Benchmarking Carrier Ethernet Technologies Workshop Session MI.1: PW/MPLS Krakow, Poland Lieven...

Benchmarking Carrier Ethernet Technologies WorkshopSession MI.1: PW/MPLS Krakow, Poland

Lieven Levrau

30th April 2008

2 | PW/MPLS | April 2008 All Rights Reserved © Alcatel-Lucent 2008, XXXXX

Agenda

1. Multi Segment Pseudo Wires

2. Multi-Segment Pseudo Wire OAM

3. Advanced Topics for MS-PW


Service and Network Scale

Multi Segment Pseudo Wires1


Extending the MPLS Enabled Area

Diving L2VPN scalability requirements

CE

CECE MPLS

MPLS

PE2

IP/MPLSBackbone

CE

CE

MPLS Aggregation Networks

MPLS Aggregation Network

CE

Full mesh of tunnelsand T-LDP sessions

Tunnels/Signallingsessions grow exponentially

Scale VLL and VPLS services over a multi-area network or between providers

Remove the need for a full mesh of Targeted LDP sessions between PEs

Remove the need for a full mesh of RSVP-TE tunnels between PEs

Minimise number of tunnels terminating on access/aggregation

LSR

LSR

PE1

LSR

MPLS

PE6

PE4

PE3

PE5

CE


Multi-Segment PWs (PW switching)

CE

CECE

IP/MPLSBackbon

e

CE

CE

MPLS Aggregation Networks

S-PE

S-PE

MPLS Aggregation

Network

T-PE

CE

S-PE

CE

MPLSMPLS

MPLS

T-PE/S-PE

T-PE

T-PE

MPLS tunnel

Pseudo wire segments

Switching PETunnels terminatedPWs switched betweeningress/egress tunnels

Terminating PETunnels & PWs terminated

Multi-segment PW

T-PE

draft-ietf-pwe3-ms-pw-arch-02.txtdraft-ietf-pwe3-segmented-pw-04.txt

FECFEC FEC FEC

FEC FEC

FECs configured at S-PEs, label bindings advertisedPW cross connect configured at S-PEsPWs switched between ingress/egress tunnels

• Simple PW label swap• PW status messages mapped at each S-PE• PW switching point TLV for loop detection


Multi-segment Pseudo-wire – How can you use them ?

Ethernet VLLs with SS-PW

CE

CE

CE

CE

CE

MPLS MPLS

MPLS

MPLSPE

PE

PE

PE

P P

PEPE

MPLS tunnelSS-PW

T-LDP

T-LDP

T-LDP


Multi-segment Pseudo-wire – How can you use them ?

Ethernet VLLs with MS-PW

CE

CE

CE

CE

CE

MPLS MPLS

MPLS

MPLS tunnel

T-LDP

T-LDP

T-LDP

MPLS

S-PE S-PE

T-PEMS-PW

T-PE

T-PE

T-PE

T-LDP

T-LDP

T-LDP

S-PE

T-PE

T-LDP

T-LDP


Multi-Segment Pseudo Wire OAM2


MS-PWs introduce two new requirements on OAM:

Ability to test connectivity of segments of a PW, and to trace PW path

Ability to generate defect notifications if a PW segment fails

OAM for PWs

MPLSFR AC FR AC

FR PW

LSP Tunnel

CE 2

(FR Network) (FR Network)

PE 1

L2 I/F

PE 2

MPLS

L2 I/F

PW status

LMI full status LMI full status

MPLS

PWCE 1PW

PW

VCCV channel

PW have OAM capabilities to check / diagnose PW layer

Connectivity testing:

Virtual Circuit Connectivity Verification (VCCV)– Uses a dedicated channel on a PW to test connectivity

Defect notifications:

Defect status mapped between AC and PW in the PE– Interworking with ATM OAM & FR LMI

PW status signalling propagates defect notifications along PW


Multi-Segment Pseudo Wire OAM

Provide and coordinate OAM at the relevant levels in the MPLS network

OAM Procedures for VPWS Interworking: draft-ietf-l2vpn-vpws-iw-oam-

PW OAM Message Mapping: draft-ietf-pwe3-oam-msg-map-

Proactive & reactive OAM mechanisms, independent at all levels

Multi-segment PWs require extensions to single segment PW OAM to allow: Segmented OAM (between 1 or more T/S-PEs) Propagation of defect notifications between PW segments & ingress/egress

tunnels

Multi-segment PWs require extensions to single segment PW OAM to allow: Segmented OAM (between 1 or more T/S-PEs) Propagation of defect notifications between PW segments & ingress/egress

tunnels

Tunnel LSP Levele.g MPLS OAM

Tunnel LSP Levele.g MPLS OAM

RFC4379draft-ietf-bfd-mpls-02.txt

PW Levele.g VCCV, PW status

PW Levele.g VCCV, PW status

draft-ietf-pwe3-vccv-07.txtdraft-ietf-pwe3-control-protocol-17.txt

Service Levele.g VRF-Ping, MAC-Ping

Service Levele.g VRF-Ping, MAC-Ping

draft-stokes-vkompella-l2vpn-hvpls-oam-00.txt


Advanced topics

Simplified Provisioning and Management of Advanced

Service3


Emerging Requirements for MS-PW Provisioning

Maintain the same provisioning model as SS-PWs

“One-touch” provisioning for PWs

Remove the requirement to provision the S-PEs

Only provision the T-PEs

This has two new protocol implications:

Signalling must enable the full MS-PW to be established. This needs T-LDP to be extended to multiple hops.

