draft-ietf-mboned-ieee802-mcast-problems-03.txt   draft-ietf-mboned-ieee802-mcast-problems-04.txt 
Internet Area C. Perkins Internet Area C. Perkins
Internet-Draft M. McBride Internet-Draft M. McBride
Intended status: Informational Futurewei Intended status: Informational Futurewei
Expires: April 26, 2019 D. Stanley Expires: June 1, 2019 D. Stanley
HPE HPE
W. Kumari W. Kumari
Google Google
JC. Zuniga JC. Zuniga
SIGFOX SIGFOX
October 23, 2018 November 28, 2018
Multicast Considerations over IEEE 802 Wireless Media Multicast Considerations over IEEE 802 Wireless Media
draft-ietf-mboned-ieee802-mcast-problems-03 draft-ietf-mboned-ieee802-mcast-problems-04
Abstract Abstract
Well-known issues with multicast have prevented the deployment of Well-known issues with multicast have prevented the deployment of
multicast in 802.11 [dot11], [mc-props], [mc-prob-stmt], and other multicast in 802.11 [dot11], [mc-props], [mc-prob-stmt], and other
local-area wireless environments. IETF multicast experts have been local-area wireless environments. This document offers guidance on
meeting together to discuss these issues and provide IEEE updates. known limitations and problems with wireless multicast. Also
The mboned working group is chartered to receive regular reports on described are certain multicast enhancement features that have been
the current state of the deployment of multicast technology, create specified by the IETF and by IEEE 802 for wireless media, as well as
"practice and experience" documents that capture the experience of some operational choices that can be taken to improve the performace
those who have deployed and are deploying various multicast of the network. Finally, some recommendations are provided about the
technologies, and provide feedback to other relevant working groups. usage and combination of these features and operational choices.
This document offers guidance on known limitations and problems with
wireless multicast. Also described are various multicast enhancement
features that have been specified at IETF and IEEE 802 for wireless
media, as well as some operational chioces that can be taken to
improve the performace of the network. Finally, some recommendations
are provided about the usage and combination of these features and
operational choices.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 26, 2019.
This Internet-Draft will expire on June 1, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Identified mulitcast issues . . . . . . . . . . . . . . . . . 5 3. Identified multicast issues . . . . . . . . . . . . . . . . . 5
3.1. Issues at Layer 2 and Below . . . . . . . . . . . . . . . 5 3.1. Issues at Layer 2 and Below . . . . . . . . . . . . . . . 5
3.1.1. Multicast reliability . . . . . . . . . . . . . . . . 5 3.1.1. Multicast reliability . . . . . . . . . . . . . . . . 5
3.1.2. Lower and Variable Data Rate . . . . . . . . . . . . 5 3.1.2. Lower and Variable Data Rate . . . . . . . . . . . . 5
3.1.3. High Interference . . . . . . . . . . . . . . . . . . 6 3.1.3. High Interference . . . . . . . . . . . . . . . . . . 6
3.1.4. Power-save Effects on Multicast . . . . . . . . . . . 6 3.1.4. Power-save Effects on Multicast . . . . . . . . . . . 7
3.2. Issues at Layer 3 and Above . . . . . . . . . . . . . . . 7 3.2. Issues at Layer 3 and Above . . . . . . . . . . . . . . . 7
3.2.1. IPv4 issues . . . . . . . . . . . . . . . . . . . . . 7 3.2.1. IPv4 issues . . . . . . . . . . . . . . . . . . . . . 8
3.2.2. IPv6 issues . . . . . . . . . . . . . . . . . . . . . 8 3.2.2. IPv6 issues . . . . . . . . . . . . . . . . . . . . . 8
3.2.3. MLD issues . . . . . . . . . . . . . . . . . . . . . 8 3.2.3. MLD issues . . . . . . . . . . . . . . . . . . . . . 8
3.2.4. Spurious Neighbor Discovery . . . . . . . . . . . . . 9 3.2.4. Spurious Neighbor Discovery . . . . . . . . . . . . . 9
4. Multicast protocol optimizations . . . . . . . . . . . . . . 9 4. Multicast protocol optimizations . . . . . . . . . . . . . . 10
4.1. Proxy ARP in 802.11-2012 . . . . . . . . . . . . . . . . 10 4.1. Proxy ARP in 802.11-2012 . . . . . . . . . . . . . . . . 10
4.2. IPv6 Address Registration and Proxy Neighbor Discovery . 10 4.2. IPv6 Address Registration and Proxy Neighbor Discovery . 10
4.3. Buffering to Improve Battery Life . . . . . . . . . . . . 12 4.3. Buffering to Improve Battery Life . . . . . . . . . . . . 12
4.4. IPv6 support in 802.11-2012 . . . . . . . . . . . . . . . 12 4.4. IPv6 support in 802.11-2012 . . . . . . . . . . . . . . . 12
4.5. Conversion of multicast to unicast . . . . . . . . . . . 13 4.5. Conversion of multicast to unicast . . . . . . . . . . . 13
4.6. Directed Multicast Service (DMS) . . . . . . . . . . . . 13 4.6. Directed Multicast Service (DMS) . . . . . . . . . . . . 13
4.7. GroupCast with Retries (GCR) . . . . . . . . . . . . . . 13 4.7. GroupCast with Retries (GCR) . . . . . . . . . . . . . . 13
5. Operational optimizations . . . . . . . . . . . . . . . . . . 14 5. Operational optimizations . . . . . . . . . . . . . . . . . . 14
5.1. Mitigating Problems from Spurious Neighbor Discovery . . 14 5.1. Mitigating Problems from Spurious Neighbor Discovery . . 14
6. Multicast Considerations for Other Wireless Media . . . . . . 16 6. Multicast Considerations for Other Wireless Media . . . . . . 16
7. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 16 7. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 16
8. Discussion Items . . . . . . . . . . . . . . . . . . . . . . 17 8. Discussion Items . . . . . . . . . . . . . . . . . . . . . . 17
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17 9. Security Considerations . . . . . . . . . . . . . . . . . . . 17
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18
12. Informative References . . . . . . . . . . . . . . . . . . . 18 12. Informative References . . . . . . . . . . . . . . . . . . . 18
Appendix A. Changes between draft-ietf-mboned-ieee802-mcast-
problems revisions 03 versus 04 . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
Performance issues have been observed when multicast packet Performance issues have been observed when multicast packet
transmissions of IETF protocols are used over IEEE 802 wireless transmissions of IETF protocols are used over IEEE 802 wireless
media. Even though enhamcements for multicast transmissions have media. Even though enhancements for multicast transmissions have
been designed at both IETF and IEEE 802, incompatibilities still been designed at both IETF and IEEE 802, incompatibilities still
exist between specifications, implementations and configuration exist between specifications, implementations and configuration
choices. choices.
