . 7
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. Informative References . . . . . . . . . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
9. Normative References . . . . . . . . . . . . . . . . . . . . 9
10. Informative References . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Overview of 6LoWPAN Fragmentation 1. Introduction
The original 6LoWPAN fragmentation is defined in [RFC4944] and it is The original 6LoWPAN fragmentation is defined in [6LoWPAN] and it is
implicitly defined for use over a single IP hop though possibly implicitly defined for use over a single IP hop through possibly
multiple Layer-2 hops in a meshed 6LoWPAN Network. Although multiple Layer-2 (mesh-under) hops in a meshed 6LoWPAN Network.
[RFC6282] updates [RFC4944], it does not redefine 6LoWPAN Although [6LoWPAN-HC] updates [6LoWPAN], it does not redefine 6LoWPAN
fragmentation. fragmentation.
This means that over a Layer-3 (route-over) network, an IP packet is
expected to be reassembled at every hop at the 6LoWPAN sublayer,
pushed to Layer-3 to be routed, and then fragmented again if the next
hop is another similar 6LoWPAN link. This draft introduces an
alternate approach called 6LoWPAN Fragment Forwarding (FF) whereby an
intermediate node forwards a fragment as soon as it is received if
the next hop is a similar 6LoWPAN link. The routing decision is made
on the first fragment, which has all the IPv6 routing information.
The first fragment is forwarded immediately and a state is stored to
enable forwarding the next fragments along the same path.
Done right, 6LoWPAN Fragment Forwarding techniques lead to more
streamlined operations, less buffer bloat and lower latency. It may
be wasteful if some fragments are missing after the first one since
the first fragment will still continue till the 6LoWPAN endpoint that
will attempt to perform the reassembly, and may be misused to the
point that performances fall behind that of per-hop recomposition.
This specification provides a generic overview of FF, discusses
advantages and caveats, and introduces a particular 6LoWPAN Fragment
Forwarding technique called Virtual Reassembly Buffer that can be
used while conserving the message formats defined in [6LoWPAN].
2. Overview of 6LoWPAN Fragmentation
We use Figure 1 to illustrate 6LoWPAN fragmentation. We assume node We use Figure 1 to illustrate 6LoWPAN fragmentation. We assume node
A forwards a packet to node B, possibly as part of a multi-hop route A forwards a packet to node B, possibly as part of a multi-hop route
between IPv6 source and destination nodes which are neither A nor B. between IPv6 source and destination nodes which are neither A nor B.
+---+ +---+ +---+ +---+
... ---| A |-------------------->| B |--- ... ... ---| A |-------------------->| B |--- ...
+---+ +---+ +---+ +---+
# (frag. 5) # (frag. 5)
123456789 123456789 123456789 123456789
+---------+ +---------+ +---------+ +---------+
| # ###| |### # | | # ###| |### # |
+---------+ +---------+ +---------+ +---------+
outgoing incoming outgoing incoming
fragmentation reassembly fragmentation reassembly
buffer buffer buffer buffer
Figure 1: Fragmentation at node A, reassembly at node B. Figure 1: Fragmentation at node A, reassembly at node B.
Node A starts by compacting the IPv6 packet using the header Node A starts by compacting the IPv6 packet using the header
compression mechanism defined in [RFC6282]. If the resulting 6LoWPAN compression mechanism defined in [6LoWPAN-HC]. If the resulting
packet does not fit into a single link-layer frame, node A's 6LoWPAN 6LoWPAN packet does not fit into a single Link-Layer frame, node A's
sublayer cuts it into multiple 6LoWPAN fragments, which it transmits 6LoWPAN sublayer cuts it into multiple 6LoWPAN fragments, which it
as separate link-layer frames to node B. Node B's 6LoWPAN sublayer transmits as separate Link-Layer frames to node B. Node B's 6LoWPAN
reassembles these fragments, inflates the compressed header fields sublayer reassembles these fragments, inflates the compressed header
back to the original IPv6 header, and hands over the full IPv6 packet fields back to the original IPv6 header, and hands over the full IPv6
to its IPv6 layer. packet to its IPv6 layer.
