Video and Multicast
Services over MPLS
Rahul Aggarwal
Distinguished Engineer
Juniper Networks

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MPLS Multicast Applications & Services
 Multicast in VPLS
• VPLS as a service• VPLS as infrastructure for delivering other services

 Multicast in BGP-MPLS VPN• BGP-VPN as a service• BGP-VPN as infrastructure for delivering other services

 Broadcast Video Transport / IPTV Service
 Internet Multicast

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2Exploring the Commonalities
 Common architecture for VPLS Multicast andBGP-MVPNs• Inclusive Trees• Selective Trees Common mechanisms for VPLS Multicast andBGP-MVPNs• BGP for Auto-Discovery• BGP for exchanging customer multicast routing
information among PEs• P2MP RSVP-TE or P2MP LDP for P-Tunnel signaling

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3Agenda Multicast in VPLS
 Multicast in BGP-MPLS VPN
 MPLS Multicast Data Plane for NGEN MVPN and
VPLS Multicast
 Broadcast Video Transport / IPTV ServiceCopyright © 2007 Juniper Networks, Inc.

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VPLS Multicast - Agenda
 VPLS Multicast Architecture P2MP LSPs for Intra-AS VPLS Control Plane P2MP LSPs for Intra-AS VPLS Data Plane

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NGEN VPLS Multicast Architecture VPLS Auto-Discovery• Use existing BGP VPLS auto-discovery mechanisms
with enhancements

 Enable the use of P-multicast Trees for VPLS
multicast traffic• Draft-ietf-l2vpn-vpls-mcast-02.txt• Inclusive Trees or Selective Trees Elimination of flooding for VPLS IP multicast
traffic is desirable• Further technical work is required

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VPLS Multicast : Ingress Replication vsP2MP LSPs
VPLS w Ingress Replication:
Ingress PE makes 5 copies
of every broadcast,multicast and floodedpacket

VPLS /w P2MP LSPs:
All links carry at most 1 copyof each packet

Ingress
PEIngress
PE

Dataplanebottleneck

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P2MP LSPs for Intra-AS VPLS LDP-VPLS with BGP Auto-Discovery or BGP-VPLS
 VPLS support for P2MP LSPs as described in draft-ietfl2vpn-vpls-mcast-01.txt• Enhances BGP Auto-Discovery (AD) Each PE with a site in a VPLS is the root of a P2MP LSP
other PEs in the AS that have sites in that VPLS
• One P2MP LSP per VPLS (Inclusive Tree)• Possibility of “Aggregation” leaves headroom for growth• Upstream assigned labels (draft-ietf-mpls-upstream-labelCopyright © 2007 Juniper Networks, Inc.

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P2MP LSPs for Intra-AS VPLS…
 All the multicast/broadcast/unknown unicast traffic
received from the VPLS site is sent over the P2MP LSP• Inclusive Tree BGP P-Tunnel Attribute, carried in the BGP-VPLS updates,
signals the VPLS-P2MP LSP binding• From the root of the P2MP LSP to the leaves of the P2MP LSP• Same P-Tunnel Attribute is used in BGP-MVPN (more on thislater) An egress PE MUST be able to determine the sender PE(root of the P2MP LSP) in order to perform learning

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Inter-AS VPLS Multicast
Segmented Inter-AS Trees Inter-AS Tunnel rooted at the source PE• Other ASs are nodes on this inter-AS tunnel• One Inter-AS tunnel for one <VPLS, PE> i.e. one Inter-AS tunnel
Per VE ID

 Inter-AS Tunnel comprises “segments”• AS-AS tunnel segments that connect ASs together on the inter-AStunnel• Intra-AS tunnel segment used by an AS to deliver traffic toPEs/ASBRs within an AS on the inter-AS tunnel

 Inter-AS tunnels constructed by stitching intra-AS tunnelsegments• Independent P-Tunneling technology per AS

