Generalized MPLS Premiere Journée Française sur l’IETF

Generalized MPLSPremiere Journée Française sur

l’IETF

Papadimitriou [email protected]

Papadimitriou D. - Alcatel IPO NA (NSG) DNAC - November 2001

Table of Content

GMPLS Key Drivers Evolution of a Standard (from MPLS to

GMPLS) GMPLS

Paradigm and Concepts Technology Signalling TE-Routing

Key Differences between GMPLS and MPLS What about MPLambdaS ? Applications and Future GMPLS evolutions Conclusion


GMPLS Key Drivers

Dynamic and Distributed LSP Explicit TE-Route Computation (today: simulation, manual planning and human action)

Dynamic and Distributed intra and inter-domain LSP Setup/ Deletion/ Modification (today: manual and step-by-step provisioning - doesn’t provide “bandwidth on demand” capability)

Network resource optimization when using a peer interconnection model with multi-layer traffic-engineering and protection/restoration (today: provisioned model implies at least waste of 40% - 60% network resources)

Per-LSP (per-LSP Group) Fast Restoration in 200ms to < 1s (today: centralized computation based on restricted scenarios implying restoration time > 5s) and Signalled Protection in < 50ms (as specified in ITU-T G.841)


GMPLS Key Drivers (cont’d)

Simplified Network control and management (today: each transport layer has its own control and management plane implying waste of 60% - 80% carrier resources)

Removes strong limitations of today proprietary protocols:

b/w network nodes (EMS/control plane) and Centralized NM System

b/w Centralized NM Systems (implying additional proprietary developments)

Conclusion: GMPLS can provide “carrier class” response to new generation transmission networks challenges

Scope: Demystify GMPLS paradigm and related concepts


Control and Transmission Plane Evolutions

Transport plane

Control/management plane

analog(copper)

digital (PDH,SDH)

optical(analog, but now on fiber)

point-to-point

wavelengthswitched

burst/packet

switched

operator-assisted/centrally managed provisioning

non transparent

today1970 1995

automated path setup under distributed control using

GMPLS

opaque

optical

optical


Evolution of a Standard (Scope)

AO Packet Sw itchingUnder developm ent

AO Wavelength w itchingGM PLS (IETF)

AO/NNI Project (O IF)

AO Packet Sw itchingUnder developm entGM PLS Extensions

"Optical SDH/Sonet" since 1998M PLam bdaS/GM PLS (IETF)

UNI - NNI Specifications (O IF)based on Pre-OTN Standards

OT NIT U-T G.709 - G.872"Step to All-Optical"

OT NIT U-T G.709 - G.872

Non-Transparent Optical Netw orksUNI - NNI Specifications

SDH/SonetIT U-T G .707 / ANSI T 1.105

IP/MPLS Developments (since 1996)

IETF Standards


Evolution of a Standard

MPLS: MultiProtocol Label Switching IP packet based Packet Traffic Engineering (MPLS-TE)

MPS: MultiProtocol Lambda Switching MPLS control applied on optical channels

(wavelengths/lambda’s) and IGP TE extensions GMPLS: Generalized MPLS

MPLS control applied on circuits (SDH/Sonet) and optical channel layer and IGP TE extensions

New Protocol introduction: LMP GMPLS: “separation” b/w Technology

dependent and independent LMP extended to “passive devices” via LMP-

WDM GMPLS covers G.707 SDH, G.709 OTN…

IETF 46-48

IETF48-49

IETF50-51


Generalized MPLS Paradigm

GMPLS is based on several premises: maintaining 1:1 relationship control plane technology

and instance with transport plane layer(s) is counter-productive

• “integrated IP/MPLS-Optical control plane” concept maintaining N transport plane layer(s) is counter-

productive• only IP/MPLS packet technologies will remain in long-run• ATM layer pushed toward ACCESS networks• SDH/Sonet layer used as framing for p2p links (just as

Layer-2 IP-over-PPP) re-use MPLS-TE as “non-packet” LSP control plane

• “lightpath” defines switched path (label space values: wavelengths)

• generalize Address Prefix to “non-packet” terminating interfaces

• generalize TE concept to “non-packet” resources


Let’s Be Cautious ! GMPLS “optical” and “optical” GMPLS GMPLS “protocol” but “protocol suite” … a “philosophy” ? GMPLS (as protocol suite)

tends to “ubiquity” by including MPLS (subset of GMPLS) applies to ANY control plane interconnection

(peer/overlay) and service model (domain/unified) covers “standard” mainly ITU-T/T1X1 transmission layers

• issue: who drives ? Transmission or Control plane ? GMPLS (as distributed control plane concept)

collaboration with NMS (during transition phase) in particular for first all-optical deployments

next steps NMS limited to SNMP/Policy/VPN and LDAP Services

and after … ???