In Figure 1, a packet forwarded by node A to node B is cut into nine In Figure 1, a packet forwarded by node A to node B is cut into nine
fragments, numbered 1 to 9. Each fragment is represented by the '#' fragments, numbered 1 to 9 as follows:
symbol. Node A has sent fragments 1, 2, 3, 5, 6 to node B. Node B
has received fragments 1, 2, 3, 6 from node A. Fragment 5 is still * Each fragment is represented by the '#' symbol.
being transmitted at the link layer from node A to node B.
* Node A has sent fragments 1, 2, 3, 5, 6 to node B.
* Node B has received fragments 1, 2, 3, 6 from node A.
* Fragment 5 is still being transmitted at the link layer from node
A to node B.
The reassembly buffer for 6LoWPAN is indexed in node B by: The reassembly buffer for 6LoWPAN is indexed in node B by:
o a unique Identifier of Node A (e.g., Node A's link-layer address) * a unique Identifier of Node A (e.g., Node A's Link-Layer address)
o the datagram_tag chosen by node A for this fragmented datagram
Because it may be hard for node B to correlate all possible link- * the datagram_tag chosen by node A for this fragmented datagram
layer addresses that node A may use (e.g., short vs. long addresses), Because it may be hard for node B to correlate all possible Link-
node A must use the same link-layer address to send all the fragments Layer addresses that node A may use (e.g., short vs. long addresses),
of a same datagram to node B. node A must use the same Link-Layer address to send all the fragments
of the same datagram to node B.
Conceptually, the reassembly buffer in node B contains, assuming that Conceptually, the reassembly buffer in node B contains:
node B is neither the source nor the final destination:
o a datagram_tag as received in the incoming fragments, associated * a datagram_tag as received in the incoming fragments, associated
to link-layer address of node A for which the received to Link-Layer address of node A for which the received
datagram_tag is unique, datagram_tag is unique,
o the link-layer address that node B uses to forward the fragments
o the link-layer address of the next hop that is resolved on the * the actual packet data from the fragments received so far, in a
first fragment
o a datagram_tag that node B uniquely allocated for this datagram
and that is used when forwarding the fragments of the datagram
o the actual packet data from the fragments received so far, in a
form that makes it possible to detect when the whole packet has form that makes it possible to detect when the whole packet has
been received and can be processed or forwarded, been received and can be processed or forwarded,
o a datagram_size,
o a buffer for the remainder of a previous fragment left to be sent, * a state indicating the fragments already received,
o a timer that allows discarding a partially reassembled packet
* a datagram_size,
* a timer that allows discarding a partially reassembled packet
after some timeout. after some timeout.
A fragmentation header is added to each fragment; it indicates what A fragmentation header is added to each fragment; it indicates what
portion of the packet that fragment corresponds to. Section 5.3 of portion of the packet that fragment corresponds to. Section 5.3 of
[RFC4944] defines the format of the header for the first and [6LoWPAN] defines the format of the header for the first and
subsequent fragments. All fragments are tagged with a 16-bit subsequent fragments. All fragments are tagged with a 16-bit
"datagram_tag", used to identify which packet each fragment belongs "datagram_tag", used to identify which packet each fragment belongs
to. Each datagram can be uniquely identified by the sender link- to. Each datagram can be uniquely identified by the sender Link-
layer addresses of the frame that carries it and the datagram_tag Layer addresses of the frame that carries it and the datagram_tag
that the sender allocated for this datagram. Each fragment can be that the sender allocated for this datagram. [6LoWPAN] also mandates
identified within its datagram by the datagram-offset. that the first fragment is sent first and with a particular format
that is different than that of the next fragments. Each fragment but
the first one can be identified within its datagram by the datagram-
offset.