Many IETF protocols depend on multicast/broadcast for delivery of Many IETF protocols depend on multicast/broadcast for delivery of
control messages to multiple receivers. Multicast is used for control messages to multiple receivers. Multicast is used for
various purposes such as neighborhood discovery, network flooding, various purposes such as neighbor discovery, network flooding,
address resolution, as well minimizing media occupancy for the address resolution, as well minimizing media occupancy for the
transmission of data that is intended for multiple receivers. In transmission of data that is intended for multiple receivers. In
addition to protocol use of broadcast/multicast for control messages, addition to protocol use of broadcast/multicast for control messages,
more applications, such as push to talk in hospitals, video in more applications, such as push to talk in hospitals, or video in
enterprises and lectures in Universities, are streaming over wifi. enterprises, universities, and homes, are sending multicast IP to end
Many types of end devices are increasingly using wifi for their user devices, which are increasingly using wifi for their
connectivity. connectivity.
IETF protocols typically rely on network protocol layering in order IETF protocols typically rely on network protocol layering in order
to reduce or eliminate any dependence of higher level protocols on to reduce or eliminate any dependence of higher level protocols on
the specific nature of the MAC layer protocols or the physical media. the specific nature of the MAC layer protocols or the physical media.
In the case of multicast transmissions, higher level protocols have In the case of multicast transmissions, higher level protocols have
traditionally been designed as if transmitting a packet to an IP traditionally been designed as if transmitting a packet to an IP
address had the same cost in interference and network media access, address had the same cost in interference and network media access,
regardless of whether the destination IP address is a unicast address regardless of whether the destination IP address is a unicast address
or a multicast or broadcast address. This model was reasonable for or a multicast or broadcast address. This model was reasonable for
networks where the physical medium was wired, like Ethernet. networks where the physical medium was wired, like Ethernet.
Unfortunately, for many wireless media, the costs to access the Unfortunately, for many wireless media, the costs to access the
medium can be quite different. Multicast over wifi has often been medium can be quite different. Multicast over Wi-Fi has often been
plagued by such poor performance that it is disallowed. Some plagued by such poor performance that it is disallowed. Some
enhancements have been designed in IETF protocols that are assumed to enhancements have been designed in IETF protocols that are assumed to
work primarily over wireless media. However, these enhancements are work primarily over wireless media. However, these enhancements are
usually implemented in limited deployments and not widespread on most usually implemented in limited deployments and not widespread on most
wireless networks. wireless networks.
IEEE 802 wireless protocols have been designed with certain features IEEE 802 wireless protocols have been designed with certain features
to support multicast traffic. For instance, lower modulations are to support multicast traffic. For instance, lower modulations are
used to transmit multicast frames, so that these can be received by used to transmit multicast frames, so that these can be received by
all stations in the cell, regardless of the distance or path all stations in the cell, regardless of the distance or path
attenuation from the base station or access point. However, these attenuation from the base station or access point. However, these
lower modulation transmissions occupy the medium longer; they hamper lower modulation transmissions occupy the medium longer; they hamper
efficient transmission of traffic using higher order modulations to efficient transmission of traffic using higher order modulations to
nearby stations. For these and other reasons, IEEE 802 working nearby stations. For these and other reasons, IEEE 802 working
groups such as 802.11 have designed features to improve the groups such as 802.11 have designed features to improve the
performance of multicast transmissions at Layer 2 [ietf_802-11]. In performance of multicast transmissions at Layer 2 [ietf_802-11]. In
addition to protocol design features, certain operational and addition to protocol design features, certain operational and
configuration enhancements can ameliorate the network performance configuration enhancements can ameliorate the network performance
issues created by multicast traffic. as described in Section 5. issues created by multicast traffic, as described in Section 5.
In discussing these issues over email, and in a side meeting at IETF There seems to be general agreement that these problems will not be
99, it has been generally agreed that these problems will not be fixed anytime soon, primarily because it's expensive to do so, and
fixed anytime soon primarily because it's expensive to do so and multicast is unreliable. Compared to unicast over Wi-Fi, multicast
multicast is unreliable. A big problem is that multicast is somewhat is often treated as somewhat a second class citizen, even though
a second class citizen, to unicast, over wifi. There are many there are many protocols using multicast. Something needs to be
protocols using multicast and there needs to be something provided in provided in order to make them more reliable. IPv6 neighbor
order to make them more reliable. The problem of IPv6 neighbor discovery saturating the Wi-Fi link is only part of the problem. Wi-
discovery saturating the wifi link is only part of the problem. Wifi Fi traffic classes may help. This document is intended to help make
traffic classes may help. We need to determine what problem should the determination about what problems should be solved by the IETF
be solved by the IETF and what problem should be solved by the IEEE and what problems should be solved by the IEEE (see Section 8).
(see Section 8). A "multicast over wifi" IETF mailing list has been
formed (mcast-wifi@ietf.org) for further discussion. This draft will
be updated according to the current state of discussion.
This document details various problems caused by multicast This document details various problems caused by multicast
transmission over wireless networks, including high packet error transmission over wireless networks, including high packet error
rates, no acknowledgements, and low data rate. It also explains some rates, no acknowledgements, and low data rate. It also explains some
enhancements that have been designed at IETF and IEEE 802 to enhancements that have been designed at IETF and IEEE 802 to
ameliorate the effects of multicast traffic. Recommendations are ameliorate the effects of multicast traffic. Recommendations are
also provided to implementors about how to use and combine these also provided to implementors about how to use and combine these
enhancements. Some advice about the operational choices that can be enhancements. Some advice about the operational choices that can be
taken is also included. It is likely that this document will also be taken is also included. It is likely that this document will also be
considered relevant to designers of future IEEE wireless considered relevant to designers of future IEEE wireless
specifications. specifications.