The S-PE path between the T-PEs is no longer determined by the MPLS tunnel. This needs automatic PW path selection.

Proposed solutions are forward-looking and not yet implementedProposed solutions are forward-looking and not yet implemented


Extending T-LDP for Dynamic Multi-Segment PWs

Operational consistency with SS-PWs

Reuse existing provisioning models

Simple application to existing VPLS deployments

Same OAM mechanisms

Implementation consistency with SS-PWs

Existing PW implementations are LDP

Minimal changes, mainly for addressing remote PEs

T-LDP addressing uses FEC 129 with AII type 2 from draft-ietf-pwe3-aii-aggregate-

0 1 2 3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| AII Type=02 | Length | Global ID |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Global ID (contd.) |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Prefix |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| AC ID |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

draft-ietf-pwe3-dynamic-ms-pw-06.txt



Support for QoS and TE for PWs

Allows S-PEs to perform CAC

Consistent traffic parameters, irrespective of PW type

Translation done by layer 2 aware T-PE

Allow asymmetric BW assignment to PWs

T-LDP extended with forward and reverse SENDER_TSPEC

0 1 2 3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

|1|0| PW BW TLV (0x096E) | TLV Length |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Forward SENDER_TSPEC |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Reverse SENDER_TSPEC |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Committed rate bucket/sizePeak RateMinimum policed unitMax packet size




CE

CECE

IP/MPLSBackbone

CE

CE

S-PE

S-PE

T-PE

CE

S-PE

CE

MPLSMPLS

MPLS

T-PE/S-PE

T-PE

T-PE

MPLS tunnel

T-PE

T-LDP

T-LDP

T-LDP

FEC 129 providesa unique key for the Attachment circuit (AII)

Global ID (e.g. AS#) + AC identifierGlobal ID (e.g. AS#) + AC identifier

Fully qualified info in signalled FEC allows T-PE/S-PE toselect next hop

MS-PW



Requirements for Routing PWs

Automatically select path for the MS-PW

Not all routers are S-PEs, not all S-PEs are PW switching or dynamic MS-PW signalling capable

Cannot rely on IGP next hop

Must know connectivity state at PWE3 level

In metro networks, assume all S-PEs in the same AS, and are often MP-BGP incapable domains anyway

Routers may be small devices and support a minimal routing implementation

...but we also need a solution for inter-AS

Potentially a large number of small nodes

Automated link state routing to avoid failed links / determine which is the least cost path to reduce provisioning overhead

Support a combination of static and dynamically learned routes

CE

CE

CE

CE


Advertising PWE3 Reachability in BGP

CE

CECE

IP/MPLSBackbone

CE

CE

S-PE

S-PE

T-PE

CE

S-PE

CE

MPLSMPLS

MPLS

T-PE/S-PE

T-PE

T-PE

MPLS tunnel

T-PE

T-LDP

T-LDP

T-LDP

MS-PW

Aggregated FECs advertised between BGP speaking S/T-PEsProvides next-hop reachability through an S/T-PE



Advertising PWE3 Topology in IGP

OSPF is extensible via opaque link state advertisements (LSAs)

These are already used for flooding traffic engineering information

Can also be used to advertise aggregated PW AIIs within a single area

Each S/T-PE can advertise its local topology using these LSAs

Nodes that do not understand LSAs will simply flood them

Must not to disrupt or over burden the routing protocols that manage the infrastructure of a service providers network

Use aggregation of attachment identifiers

Prioritisation of LSAs

draft-dolganow-pwe3-ospf-ext-.txt

S-PE

S-PES-PE

S-PE

S-PE

T-PEsT-PEs

PW Adjacency TLVAII TLV

S-PE


Summary of Candidate PW Routing Solutions

IGP Extensions

IGP knows the state of the physical topology and potential PWE3 topology

OSPF and IS-IS extensible to allow PWE3 topology and ACs to be advertised using currently defined mechanisms

IGP is always present and is less costly to deploy:

Does not require additional routing protocol or management layer

Potentially simple to implement in basic PW CPEs

Multi-Protocol BGP (MP-BGP)

Allows reachability through a given S-PE to be advertised

Only provides PW next-hop information

Requires BGP to be deployed

Although often used for MPLS based L3 services

Path Computation Element (PCE)

Enables best path through a domain to be calculated

Needs to learn underlying PWE3 topology

Requires PCE to be deployed

Targeted at Inter-AS scenarios

IGP, BGP and PCE solutions are complementary


IP/MPLS is “the” technology to transport multi services

Scalable

Resilient

Manageable


www.alcatel-lucent.comThank you !

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