Node B's typical behavior, per [RFC4944], is as follows. Upon Node B's typical behavior, per [6LoWPAN], is as follows. Upon
receiving a fragment from node A with a datagram_tag previously receiving a fragment from node A with a datagram_tag previously
unseen from node A, node B allocates a buffer large enough to hold unseen from node A, node B allocates a buffer large enough to hold
the entire packet. The length of the packet is indicated in each the entire packet. The length of the packet is indicated in each
fragment (the datagram_size field), so node B can allocate the buffer fragment (the datagram_size field), so node B can allocate the buffer
even if the first fragment it receives is not fragment 1. As even if the first fragment it receives is not fragment 1. As
fragments come in, node B fills the buffer. When all fragments have fragments come in, node B fills the buffer. When all fragments have
been received, node B inflates the compressed header fields into an been received, node B inflates the compressed header fields into an
IPv6 header, and hands the resulting IPv6 packet to the IPv6 layer. IPv6 header, and hands the resulting IPv6 packet to the IPv6 layer
whihc performs the route lookup.
This behavior typically results in per-hop fragmentation and This behavior typically results in per-hop fragmentation and
reassembly. That is, the packet is fully reassembled, then reassembly. That is, the packet is fully reassembled, then
(re)fragmented, at every hop. (re)fragmented, at every hop.
2. Limits of Per-Hop Fragmentation and Reassembly 3. Limits of Per-Hop Fragmentation and Reassembly
There are at least 2 limits to doing per-hop fragmentation and There are at least 2 limits to doing per-hop fragmentation and
reassembly. See [ARTICLE] for detailed simulation results on both reassembly. See [ARTICLE] for detailed simulation results on both
limits. limits.
2.1. Latency 3.1. Latency
When reassembling, a node needs to wait for all the fragments to be When reassembling, a node needs to wait for all the fragments to be
received before being able to generate the IPv6 packet, and possibly received before being able to generate the IPv6 packet, and possibly
forward it to the next hop. This repeats at every hop. forward it to the next hop. This repeats at every hop.
This may result in increased end-to-end latency compared to a case This may result in increased end-to-end latency compared to a case
where each fragment is forwarded without per-hop reassembly. where each fragment is forwarded without per-hop reassembly.
2.2. Memory Management and Reliability 3.2. Memory Management and Reliability
Constrained nodes have limited memory. Assuming 1 kB reassembly Constrained nodes have limited memory. Assuming a reassembly buffer
buffer, typical nodes only have enough memory for 1-3 reassembly for a 6LoWPAN MTU of 1280 bytes as defined in section 4 of [6LoWPAN],
buffers. typical nodes only have enough memory for 1-3 reassembly buffers.
To illustrate this we use the topology from Figure 2, where nodes A, To illustrate this we use the topology from Figure 2, where nodes A,
B, C and D all send packets through node E. We further assume that B, C and D all send packets through node E. We further assume that
node E's memory can only hold 3 reassembly buffers. node E's memory can only hold 3 reassembly buffers.
+---+ +---+ +---+ +---+
... --->| A |------>| B | ... --->| A |------>| B |
+---+ +---+\ +---+ +---+\
\ \
+---+ +---+ +---+ +---+
skipping to change at page 5, line 25 skipping to change at page 6, line 5
... --->| C |------>| D | ... --->| C |------>| D |
+---+ +---+ +---+ +---+
Figure 2: Illustrating the Memory Management Issue. Figure 2: Illustrating the Memory Management Issue.
When nodes A, B and C concurrently send fragmented packets, all 3 When nodes A, B and C concurrently send fragmented packets, all 3
reassembly buffers in node E are occupied. If, at that moment, node reassembly buffers in node E are occupied. If, at that moment, node
D also sends a fragmented packet, node E has no option but to drop D also sends a fragmented packet, node E has no option but to drop
one of the packets, lowering end-to-end reliability. one of the packets, lowering end-to-end reliability.
3. Virtual Reassembly Buffer (VRB) Implementation 4. Forwarding Fragments
A 6LoWPAN Fragment Forwarding technique makes the routing decision on
the first fragment, which is always the one with the IPv6 address of
the destination. Upon a first fragment, a forwarding node (e.g. node
B in a A->B->C sequence) that does fragment forwarding MUST attempt
to create a state and forward the fragment. This is an atomic
operation, and if the first fragment cannot be forwarded then the
state MUST be removed. When a forwarding node receives a fragment
other than a first fragment, it MUST look up state based on the
source Link-Layer address and the datagram_tag in the received
fragment. If no such state is found, the fragment MUST be dropped;
otherwise the fragment MUST be forwarded using the information in the
state found. Since the datagram_tag is uniquely associated to the
source Link-Layer address of the fragment, the forwarding node MUST
assign a new datagram_tag from its own namespace for the next hop and
rewrite the fragment header of each fragment with that datagram_tag.
