study of ipv6 multicast deployment in mpls networks · mpls networks wim verrydt - ciprian...

1© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialIPv6 Today – Technology and Deployment

Study of IPv6 Multicast Deployment in MPLS Networks

Wim Verrydt - Ciprian PopoviciuIPv6 Today – Technology and DeploymentBucharest, August 2, [email protected] - [email protected]

mailto:[email protected]

mailto:[email protected]


Introduction

• MPLS 6PE (Provider Edge)Widely deployed architecture for forwarding IPv6 unicast packets across an IPv4 / MPLS enabled core infrastructure

• IPv6 MulticastNew types of end-user applications will significantly increase the need for deploying IPv4 and IPv6 multicast solutions

• 2 possible architecture options for deploying IPv6 multicast across an existing IPv4 / MPLS core infrastructure

Both rely on MPLS 6PE to transport IPv6 unicast packets


Agenda

• IntroductionMPLS and its applications

MPLS 6PE for IPv6 unicast

IPv6 multicast

2 possible architecture options for deploying IPv6 multicast across an existing IPv4 / MPLS core infrastructure

• Solution I – Native IPv6 Multicast Forwarding

• Solution II – Layer 2 Encapsulated IPv6 Multicast Forwarding

• Conclusions


Introduction – MPLS and its Applications

VRF

VRF

VRF

LDP LDPLDP

iBGP—VPNv4 Label Exchange

iBGP—VPNv4 iBGP—VPNv4PE

PE

PE

CE

CE

CE

CE

Overlapping Addresses AreMade Unique by Appending RD and Creating VPNv4 Addresses

CE

RFC 4364: MPLS VPNs


P

P

P

Pv6

IPv4MPLSv4

v6

v4

v4

v6

v6

CE

CE

6PE

6PE 6PE

6PE

192.254.10.0

2001:0421::

2001:0420::

192.76.10.0

145.95.0.0

2001:0621::

2001:0620::

Dual-Stack IPv4-IPv6 RoutersDual-Stack IPv4-IPv6 Routers

CE

Introduction – MPLS 6PE for IPv6 Unicast

• IPv4 / MPLS core infrastructure is IPv6-unaware

• PEs are updated to support dual-stack / 6PE

• IPv6 reachability exchanged among 6PEs via iBGP (MBGP)

• IPv6 packets transported from 6PE to 6PE inside MPLS

iBGP (MBGP) Sessions


Introduction – IPv6 Multicast

Service IPv4 Multicast IPv6 Multicast

Addressing Range 32-bit, Class D 128-bit (112-bit Group)

Routing Protocol Independent, All IGPs and MBGP

Protocol Independent, All IGPs and MBGP with IPv6

Multicast SAFI

ForwardingPIM-DM, PIM-SM,

PIM-SSM, PIM-bidir, PIM-BSR

PIM-SM, PIM-SSM, PIM-bidir, PIM-BSR

Group Management IGMPv1, v2, v3 MLDv1, v2

Domain Control Boundary, Border Scope Identifier

Interdomain Solutions MSDP across Independent PIM Domains

Single RP within Globally Shared Domains


Architecture Options

• Native IPv6 Multicast ForwardingIPv6 Multicast packets forwarded nativelyRequires core to be IPv6 enabledIPv6 Unicast forwarding performed though 6PENo constraints on the location of multicast sources and receivers

• Layer 2 Encapsulated IPv6 Multicast ForwardingIPv6 Multicast packets L2 MPLS encapsulated and forwarded across an IPv4 / MPLS enabled coreCore remains IPv6 agnosticIPv6 Unicast forwarding performed though 6PEContent distribution application – well-known sources and receivers


Agenda

• IntroductionMPLS and its applicationsMPLS 6PE for IPv6 unicastIPv6 multicast2 possible architecture options for deploying IPv6 multicast across an existing IPv4 / MPLS core infrastructure

• Solution I – Native IPv6 Multicast Forwarding• Solution II – Layer 2 Encapsulated IPv6 Multicast

Forwarding• Conclusions


Solution I - Native IPv6 Multicast Forwarding

• Reference network topology

TGN4 TGN1

TGN3

6PE1

6PE2 = RP6PE3

6PE4

R4 R1

P

ISP NetworkAS1IS-IS, MPLS

AS2CustomerNetworkOSPF

FF1E::1

FF1E::3FF1E::2

Mcast SourceMcast Receiver


Solution I - Native IPv6 Multicast Forwarding

• IPv6 Multicast packets forwarded natively

• Requires core to be IPv6 enabled

• IPv6 Unicast forwarding performed though 6PE

• No constraints on the location of multicast sources and receivers

Within ISP backbone, customer network, external AS

• IPv6 multicast control plane operation requires distribution of IPv6 unicast routing in backbone

PIM Register, PIM Register-Stop messages

PIM Join / Prune messages

Reverse Path Forwarding (RPF) check


Native IPv6 Multicast Forwarding – Source Registering

TGN4 TGN1

TGN3

6PE1

6PE2 = RP6PE3

6PE4

R4 R1

P



FF1E::1

FF1E::3FF1E::2

Mcast Source

Mcast Receiver

Mcast packet: (S,G)Source-registerUcast: (6PE3, RP)

Register-stopUcast: (RP, 6PE3)

PIM JoinPIM Join Multicast data stream


Native IPv6 Multicast Forwarding – PIM (*,G) Join / Prune

TGN4 TGN1

TGN3

6PE1

6PE2 = RP6PE3

6PE4

R4 R1

P



FF1E::1

FF1E::3FF1E::2

Mcast Source

Mcast ReceiverMulticast data stream

PIM JoinPIM Join

RPF to RP?

