The document discusses whether IPv6 and IP multicast work better together. It finds that they do work well together as IPv6 was designed to support multicast. IPv6 uses multicast for many functions like neighbor discovery. Deployments also show that IPv6 multicast can be used to deliver live streaming content and save bandwidth. Considerations like wireless impacts are discussed. The conclusion is that IPv6 and multicast are better deployed together.

1. © 2014 Cisco and/or its affiliates. All rights reserved. 1© 2014 Cisco and/or its affiliates. All rights reserved. 1
IPv6 and IP Multicast…
better together?
Steve Simlo – Product Manager NOSTG
ssimlo@cisco.com
June 2014
@stevesimlo
Steve Simlo

2. © 2014 Cisco and/or its affiliates. All rights reserved. 2
Research & Discovery
Energy
Efficiency
Predictive maintenance
Industrial Automation
Smart
Home
Defense
Asset
tracking
Intelligent Building
Smart Cities
Smart Grid
Car 2 Car
Agriculture

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* Ingress streams to Akamai network Source: Akamai Packet Video Workshop 2013 presentation
*

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• Collected by a mostly silent node in promiscuous mode
• 75% of IPv6 traffic was multicast
3%
5%
30%
2%
49%
11%
IPv6 Multicast Traffic
mcast RS
mcast RA
mcast NS
mcast NA
mDNS
NS from ::
18%
NS host
for
routers
39%
NS router
for hosts
30%
NS host for
hosts
13%
Multicast NS

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Server
Router
Unicast
Server
Router
Multicast
Number of Streams

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IPv6 Address Family
Multicast AnycastUnicast
Assigned Solicited Node
Unique Local Link Local Global Special Embedded
*IPv6 does not use broadcast
Well
Known
Temp

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• Audio/Video
• Push Media
• Distribution
• Announcement
• Monitoring
• Market Data Applications
• Conferencing
• Sharing Resources
• Games
• Others
• Resource Discovery
• Data Collection
• Others
One to
Many
Many to
Many
Many to
One
Multicast Applications

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http://www.istockphoto.com/photo/cherry-tree-prunus-avium-on-grass-field-isolated-on_white-13136197
http://www.shutterstock.com/pic.mhtml?src=PS5DwrRy6S3EBRIUs8iKRA-1-1&id=44779297

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• Mechanism for transmitting
information from a single
source (root) to many
receivers (leaves)
• Single copy of a datagram is
sent from the source and
replicated through the tree to
receivers
• No restriction on physical or
geographical boundary
Source
Downthetree
Single copy
of datagram
Replication
ReceiversReceivers
Replication

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Source 1
Source 2
Source 3
(S1,G)
(S2,G)
(S3,G)
 The good
• Optimal forwarding
• No RP needed
 The bad
• Needs more memory
• Either needs receiver signalling (MLDv2) or RP
discovery / announcement

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Source 1
Source 2
Source 3
Rendezvous Point
(*,G))
 The good
• Needs less memory
 The bad
• Traffic may be flooded to all active receivers
• Forwarding path may be suboptimal
• RP discovery, announcement, management
absolutely needed

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http://inhabitat.com/photos-acros-japan-is-a-mountainous-green-roofed-pyramid-planted-with-trees/
• PIM Sparse Mode
• PIM BiDir(ectional)
• Source Specific Multicast

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• PIM-SM and PIM-BiDir require a method to discover RPs (and related
groups)
• Static RP assignment
Provides static group-to-RP mapping
Anycast address may be used for redundancy
• Embedded-RP (RFC 3956)
RP and associated group address embedded in IPv6 multicast address
Single RP address only can be mapped to a group, no PIM BiDir support
Anycast address may be used for redundancy
• Boot-Strap Router (BSR) (RFC 5059)
Provides automated group-to-RP mapping and RP redundancy

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• PIMv6 implements PIM SM, SSM and BiDir
• PIMv6 has standardised and rationalised RP
announcements
• PIMv6 has no dependency on Interdomain MSDP
peering
• PIMv6 does not implement Dense Mode
• More modern devices support MLD version 2
(needed for PIM SSM)

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• IGMPv1 behaviour
• Dense Mode
• MSDP
• Auto RP

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• Latest spec (as of April 2014)
–http://tools.ietf.org/html/draft-ietf-mboned-auto-
multicast-17
–Allow multicast content distribution to extend to
unicast-only connected receivers
–Bring the flat scaling properties of multicast to the
Internet
• Provide the benefits of multicast
wherever multicast is deployed
–Let the networks which have deployed multicast benefit
from their deployment
• Work seamlessly with existing
applications
–No OS kernel changes

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MLD
MLD
PIM
 IPv6 uses MLDv2 for Link Local Groups
The original specification of the Multicast Listener Discovery Protocol (MLD) for IPv6
[RFC 2710] mandates the use of a link-local IPv6 source address for the transmission of
MLD messages. In addition, MLD also requires nodes to send MLD Report messages when
joining any IPv6 multicast group (except the All-Nodes address and addresses of scope
less than 2).
 MLD Snooping usually cannot filter these groups

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Personal Computer
Operating Systems
• Windows
• Mac OS X
• Linux
Appliances &
Networking
• Printers
• Access Points
• Switches
• Routers
AV Equipment
• Speakers
• Cameras
• Displays
• AV Receivers