Compared to Section 2, the conceptual reassembly buffer in node B now
contains, assuming that node B is neither the source nor the final
destination:
* a datagram_tag as received in the incoming fragments, associated
to Link-Layer address of node A for which the received
datagram_tag is unique,
* the Link-Layer address that node B uses as source to forward the
fragments
* the Link-Layer address of the next hop C that is resolved on the
first fragment
* a datagram_tag that node B uniquely allocated for this datagram
and that is used when forwarding the fragments of the datagram
* a datagram_size,
* a buffer for the remainder of a previous fragment left to be sent,
* a timer that allows discarding the stale FF state after some
timeout.
A node that has not received the first fragment cannot forward the
next fragments. This means that if node B receives a fragment, node
A was in possession of the first fragment at some point. In order to
keep the operation simple, it makes sense to be consistent with
[6LoWPAN] and enforce that the first fragment is always sent first.
When that is done, if node B receives a fragment that is not the
first and for which it has no state, then node B treats this as an
error and refrain from creating a state or attempting to forward.
This also means that node A should perform all its possible retries
on the first fragment before it attempts to send the next fragments,
and that it should abort the datagram and release its state if it
fails to send the first fragment.
One benefit of Fragment Forwarding is that the memory that is used to
store the packet is now distributed along the path, which limits the
buffer bloat effect. Multiple fragments may progress in parallel
along the network as long as they do not interfere. An associated
caveat is that on a half duplex radio, if node A sends the next
fragment at the same time as node B forwards the previous fragment to
a node C down the path then node B will miss the next fragment. If
node C forwards the previous fragment to a node D at the same time
and on the same frequency as node A sends the next fragment to node
B, this may result in a hidden terminal problem at B whereby the
transmission from C interferes with that from A unbeknownst of node
A. It results that consecutive fragments must be reasonably spaced
in order to avoid the 2 forms of collision described above. A node
that has multiple packets or fragments to send via different next-hop
routers may interleave the messages in order to alleviate those
effects.
5. Virtual Reassembly Buffer (VRB) Implementation
Virtual Reassembly Buffer (VRB) is the implementation technique Virtual Reassembly Buffer (VRB) is the implementation technique
described in [I-D.ietf-lwig-6lowpan-virtual-reassembly] in which a described in [LWIG-VRB] in which a forwarder does not reassemble each
forwarder does not reassemble each packet in its entirety before packet in its entirety before forwarding it.
forwarding it.
VRB overcomes the limits listed in Section 2. Nodes do not wait for VRB overcomes the limits listed in Section 3. Nodes do not wait for
the last fragment before forwarding, reducing end-to-end latency. the last fragment before forwarding, reducing end-to-end latency.
Similarly, the memory footprint of VRB is just the VRB table, Similarly, the memory footprint of VRB is just the VRB table,
reducing the packet drop probability significantly. reducing the packet drop probability significantly.
There are, however, limits: There are, however, limits:
Non-zero Packet Drop Probability: The abstract data in a VRB table Non-zero Packet Drop Probability: The abstract data in a VRB table
entry contains at a minimum the MAC address of the predecessor entry contains at a minimum the Link-Layer address of the
and that of the successor, the datagram_tag used by the predecessor and that of the successor, the datagram_tag used by
predecessor and the local datagram_tag that this node will swap the predecessor and the local datagram_tag that this node will
with it. The VRB may need to store a few octets from the last swap with it. The VRB may need to store a few octets from the
fragment that may not have fit within MTU and that will be last fragment that may not have fit within MTU and that will be
prepended to the next fragment. This yields a small footprint prepended to the next fragment. This yields a small footprint
that is 2 orders of magnitude smaller compared to needing a that is 2 orders of magnitude smaller compared to needing a
1280-byte reassembly buffer for each packet. Yet, the size of 1280-byte reassembly buffer for each packet. Yet, the size of the
the VRB table necessarily remains finite. In the extreme case VRB table necessarily remains finite. In the extreme case where a
where a node is required to concurrently forward more packets node is required to concurrently forward more packets that it has
that it has entries in its VRB table, packets are dropped. entries in its VRB table, packets are dropped.
