Inter-region Traffic Engineering

Transcript Inter-region Traffic Engineering

Inter-Domain GMPLS Traffic Engineering

Agenda

        Scope Potential benefits for R&E networks Challenges Requirements Inter-domain GMPLS TE Components Comparison of signaling approaches Standards status (IETF) Juniper’s Roadmap Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 2

Scope

 “Inter”-domain interface • IGP areas • Autonomous Systems (AS) • Any two GMPLS path computation domains • Client Layer2 network and MPLS transport network  Packet and non-packet LSPs Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 3

Example: Inter-area

CE2 CE1 domain 2 ABR1 P PE1 P Area 1 Area 0 ABR2 domain 1

domain boundary: ABR

ABR3 ABR4 P Area 2 domain 3 PE2

Example: Inter-AS

CE1 presence of inter domain link poses additional problems to be addressed for TE ASBR1 ASBR3 ASBR5 ASBR7 CE2 P P P PE2 AS1 PE1 domain 1 ASBR2 AS2 ASBR4 domain 2 ASBR6 ASBR8 AS3 domain 3

Example: Overlay

Fiber-switched LSP

-switched LSP GMPLS overlay Edge LSR1 PE1 P Packet LSP Different addressing and routing realms Optical core network P Edge LSR3 P PE2 IP overlay network domain 1 Edge LSR2 domain 2 PE3 Edge LSR4 IP overlay network domain 3

Potential benefits for R&E networks

 Today situation in R&E Networks • A significant usage of L2 circuits over MPLS for national and international projects (e.g 6net, ATLAS, VLBI, KARLBOL, ATRIUM, etc…) • “Bandwidth on Demand” activity in GEANT 2 and optical networks development  Complimentary to Inter-domain VPN • 2547bis is about VPN auto-discovery and signaling across multiple domains • Inter-domain GMPLS TE is about Traffic Engineering • Constraint based path computation, re-optimization and protection schemes Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 7

Challenges

   Lack of complete topology information to effectively map traffic • need to preserve restricted information sharing, routing protection for scalability, and privacy (in case of multiple providers) No assumptions can be made about influencing routing and management decisions in another domain • such decisions would be local to that domain and local administrative policies may alone influence them.

Scalability considerations • at the control plane (signaling) • at the data/forwarding plane (MPLS forwarding state) Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 8

Inter-domain GMPLS TE Components

Inter-domain GMPLS TE : Routing

   Reachability • Unchanged Topology • No leaking of any topology information outside the domain TE information • May require advertising local TE information of certain links on domain boundaries (e.g. ASBR-ASBR link) into the IGP TED within that domain to improve path computation and reduce crankback • This is not advertised across different domains Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 10

Inter-domain GMPLS TE: Path computation

     GMPLS TE path • Loose and/or strict hops • Depends on available visibility into other domains Computation options • Offline tools + configuration on head-end • IP reachability for determining next loose-hop + CSPF on the LSR • Path Computation Element (PCE) Per-region path computation for any “loose-hop expansion” irrespective of above options Crankback mechanisms Any of the above path computation options may be used with any of the signaling mechanisms.

Inter-domain GMPLS TE: Signaling

 Single contiguous LSP end-to-end  Non-contiguous, comprising of different LSP pieces per domain, combined using, • Nesting (N:1) • Stitching (1:1) LSP Hierarchy signaling approach.

Inter-domain GMPLS TE: Policies and SLAs

  Policies • Mapping TE constraints, QoS paramaters, authentication; etc • TE related administrative actions • admission control, triggering re-optimization, allow/disallow/ignore other TE control from outside SLAs • QoS guarantees • Billing and accounting purposes • Settlement Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 13

Comparison of signaling approaches

Contiguous Non-contiguous  Single contiguous end-to-end TE LSP spanning multiple domains • Emphasis on control at head end LSR of inter-domain TE LSP  Inter-domain TE LSP comprises of multiple LSP “pieces” • It may be

nested

stitched

domain to a

different

domain in each local TE LSP in that • Hierarchical in nature (both control & forwarding planes) • Emphasis on localizing control within each domain as far as possible • Local re-optimization and protection  Terminology • FA-LSP: nesting, many-to-one • LSP segment: stitching, 1:1 Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 14

Non-contiguous LSP setup

Inter-domain TE LSP Intra-domain TE LSP Data path

CE1 Inter-domain LSP partial path computation to next ASBR(ASBR3) PATH RESV Nesting over pre-provisioned intra-domain TE LSP CE2 PE1

P ASBR1 ASBR3 P ASBR5 ASBR7 P PE2 Inter-domain LSP from PE1 to PE2 AS1 ASBR2 ASBR4 Inter-domain LSP partial path computation to next ASBR AS2 ASBR6 ASBR8 Forward inter domain LSP setup request to ASBR AS3 Dynamic setup of intra-domain TE LSP

Proprietary and Confidential www.juniper.net 15

Non-contiguous LSP re-optimization

CE1 AS1 PE1 P Intra-domain LSP re-routes to optimal path ASBR1 ASBR3 P Link becomes sub optimal ASBR5 ASBR7 P CE2 PE2 AS2 ASBR2 ASBR4 Inter-domain LSP segment will now be nested along optimal path ASBR6 ASBR8 AS3

Proposed solution: protection

CE1 P Within a domain, enough to protect intra-domain TE LSP Link to protect ASBR1 ASBR3 Node to protect Within a domain protection works like with regular ASBR5 RSVP-TE ASBR7 P AS1 PE1 signal link protection backup ASBR2 ASBR4 Node protection backup path will go through ERO expansion as before NNHop = ASBR5 AS2 P CE2 PE2 AS3 ASBR6 ASBR8

ASBR-ASBR link protection backup/detour ASBR3 node protection backup/ detour

IETF status

PCC-PCE protocol specification for inter-domain application PCE architecture, PCC-PCE communication protocol requirements, discovery mechanisms Inter-domain TE LSP framework draft-ietf-ccamp-inter domain-framework-02.txt

Inter-domain TE LSP signaling draft-ietf-ccamp-inter domain-rsvp-te-00.txt

Inter-provider TE policies, SLAs, QoS Several proposed solutions for PCC-PCE protocol Inter-domain TE LSP routing + per domain path computation draft-vasseur-ccamp-inter domain-pd-path-comp-00.txt

LSP Hierarchy In RFC queue draft-ietf-mpls-lsp-hierarchy-08.txt

Juniper Roadmap

PCE for path computation Follow standard specification PCE for Inter-area TE LSPs Inter-AS TE solution Inter-AS MPLS TE, Other Improvements Inter-area TE solution ready Inter-area MPLS TE Inter-AS MPLS TE applications Policies, mappings, SLAs Inter-AS TE Routing (ASBR-ASBR link), Explore improvements - dynamic FAs Start with inter-area TE Inter-domain TE routing - determining exit LSR from the domain Per-domain path computation with loose-hop expansion Additional inter-domain signaling functionalities, if any LSP Hierarchy Nesting e2e LSPs into pre-provisioned FA LSPs Scalability of control and data plane Re-optimization and protection (FRR) of e2e LSPs over FA-LSP Base for inter-domain signaling Copyright © 2003 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 19

Thank you!