2. Terminology 2. Terminology
This document uses the following definitions: This document uses the following definitions:
ACK
IEEE 802.11 Access Point
AP AP
IEEE 802.11 Access Point. The 802.11 layer 2 acknowledgement
basic rate basic rate
The "lowest common denominator" data rate at which multicast and The slowest rate of all the connected devices, at which multicast
broadcast traffic is generally transmitted. and broadcast traffic is generally transmitted
DTIM DTIM
Delivery Traffic Indication Map (DTIM): An information element Delivery Traffic Indication Map (DTIM): An information element
that advertises whether or not any associated stations have that advertises whether or not any associated stations have
buffered multicast or broadcast frames. buffered multicast or broadcast frames
MCS MCS
Modulation and Coding Scheme. Modulation and Coding Scheme
NOC
Network Operations Center
PER
Packet Error Rate
STA STA
802.11 station (e.g. handheld device). 802.11 station (e.g. handheld device)
TIM TIM
Traffic Indication Map (TIM): An information element that Traffic Indication Map (TIM): An information element that
advertises whether or not any associated stations have buffered advertises whether or not any associated stations have buffered
unicast frames. unicast frames
3. Identified mulitcast issues 3. Identified multicast issues
3.1. Issues at Layer 2 and Below 3.1. Issues at Layer 2 and Below
In this section we describe some of the issues related to the use of In this section we describe some of the issues related to the use of
multicast transmissions over IEEE 802 wireless technologies. multicast transmissions over IEEE 802 wireless technologies.
3.1.1. Multicast reliability 3.1.1. Multicast reliability
Multicast traffic is typically much less reliable than unicast Multicast traffic is typically much less reliable than unicast
traffic. Since multicast makes point-to-multipoint communications, traffic. Since multicast makes point-to-multipoint communications,
skipping to change at page 5, line 42 skipping to change at page 5, line 48
for wireless links is much worse, and is quite sensitive to the for wireless links is much worse, and is quite sensitive to the
presence of background traffic. Consequently, there can be a high presence of background traffic. Consequently, there can be a high
packet error rate (PER) due to lack of retransmission, and because packet error rate (PER) due to lack of retransmission, and because
the sender never backs off. It is not uncommon for there to be a the sender never backs off. It is not uncommon for there to be a
packet loss rate of 5% or more, which is particularly troublesome for packet loss rate of 5% or more, which is particularly troublesome for
video and other environments where high data rates and high video and other environments where high data rates and high
reliability are required. reliability are required.
3.1.2. Lower and Variable Data Rate 3.1.2. Lower and Variable Data Rate
One big difference between multicast over wired versus multicast over Multicast over wired differs from multicast over wireless because
wired is that transmission over wired links often occurs at a fixed transmission over wired links often occurs at a fixed rate. Wi-Fi,
rate. Wifi, on the other hand, has a transmission rate which varies on the other hand, has a transmission rate which varies depending
depending upon the client's proximity to the AP. The throughput of upon the STA's proximity to the AP. The throughput of video flows,
video flows, and the capacity of the broader wifi network, will and the capacity of the broader Wi-Fi network, will change and will
change and will impact the ability for QoS solutions to effectively impact the ability for QoS solutions to effectively reserve bandwidth
reserve bandwidth and provide admission control. and provide admission control.
For wireless stations associated with an Access Points, the power For wireless stations associated with an Access Point, the power
necessary for good reception can vary from station to station. For necessary for good reception can vary from station to station. For
unicast, the goal is to minimize power requirements while maximizing unicast, the goal is to minimize power requirements while maximizing
the data rate to the destination. For multicast, the goal is simply the data rate to the destination. For multicast, the goal is simply
to maximize the number of receivers that will correctly receive the to maximize the number of receivers that will correctly receive the
multicast packet; generally the Access Point has to use a much lower multicast packet; generally the Access Point has to use a much lower
data rate at a power level high enough for even the farthest station data rate at a power level high enough for even the farthest station
to receive the packet. Consequently, the data rate of a video to receive the packet, for example as briefly mentioned in [RFC5757].
stream, for instance, would be constrained by the environmental Consequently, the data rate of a video stream, for instance, would be
considerations of the least reliable receiver associated with the constrained by the environmental considerations of the least reliable
Access Point. receiver associated with the Access Point.
Because more robust modulation and coding schemes (MCSs) have longer Because more robust modulation and coding schemes (MCSs) have longer
range but also lower data rate, multicast / broadcast traffic is range but also lower data rate, multicast / broadcast traffic is
generally transmitted at the lowest common denominator rate, also generally transmitted at the slowest rate of all the connected
known as the basic rate. The amount of additional interference devices, also known as the basic rate. The amount of additional
depends on the specific wireless technology. In fact backward interference depends on the specific wireless technology. In fact
compatibility and multi-stream implementations mean that the maximum backward compatibility and multi-stream implementations mean that the
unicast rates are currently up to a few Gb/s, so there can be a more maximum unicast rates are currently up to a few Gb/s, so there can be
than 3 orders of magnitude difference in the transmission rate a more than 3 orders of magnitude difference in the transmission rate
between the basic rates to optimal unicast forwarding. Some between multicast / broadcast versus optimal unicast forwarding.
techinues employed to increase spectral efficiency, such as spatial Some techinues employed to increase spectral efficiency, such as
multiplexing in mimo systems, are not available with more than one spatial multiplexing in mimo systems, are not available with more
intended reciever; it is not the case that backwards compatibility is than one intended reciever; it is not the case that backwards
the only factor responsible for lower multicast transmission rates. compatibility is the only factor responsible for lower multicast
transmission rates.
Wired multicast also affects wireless LANs when the AP extends the Wired multicast also affects wireless LANs when the AP extends the
wired segment; in that case, multicast / broadcast frames on the wired segment; in that case, multicast / broadcast frames on the
wired LAN side are copied to WLAN. Since broadcast messages are wired LAN side are copied to WLAN. Since broadcast messages are
transmitted at the most robust MCS, many large frames are sent at a transmitted at the most robust MCS, many large frames are sent at a
slow rate over the air. slow rate over the air.
3.1.3. High Interference 3.1.3. High Interference
Transmissions at a lower rate require longer occupancy of the Transmissions at a lower rate require longer occupancy of the
wireless medium and thus take away from the airtime of other wireless medium and thus take away from the airtime of other
communications and degrade the overall capacity. Furthermore, communications and degrade the overall capacity. Furthermore,
transmission at higher power, as is required to reach all multicast transmission at higher power, as is required to reach all multicast
clients associated to the AP, proportionately increases the area of STAs associated to the AP, proportionately increases the area of
interference. interference.
