Recent and Future
Developments in Profitable
MPLSMatt Kolon
MPLS JapanOctober 2003

Copyright © 2003 Juniper Networks, Inc.

www.juniper.net

Virtual Private LAN Service
VPN A
Site 1

VPN A
Site2

CE–A2

VPN B
Site2

CE–A1PPPE 2

PE 1

CE–B2

VPN B
Site 1

P
CE–B1

PPE 3

VPN A
Site 3

CE–A3

•

A private Ethernet network constructed over a ‘shared’ infrastructure
which may span several metro areas•Multipoint to Multipoint Ethernet connectivity where the SP network
looks like an Ethernet broadcast domain•Compliments Layer 3 2547 and Layer 2 VPNsCopyright © 2003 Juniper Networks, Inc.

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Another kind of VPN?
• Another choice for customers• This is a good thing!
• Another revenue opportunity• This is also a good thing!

• But on to the details:• How can we implement this new service in a way that••allows excellent performance but low operational cost?
How can we build an economical, practical service?
How can we best capitalize on our current skills andinfrastructure?

Copyright © 2003 Juniper Networks, Inc.

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VPLS Operations• Control Plane• VPN Discovery•• Discover who are the PE members of a given VPN
VPN Signaling• Setup and teardown of the pseudo-wires between VPLS
instances that constitute the VPLS Domain• Forwarding Plane (not talking about this today)• MAC Learning and Packet Forwarding• MAC Aging• MAC Flushing

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VPLS Control Plane•

Control Plane••

VPN Auto-Discovery• Auto-discovery can be done by BGP• IETF proposals to extend DNS or RADIUS for auto-discovery
VPN Signaling•

Demultiplexors can be signaled•

by targeted LDP (draft-lasserre-vkompella-ppvpn-vpls)••^2O(N ) LDP sessions operational challenge

by BGP (draft-kompella-ppvpn-vpls)•O(N) BGP sessions operational challenge•

A single MP-BGP NLRI supports both Auto-Discovery andSignaling•

Using two different protocols for Auto-discovery & Signaling•

More complexity and inter-protocol interactions•

More protocol state in the network

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BGP does bothAuto-discovery & Signaling• IP VPN services (aka RFC2547 VPN)
•RFC2547, draft-ietf-ppvnp-2547bis• BGP for VPN auto-discovery•

draft-ietf-ppvpn-bgpvpn-auto• IPv6 VPN••

draft-ietf-ppvpn-bgp-ipv6-vpn-03.txt
Extensions to RFC 2547bis to support IPv6 VPNs

• Virtual Private LAN Service (VPLS)•

draft-kompella-ppvpn-vpls• BGP is a proven, multi-vendor solution deployedin production networks today
Copyright © 2003 Juniper Networks, Inc.

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VPLS Control Plane functionality with MP-BGP• Using BGP for VPN Auto-discovery andSignaling provides the following benefits:••••

A single MP-BGP NLRI for most efficient AutoDiscovery and Signaling• No additional overhead• No need for complex inter-protocol interactions
Same framework as IP-VPNs (2547bis), and others
Takes advantage of all the scalability, redundancy
and operational simplicity features available in BGP:
• Route Reflectors, Refresh, ORF, etc…
Supports Multi-AS/Multi-provider operations

Copyright © 2003 Juniper Networks, Inc.

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VPLS Auto-discovery & Signaling
MP-iBGP

Site 2PE-2

CE-2
Vlan 10640

LSP

VFT

Site 2 VCT NLRI
Route Dist
VE ID
Sites
Label base

100:1.2.3.22VFTLSP

Site 3PE-3

320

CE-3Vlan 10

Site 3 VCT NLRI
100:1.2.3.3320
2000

Route Dist
VE ID
Sites
Label base

Route Target

RED

Route Target

RED

Next Hop

PE-2

Next Hop

PE-3

Text

203000PE-PE VCT distribution using Multi-Protocol BGP (RFC 2858)
Requires full-mesh MP-iBGP or Route Reflectors
Route Distinguisher: disambiguates VCT information
Route Target: determines VPN topology
Analogous to CE-PE routes advertisements in RFC2547 VPNs
VPLS requires one single NLRI advertisement per VPLS instance per PE
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BGP Delivers Scalable
Route Reflector Architecture
PE 1PE 1PE 4RRPE 5PE 2PE 3PE 6PE 7Text

New PE added

Existing LDP sessions
New LDP sessions

Targeted LDP: New PE Added
7 PEs need to be configured to establish
LDP sessions between PEs. All 7 need tobe configured again if MD5 authentication
desired.