PIM Join

RPF to RP?

Multicast data streamRPF to RP?


Native IPv6 Multicast Forwarding – PIM (S,G) Join / Prune

TGN4 TGN1

TGN3

6PE1

6PE2 = RP6PE3

6PE4

R4 R1

P



FF1E::1

FF1E::3FF1E::2

Mcast Source

Mcast Receiver

PIM JoinPIM Join

RPF to source?

Multicast data stream

RPF to source?

RPF to source?

PIM Join

Multicast data stream


Native IPv6 Multicast Forwarding – RPF Check

TGN4 TGN1

TGN3

6PE1

6PE2 = RP6PE3

6PE4

R4 R1

P



FF1E::1

FF1E::3FF1E::2

Mcast Source

Mcast Receiver

RPF check?

Multicast data streamRPF check?

RPF check?

RPF check?


Native IPv6 Multicast Forwarding – IGP and BGP Routing Design

IGPBGP unicast

SAFI=1/4

BGP multicast

SAFI=2

ISP RP address PIM Register, PIM J/P, RPF check

PIM Register, PIM J/P, RPF check

PIM Register-Stop

PIM Register-Stop

External first-hop router address PIM Register-Stop

XNot required on P router

ISP / Customer / External multicast source

PIM J/P, RPF check X

X

External RP addressX

Not required on P router

X

ISP first-hop router address X

Customer first-hop router address

XNot required on P router


Native IPv6 Multicast Forwarding – Conclusion

• IPv6 multicast forwarding can be added relatively easy to an existing IPv6 6PE architecture

• Requires core to be IPv6 enabled

• IPv6 IGP only needs to carry a very limited number of prefixes

• Core “P” routers do not require BGP IPv6 unicast (SAFI=1/4) . Only BGP IPv6 multicast (SAFI=2)operation is required because PIM Register / Register-Stop messages are MPLS 6PE forwarded

• Capability of infrastructure to perform hardware assisted IPv6 multicast packet forwarding needs to be taken into consideration


Agenda



IPv6 multicast




• Conclusion


SP CoreOSPF, MPLS

SP CoreOSPF, MPLS

Solution II – Layer 2 Encapsulated IPv6 Multicast Forwarding

Access (OSPFv3)

Data Center Content Servers

Mcast Replication Routers

Layer 2 Tunnel Endpoints

MRMR

Access 1IPv4/IPv6Access 1

IPv4/IPv6Access 2

IPv4/IPv6Access 2

IPv4/IPv6Access 3

IPv4/IPv6Access 3

IPv4/IPv6

Aggregation (OSPF, MPLS)

Listener

PEPE

MR PE MRPEMcast Replic

ation Routers

Layer 2 Tunnel E

ndpoints

Mcast iBGP / eBGP


Solution II – Layer 2 Encapsulated IPv6 Multicast Forwarding

• IPv6 Multicast packets L2 MPLS encapsulated and forwarded across an IPv4 / MPLS enabled core

• Core remains IPv6 agnostic

• IPv6 Unicast forwarding performed though 6PE

• Content distribution application – sources located in SP data centers, receivers located at the access layer

Well-known SPT with root in data center and leafs in access layer. Allows pre-configuration

Multicast routing - PIM-SSM

Receiver management - MLDv2 (setop box) or MLDv1 (*,G) report mapping to predefined sources


Layer 2 Encapsulated IPv6 Multicast Forwarding –Routing Design

• Simple IPv6 multicast forwarding paradigm – SPT built with help of several L2 tunnels

• PIM SSM – no need for an RP

• Leads to a simplified IPv6 routing designDedicated set of IPv6 prefixes identifying sources and tunnel links –used for RPF calculation. Distinct from prefixes used for IPv6 unicast service

IPv6 multicast iBGP / eBGP (SAFI=2) across L2 tunnels – required for PIM J/P and RPF calculation

IGP (OSPFv3) in access layer (dual-stack)

Across L2 Tunnels

BGP SAFI=2

PIM J/P, RPF check X

Access Layer

IGP

Multicast source address X


Layer 2 Encapsulated IPv6 Multicast Forwarding –Routing Design - Conclusion

• An IPv6 multicast infrastructure can be deployed across an MPLS network in order to support a content distribution service

• Core “P” routers not required to become IPv6 aware

• Well-known sources and receivers allows setup of a L2 tunnel based SPT for IPv6 traffic across the MPLS core

• Only multicast source prefixes require advertisement in BGP IPv6 multicast (SAFI=2)across L2 tunnels and in the local IGP at the access layer


Agenda



IPv6 multicast




• Conclusion


Overall Conclusion

• Multiple solutions exist to add an IPv6 multicast forwarding capability to an existing, 6PE based, IPv6 unicast service – 2 solutions have been discussed

• Native IPv6 multicast forwardingMPLS core needs to be IPv6 enabledDistribution of IPv6 routing information in core is requiredFlexible location of sources and receivers

• L2 encapsulated IPv6 multicast forwarding MPLS core remains IPv6 agnosticContent distribution service with well-known sources and receiversRequires limited distribution of IPv6 routing information


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