Let’s Be Cautious ! (cont’d) Drawbacks and Challenges

“Full applicability” with multi-service devices in “integrated networks”

Pushing “routing protocols” to some limits … requiring LS IGP enhancements, LMP, etc.

Future GMPLS developments could suffer from a lack of “scientific” coverage

IETF Sub-IP Area WG Positioning IPO WG plays “driving role” … from (all-)optical

viewpoint CCAMP WG plays “driving role” … from control and

(monitoring) measurement protocols PPVPN WG can be considered here as “service enabler” Many collaborations with other WG (MPLS, OSPF, ISIS,

etc.) and other bodies: ITU-T/T1X1, IEEE, etc.


Distributed Control Plane Concept

Management Plane

Control Plane

Transport Plane

Distributed

Control Channels

Transport Channels

Management Channels

Network Management

System

Network Controller

Network Device


GMPLS Technology GMPLS supports five types of interfaces:

PSC - Packet Switching Capable: IP/MPLS L2SC - Layer-2 Switching Capable: ATM, FR, Ethernet TDM - Time-Division Multiplexing: Sonet, SDH, G.709

ODU LSC - Wavelength Switching: Lambda, G.709 OCh FSC - Fiber Switching

GMPLS extends MPLS/MPLS-TE control plane LSP establishment spanning PSC or L2SC interfaces is

defined in MPLS/MPLS-TE control planes GMPLS extends these control planes to support this five

classes of interfaces (i.e. layers) As MPLS-TE, GMPLS provides

separation b/w transmission, control and management plane

network management using SNMP (dedicated MIB)


GMPLS Technology GMPLS control plane supports:

domain and unified service model overlay, augmented & peer control plane

interconnection model (known as overlay and peer models)

GMPLS control plane architecture includes several extended MPLS-TE building blocks:

Signalling Protocols: RSVP-TE and CR-LDP Intra-domain Routing Protocols: OSPF-TE and ISIS-TE Inter-domain Routing Protocol: BGP Link Management Protocol (LMP): new

TE-Routing enhanced scalability and flexibility Link Bundling (TE-Links) Generalized Unnumbered interfaces Extended Explicit Routing


GMPLS Signalling

Downstream on demand Label Allocation Ingress LSR initiated Ordered Control Liberal Label retention mode (conservative not

excluded) No distinction b/w Intra and Inter-domain (except

policy) No restriction on LSP establishment strategy

Control/Signalling driven Topology driven Data/Flow driven

Constraint-based Routing: strict and loose explicit routing (hop-by-hop not

excluded) strict routing limited to intra-area routing ! inter-area routing under specification


GMPLS Signalling Label Space per transport technology (in addition to

MPLS) “Wavelengths” for Lambda LSP SDH/Sonet for TDM LSP G.709 OTN for TDM ODUk and OCh LSP

Signalling Extensions Label Request including:

• LSP Encoding Type• Switching Type• Payload Type

Upstream Label: bi-directional LSP Label Set: tackle wavelength continuity in AO Networks Suggested Label: to improve processing Traffic Parameters including:

• TDM: SDH (ITU-T G.707) and Sonet (ANSI T1.105)• OTN: G.709 OTN (ITU-T G.709) and Pre-OTN


Downstream-on-demand Ordered Control

Suggested Label: 8

Upstream Label: 4

Egress LSR

Ingress LSR

Suggested Label: 3

Upstream Label: 6 Downstream Label: 9

Downstream Label: 5

Suggested Label: 9

Upstream Label: 2

Downstream Label: 8


Traffic Parameters and Label Space

Traffic Parameters Technology “independent” traffic parameters:

• Packet• ATM/Frame Relay• MPLambdaS

Technology “dependent” traffic parameters:• TDM: SDH (ITU-T G.707) and Sonet (ANSI

T1.105)• Optical: G.709 OTN (ITU-T G.709) and Pre-OTN

Extended Label Space (Generalized Label) Wavelength (Waveband) Label Space SDH/SONET Label Space G.709 OTN Label Space


