Optical Control Plane, Optical/IP integration Concepts and Issues

Optical Control Plane,Optical/IP integration Concepts

and Issues

Optical Control Plane,Optical/IP integration Concepts

and Issues

Greg Bernstein

[email protected]

Greg Bernstein

[email protected]

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Issues and Requirements…Issues and Requirements…

• Standards are emerging for control of optical networks…– Primarily aimed at service providers and carriers

• Some of these efforts were started under vastly different circumstances than the optical networking industry now faces

• Some of these control standards were ahead of any interoperability standards at the optical layer

• Good IP/Optical integration would require at least:– Information about the optical network topology/resources

– Timely IP level traffic statistics

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Also see: “Control Plane Design for Reliable Optical Networks”, IEEE Communications Magazine, Feb., 2002, by folks at AT&T Labs. Also see http://www.networkwatch.rhk.com/ShowAnalysis.asp?analysisId=106

Also see: “Control Plane Design for Reliable Optical Networks”, IEEE Communications Magazine, Feb., 2002, by folks at AT&T Labs. Also see http://www.networkwatch.rhk.com/ShowAnalysis.asp?analysisId=106

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Goals: Automation of Optical Control FunctionsGoals: Automation of Optical Control Functions

• Automatic Neighbor Discovery– Allows a node to determine the identity of each

neighboring node and the set of links that connect them

• Topology and Resource Status Dissemination– Allows every node to automatically discover the

complete network topology and resources

• Signaling for Connection Provisioning

– Allows the establishment and restoration of a path from one end of the connection

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Optical Control Plane FunctionsOptical Control Plane Functions

4. Path Calculation (NE-based or EMS-based)4. Path Calculation (NE-based or EMS-based)

NETWORK MGMT PLANENETWORK MGMT PLANE

1. Neighbor Discovery1. Neighbor Discovery

2. Global Topology Dissemination2. Global Topology Dissemination

CONTROL PLANECONTROL PLANE

Inventory & Resource ManagementInventory & Resource Management

Dynamic ProvisioningDynamic Provisioning 5. Establish Connection5. Establish Connection

DATA PLANEDATA PLANE

3. Connection Request3. Connection Request

OUNIOUNIUserUser UserUser

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Standards Bodies and OrganizationsStandards Bodies and Organizations

Charter: Global Telecom Architecture and StandardsMembership Fee: minimum $18,900/yr (31,500 Swiss Fr.)No. of Members: 189 Member States + 434 Sector Members

Member Organizations: • Global Service Providers• PTTs, ILECs, IXCs• Telecom equipment vendors• Governments (e.g., US State Department)

Charter: Global Telecom Architecture and StandardsMembership Fee: minimum $18,900/yr (31,500 Swiss Fr.)No. of Members: 189 Member States + 434 Sector Members

Member Organizations: • Global Service Providers• PTTs, ILECs, IXCs• Telecom equipment vendors• Governments (e.g., US State Department)

Charter: Evolution of the Internet (IP) ArchitectureMembership Fee: NoneMembership: Individuals – community model

Active Participants: • ISPs• Service Provider IP Divisions • IP/Ethernet Vendors

Charter: Evolution of the Internet (IP) ArchitectureMembership Fee: NoneMembership: Individuals – community model

Active Participants: • ISPs• Service Provider IP Divisions • IP/Ethernet Vendors

Charter: Development of Optical Networking Products and ServicesMembership Fee: $8000/yrNo. of Members: 312 Principal Members

Member Organizations: • PTTs, ISPs, ILECs, IXCs • Optical Networking Vendors

Charter: Development of Optical Networking Products and ServicesMembership Fee: $8000/yrNo. of Members: 312 Principal Members

Member Organizations: • PTTs, ISPs, ILECs, IXCs • Optical Networking Vendors

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Control Plane InterfacesControl Plane Interfaces

User AdminDomain

User AdminDomain

Provider A Admin Domain

Provider C Admin DomainUNI UNI

E-NNI

E-NNI

Provider B Admin Domain

firewall

firewall

L2/L3

L2/L3

LoadBalancer

LoadBalancer

firewall

firewall

L2/L3

L2/L3

LoadBalancer

LoadBalancer

Domain A1 Domain A2

E-NNI

I-NNI

I-NNII-NNI

Provider A has dividedtheir network into multiplecontrol domains (e.g., vendor, geographic, technology, political, etc.)

Provider B’s network is a single control domain

UNI: operations between end-user and service provider admin domainsE-NNI: multi-control domain operation for a single service provider; multi-control domain operation among different service providersI-NNI: intra-control domain operation

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Why do Neighbor Discovery?Why do Neighbor Discovery?

• Allows automatic inventorying of physical links between nodes– Can determine inconsistent physical wiring

• Allows automatic identification of node-pair neighbors

– Useful for path computation and signaling

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Neighbor Discovery at which layer? Between which layer?Neighbor Discovery at which layer? Between which layer?

