Download Generalized MPLS

Generalized MPLS
Premiere Journée Française sur l’IETF
Papadimitriou Dimitri
[email protected]
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Control and Transmission Plane Evolutions
1970
analog
(copper)
1995
today
digital
(PDH,SDH)
optical
(analog, but now on fiber)
point-to-point
wavelength
switched
opaque
Transport plane
optical
non transparent
operator-assisted/centrally managed
provisioning
burst/packet
switched
optical
automated path setup under
distributed control using GMPLS
Control/management plane
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Evolution of a Standard (Scope)
IP/MPLS Developments
(since 1996)
IETF Standards
SDH/Sonet
ITU-T G.707 / ANSI T1.105
"Optical SDH/Sonet" since 1998
MPLambdaS/GMPLS (IETF)
UNI - NNI Specifications (OIF)
based on Pre-OTN Standards
AO Wavelength witching
GMPLS (IETF)
AO/NNI Project (OIF)
AO Packet Switching
Under development
GMPLS Extensions
OTN
ITU-T G.709 - G.872
Non-Transparent Optical Networks
UNI - NNI Specifications
OTN
ITU-T G.709 - G.872
"Step to All-Optical"
AO Packet Switching
Under development
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Evolution of a Standard

IETF
46-48

IETF
48-49
MPLS: MultiProtocol Label Switching

IP packet based

Packet Traffic Engineering (MPLS-TE)
MPlS: MultiProtocol Lambda Switching


GMPLS: Generalized MPLS

IETF
50-51


MPLS control applied on optical channels
(wavelengths/lambda’s) and IGP TE extensions
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


Papadimitriou D. - Alcatel IPO NA (NSG)
LMP extended to “passive devices” via LMP-WDM
GMPLS covers G.707 SDH, G.709 OTN…
DNAC - November 2001
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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 … ???



Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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.
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Distributed Control Plane Concept
Management
Plane
Network
Controller
Control Plane
Network
Device
Transport Plane
Network
Management
System
Management
Channels
Control
Channels
Transport
Channels
Distributed
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
GMPLS Technology

GMPLS supports five types of interfaces:

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
GMPLS extends MPLS/MPLS-TE control plane

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
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
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)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
GMPLS Technology

GMPLS control plane supports:



GMPLS control plane architecture includes several extended
MPLS-TE building blocks:

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
domain and unified service model
overlay, augmented & peer control plane interconnection model
(known as overlay and peer models)
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

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Link Bundling (TE-Links)
Generalized Unnumbered interfaces
Extended Explicit Routing
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
GMPLS Signalling

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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
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
Control/Signalling driven
Topology driven
Data/Flow driven
Constraint-based Routing:
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strict and loose explicit routing (hop-by-hop not excluded)
strict routing limited to intra-area routing !
inter-area routing under specification
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
GMPLS Signalling

Label Space per transport technology (in addition to MPLS)

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“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

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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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Downstream-on-demand Ordered Control
Ingress LSR
Downstream Label: 8
Suggested Label: 8
Upstream Label: 4
Downstream Label: 5
Suggested Label: 3
Upstream Label: 6
Downstream Label: 9
Suggested Label: 9
Upstream Label: 2
Egress LSR
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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)
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Wavelength (Waveband) Label Space
SDH/SONET Label Space
G.709 OTN Label Space
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
SDH/Sonet Traffic Parameters
Signal Type (8-bits)
RCC (8-bits)
NCC (16-bits)
NVC (16-bits)
Multiplier (16-bits)
Transparency (32-bits)
Signal Type


SDH: LOVC/TUG and HOVC/AUG
SONET: VT/VTG and STS SPE/STS-Group
Request Contiguous Concatenation (RCC)



Standard Contiguous Concatenation
Arbitrary Contiguous Concatenation
Flexible Contiguous Concatenation
Number of components (timeslots)
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
Multiplier (multiple connections)
Transparency



Papadimitriou D. - Alcatel IPO NA (NSG)
NCC: Contiguous concatenation
NVC: Virtual concatenation
RS/Section OH
MS/Line OH
per OH Byte (on-demand)
DNAC - November 2001
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)
S (1,..,N)



U (1,..,4) K (1,..4) L (1,..,8) M (1,..,10)
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))
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
G.709 OTN Traffic Parameters
Signal Type (8-bits)
NMC (16-bits)
RMT (8-bits)
NVC (16-bits)
Multiplier (16-bits)
Reserved (32-bits)
Signal Type


DTH: ODU1, ODU2 and ODU3
OTH: OCh at 2.5, 10 and 40 Gbps
Request Multiplexing Type (RMT)


Number of components

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NMC: Direct Multiplexing
NVC: Virtual Components
Multiplier (multiple connections)
Direct Multiplexing (flexible)
Default: no multiplexing (mapping)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
G.709 OTN Label Space - Definitions

Label Structure defined as Tree:

Root: OTUk signal and Leaves: ODUj signals (k  j)
Reserved

k3
k2
k1
3 fields k1, k2 and k3 self-consistently characterising ODUk label space

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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)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
TE-Routing Extensions for SDH/Sonet

TE-Routing information transported

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
TLVs describing capabilities of SDH/SONET links

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
OSPF: Link State Advertisements (LSAs) grouped in OSPF Packet
Data Units (PDUs)
IS-IS: Link State PDUs (LSPs)
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
TE-Routing Extensions for G.709 OTN

TE-Routing information transported



TLVs describing capabilities of G.709 OTN links



OSPF: Link State Advertisements (LSAs) grouped in OSPF Packet
Data Units (PDUs)
IS-IS: Link State PDUs (LSPs)
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Link Management Protocol - LMP

LMP Protocol provides:


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
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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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”
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
What about MPLambdaS ?

Each OXC includes the equivalent of MPLS-capable LabelSwitching Router (LSR)


Lambda LSP (or Lightpaths) are considered similar to MPLS
Label-Switched Paths (LSPs)



MPLS control plane is implemented in each OXC
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”)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
GMPLS Application Scope

Optical Internetworking Forum - OIF

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ITU-T SG15
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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


UNI 1.0 Signalling Protocol
Expected to become major NNI 1.0 Protocol Suite
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)
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
Future Developments



Extend connection services to p2mp and mp2mp
GMPLS-based Meshed Protection/Restoration
Tackling All-Optical challenges

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


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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
References - GMPLS


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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-mplsgeneralized-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-rsvpte-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-ldp04.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-gmplssonet-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, draftfontana-ccamp-gmpls-g709-02.txt, November 2001
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
References - (G)MPLS-TE
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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
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
References - MPLS-TE Optical
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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-nonlinear-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-impairmentscrosstalk-00.txt, November 2001
D. Papadimitriou et al., ‘Enhanced LSP Services’, Internet Draft, Work in
progress, draft-papadimitriou-enhanced-lsps-04.txt, July 2001
Papadimitriou D. - Alcatel IPO NA (NSG)
DNAC - November 2001
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