Transcript 20021027-IPOptical-Bernstein

Optical Control Plane,
Optical/IP integration Concepts
and Issues
Greg Bernstein
[email protected]
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
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Goals: 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 Functions
Inventory & Resource Management
2. Global Topology Dissemination
1. Neighbor Discovery
NETWORK
MGMT PLANE
User
User
OUNI
CONTROL PLANE
DATA PLANE
3. Connection Request
4. Path Calculation (NE-based or EMS-based)
Dynamic Provisioning
5. Establish Connection
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Standards Bodies and Organizations
Charter: Global Telecom Architecture and
Standards
Membership 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) Architecture
Charter: Development of Optical
Networking Products and Services
Membership Fee: None
Membership: Individuals – community model
Membership Fee: $8000/yr
No. of Members: 312 Principal Members
Active Participants:
• ISPs
• Service Provider IP Divisions
• IP/Ethernet Vendors
Member Organizations:
• PTTs, ISPs, ILECs, IXCs
• Optical Networking Vendors
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Control Plane Interfaces
User Admin
Domain
Load
Balancer
User Admin
Domain
Load
Balancer
L2/L3
firewall
L2/L3
firewall
L2/L3
Load
L2/L3
firewall
Balancer
Load
firewall
Balancer
Provider C
Admin Domain
UNI
UNI
Provider A
Admin Domain
Provider B
Admin Domain
E-NNI
E-NNI
I-NNI
Provider A has divided
their network into multiple
control domains (e.g., vendor,
geographic, technology,
political, etc.)
Provider B’s
network is a
single control
domain
E-NNI
Domain A1
I-NNI
Domain A2
I-NNI
UNI: operations between end-user and service provider admin domains
E-NNI: multi-control domain operation for a single service provider;
multi-control domain operation among different service providers
I-NNI: intra-control domain operation
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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?
PLR-STE neighbor discovery
STE-LTE neighbor discovery
STE-STE neighbor discovery
PTE
LTE
STE
PLR
PLR
STE
LTE
PTE
LTE-LTE neighbor discovery
PLR-PLR neighbor discovery
Definitions
PLR - Physical Layer Regenerator
STE - Section Terminating Equipment
LTE - Line Terminating Equipment
PTE - Path Terminating Equipment
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Optical 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:
Traditional IP link state IGPs (OSPF, IS-IS)
• 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-byhop forwarding paradigm)
– Overly simplistic for optical networks
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 View
Protection: 1:N, N = 3; SRLG: 237
Capacity: 102 STS-1, 30 STS-3c,
NE 3
4 STS-12c, 1 STS-48c
NE 1
Protection: 4F-BLSR; SRLG: 1, 17
Capacity: 16 STS-1, 4 STS-3, 1
STS-12c
NE 4
Protection: 1:N, N = 2;
SRLG: 138
Capacity: 105 STS-1,
33 STS-3c, 8 STS-12c,
2 STS-48c
Protection: 4F-BLSR;
SRLG: 5, 580
Capacity: 28 STS-1, 8
STS-3c, 2 STS-12c
Protection: 4F-BLSR;
SRLG: 101, 880
Capacity: 16 STS-1, 4
STS-3c, 1 STS-12c
NE 2
Protection: 1:N, N = 1; SRLG: 80, 12
Capacity: 97 STS-1, 31 STS-3c, 6
STS-12c, 2 STS-48c
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NE 5
Connection 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
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Inter-Domain
Networking (NNI)
The “Inter-domain” model is an inherent part of
the current ITU-T standards for the control of
optical networks
Domain 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 Issues
Domain X
Carrier A
Domain Y
UNI
Feature-Rich
Intra-domain
Protocol
UNI
Carrier B
Domain Z
Generic Interdomain
Interdomain
Protocol
• Within Domain: homogeneous
systems and protocols
• Different Domains:
heterogeneous systems and
protocols
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UNI
 Domain Model
Control 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 Domains
• Goals
– Enable interoperability by utilizing discovery, signaling and routing
protocols between control domains
protocol between
domains
A
Control Domain 2
Control Domain 1
protocol between
domains
Control Domain 4
protocol between
domains
Z
Control Domain 3
Control Domain 5
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