No Fragment Recovery: There is no mechanism in VRB for the node that No Fragment Recovery: There is no mechanism in VRB for the node that
reassembles a packet to request a single missing fragment. reassembles a packet to request a single missing fragment.
Dropping a fragment requires the whole packet to be resent. This
causes unnecessary traffic, as fragments are forwarded even when
the destination node can never construct the original IPv6 packet.
Dropping a fragment requires the whole packet to be resent. This
causes unnecessary traffic, as fragments are forwarded even when
the destination node can never construct the original IPv6
packet.
No Per-Fragment Routing: All subsequent fragments follow the same No Per-Fragment Routing: All subsequent fragments follow the same
sequence of hops from the source to the destination node as the sequence of hops from the source to the destination node as the
first fragment, because the IP header is required to route the first fragment, because the IP header is required to route the
fragment and is only present in the first fragment. A side fragment and is only present in the first fragment. A side effect
effect is that the first fragment must always be forwarded first. is that the first fragment must always be forwarded first.
The severity and occurrence of these limits depends on the link-layer The severity and occurrence of these limits depends on the Link-Layer
used. Whether these limits are acceptable depends entirely on the used. Whether these limits are acceptable depends entirely on the
requirements the application places on the network. requirements the application places on the network.
If the limits are present and not acceptable for the application, If the limits are present and not acceptable for the application,
future specifications may define new protocols to overcome these future specifications may define new protocols to overcome these
limits. One example is [I-D.ietf-6lo-fragment-recovery] which limits. One example is [FRAG-RECOV] which defines a protocol which
defines a protocol which allows fragment recovery. allows fragment recovery.
4. Security Considerations
An attacker can perform a Denial-of-Service (DoS) attack on a node 6. Security Considerations
implementing VRB by generating a large number of bogus "fragment 1"
fragments without sending subsequent fragments. This causes the VRB
table to fill up. Note that the VRB does not need to remember the
full datagram as received so far but only possibly a few octets from
the last fragment that could not fit in it. It is expected that an
implementation protects itself to keep the number of VRBs within
capacity, and that old VRBs are protected by a timer of a reasonable
duration for the technology and destroyed upon timeout.
Secure joining and the link-layer security that it sets up protects Secure joining and the Link-Layer security that it sets up protects
against those attacks from network outsiders. against those attacks from network outsiders.
5. IANA Considerations "IP Fragmentation Considered Fragile" [FRAG-ILE] discusses security
threats that are linked to using IP fragmentation. The 6LoWPAN
fragmentation takes place underneath, but some issues described there
may still apply to 6lo fragments.
No requests to IANA are made by this document. * Overlapping fragment attacks are possible with 6LoWPAN fragments
but there is no known firewall operation that would work on
6LoWPAN fragments at the time of this writing, so the exposure is
limited. An implementation of a firewall SHOULD NOT forward
fragments but recompose the IP packet, check it in the
uncompressed form, and then forward it again as fragments if
necessary.
6. Acknowledgments * Resource exhaustion attacks are certainly possible and a sensitive
issue in a constrained network. An attacker can perform a Denial-
of-Service (DoS) attack on a node implementing VRB by generating a
large number of bogus first fragments without sending subsequent
fragments. This causes the VRB table to fill up. When hop-by-hop
reassembly is used, the same attck can be more damaging if the
node allocates a full datagram_size for each bogus first fragment.
With the VRB, the attack can be performed remotely on all nodes
along a path, but each node suffers a lesser hit. this is because
the VRB does not need to remember the full datagram as received so
far but only possibly a few octets from the last fragment that
could not fit in it. An implementation MUST protect itself to
keep the number of VRBs within capacity, and that old VRBs are
protected by a timer of a reasonable duration for the technology
and destroyed upon timeout.