SDH/Sonet Traffic Parameters

Signal Type SDH: LOVC/TUG and HOVC/AUG SONET: VT/VTG and STS SPE/STS-

GroupRequest Contiguous Concatenation

(RCC) Standard Contiguous Concatenation Arbitrary Contiguous Concatenation Flexible Contiguous Concatenation

Number of components (timeslots)

NCC: Contiguous concatenation NVC: Virtual concatenationMultiplier (multiple connections)Transparency RS/Section OH MS/Line OH per OH Byte (on-demand)

Signal Type (8-bits) RCC (8-bits)

NVC (16-bits)

NCC (16-bits)

Multiplier (16-bits)

Transparency (32-bits)


SDH/Sonet Label Space Numbering scheme:

For SDH, extension of G.707 numbering scheme (K, L, M) For SONET, field U = 0 = K (not significant). Only S, L and

M fields are significant Each letter indicates a possible branch number starting at

parent node in multiplex structure (increasing order from top of multiplex structure)

U (1,..,4) S (1,..,N) M (1,..,10) L (1,..,8) K (1,..4)

S - indicates a specific AUG-1/STS-1 inside an STM-N/STS-N multiplex U - only significant for SDH, indicates a specific VC inside a given AUG-1 K - only significant for SDH VC-4 (ignored for HO VC-3), indicates a

specific branch of a VC-4. L - indicates a specific branch of a TUG-3, VC-3 or STS-1 SPE (not

significant for unstructured VC-4 or STS-1 SPE) M - indicates a specific branch of a TUG-2/VT Group (not significant for

unstructured VC-4, TUG-3, VC-3 or STS-1 SPE (M=0))


G.709 OTN Traffic Parameters

Signal Type DTH: ODU1, ODU2 and ODU3 OTH: OCh at 2.5, 10 and 40 GbpsRequest Multiplexing Type (RMT) Direct Multiplexing (flexible) Default: no multiplexing (mapping)

Number of components NMC: Direct Multiplexing NVC: Virtual ComponentsMultiplier (multiple

connections)

NVC (16-bits)

NMC (16-bits)

Multiplier (16-bits)

Reserved (32-bits)

RMT (8-bits) Signal Type (8-bits)


G.709 OTN Label Space - Definitions

Label Structure defined as Tree: Root: OTUk signal and Leaves: ODUj signals (k j)

3 fields k1, k2 and k3 self-consistently characterising ODUk label space

k1 (1-bit): unstructured client signal mapped into ODU1 (k1 = 1) via OPU1

k2 (3-bit): unstructured client signal mapped into ODU2 (k2 = 1) via OPU2 or the position of ODU1 tributary slot in ODTUG2 (k2 = 2,..,5) mapped into ODU2 (via OPU2)

k3 (6-bit): unstructured client signal mapped into ODU3 (k3 = 1) via OPU3 or the position of ODU1 tributary slot in ODTUG3 (k3 = 2,..,17) mapped into ODU3 (via OPU3) or the position of ODU2 tributary slot in ODTUG3 (k3 = 18,..,33) mapped into ODU3 (via OPU3)

k1 Reserved k2 k3


G.709 OTN Label Space - Examples

If label k[i]=1 (i = 1, 2 or 3) and labels k[j]=0 (j = 1, 2 and 3with j=/=i), then ODUk signal ODU[i] not structured and mapped into the corresponding OTU[i] (mapping of an ODUk into an OTUk)

Numbering starts at 1 and Label Field = 0 invalid Examples:

k3=0, k2=0, k1=1 indicates an ODU1 mapped into an OTU1 k3=0, k2=1, k1=0 indicates an ODU2 mapped into an OTU2 k3=1, k2=0, k1=0 indicates an ODU3 mapped into an OTU3 k3=0, k2=3, k1=0 indicates the second ODU1 into an

ODTUG2 mapped into an ODU2 (via OPU2) mapped into an OTU2

k3=5, k2=0, k1=0 indicates the fourth ODU1 into an ODTUG3 mapped into an ODU3 (via OPU3) mapped into an OTU3


GMPLS TE-Routing Extensions

GMPLS based on IP routing and addressing models

IPv4/v6 addresses used to identify PSC and non-PSC interfaces

Re-using of existing routing protocols enables: benefits from existing intra and inter domain traffic-

engineering extensions benefits from existing inter-domain policy

To cover SDH/Sonet, G.709 OTN transmission technology GMPLS-TE defines technology dependent TE extensions

Increasing scalability using Link bundling and unnumbered interfaces

LSP Hierarchy (and region) through Forwarding Adjacency concept (FA-LSP)