Copyright © 2003 Juniper Networks, Inc.

PE 4PE 5PE 2PE 3PE 6PE 7

New PE added

Existing BGP sessions
New BGP
Session

BGP: New PE Added
PE and Route Reflector need to beconfigured for 1 BGP session establishedwith route reflector

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Why not BGP + LDP ?
• BGP or LDP for signaling (distributing VPN labels) is awrong comparison; ignores autodiscovery• Compare BGP for both autodiscovery and signaling
with BGP for autodiscovery and LDP for signaling• With BGP + LDP approach, signaling of VPN labels
requires a completely separate protocol (LDP)• With BGP approach signaling, of VPN labels is a“side effect” of (BGP-based) autodiscovery• The overhead of using BGP for both autodiscovery andsignaling is about the same as using BGP just forautodiscovery

Copyright © 2003 Juniper Networks, Inc.

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Overloading BGP ?
• Common concern:{public Internet + RFC2547 VPNs + V6 VPNs + L2 VPNs +VPLS}
will overload BGP, causing it to crash• Real question:
should a single PE provide all of the above services ?
•If so, it doesn’t matter which protocol –either the PE device can take it, or not•

Putting these services in different protocols doesn’t reduce overall
stress on the PE!

•Existence proof that some PEs can take it

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Overloading BGP ? (cont.)•

Other concern: BGP is complex to implement•

The (perceived) vendor complexity of implementing MultiProtocol BGP is well worth the greatly simplified operations
for the Service Providers•

Using Multi-Protocol BGP for both auto-discovery anddistributing VPN labels means fewer protocols to operate,
manage and debug•

Therefore it means cost savings in terms of:

Copyright © 2003 Juniper Networks, Inc.

•Educating the NOC staff•

Building tools/expertise to monitor VPNs•

Building tools/expertise to debug and manage the VPNs

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BGP/MPLS VPLS Scalability“divide and conquer”• Two levels of labels to keep P routers free of all the••VPN routing information (v4, v6, L2 VPNs & VPLS)PE router has to maintain VPN information only forVPNs whose sites are directly connected to the PE
routerPartition BGP Route Reflectors within the VPN
Service Provider among VPNs served by the Provider• No single component within the system is required to•maintain information for all the VPNs
Routing/forwarding capacity of the system isn’t boundedby the capacity of an individual component
Applies to RFC2547 VPN, L2 VPN and VPLS !

Copyright © 2003 Juniper Networks, Inc.

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Inter-AS/Inter-provider operations
Exchange VPN information + VPN labels across
AS/provider boundary by using BGP between BGP
Route Reflectors in each AS/provider

Perhaps mostimportant of all!

Route Reflectors preserve the next hop information and theVPN label across the AS/provider

PEs learn routes and label information of the PEs in theneighboring ASs through ASBRs
Using labeled IPv4 routes

No VPN information (e.g., VRF, VFT) on ASBRs
Applies to RFC2547 VPN, L2 VPN and VPLS !

Copyright © 2003 Juniper Networks, Inc.

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SummaryCustomers want:•••

IP VPNs (RFC 2547 VPN)
Point-to-point Layer 2 VPNs
Virtual Private LAN Service (VPLS)•Service Providers can offer all of the above:••

Over a common infrastructure (MPLS)
With a common BGP framework••••

Auto-discovery and Signaling
Product proven, multivendor
Leveraging BGP scalability
Supporting multi-AS/multi-provider

A single operational infrastructure and a small setof basic mechanisms means considerable savingsfor providers, and maximum flexibility and choicefor your customers.

Copyright © 2003 Juniper Networks, Inc.

www.juniper.net

Thank you!
Matt Kolon
matt@juniper.net

Copyright © 2003 Juniper Networks, Inc.

www.juniper.net

References
draft-augustyn-vpls-archdraft-ietf-ppvpn-vpls-requirements
draft-kompella-ppvpn-vpls
draft-kompella-ppvpn-l2vpn
draft-lasserre-vkompella-ppvpn-vpls
draft-martini-l2circuit-encap-mpls
draft-martini-l2circuit-trans-mpls

Copyright © 2003 Juniper Networks, Inc.

www.juniper.net