 Propagation of BGP-VPLS AD routes from the source AS
to other ASs results in the creation of the inter-AS tunnel• In conjunction with specific tunnel signaling protocols

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VPLS Multicast
Elimination of Flooding PE - CE Flooding• Problem - PE sends an IP multicast packet to all theCEs in the VPLS
• Solution – IGMP snooping or PIM snooping PE – PE Flooding• Problem – PE sends an IP multicast packet to all PEsin the VPLS
• Solution – Selective VPLS Multicast Trees• Propagate “snooped” IP multicast state in BGP to other PEs– IGMP/PIM snooping on PWs may not be scalable• Draft-raggarwa-l2vpn-vpls-mcast-ctrl would need to bematured

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11Agenda Multicast in VPLS
 Multicast in BGP-MPLS VPN
 MPLS Multicast Data Plane for NGEN MVPN andVPLS Multicast
 Broadcast Video Transport / IPTV ServiceCopyright © 2007 Juniper Networks, Inc.

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NGEN-MVPN Solution Goals
 Extend 2547 VPN service offering to include
support for IP multicast for 2547 VPN customers
 Follow the same architecture/model as 2547 VPNunicast• No need to have the PIM/GRE Virtual Router model for
multicast (i.e. draft-rosen) and the BGP/MPLS 2547
model for unicast

 Re-use 2547 VPN unicast mechanisms, withextensions, as necessary• No need to restrict multicast to only IP/GRE data plane
while unicast uses MPLS LSPs

 Retain as much as possible the flexibility andscalability of 2547 VPN unicast

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NGEN-MVPN Intra-AS Control Plane
Functionality
 Using BGP for auto-discovery and binding PTunnels to customer multicast streams• Provides common mechanism for both Inclusive andfor Selective P-Tunnels• As both Inclusive and Selective P-Tunnels are needed Using BGP to provide (constrained) C-multicast
routing information exchange among PEs• C-PIM-SM in SSM mode using BGP C-Multicast
Source Tree routes• C-PIM-SM in ASM mode using BGP C-Multicast
Source Tree routes and Source Active Auto-discoveryroutes• Results in Inter-site traffic always flowing on Shortest PathTrees• C-Control traffic exchange through the SP network isout-of-band from the C-Data traffic exchange
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Exchange of C-Multicast Routes using BGP…
 Let us focus on customers running PIM-SM in
SSM mode• Only Source Tree Join C-Multicast routes required• Semantically similar to PIM Join (C-S, C-G) PIM-SM in ASM mode can be supported with afew enhancements to the procedures for PIM-SM
in SSM mode

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15NGEN MVPN Intra-AS
Putting it Together (PIM-SM in SSM Mode)
C-S, C-G forwarding
State in VRF A
VPN A
Site 1

CE -A1

PIM C-Join
C-S, C-G
PE 4

VPN A
Site 4CE-A4C-S, C-G
forwarding statein VRF A
PE 2

VRF-A

CE-B3

VRF-A

PIM C-Join
C-S, C-G

VRF-A

VPN B
Site 1

PIM C-Join
C-S, C-G

VRF-B

PE 1
VRF-B

C-S -> C-GRR

CE-A3

CE-B1
PE 3

BGP MVPN C-Mcast Routing Information:<RD, C-S, C-G, PE2’s VRF A Route Import RT>
P2MP TE Inclusive P-Tnl: PE2 as Root

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VPN B
Site 3

VPN ASite 3

RR Aggregates C-Multicast Routes- no explicit tracking by default

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NGEN-MVPN Inter-AS Functionality
 “Segmented” Inter-AS tunnels constructed bystitching intra-AS tunnel segments• Independent P-Tunneling technology per provider• Provided by BGP based inter-AS auto-discovery Routing peerings between ASes/Providers onlyat ASBRs or RRs• Including exchange of C-Multicast routes• Avoids the need to require PEs in different ASes/Providers tohave direct PIM peering with each other Works with all three options for inter-AS unicast