3.1.4. Power-save Effects on Multicast 3.1.4. Power-save Effects on Multicast
One of the characteristics of multicast transmission is that every One of the characteristics of multicast transmission is that every
station has to be configured to wake up to receive the multicast, station has to be configured to wake up to receive the multicast,
even though the received packet may ultimately be discarded. This even though the received packet may ultimately be discarded. This
process can have a large effect on the power consumption by the process can have a large effect on the power consumption by the
multicast receiver station. multicast receiver station.
skipping to change at page 8, line 23 skipping to change at page 8, line 36
o IPv6 Neighbor Discovery Protocol (NDP) o IPv6 Neighbor Discovery Protocol (NDP)
o Duplicate Address Detection (DAD) o Duplicate Address Detection (DAD)
o Address Resolution o Address Resolution
o Service Discovery o Service Discovery
o Route Discovery o Route Discovery
o Decentralized Address Assignment o Decentralized Address Assignment
o Geographic routing o Geographic routing
IPv6 NDP Neighbor Solicitation (NS) messages used in DAD and Address IPv6 NDP Neighbor Solicitation (NS) messages used in DAD and Address
Lookup make use of Link-Scope multicast. In contrast to IPv4, an Lookup make use of Link-Scope multicast. In contrast to IPv4, an
IPv6 Node will typically use multiple addresses, and may change them IPv6 node will typically use multiple addresses, and may change them
often for privacy reasons. This multiplies the impact of multicast often for privacy reasons. This intensifies the impact of multicast
messages that are associated to the mobility of a Node. Router messages that are associated to the mobility of a node. Router
advertisement (RA) messages are also periodically multicasted over
the Link.
IPv6 NDP Neighbor Solicitation (NS) messages used in DAD and Address
Lookup make use of Link-Scope multicast. In contrast to IPv4, an
IPv6 Node will typically use multiple addresses, and may change them
often for privacy reasons. This multiplies the impact of multicast
messages that are associated to the mobility of a Node. Router
advertisement (RA) messages are also periodically multicasted over advertisement (RA) messages are also periodically multicasted over
the Link. the Link.
Neighbors may be considered lost if several consecutive Neighbor Neighbors may be considered lost if several consecutive Neighbor
Discovery packets fail. Discovery packets fail.
3.2.3. MLD issues 3.2.3. MLD issues
Multicast Listener Discovery(MLD) [RFC4541] is often used to identify Multicast Listener Discovery(MLD) [RFC4541] is often used to identify
members of a multicast group that are connected to the ports of a members of a multicast group that are connected to the ports of a
switch. Forwarding multicast frames into a WiFi-enabled area can use switch. Forwarding multicast frames into a Wi-Fi-enabled area can
such switch support for hardware forwarding state information. use such switch support for hardware forwarding state information.
However, since IPv6 makes heavy use of multicast, each STA with an However, since IPv6 makes heavy use of multicast, each STA with an
IPv6 address will require state on the switch for several and IPv6 address will require state on the switch for several and
possibly many multicast solicited-node addresses. Multicast possibly many multicast solicited-node addresses. Multicast
addresses that do not have forwarding state installed (perhaps due to addresses that do not have forwarding state installed (perhaps due to
hardware memory limitations on the switch) cause frames to be flooded hardware memory limitations on the switch) cause frames to be flooded
on all ports of the switch. on all ports of the switch.
3.2.4. Spurious Neighbor Discovery 3.2.4. Spurious Neighbor Discovery
On the Internet there is a "background radiation" of scanning traffic On the Internet there is a "background radiation" of scanning traffic
(people scanning for vulnerable machines) and backscatter (responses (people scanning for vulnerable machines) and backscatter (responses
from spoofed traffic, etc). This means that routers very often from spoofed traffic, etc). This means that routers very often
receive packets destined for machines whose IP addresses may or may receive packets destined for IP addresses regardless of whether they
not be in use. In the cases where the IP is assigned to a host, the are in use. In the cases where the IP is assigned to a host, the
router broadcasts an ARP request, gets back an ARP reply, and caches router broadcasts an ARP request, gets back an ARP reply, and caches
it; then traffic can be delivered to the host. When the IP address it; then traffic can be delivered to the host. When the IP address
is not in use, the router broadcasts one (or more) ARP requests, and is not in use, the router broadcasts one (or more) ARP requests, and
never gets a reply. This means that it does not populate the ARP never gets a reply. This means that it does not populate the ARP
cache, and the next time there is traffic for that IP address the cache, and the next time there is traffic for that IP address the
router will rebroadcast the ARP requests. router will rebroadcast the ARP requests.
The rate of these ARP requests is proportional to the size of the The rate of these ARP requests is proportional to the size of the
subnets, the rate of scanning and backscatter, and how long the subnets, the rate of scanning and backscatter, and how long the
router keeps state on non-responding ARPs. As it turns out, this router keeps state on non-responding ARPs. As it turns out, this
rate is inversely proportional to how occupied the subnet is (valid rate is inversely proportional to how occupied the subnet is (valid
ARPs end up in a cache, stopping the broadcasting; unused IPs never ARPs end up in a cache, stopping the broadcasting; unused IPs never
respond, and so cause more broadcasts). Depending on the address respond, and so cause more broadcasts). Depending on the address
space in use, the time of day, how occupied the subnet is, and other space in use, the time of day, how occupied the subnet is, and other
unknown factors, on the order of 2000 broadcasts per second have been unknown factors, on the order of 2000 broadcasts per second have been
observed at the IETF NOCs. observed, for instance at the NOCs during IETF face-to-face meetings.
On a wired network, there is not a huge difference between unicast, On a wired network, there is not a huge difference between unicast,
multicast and broadcast traffic. Due to hardware filtering (see, multicast and broadcast traffic. Due to hardware filtering (see,
e.g., [Deri-2010]), inadvertently flooded traffic (or high amounts of e.g., [Deri-2010]), inadvertently flooded traffic (or high amounts of
ethernet multicast) on wired networks can be quite a bit less costly, ethernet multicast) on wired networks can be quite a bit less costly,
compared to wireless cases where sleeping devices have to wake up to compared to wireless cases where sleeping devices have to wake up to
process packets. Wired Ethernets tend to be switched networks, process packets. Wired Ethernets tend to be switched networks,
further reducing interference from multicast. There is effectively further reducing interference from multicast. There is effectively
no collision / scheduling problem except at extremely high port no collision / scheduling problem except at extremely high port
utilizations. utilizations.