TE-Routing Extensions for SDH/Sonet

TE-Routing information transported OSPF: Link State Advertisements (LSAs) grouped in

OSPF Packet Data Units (PDUs) IS-IS: Link State PDUs (LSPs)

TLVs describing capabilities of SDH/SONET links Link Capability and Allocation

• LS-MC TLV: Link SDH/SONET Multiplex Capability TLV• LS-CC TLV: Link SDH/SONET Concatenation Capability

TLV • LS-PC TLV: Link SDH/SONET Protection Capability TLV • LS-UA TLV: Link SDH/SONET Unallocated Component TLV

Node Capability• RS-I TLV: Router SDH Interconnection TLV• RS-SI TLV: Router SDH-SONET Interworking TLV

Clearly demonstrates rationale for link bundling and unnumbered interfaces


TE-Routing Extensions for G.709 OTN

TE-Routing information transported OSPF: Link State Advertisements (LSAs) grouped in

OSPF Packet Data Units (PDUs) IS-IS: Link State PDUs (LSPs)

TLVs describing capabilities of G.709 OTN links At ODU Layer

• LD-MP TLV: Link ODUk Mapping Capability TLV• LD-MC TLV: Link ODUk Multiplexing Capability TLV• LD-CC TLV: Link ODUk Concatenation Capability TLV• LD-UA TLV: Link ODUk Unallocated Component TLV

At OCh Layer• LO-MC TLV: Link OCh Multiplexing Capability TLV • LO-UA TLV: Link OCh Unallocated Component TLV

Clearly demonstrates rationale for link bundling and unnumbered interfaces


Link Management Protocol - LMP

LMP Protocol provides: Control Channel dynamic configuration Control Channel maintenance (Hello Protocol) Link Verification (Discovery, Mis-wiring) Link Property Correlation (Link bundling) Fault Management

• detection (using LoS/LoL/etc.)• localization/correlation (alarm suppression)• notification

LMP extended at OIF to cover UNI Neighbor and Service Discovery NNI Adjacency, Neighbor and Service Discovery Further elaboration for SDH/Sonet and G.709

specifics


Key Differences with MPLS-TE Label space(s) including timeslot, wavelength, or

physical space while label stacking is NOT supported Same type of Ingress and Egress LSR interface per LSP Control Sonet/SDH, G.709 OTN, Lambda LSP while

payload can include G.707 SDH/Sonet, G.709 OTN, Lambda, Ethernet, etc.

Bandwidth allocation in discrete units (TDM, LSC and FSC interfaces)

Downstream on demand ordered control (label distribution)

Bi-directional LSP setup (using Upstream Label) Reduced bi-directional LSP setup latency (using

Suggested Label)


Key Differences with MPLS-TE (cont’d)

Label Set to restrict the label choice by downstream node (photonic networks w/o wavelength conversion)

Forwarding Adjacencies in addition to Routing Adjacencies

Fast failure notification/location (for LSP restoration)

Provides enhanced recovery mechanisms (control-plane) in case of signalling channel and/or node failure and “graceful restart”


Each OXC includes the equivalent of MPLS-capable Label-Switching Router (LSR)

MPLS control plane is implemented in each OXC Lambda LSP (or Lightpaths) are considered

similar to MPLS Label-Switched Paths (LSPs) Selection of wavelengths (or lambdas) and OXC

ports are considered similar to selection of labels MPLS signaling protocols (such as RSVP-TE, CR-

LDP) adapted for Lambda LSP setup/delete/etc. IGPs (such as OSPF, ISIS) with “optical” traffic-

engineering extensions used for topology/resource discovery using IP address space (no “reachability extensions”)

What about MPLambdaS ?


GMPLS Application Scope Optical Internetworking Forum - OIF

UNI 1.0 Signalling Protocol Expected to become major NNI 1.0 Protocol Suite

ITU-T SG15 Q12/Q15: ASTN (G.807)/ASON Model Q9/Q12/Q15: G.DCM using Traffic Parameters Q12/Q15: G.RTG using TE-Routing Extensions Q9/Q11/Q15: G.VBI (LMP-WDM/OLI)

ATM Forum GMPLS as “control plane” for ATM networks

Interoperability Tests OIF UNI Interoperability Test (SuperComm’01 - June’01) GMU MPLS/GMPLS Interop Test (October’01) New: OIF NNI Interoperability Test (SuperComm’02 -

June’02)