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NGEN MVPN Data Plane Inclusive Trees• Traffic for a particular (C-S, C-G) sent on an Inclusive
Tree is received by all the PEs that have a receiver site
in the MVPN Selective Trees• Traffic for a particular (C-S, C-G) sent on a SelectiveTree is received only by those PEs that have a receiverin (C-S, C-G)
• May be used for high bandwidth streams

 A MVPN may use ONLY Selective Trees Inclusive and Selective Trees may be Aggregate
Trees
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BGP-MVPN IETF Status MVPN architecture draft specifies various
options that include BGP-MVPN• Draft-ietf-l3vpn-2547bis-mcast

 BGP-MVPN draft specifies BGP specificprocedures• Draft-ietf-l3vpn-2547bis-mcast-bgp

 Operational consideration draft [co-authored byseveral SPs] recommends BGP-MVPN design
options• draft-morin-l3vpn-mvpn-considerations

Juniper implements the standards being
developed in L3VPN WG
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MVPN Deployment
Recommendation
 Deploy BGP-MVPN based on draft-ietf-l3vpn2547bis-mcast-bgp and recommendations indraft-morin-l3vpn-mvpn-considerations• Implemented by JunOS

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Agenda Multicast in BGP-MPLS VPN Multicast in VPLS MPLS Multicast Data Plane for NGEN MVPN andVPLS Multicast
 Broadcast Video Transport / IPTV ServiceCopyright © 2007 Juniper Networks, Inc.

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Broadcast Video Transport / IPTV Service
 Requirements
 P2MP MPLS TE
 The role of NGEN MVPN and VPLS

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22Broadcast Video Transport / IPTV ServiceRequirements
 It has to be there all the time - availability• In most cases only a few frames or 10s of ms of loss
can be tolerated Timing constraints – continuity• End to end latency and jitter requirements are stringent

 Bandwidth Requirements• Compressed 5-80Mbit/s• Uncompressed 270Mbit/s

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MPLS Multicast Technology forBroadcast Video
Root/source Initiated e.g.
P2MP RSVP-TE

Leaf/receiver driven e.g.
mLDP

Has resource reservation
mechanisms

No resource reservation
mechanisms

Supports explicit routing along No equivalent support
paths different from hop-by-hop
IP routing
P2MP LSP signalled by the root=> allows flexible P2MPcomputation algorithms
SupportS Minimum cost trees

Do not support Minimum cost trees

Fast reroute and Make-beforebreak capabilities
Allows various protection
mechanisms such as activeactive; active-standby (nextslide)

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Receiver initiated trees arelimited in tree computation
flexibility
No such capabilities
No equivalent mechanisms

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24Broadcast Video Transport / IPTV Service
MPLS Multicast Technology
 P2MP MPLS TE meets the requirements• State maintenance: aided by RSVP Refresh Reduction

 P2MP MPLS TE is deployed in several networks• RFC 4875

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Broadcast Video Transport / IPTV ServiceAvailability Paradigms with P2MP MPLS TE
 Transmit the video stream twice• Diverse end-to-end paths• Twice the bandwidth consumption• Requires the control and explicit routing of P2MP MPLS TE• Special video equipment to “choose” the best stream – potentiallyat most a few frames lost in any failure case Transmit the video stream once
• Reduces the bandwidth consumption• Greater capabilities required from the network• 10s of ms of failure recovery in majority of cases - Fast-reroute• A backup stream that takes over in some cases• E.g. Ingress Node Failure These two approaches can co-exist• Different approaches for different streams
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Mapping Broadcast Video Transport / IPTV
Service into P2MP MPLS TE LSPs
 Static configuration on ingress LSRs
• Static routes or P2MP CCC• Deployed in several networks on JunOS platforms

 NGEN MVPNs with P2MP MPLS TE• Will be delivered by JunOS soon
• Use NGEN MVPN to provide infrastructure VPLS P2MP TE Support• Shipping in JunOS• Use VPLS to provide infrastructure All of these are potential candidates for both
backbone and metro networks
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Mapping Video Service into P2MP MPLS TE LSPs
Considerations
 Operational ease
• Does static mapping on the ingress suffice ?