skipping to change at page 10, line 43 skipping to change at page 10, line 49
(6LoWPAN) denotes a low power lossy network (LLN) that supports (6LoWPAN) denotes a low power lossy network (LLN) that supports
6LoWPAN Header Compression (HC) [RFC6282]. A 6TiSCH network 6LoWPAN Header Compression (HC) [RFC6282]. A 6TiSCH network
[I-D.ietf-6tisch-architecture] is an example of a 6LowPAN. In order [I-D.ietf-6tisch-architecture] is an example of a 6LowPAN. In order
to control the use of IPv6 multicast over 6LoWPANs, the 6LoWPAN to control the use of IPv6 multicast over 6LoWPANs, the 6LoWPAN
Neighbor Discovery (6LoWPAN ND) [RFC6775] standard defines an address Neighbor Discovery (6LoWPAN ND) [RFC6775] standard defines an address
registration mechanism that relies on a central registry to assess registration mechanism that relies on a central registry to assess
address uniqueness, as a substitute to the inefficient Duplicate address uniqueness, as a substitute to the inefficient Duplicate
Address Detection (DAD) mechanism found in the mainstream IPv6 Address Detection (DAD) mechanism found in the mainstream IPv6
Neighbor Discovery Protocol (NDP) [RFC4861][RFC4862]. Neighbor Discovery Protocol (NDP) [RFC4861][RFC4862].
The 6lo Working Group has specified an update The 6lo Working Group has specified an update [RFC8505] to RFC6775.
[I-D.ietf-6lo-rfc6775-update] to RFC6775. Wireless devices can Wireless devices can register their address to a Backbone Router
register their address to a Backbone Router
[I-D.ietf-6lo-backbone-router], which proxies for the registered [I-D.ietf-6lo-backbone-router], which proxies for the registered
addresses with the IPv6 NDP running on a high speed aggregating addresses with the IPv6 NDP running on a high speed aggregating
backbone. The update also enables a proxy registration mechanism on backbone. The update also enables a proxy registration mechanism on
behalf of the registered node, e.g. by a 6LoWPAN router to which the behalf of the registered node, e.g. by a 6LoWPAN router to which the
mobile node is attached. mobile node is attached.
The general idea behind the backbone router concept is that broadcast The general idea behind the backbone router concept is that broadcast
and multicast messaging should be tightly controlled in a variety of and multicast messaging should be tightly controlled in a variety of
Wireless Local Area Networks (WLANs) and Wireless Personal Area Wireless Local Area Networks (WLANs) and Wireless Personal Area
Networks (WPANs). Connectivity to a particular link that provides Networks (WPANs). Connectivity to a particular link that provides
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LLN nodes can move freely from an LLN anchored at one IPv6 Backbone LLN nodes can move freely from an LLN anchored at one IPv6 Backbone
Router to an LLN anchored at another Backbone Router on the same Router to an LLN anchored at another Backbone Router on the same
backbone, keeping any of the IPv6 addresses they have configured. backbone, keeping any of the IPv6 addresses they have configured.
The Backbone Routers maintain a Binding Table of their Registered The Backbone Routers maintain a Binding Table of their Registered
Nodes, which serves as a distributed database of all the LLN Nodes. Nodes, which serves as a distributed database of all the LLN Nodes.
An extension to the Neighbor Discovery Protocol is introduced to An extension to the Neighbor Discovery Protocol is introduced to
exchange Binding Table information across the Backbone Link as needed exchange Binding Table information across the Backbone Link as needed
for the operation of IPv6 Neighbor Discovery. for the operation of IPv6 Neighbor Discovery.
RFC6775 and follow-on work (e.g., [I-D.ietf-6lo-ap-nd], do address RFC6775 and follow-on work [RFC8505] address the needs of LLNs, and
the needs of LLNs, and similar techniques are likely to be valuable similar techniques are likely to be valuable on any type of link
on any type of link where sleeping devices are attached, or where the where sleeping devices are attached, or where the use of broadcast
use of broadcast and multicast operations should be limited. and multicast operations should be limited.
4.3. Buffering to Improve Battery Life 4.3. Buffering to Improve Battery Life
Methods have been developed to help save battery life; for example, a Methods have been developed to help save battery life; for example, a
device might not wake up when the AP receives a multicast packet. device might not wake up when the AP receives a multicast packet.
The AP acts on behalf of STAs in various ways. To enable use of the The AP acts on behalf of STAs in various ways. To enable use of the
power-saving feature for STAs in its BSS, the AP buffers frames for power-saving feature for STAs in its BSS, the AP buffers frames for
delivery to the STA at the time when the STA is scheduled for delivery to the STA at the time when the STA is scheduled for
reception. If an AP, for instance, expresses a DTIM (Delivery reception. If an AP, for instance, expresses a DTIM (Delivery
Traffic Indication Message) of 3 then the AP will send a multicast Traffic Indication Message) of 3 then the AP will send a multicast
packet every 3 packets. In fact, when any single wireless client packet every 3 packets. In fact, when any single wireless STA
associated with an access point has 802.11 power-save mode enabled, associated with an access point has 802.11 power-save mode enabled,
the access point buffers all multicast frames and sends them only the access point buffers all multicast frames and sends them only
after the next DTIM beacon. after the next DTIM beacon.
But in practice, most AP's will send a multicast every 30 packets. In practice, most AP's will send a multicast every 30 packets. For
For unicast there's a TIM (Traffic Indication Message); but since unicast the AP could send a TIM (Traffic Indication Message), but for
multicast is going to everyone, the AP sends a broadcast to everyone. multicast the AP sends a broadcast to everyone. DTIM does power
DTIM does power management but clients can choose whether or not to management but STAs can choose whether or not to wake up or not and
wake up or not and whether or not to drop the packet. Unfortunately, whether or not to drop the packet. Unfortunately, without proper
without proper administrative control, such clients may no longer be administrative control, such STAs may be unable to determine why
able to determine why their multicast operations do not work. their multicast operations do not work.
4.4. IPv6 support in 802.11-2012 4.4. IPv6 support in 802.11-2012
IPv6 uses Neighbor Discovery Protocol (NDP) instead of ARP. Every IPv6 uses Neighbor Discovery Protocol (NDP) instead of ARP. Every
IPv6 node subscribes to a special multicast address for this purpose. IPv6 node subscribes to a special multicast address for this purpose.
Here is the specification language from clause 10.23.13 of Here is the specification language from clause 10.23.13 of
[dot11-proxyarp]: [dot11-proxyarp]:
"When an IPv6 address is being resolved, the Proxy Neighbor "When an IPv6 address is being resolved, the Proxy Neighbor
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wireless medium. wireless medium.
4.5. Conversion of multicast to unicast 4.5. Conversion of multicast to unicast
It is often possible to transmit multicast control and data messages It is often possible to transmit multicast control and data messages
by using unicast transmissions to each station individually. by using unicast transmissions to each station individually.
