Transcript Inter-region Traffic Engineering

Inter-Domain
GMPLS Traffic
Engineering
Jean-Marc Uze
[email protected]
TNC2005, Poznan, June 7th, 2005
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Agenda
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Scope
Potential benefits for R&E networks
Challenges
Requirements
Inter-domain GMPLS TE Components
Comparison of signaling approaches
Standards status (IETF)
Juniper’s Roadmap
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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
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Example: Inter-area
CE2
CE1
domain 2
ABR3
ABR1
P
PE1
Area 1
P
P
Area 0
Area 2
ABR2
domain 1
domain boundary: ABR
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ABR4
PE2
domain
3
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Example: Inter-AS
presence of interdomain link poses
additional problems
to be addressed for
TE
CE1
ASBR1
ASBR3
ASBR5
ASBR7
P
P
PE1
CE2
P
AS1
AS3
AS2
ASBR2
domain 1
ASBR4
PE2
ASBR6
domain 2
ASBR8
domain 3
domain boundary: ASBR-ASBR link
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Example: Overlay
Fiber-switched LSP
Packet LSP
l-switched LSP
Different addressing
and
routing realms
GMPLS overlay
Optical core
network
Edge LSR1
P
PE1
Edge LSR3
OXC
P
OXC
P
PE2
OXC
OXC
OXC
Edge LSR2
IP overlay network
domain 1
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domain 2
PE3
Edge LSR4
IP overlay network
domain 3
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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
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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)
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Inter-domain GMPLS TE
Components
 Routing
• Reachability
• Topology
• TE information
 Path computation
 Signaling
 Policies and SLAs
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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
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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.
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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.
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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
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Comparison of signaling
approaches
Contiguous
Non-contiguous
 Single contiguous end-to-end
TE LSP spanning multiple
domains
Inter-domain TE LSP comprises of
multiple LSP “pieces”
• Emphasis on control at headend LSR of inter-domain TE LSP
• It may be nested or stitched in each
domain to a different local TE LSP in that
domain
• 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
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Non-contiguous LSP setup
Inter-domain TE LSP
Intra-domain TE LSP
Data path
Inter-domain LSP
partial path
computation to next
ASBR(ASBR3)
CE1
PATH
RESV
CE2
Nesting over pre-provisioned
intra-domain TE LSP
ASBR1
ASBR3
ASBR5
P
P
AS1
AS2
PE1
ASBR2
Inter-domain LSP
from PE1 to PE2
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ASBR4
Inter-domain LSP
partial path
computation to next
ASBR
ASBR7
PE2
P
AS3
ASBR6
Forward interdomain LSP setup
request to ASBR
ASBR8
Dynamic setup of
intra-domain TE
LSP
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Non-contiguous LSP re-optimization
CE2
CE1
Link becomes suboptimal
Intra-domain LSP
re-routes to
optimal path
ASBR1
PE1
ASBR3
ASBR5
ASBR7
P
P
PE2
P
AS1
AS2
ASBR2
ASBR4
AS3
ASBR6
ASBR8
Inter-domain LSP
segment will now be
nested along optimal
path
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Proposed solution: protection
Within a domain,
enough to protect
intra-domain TE LSP
CE1
Link to
protect
ASBR1
PE1
Node to protect
ASBR3
Within a domain
protection works
like with regular
RSVP-TE
ASBR5
ASBR7
P
P
P
AS1
signal linkprotection
backup
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ASBR4
Node protection backup
path will go through ERO
expansion as before
NNHop = ASBR5
PE2
AS3
AS2
ASBR2
CE2
ASBR6
ASBR8
ASBR-ASBR link protection backup/detour
ASBR3 node protection backup/ detour
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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-interdomain-framework-02.txt
Several proposed solutions
for PCC-PCE protocol
Inter-domain TE LSP
signaling
Inter-domain TE LSP
routing + per domain path
computation
draft-ietf-ccamp-interdomain-rsvp-te-00.txt
draft-vasseur-ccamp-interdomain-pd-path-comp-00.txt
LSP Hierarchy
In RFC queue
draft-ietf-mpls-lsp-hierarchy-08.txt
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Inter-provider TE
policies, SLAs, QoS
Inter-area and inter-AS
MPLS TE requirements
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Juniper Roadmap
PCE for path
computation
Inter-AS TE
solution
Follow standard specification
PCE for Inter-area TE LSPs
Inter-AS MPLS TE applications
Policies, mappings, SLAs
Inter-AS TE Routing (ASBR-ASBR link),
Explore improvements - dynamic FAs
Inter-area TE solution ready
Start with inter-area TE
Inter-domain TE routing - determining exit LSR from the domain
Per-domain path computation with loose-hop expansion
Inter-area MPLS TE
Additional inter-domain signaling functionalities, if any
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
LSP Hierarchy
Base for inter-domain signaling
Inter-AS MPLS TE,
Other Improvements
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Thank you!
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