 Ingress PE resiliency• VPLS and MVPN multi-homing is an option• Static mapping may need some more functionality that isupcoming in JunOS

 Does the ingress LSR need to dynamically discoverreceivers of a particular (C-S, C-G) ?
• May be needed if Selective Trees have be dynamically signalled
to an egress node if/when it has receivers for a particular (C-S, CG)• NGEN MVPN are a good fit for dynamic selective P2MP TE LSPs.

 Is there a need to provide backhaul for other services ?
• In a metro network, NGEN MVPNs or VPLS may be used forbackhaul

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BGP-MVPN and VPLS Multicast MPLS
Multicast P-Tunnel Requirements
 Support for both Inclusive and Selective P-Tunnels
 Support for aggregation of P-Tunnels via P2MP LSPhierarchy• Both for Inclusive and Selective P-Tunnels

 Support for intra-AS segments of an Inter-AS segmentedtree
 OAM support• LSP-Ping for multicast P-Tunnels• BFD for multicast P-Tunnels

 When needed support for TE, fast-reroute Minimal
configuration overhead Optimized for the most common C-multicast protocols(PIM-SM and PIM-SSM)
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29Additional VPLS Multicast P-Tunnel
Requirement
 Egress PE MUST be able to identify the sender
PE in order to perform learning for packets
received on the P-tunnel

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BGP MVPN and VPLS Multicast
MPLS P-Tunnel Protocol Choices
 P2MP RSVP-TE
 mLDP• P2MP LDP• MP2MP LDP
 It is important to make an educated choice as the unicast
comparison models do not necessarily apply to multicast. E.g.
• P2MP RSVP-TE does not require leaf configuration• P2MP RSVP-TE and P2MP LDP require the same forwardingstate P2MP LSPs (RSVP-TE or LDP) are required• E..g. Selective Trees MP2MP LDP LSPs does not meet certain essential requirements
currently• Procedures to identify the sender PE for VPLS not specified• Does not allow a MVPN to run in Selective Tree only mode

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P2MP TE as the Data Plane for VPLS
Multicast and NGEN MVPN Meets the requirements
 Advantages to using P2MP RSVP-TE to meet all
the requirements of various services with asingle protocol• Instead of using P2MP RSVP-TE for broadcast video /IPTV and other protocols (e.g. P2MP LDP) for VPLS
multicast and NGEN MVPN

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Internet Multicast
 Use BGP-MVPNs as infrastructure for internet
multicast service• Use the internet unicast table to determine reachability
to the multicast sources• Carry C-multicast routes in BGP allowing the ingressPEs to determine the receivers• BGP and PIM free core
• Choice of P2MP RSVP-TE or P2MP LDPCopyright © 2007 Juniper Networks, Inc.

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Internet Multicast…
 Use of BGP-MVPNs has several otherbenefits• Uniform PE-PE control plane based on BGP as for
VPLS multicast, BGP-MVPN and broadcast videoservice• The option to use a combination of Inclusive andselective trees to allow trading off bandwidth with state• There could be a single Inclusive tree by default for all
internet multicast traffic !

• BGP control plane scaling benefits• Supports both C-PIM-SSM and C-PIM-SM

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Conclusion
 Technology for delivering multicast and video
services over MPLS is mature Video over MPLS is deployed in several networks
using P2MP RSVP-TE
 A BGP based control plane and MPLS data plane
provides a scalable and operationally uniform
solution for various unicast and multicast
services There is shipping code with BGP MVPN andVPLS P2MP LSPs
 Advantages to using a single protocol, P2MP
RSVP-TE, as the data plane for all MPLS
multicast servicesCopyright © 2007 Juniper Networks, Inc.

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