4.6. Directed Multicast Service (DMS) 4.6. Directed Multicast Service (DMS)
There are situations where more is needed than simply converting There are situations where more is needed than simply converting
multicast to unicast. For these purposes, DMS enables a client to multicast to unicast. For these purposes, DMS enables a STA to
request that the AP transmit multicast group addressed frames request that the AP transmit multicast group addressed frames
destined to the requesting clients as individually addressed frames destined to the requesting STAs as individually addressed frames
[i.e., convert multicast to unicast]. Here are some characteristics [i.e., convert multicast to unicast]. Here are some characteristics
of DMS: of DMS:
o Requires 802.11n A-MSDUs o Requires 802.11n A-MSDUs
o Individually addressed frames are acknowledged and are buffered o Individually addressed frames are acknowledged and are buffered
for power save clients for power save STAs
o The requesting STA may specify traffic characteristics for DMS o The requesting STA may specify traffic characteristics for DMS
traffic traffic
o DMS was defined in IEEE Std 802.11v-2011 o DMS was defined in IEEE Std 802.11v-2011
o DMS requires changes to both AP and STA implementation. o DMS requires changes to both AP and STA implementation.
DMS is not currently implemented in products. See [Tramarin2017] and DMS is not currently implemented in products. See [Tramarin2017] and
[Oliva2013] for more information. [Oliva2013] for more information.
4.7. GroupCast with Retries (GCR) 4.7. GroupCast with Retries (GCR)
GCR (defined in [dot11aa]) provides greater reliability by using GCR (defined in [dot11aa]) provides greater reliability by using
either unsolicited retries or a block acknowledgement mechanism. GCR either unsolicited retries or a block acknowledgement mechanism. GCR
increases probability of broadcast frame reception success, but still increases probability of broadcast frame reception success, but still
does not guarantee success. does not guarantee success.
For the block acknowledgement mechanism, the AP transmits each group For the block acknowledgement mechanism, the AP transmits each group
addressed frame as conventional group addressed transmission. addressed frame as conventional group addressed transmission.
Retransmissions are group addressed, but hidden from non-11aa Retransmissions are group addressed, but hidden from non-11aa STAs.
clients. A directed block acknowledgement scheme is used to harvest A directed block acknowledgement scheme is used to harvest reception
reception status from receivers; retransmissions are based upon these status from receivers; retransmissions are based upon these
responses. responses.
GCR is suitable for all group sizes including medium to large groups. GCR is suitable for all group sizes including medium to large groups.
As the number of devices in the group increases, GCR can send block As the number of devices in the group increases, GCR can send block
acknowledgement requests to only a small subset of the group. GCR acknowledgement requests to only a small subset of the group. GCR
does require changes to both AP and STA implementation. does require changes to both AP and STA implementation.
GCR may introduce unacceptable latency. After sending a group of GCR may introduce unacceptable latency. After sending a group of
data frames to the group, the AP has do the following: data frames to the group, the AP has do the following:
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This latency may not be acceptable for some traffic. This latency may not be acceptable for some traffic.
There are ongoing extensions in 802.11 to improve GCR performance. There are ongoing extensions in 802.11 to improve GCR performance.
o BAR is sent using downlink MU-MIMO (note that downlink MU-MIMO is o BAR is sent using downlink MU-MIMO (note that downlink MU-MIMO is
already specified in 802.11-REVmc 4.3). already specified in 802.11-REVmc 4.3).
o BA is sent using uplink MU-MIMO (which is a .11ax feature). o BA is sent using uplink MU-MIMO (which is a .11ax feature).
o Additional 802.11ax extensions are under consideration; see o Additional 802.11ax extensions are under consideration; see
[mc-ack-mux] [mc-ack-mux]
o Latency may also be reduced by simultaneously receiving BA o Latency may also be reduced by simultaneously receiving BA
information from multiple clients. information from multiple STAs.
5. Operational optimizations 5. Operational optimizations
This section lists some operational optimizations that can be This section lists some operational optimizations that can be
implemented when deploying wireless IEEE 802 networks to mitigate the implemented when deploying wireless IEEE 802 networks to mitigate the
issues discussed in Section 3. issues discussed in Section 3.
5.1. Mitigating Problems from Spurious Neighbor Discovery 5.1. Mitigating Problems from Spurious Neighbor Discovery
ARP Sponges ARP Sponges
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for some interval. Unfortunately, the core routers which we for some interval. Unfortunately, the core routers which we
are using do not support this. When a host connects to network are using do not support this. When a host connects to network
and gets an IP address, it will ARP for its default gateway and gets an IP address, it will ARP for its default gateway
(the router). The router will update its cache with the IP to (the router). The router will update its cache with the IP to
host MAC mapping learnt from the request (passive ARP host MAC mapping learnt from the request (passive ARP
learning). learning).
Firewall unused space Firewall unused space
The distribution of users on wireless networks / subnets The distribution of users on wireless networks / subnets
changes from meeting to meeting (e.g the "IETF-secure" SSID was changes from meeting to meeting (e.g SSIDs are renamed, some
renamed to "IETF", fewer users use "IETF-legacy", etc). This SSIDs lose favor, etc). This makes utilization for particular
utilization is difficult to predict ahead of time, but we can SSIDs difficult to predict ahead of time, but usage can be
monitor the usage as attendees use the different networks. By monitored as attendees use the different networks. Configuring
configuring multiple DHCP pools per subnet, and enabling them multiple DHCP pools per subnet, and enabling them sequentially,
sequentially, we can have a large subnet, but only assign can create a large subnet, from which only addresses in the
addresses from the lower portions of it. This means that we lower portions are assigned. Therefore input IP access lists
can apply input IP access lists, which deny traffic to the can be applied, which deny traffic to the upper, unused
upper, unused portions. This means that the router does not portions. Then the router does not attempt to forward packets
attempt to forward packets to the unused portions of the to the unused portions of the subnets, and so does not ARP for
subnets, and so does not ARP for it. This method has proven to it. This method has proven to be very effective, but is
be very effective, but is somewhat of a blunt axe, is fairly somewhat of a blunt axe, is fairly labor intensive, and
labor intensive, and requires coordination. requires coordination.