Future Developments Extend connection services to p2mp and mp2mp GMPLS-based Meshed Protection/Restoration Tackling All-Optical challenges

optical routing impairments transparency

Integrate optical (Layer-1/Layer-0) VPN architecture

Keeping track of G.709 OTN evolutions Define a global management model including

performance monitoring/management security and policy ‘optical’ VPN scheduling services billing/accounting


References - GMPLS E.Mannie, D.Papadimitriou et al., ‘Generalized MPLS Architecture’,

Informationa Draft, draft-ietf-ccamp-gmpls-architecture-01.txt, November 2001

P. Ashwood-Smith, Lou Berger et al., ‘Generalized MPLS Signaling – Signaling Functional Requirements,’ Internet Draft, Work in progress, draft-ietf-mpls-generalized-signalling-06.txt, October 2001

P. Ashwood-Smith, Lou Berger et al., ‘Generalized MPLS Signaling – RSVP-TE Extensions,’ Internet Draft, Work in progress, draft-ietf-mpls-generalized-rsvp-te-05.txt, October 2001

P. Ashwood-Smith, Lou Berger et al., ‘Generalized MPLS Signaling – CR-LDP Extensions,’ Internet Draft, Work in progress, draft-ietf-mpls-generalized-cr-ldp-04.txt, July 2001

E.Mannie, D.Papadimitriou et al., ‘Generalized MPLS Extensions for SONET and SDH Control’, Internet Draft, Work in progress, draft-ietf-ccamp-gmpls-sonet-sdh-02.txt, October 2001

M.Fontana, D.Papadimitriou et al., ‘Generalized MPLS Extensions for G.079 Optical Transport Networks Control’, Internet Draft, Work in progress, draft-fontana-ccamp-gmpls-g709-02.txt, November 2001


References - (G)MPLS-TE K.Kompella, Y.Rekhter, “Signalling Unnumbered Links in RSVP-TE”,

Internet Draft, Work in progress, draft-ietf-mpls-rsvp-unnum-03.txt, November 2001

K.Kompella, Y.Rekhter, “Signalling Unnumbered Links in CR-LDP”, Internet Draft, Work in progress, draft-ietf-mpls-crldp-unnum-02.txt, March 2001

K.Kompella and Y.Rekhter, LSP Hierarchy with MPLS TE, Internet Draft, Work in progress, draft-ietf-mpls-lsp-hierarchy-03.txt, November 2001

K.Kompella, Y.Rekhter and L. Berger, “Link Bundling in MPLS Traffic Engineering”, Internet Draft, Work in progress, draft-ietf-mpls-bundle-01.txt, November 2001

K. Kompella et al., “Routing Extensions in Support of Generalized MPLS”, Internet Draft, Work in progress, draft-ietf-ccamp-gmpls-routing-01.txt, November 2001

K. Kompella et al., “IS-IS Extensions in Support of Generalized MPLS”, Internet Draft, Work in progress, draft-ietf-isis-gmpls-extensions-05.txt, November 2001

K. Kompella et al. “OSPF Extensions in Support of Generalized MPLS”, Internet Draft, Work in progress, draft-ietf-ccamp-ospf-gmpls-extensions-01.txt, November 01


References - MPLS-TE Optical D. Awduche et al., ‘Multi-Protocol Lambda Switching: Combining

MPLS Traffic Engineering Control With Optical Cross-Connects,’ Internet Draft, Work in progress, draft-awduche-mpls-te-optical-03.txt, April 2001

B. Rajagopalan et al., ‘IP over Optical Networks: A Framework,’ Internet Draft, Work in progress, draft-ietf-ipo-framework-01.txt, July 2001

A.Chiu, J.Strand et al., ‘Impairments And Other Constraints On Optical Layer Routing,’ Internet Draft, Work in progress, draft-ietf-ipo-impairments-00.txt, May 2001

D. Papadimitriou et al., ‘Non-linear routing impairments in wavelength switched optical networks,’ Internet Draft, Work in progress, draft-papadimitriou-ipo-non-linear-routing-impairments-01.txt, November 2001

D. Papadimitriou et al., ‘Linear Crosstalk for Impairment-based Optical Routing,’ Internet Draft, Work in progress, draft-papadim-ipo-impairments-crosstalk-00.txt, November 2001

D. Papadimitriou et al., ‘Enhanced LSP Services’, Internet Draft, Work in progress, draft-papadimitriou-enhanced-lsps-04.txt, July 2001

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