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 All Multicast messages require ALL hosts on link to stay awake (1-10ms)
Even if the message is not for them
 Multicast [on WiFi, battery/sleepy nodes]
Wasting bandwidth – sent promiscuously as broadcast
Waking up hosts unnecessarily
Looking at ND (RS, RA, DAD, address resolution)
 Duplicate address detection
Currently requires always-on to defend address
 Related DAD issues
Not robust against packet loss

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New command added "ipv6 nd ra solicited unicast”
Old behavior: solicited RAs multicast
New behavior: Allows solicited RAs to be unicast
In addition to sending periodic, unsolicited advertisements, a router
sends advertisements in response to valid solicitations received on
an advertising interface. A router MAY choose to unicast the
response directly to the soliciting host's address (if the
solicitation's source address is not the unspecified address), but
the usual case is to multicast the response to the all-nodes group.

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Router Solicitation (RS)
Triggered (RA)
 Scaling the 802.11 multicast reliability issues
 NDP process is multicast “chatty”, consumes airtime
 Rate limit RA’s from the legitimate router
 Inspect the RS, convert the responding RA to L2 Unicast
Periodic (RA’s)

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(NS)
00:24:56:75:44:33 2001:db8:0:20::2
00:24:56:11:93:28 2001:db8:0:20::4
(Unicast NA)
 Scaling the 802.11 multicast reliability issues
 NDP process is multicast “chatty”, consumes airtime
 Caching allows the Controller to “proxy” the NA, based on gleaning
 Intercepting the NS and unicasting it over L2 to the target
2
4

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• NTT-East rolled out native IPv6 multicast services instead of IPv4
offering IPTV, music and games:
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr200911sf1.html

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• FAN applications can leverage IPv6
Multicast services when addressing a group
of end-points. In example:
o End-points firmware upgrade
o AMI Head-end applications
o Demand reset messages
o Demand response messages
o Targeted pings Group of meters with
same read time/cycle
• IPv6 Multicast has to be integrated in
network design of Utility NOC and WAN
• On CG-Mesh, Field Area Router can act as
MLD proxy, therefore broadcasting the
Multicast packet at Layer-2 on the Mesh
Public or
Private IP
WAN
Cisco CG-
NMS
Server, DB
ASR
1000
AMI Head-
End Servers,
DB
PAN #1
PAN #2 PAN #3

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The Power of IPv6
Customer Access Aggregation
R1
R2
Core
Service Production Peering
IP&Optical
Infrastructure Cloud
Mobile
Ethernet
xDSL
FTTH
IPv6
IPv4 Lightweight 4o6 - Softwire IPv4
Non-IP – MEF OAM Keyed IPv6 tunnel
Infrastructure Cloud

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• IPv6 deployment requires multicast
• IPv6 multicast services IN DEPLOYMENT TODAY allow bandwidth
flexibility and savings for live streamed content delivery
• PIMv6 leverages IPv6 and optimizes
• IPv6 and Wireless have specific multicast considerations
• IPv6 and IP multicast….better together ? Absolutely…but look before
you leap and understand where you are leaping to and why !

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References / more information
Cisco IPv6 home page http://www.cisco.com/web/solutions/trends/ipv6/index.html
Cisco IPv6 Knowledge portal http://www.cisco.com/web/solutions/netsys/ipv6/knowledgebase/index.html
Cisco IPv6 Support community https://supportforums.cisco.com/community/netpro/network-infrastructure/ipv6-transition
Deploying IPv6 in the Internet Edge:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Borderless_Networks/Internet_Edge/InternetEdgeIPv6.html
Deploying IPv6 in Campus Networks: http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/CampIPv6.html
Deploying IPv6 in Branch Networks: http://www.cisco.com/en/US/docs/solutions/Enterprise/Branch/BrchIPv6.html
Smart Business Architecture – IPv6 Guides:
http://www.cisco.com/en/US/netsol/ns982/networking_solutions_program_home.html
IPv6 FAN architecture white paper http://www.cisco.com/web/strategy/docs/energy/ip_arch_sg_wp.pdf
Unified FAN architecture for Distribution Automation white paper
http://www.cisco.com/web/strategy/docs/energy/ida_wp.pdf
Cisco FAN solution http://www.cisco.com/web/strategy/energy/field_area_network.html
Cisco Blog IPv6 Tag http://blogs.cisco.com/tag/ipv6
The Multicast Security Toolkit http://www.cisco.com/web/about/security/intelligence/multicast_toolkit.html
Cisco IP Multicast Security http://www.cisco.com/en/US/products/ps6593/products_ios_protocol_group_home.html
Certification, USGv6/IPV6RLPh2 https://www.iol.unh.edu/services/testing/ipv6/usgv6tested.php
RIPE554 http://www.ripe.net/ripe/docs/ripe-554

30. © 2014 Cisco and/or its affiliates. All rights reserved. 30© 2014 Cisco and/or its affiliates. All rights reserved. 30
IPv6 and IP Multicast…
better together?
Steve Simlo – Product Manager NOSTG
ssimlo@cisco.com
June 2014
@stevesimlo
Steve Simlo