PLR PLR STE LTE PTESTELTEPTE

STE-STE neighbor discovery

LTE-LTE neighbor discovery

PLR-PLR neighbor discoveryDefinitions

PLR - Physical Layer Regenerator

STE - Section Terminating Equipment

LTE - Line Terminating Equipment

PTE - Path Terminating Equipment

Definitions

PLR - Physical Layer Regenerator

STE - Section Terminating Equipment

LTE - Line Terminating Equipment

PTE - Path Terminating Equipment

STE-LTE neighbor discoveryPLR-STE neighbor discovery

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Optical Link State RoutingOptical Link State Routing

• A way to discover and disseminate topology and resource information independent of the EMS

• Offloads the EMS from performing this task

• Makes this information available at every node enhanced robustness in the event of major network problems

• Timely updates of changes to all nodes

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Routing Roles:Routing Roles:

• Discovery portion

– Hello protocol (assumes data and control planes are the same)

– Not applicable, in general, to optical networks

• Topology Dissemination

– Information concerning nodes (including reachability) and links in the network

– Want and need more information for optical networks

• Route Computation

– To give IP forwarding table (heavily constrained due to hop-by-hop forwarding paradigm)

– Overly simplistic for optical networks

Traditional IP link state IGPs (OSPF, IS-IS)Traditional IP link state IGPs (OSPF, IS-IS)

Acronyms: IP (Internet Protocol), IGPs (Internal Gateway Protocols), OSPF (Open Shortest Path First), IS-IS (Intermediate System to Intermediate System)

Acronyms: IP (Internet Protocol), IGPs (Internal Gateway Protocols), OSPF (Open Shortest Path First), IS-IS (Intermediate System to Intermediate System)

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Example Network ViewExample Network View

Protection: 4F-BLSR; SRLG: 1, 17Capacity: 16 STS-1, 4 STS-3, 1 STS-12c

Protection: 4F-BLSR; SRLG: 101, 880Capacity: 16 STS-1, 4 STS-3c, 1 STS-12c

Protection: 4F-BLSR; SRLG: 5, 580Capacity: 28 STS-1, 8 STS-3c, 2 STS-12c

Protection: 1:N, N = 3; SRLG: 237Capacity: 102 STS-1, 30 STS-3c, 4 STS-12c, 1 STS-48c

Protection: 1:N, N = 2; SRLG: 138Capacity: 105 STS-1, 33 STS-3c, 8 STS-12c, 2 STS-48c

Protection: 1:N, N = 1; SRLG: 80, 12Capacity: 97 STS-1, 31 STS-3c, 6 STS-12c, 2 STS-48c

NE 1NE 1

NE 2NE 2

NE 3NE 3

NE 4NE 4

NE 5NE 5

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Connection ProvisioningConnection Provisioning

• Goals– Offload the EMS by distributing control

– Also adds scalability, survivability and potential for more services

– Interoperability

• General Solution: Use a signaling protocol!– Signaling has been used in the telephone network for 60

years or more (signaling is rather new in data networks though…)

– Need to be careful with “behavioral” aspects…• e.g., call clearing is not an acceptable default behavior in the transport domain!

– Other benefit: a robust, bandwidth efficient restoration mechanism…

– There are a number of different signaling protocols being extended

Inter-Domain Networking (NNI)

Inter-Domain Networking (NNI)

The “Inter-domain” model is an inherent part of the current ITU-T standards for the control of

optical networks

The “Inter-domain” model is an inherent part of the current ITU-T standards for the control of

optical networks

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Domain ModelDomain Model

– Networks are organized as multiple domains:

• Administrative purposes

• Scaling purposes

• Security and Isolation

• Technology / Vendor differences…

– Examples

• Internet Autonomous Systems (AS)

• ITU-T G.805/ASON Domain Model

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Deployment IssuesDeployment Issues

Domain Model Domain Model

• Within Domain: homogeneous systems and protocols

• Different Domains: heterogeneous systems and protocols

UNIUNI UNIUNI

UNIUNI

Carrier ADomain X Domain Y

Domain Z

Carrier B

Generic Interdomain Protocol

Generic Interdomain Protocol

Feature-Rich Intra-domain Protocol

Feature-Rich Intra-domain Protocol Generic Inter-

domain Protocol

Generic Inter-domain Protocol

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Control Domain ConceptsControl Domain Concepts

• Separation of Control Mechanisms

– Protocols used between domains independent of what protocols used within domain

– Internal operation of domain “invisible” outside the domain

– Independence of internal protection or restoration mechanisms

• Carrier Uses for Domains

– Inter-vendor interoperability

– Gatekeeper mechanism for suppressing signaling or routing storms between domains

– Technology differences (all-optical, SDH,…)

– Service differences (restoration, etc…)

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OIF / ITU-T NNI between Control DomainsOIF / ITU-T NNI between Control Domains

• Goals– Enable interoperability by utilizing discovery, signaling and routing protocols

between control domains

A

Control Domain 1

ZControl Domain 3

Control Domain 4

Control Domain 5

Control Domain 2

protocol between domains

protocol between domains

protocol between domains

protocol between domains

protocol between domains

protocol between domains