The authors would like to thank Yasuyuki Tanaka, for his in-depth * Attacks based on predictable fragment identification values are
review of this document. Also many thanks to Georgies Papadopoulos also possible but can be avoided. The datagramp_tag SHOULD be
and Dominique Barthel for their own reviews. assigned pseudo-randomly in order to defeat such attacks.
7. Informative References * Evasion of Network Intrusion Detection Systems (NIDS) leverages
ambiguity in the reassembly of the fragment. This sounds
difficult and mostly useless in a 6LoWPAN network since the
fragmentation is not end-to-end.
[ARTICLE] Tanaka, Y., Minet, P., and T. Watteyne, "6LoWPAN Fragment 7. IANA Considerations
Forwarding", IEEE Communications Standards Magazine ,
2019.
[I-D.ietf-6lo-fragment-recovery] No requests to IANA are made by this document.
Thubert, P., "6LoWPAN Selective Fragment Recovery", draft-
ietf-6lo-fragment-recovery-05 (work in progress), July
2019.
[I-D.ietf-lwig-6lowpan-virtual-reassembly] 8. Acknowledgments
Bormann, C. and T. Watteyne, "Virtual reassembly buffers
in 6LoWPAN", draft-ietf-lwig-6lowpan-virtual-reassembly-01
(work in progress), March 2019.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, The authors would like to thank Yasuyuki Tanaka and Dave Thaler for
their in-depth review of this document and improvement suggestions.
Also many thanks to Georgies Papadopoulos and Dominique Barthel for
their own reviews.
9. Normative References
[6LoWPAN] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4 "Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<https://www.rfc-editor.org/info/rfc4944>. <https://www.rfc-editor.org/info/rfc4944>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 [LWIG-VRB] Bormann, C. and T. Watteyne, "Virtual reassembly buffers
in 6LoWPAN", Work in Progress, Internet-Draft, draft-ietf-
lwig-6lowpan-virtual-reassembly-01, 11 March 2019,
<https://tools.ietf.org/html/draft-ietf-lwig-6lowpan-
virtual-reassembly-01>.
10. Informative References
[6LoWPAN-HC]
Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011, DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>. <https://www.rfc-editor.org/info/rfc6282>.
[FRAG-RECOV]
Thubert, P., "6LoWPAN Selective Fragment Recovery", Work
in Progress, Internet-Draft, draft-ietf-6lo-fragment-
recovery-07, 23 October 2019,
<https://tools.ietf.org/html/draft-ietf-6lo-fragment-
recovery-07>.
[FRAG-ILE] Bonica, R., Baker, F., Huston, G., Hinden, R., Troan, O.,
and F. Gont, "IP Fragmentation Considered Fragile", Work
in Progress, Internet-Draft, draft-ietf-intarea-frag-
fragile-17, 30 September 2019,
<https://tools.ietf.org/html/draft-ietf-intarea-frag-
fragile-17>.
[ARTICLE] Tanaka, Y., Minet, P., and T. Watteyne, "6LoWPAN Fragment
Forwarding", IEEE Communications Standards Magazine ,
2019.
Authors' Addresses Authors' Addresses
Thomas Watteyne (editor) Thomas Watteyne (editor)
Analog Devices Analog Devices
32990 Alvarado-Niles Road, Suite 910 32990 Alvarado-Niles Road, Suite 910
Union City, CA 94587 Union City, CA 94587
USA United States of America
Email: thomas.watteyne@analog.com Email: thomas.watteyne@analog.com
Pascal Thubert (editor)
Cisco Systems, Inc
Building D, 45 Allee des Ormes - BP1200
06254 Mougins - Sophia Antipolis
France
Phone: +33 497 23 26 34
Email: pthubert@cisco.com
Carsten Bormann Carsten Bormann
Universitaet Bremen TZI Universitaet Bremen TZI
Postfach 330440 Postfach 330440
Bremen D-28359 D-28359 Bremen
Germany Germany
Email: cabo@tzi.org Email: cabo@tzi.org
Pascal Thubert
Cisco Systems, Inc
Building D
45 Allee des Ormes - BP1200
MOUGINS - Sophia Antipolis 06254
France
Email: pthubert@cisco.com
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