T' Blaga, V' Dobrota, K' Steenhaut, I' Trestian, G' Lazar

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Steps towards Native IPv6 Multicast CastGate
Router with PIM-SM Support

• T. Blaga, V. Dobrota, K. Steenhaut, I. Trestian,
  G. Lazar
• Technical University of Cluj-Napoca, Romania
• Vrije Universiteit Brussel, Belgium

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Agenda
I. Introduction II. Protocol Independent
Multicast III. Testbed for Native IPv6
Multicast
IV. Alternative Multicast Technologies V. Propos
ed Improvements
VI. Conclusions
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I. Introduction
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Introduction

• Multicast aspects
• group membership IGMP for IPv4 and MLD for IPv6
• distribution trees
• source-based
• core-based
• Measure join latency, control overhead,
  forwarding delay and jitter
• Alternative multicast solution
• CastGate and CastGate Router
• Proposed solution towards IPv6 multicast
• IPv6 CastGate Router with PIM-SM support
• hybrid between multicast tunneling and native
  IPv6 multicast

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II. Protocol Independent Multicast

• PIM-DM
• PIM-SM

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PIM

• Unicast routing protocol independent
• Requires some unicast routing protocol to
  determine the network topology and the topology
  changes, like RIP or OSPF
• Two different modes
• PIM-DM (PIM Dense Mode)
• PIM-SM (PIM Sparse Mode)
• PIM-DM source-based trees using flood-and-prune
• PIM-SM core-based trees using explicit joins
• IPv6 PIM does not imply major changes, only the
  type of addresses used

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PIM-DM

• Operation of PIM-DM similar to DVMRP without the
  route exchange
• Assert messages to determine a designated
  forwarder
• Multicast forwarding performed on oilist (output
  interfaces list)
• Oilist contains
• Interfaces on which neighbors were discovered
• Interfaces on which multicast receivers have been
  discovered
• ALL-PIM-ROUTERS address
• 224.0.0.13
• FF02D

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PIM-SM

• Each receiver has to explicitly join the
  multicast tree
• Core-based tree with a shared root RP
  (Rendez-vous Point)
• PIM-SM operation
• Neighbor discovery
• RP registering
• RP joining/pruning
• Mechanism to elect DR
• Mechanism to switch to the source-based tree when
  a threshold is exceeded

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III. Testbed for Native IPv6 Multicast
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Testbed for Native IPv6 Multicast

• FreeBSD KAME routing daemons
• PIM-DM pim6ddPIM-SM pim6sd

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IPv6 multicast sender/receiver

• Send and receive IPv6 multicast traffic
• m6send
• m6receive
• Operation
• Sender
• ./mXsend group_address port "text" hoplimit
• ./m6send ff151 1111 "IPv6 multicast" 4
• Receiver
• ./mXreceive group_address port
• ./m6receive ff151 1111

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Testbed for Native IPv6 Multicast

• Join latency time to first data packet
• first Multicast Listener Report sent
• receiving of data packet
• Default robustness variable 2
• 2 MLD messages sent by host
• tune for expected packet loss on the link
• Round Trip Time between receiver and source
  recorded
• Software tools
• Ethereal 0.10.7
• XML parser implemented

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Scenario for native IPv6 multicast trial
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Testbed for Native IPv6 Multicast

• PIM-DM join latency 45 higher than RTT

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Testbed for Native IPv6 Multicast

• PIM-SM join latency four times higher than RTT

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Testbed for Native IPv6 Multicast

• PIM-DM 19.01/341 bps

• PIM-SM 20.41/342 bps

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IV. Alternative Multicast Technologies

• CastGate
• CastGate Router

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Alternative Multicast Technologies

• Multicast access not available
• Reason three-fold deadlock
• ISPs
• content provider
• customer
• Alternative Group Communication Services
• tunneling
• overlay multicast
• CastGate VUB
• seamless access to multicast content
• auto-tunneling
• transition technology - increase number of
  multicast users

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CastGate
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CastGate Router

• CastGate Router

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V. Proposed Improvements

• CastGate Router with PIM-SM support
• IPv6 CastGate

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CastGate Router with PIM-SM
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IPv6 CastGate

• CastGate Enhanced UMTP (UDP Multicast Tunneling
  Protocol)
• IPv6-enabled CastGate
• tunnel IPv6 multicast over IPv4
• Tunnel Client and Tunnel Server must be IPv6
  capable
• Tunnel Database Server requires no modification
• modify Enhanced UMTP to support IPv6

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IPv6 CastGate

• IPv6 Enhanced UMTP trailer

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IPv6 CastGate

• IPv6 Enhanced UMTP
• 12-octet trailer -gt 24-octet trailer
• 16-octet trailer -gt 40-octet trailer
• new command IPv6_DATA with code 13
• S bit used to differentiate between the 24/40
  octet trailer
• new Enhanced UMTP option OPT_IPV6 with code 20

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IPv6 CastGate Router with PIM-SM

• IPv6 CastGate Router with PIM-SM support

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VI. Conclusions
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Conclusions

• Join latency in native IPv6 multicast
• PIM-DM and PIM-SM higher than RTT
• PIM-SM higher than PIM-DM
• Control overhead, forwarding delay and jitter
• Enhancements
• CastGate Router with PIM-SM support
• IPv6-enabled CastGate
• increase number of multicast users
• Final step Native IPv6 Multicast