Disabling/filtering ARP requests Disabling/filtering ARP requests
In general, the router does not need to ARP for hosts; when a In general, the router does not need to ARP for hosts; when a
host connects, the router can learn the IP to MAC mapping from host connects, the router can learn the IP to MAC mapping from
the ARP request sent by that host. This means that we should the ARP request sent by that host. This means that we should
be able to disable and / or filter ARP requests from the be able to disable and / or filter ARP requests from the
router. Unfortunately, ARP is a very low level / fundamental router. Unfortunately, ARP is a very low level / fundamental
part of the IP stack, and is often offloaded from the normal part of the IP stack, and is often offloaded from the normal
control plane. While many routers can filter layer-2 traffic, control plane. While many routers can filter layer-2 traffic,
skipping to change at page 16, line 5 skipping to change at page 16, line 5
like a really simple (and obvious) solution, but like a really simple (and obvious) solution, but
implementations / architectural issues make this difficult or implementations / architectural issues make this difficult or
awkward in practice. awkward in practice.
NAT NAT
The broadcasts are overwhelmingly being caused by outside The broadcasts are overwhelmingly being caused by outside
scanning / backscatter traffic. This means that, if we were to scanning / backscatter traffic. This means that, if we were to
NAT the entire (or a large portion) of the attendee networks, NAT the entire (or a large portion) of the attendee networks,
there would be no NAT translation entries for unused addresses, there would be no NAT translation entries for unused addresses,
and so the router would never ARP for them. The IETF NOC has and so the router would never ARP for them. However, there are
discussed NATing the entire (or large portions) attendee many reasons to avoid using NAT in such a blanket fashion.
address space, but a: elegance and b: flaming torches and
pitchfork concerns means we have not attempted this yet.
Stateful firewalls Stateful firewalls
Another obvious solution would be to put a stateful firewall Another obvious solution would be to put a stateful firewall
between the wireless network and the Internet. This firewall between the wireless network and the Internet. This firewall
would block incoming traffic not associated with an outbound would block incoming traffic not associated with an outbound
request. The IETF philosophy has been to have the network as request. But this conflicts with the need and desire to have
open as possible / honor the end-to-end principle. An attendee the network as open as possible / honor the end-to-end
on the meeting network should be an Internet host, and should principle. An attendee on the meeting network should be an
be able to receive unsolicited requests. Unfortunately, Internet host, and should be able to receive unsolicited
keeping the network working and stable is the first priority requests. Unfortunately, keeping the network working and
and a stateful firewall may be required in order to achieve stable is the first priority and a stateful firewall may be
this. required in order to achieve this.
6. Multicast Considerations for Other Wireless Media 6. Multicast Considerations for Other Wireless Media
Many of the causes of performance degradation described in earlier Many of the causes of performance degradation described in earlier
sections are also observable for wireless media other than 802.11. sections are also observable for wireless media other than 802.11.
For instance, problems with power save, excess media occupancy, and For instance, problems with power save, excess media occupancy, and
poor reliability will also affect 802.15.3 and 802.15.4. poor reliability will also affect 802.15.3 and 802.15.4.
Unfortunately, 802.15 media specifications do not yet include Unfortunately, 802.15 media specifications do not yet include
mechanisms similar to those developed for 802.11. In fact, the mechanisms similar to those developed for 802.11. In fact, the
design philosophy for 802.15 is oriented towards minimality, with the design philosophy for 802.15 is oriented towards minimality, with the
result that many such functions are relegated to operation within result that many such functions are relegated to operation within
higher layer protocols. This leads to a patchwork of non- higher layer protocols. This leads to a patchwork of non-
interoperable and vendor-specific solutions. See [uli] for some interoperable and vendor-specific solutions. See [uli] for some
additional discussion, and a proposal for a task group to resolve additional discussion, and a proposal for a task group to resolve
similar issues, in which the multicast problems might be considered similar issues, in which the multicast problems might be considered
for mitigation. for mitigation.
Similar considerations hold for most other wireless media. A brief
introduction is provided in [RFC5757] for the following:
o 802.16 WIMAX
o 3GPP/3GPP2
o DVB-H / DVB-IPDC
o TV Broadcast and Satellite Networks
7. Recommendations 7. Recommendations
This section will provide some recommendations about the usage and This section will provide some recommendations about the usage and
combinations of the multicast enhancements described in Section 4 and combinations of the multicast enhancements described in Section 4 and
Section 5. Section 5.
Future protocol documents utilizing multicast signaling should be Future protocol documents utilizing multicast signaling should be
carefully scrutinized if the protocol is likely to be used over carefully scrutinized if the protocol is likely to be used over
wireless media. wireless media.
skipping to change at page 17, line 18 skipping to change at page 17, line 25
compatible with low-duty cycle operation. compatible with low-duty cycle operation.
(FFS) (FFS)
8. Discussion Items 8. Discussion Items
This section suggests two discussion items for further resolution. This section suggests two discussion items for further resolution.
The IETF should determine guidelines by which it may be decided that The IETF should determine guidelines by which it may be decided that
multicast packets are to be sent wired. For example, 802.1ak works multicast packets are to be sent wired. For example, 802.1ak works
on ethernet and wifi. 802.1ak has been pulled into 802.1Q as of on ethernet and Wi-Fi. 802.1ak has been pulled into 802.1Q as of
802.1Q-2011. 802.1Q-2014 can be found here: 802.1Q-2011. 802.1Q-2014 can be found here:
http://www.ieee802.org/1/pages/802.1Q-2014.html. If a generic http://www.ieee802.org/1/pages/802.1Q-2014.html. If a generic
solution is not found, guidelines for multicast over wifi should be solution is not found, guidelines for multicast over Wi-Fi should be
established. established.
Perhaps a reliable registration to Layer-2 multicast groups and a Reliable registration to Layer-2 multicast groups and a reliable
reliable multicast operation at Layer-2 could provide a generic multicast operation at Layer-2 might provide a generic solution.
solution. There is no need to support 2^24 groups to get solicited There is no need to support 2^24 groups to get solicited node
node multicast working: it is possible to simply select a number of multicast working: it is possible to simply select a number of
trailing bits that make sense for a given network size to limit the trailing bits that make sense for a given network size to limit the
amount of unwanted deliveries to reasonable levels. IEEE 802.1, amount of unwanted deliveries to reasonable levels. IEEE 802.1,
802.11, and 802.15 should be encouraged to revisit L2 multicast 802.11, and 802.15 should be encouraged to revisit L2 multicast
issues. In reality, Wi-Fi provides a broadcast service, not a issues. In reality, Wi-Fi provides a broadcast service, not a
multicast service. On the physical medium, all frames are broadcast multicast service. On the physical medium, all frames are broadcast
except in very unusual cases in which special beamforming except in very unusual cases in which special beamforming
transmitters are used. Unicast offers the advantage of being much transmitters are used. Unicast offers the advantage of being much
faster (2 orders of magnitude) and much more reliable (L2 ARQ). faster (2 orders of magnitude) and much more reliable (L2 ARQ).
9. Security Considerations 9. Security Considerations
skipping to change at page 17, line 49 skipping to change at page 18, line 12
This document does not introduce any security mechanisms, and does This document does not introduce any security mechanisms, and does
not have affect existing security mechanisms. not have affect existing security mechanisms.
10. IANA Considerations 10. IANA Considerations
This document does not request any IANA actions. This document does not request any IANA actions.
11. Acknowledgements 11. Acknowledgements
This document has benefitted from discussions with the following This document has benefitted from discussions with the following
people, in alphabetical order: Pascal Thubert people, in alphabetical order: Mikael Abrahamsson, Stuart Cheshire,
Donald Eastlake, Toerless Eckert, Jake Holland, Joel Jaeggli, Pascal
Thubert
12. Informative References 12. Informative References
[arpsponge] [arpsponge]
Arien Vijn, Steven Bakker, "Arp Sponge", March 2015. Arien Vijn, Steven Bakker, "Arp Sponge", March 2015.
[Deri-2010] [Deri-2010]
Deri, L. and J. Gasparakis, "10 Gbit Hardware Packet Deri, L. and J. Gasparakis, "10 Gbit Hardware Packet
Filtering Using Commodity Network Adapters", RIPE 61, Filtering Using Commodity Network Adapters", RIPE 61,
2010, <http://ripe61.ripe.net/ 2010, <http://ripe61.ripe.net/
presentations/138-Deri_RIPE_61.pdf>. presentations/138-Deri_RIPE_61.pdf>.
[dot11] P802.11, "Part 11: Wireless LAN Medium Access Control [dot11] P802.11, "802.11-2016 - IEEE Standard for Information
(MAC) and Physical Layer (PHY) Specifications", March technology--Telecommunications and information exchange
2012. between systems Local and metropolitan area networks--
Specific requirements - Part 11: Wireless LAN Medium
Access Control (MAC) and Physical Layer (PHY)
Specification", March 2016.
[dot11-proxyarp] [dot11-proxyarp]
P802.11, "Proxy ARP in 802.11ax", September 2015. P802.11, "Proxy ARP in 802.11ax", September 2015.
[dot11aa] P802.11, "Part 11: Wireless LAN Medium Access Control [dot11aa] P802.11, "Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) Specifications Amendment 2: (MAC) and Physical Layer (PHY) Specifications Amendment 2:
MAC Enhancements for Robust Audio Video Streaming", March MAC Enhancements for Robust Audio Video Streaming", March
2012. 2012.
[I-D.ietf-6lo-ap-nd]
Thubert, P., Sarikaya, B., Sethi, M., and R. Struik,
"Address Protected Neighbor Discovery for Low-power and
Lossy Networks", draft-ietf-6lo-ap-nd-08 (work in
progress), October 2018.
[I-D.ietf-6lo-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P. and C. Perkins, "IPv6 Backbone Router", draft- Thubert, P. and C. Perkins, "IPv6 Backbone Router", draft-
ietf-6lo-backbone-router-08 (work in progress), October ietf-6lo-backbone-router-08 (work in progress), October
2018. 2018.
[I-D.ietf-6lo-rfc6775-update]
Thubert, P., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for 6LoWPAN Neighbor
Discovery", draft-ietf-6lo-rfc6775-update-21 (work in
progress), June 2018.
[I-D.ietf-6tisch-architecture] [I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-15 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-17 (work
in progress), October 2018. in progress), November 2018.
[ietf_802-11] [ietf_802-11]
Dorothy Stanley, "IEEE 802.11 multicast capabilities", Nov Dorothy Stanley, "IEEE 802.11 multicast capabilities", Nov
2015. 2015.
[mc-ack-mux] [mc-ack-mux]
Yusuke Tanaka et al., "Multiplexing of Acknowledgements Yusuke Tanaka et al., "Multiplexing of Acknowledgements
for Multicast Transmission", July 2015. for Multicast Transmission", July 2015.
[mc-prob-stmt] [mc-prob-stmt]
skipping to change at page 19, line 40 skipping to change at page 19, line 44
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>. <https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>. <https://www.rfc-editor.org/info/rfc4862>.
[RFC5757] Schmidt, T., Waehlisch, M., and G. Fairhurst, "Multicast
Mobility in Mobile IP Version 6 (MIPv6): Problem Statement
and Brief Survey", RFC 5757, DOI 10.17487/RFC5757,
February 2010, <https://www.rfc-editor.org/info/rfc5757>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 [RFC6282] 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>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>. <https://www.rfc-editor.org/info/rfc6775>.
[RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
<https://www.rfc-editor.org/info/rfc8505>.
[Tramarin2017] [Tramarin2017]
Tramarin, F., Vitturi, S., and M. Luvisotto, "IEEE 802.11n Tramarin, F., Vitturi, S., and M. Luvisotto, "IEEE 802.11n
for Distributed Measurement Systems", 2017 IEEE for Distributed Measurement Systems", 2017 IEEE
International Instrumentation and Measurement Technology International Instrumentation and Measurement Technology
Conference (I2MTC) pp. 1-6, May 2017. Conference (I2MTC) pp. 1-6, May 2017.
[uli] Pat Kinney, "LLC Proposal for 802.15.4", Nov 2015. [uli] Pat Kinney, "LLC Proposal for 802.15.4", Nov 2015.
Appendix A. Changes between draft-ietf-mboned-ieee802-mcast-problems
revisions 03 versus 04
This section lists the changes between revisions ...-03.txt and
...-04.txt of draft-ietf-mboned-ieee802-mcast-problems.
o Replaced "client" by "STA".
o Used terminology "Wi-Fi" throughout.
o Many editorial improvements and grammatical corrections.
o Modified text to be more generic instead of referring specifically
to IETF conference situations.
o Cited RFC 5757 [RFC5757] for introduction to other wireless media.
o Updated bibliographic citations.
Authors' Addresses Authors' Addresses
Charles E. Perkins Charles E. Perkins
Futurewei Inc. Futurewei Inc.
2330 Central Expressway 2330 Central Expressway
Santa Clara, CA 95050 Santa Clara, CA 95050
USA USA
Phone: +1-408-330-4586 Phone: +1-408-330-4586
Email: charliep@computer.org Email: charliep@computer.org
 End of changes. 58 change blocks. 
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