Transcript Tejas Networks Pvt. Ltd.

IP over Intelligent Optical Networks
Kumar N. Sivarajan
CTO, Tejas Networks
[email protected]
www.tejasnetworks.com
January 5, 2001
Optical Networks
 Fiber
• Provides the physical transport
Optical Access
medium
 Optical networks: Create the
pipes
• WDM: Fast pipes for voice/data
• Optical amplification: Long pipes
 IP Routers, ATM switches, SDH
equipment: Fill the pipes
 Operations Support System (OSS)
• Manage all aspects of the network
IP
ATM
Optical Network
SONET/SDH
Higher Layer Networks
Evolution of Transmission Technology
• 1st Generation: Copper is transmission medium
• 2nd Generation: Optical Fiber (late 80s)
Higher
data rates; longer link lengths
• Dense Wavelength-Division Multiplexing (DWDM,
1994)
Fiber
exhaust forces DWDM
Erbium-doped fiber amplifiers (EDFAs) lower DWDM
transmission cost
• 3rd Generation: Intelligent optical networking (1999)
Routing
and signaling for optical paths
Dense Wavelength-Division
Multiplexing (DWDM)
1
2
3
-
N
DWDM Evolution
• Faster (higher speed per wave),
40
Gb/s on the horizon
• Thicker (more waves),
160
waves possible today
• Longer (link lengths before regeneration)
A few
thousand km possible today
• 160 waves at 10 Gb/s = 1.6 Tb/s
25
million simultaneous phone calls
5 million books per minute
IP over ATM
ATM
network
Network
IP
Data link
ATM
Network
IP router
Data link
IP router
(a)
Physical
(b)
ATM over SONET
SONET
network
Network
ATM switch
SONET
Network
Data link
ATM switch
(a)
Physical
(b)
ATM
Data link
IP over ATM over SONET
Network
Data link
Network
Data link
Physical
SONET
Network
ATM
IP
Data link
Optical Pass-Through (Routing)
Node A
IP/ATM/
SDH
Node B
IP/ATM/
SDH
Node C
IP/ATM/
SDH
No optical pass-through
Node A
IP/ATM/
SDH
Node B
IP/ATM/
SDH
Node C
IP/ATM/
SDH
With optical pass-through
Intelligent Optical Networking
 Optics is not merely a transmission technology
• Optics provides a flexible layer upon which to deliver
network service
 DWDM provides enormous link capacities
• DWDM: Physical layer of Intelligent Optical Network
 Routing and signaling of optical paths
• Provides significant economies over conventional
•
network architectures
Enables revolutionary new services
 2.5
Gb/s path from Bangalore to Boston, on demand!
SONET over Optical Layer
Path
Section
Channel
Multiplex
section
Amplifier
section
Optical layer
Physical
SONET layer
Line
IP over SONET over Optical Layer
IP
Path
Section
Channel
M ultiplex
section
A m plifier
section
O p tical layer
Physical
S O N E T lay er
Line
IP over Optical Layer
IP
Data link/Framing
Channel
M ultiplex
section
Amplifier
section
O ptical layer
Physical
IP over Intelligent Optical Networks
 Establish high-speed optical layer connections (lightpaths)
 IP routers connected through lightpaths rather than fiber
 Switching (WDM crossconnects) add flexibility to the
optical layer
• Flexible, potentially rich, topology at IP layer
IP router
B
C
E Wavelength
crossconnect
Lightpaths
A
D
Intelligent Optical Networking
Developments
 Incorporate SONET/SDH multiplexing capability into
interface cards of DWDM equipment
• Connect IP routers with STM-1/4 interfaces directly to DWDM
equipment transporting STM-16/64 wavelengths
 Move protection function from SONET/SDH to optical
layer
• Rerouting all wavelengths affected by a fiber cut is more
efficiently done by optical switches than SDH equipment at ends
of lightpaths
 Add intelligence to optical layer
• Borrow algorithms/protocols from data (IP) networks
• Routing: OSPF, Signaling: MPLS
Optical Network Architectures
 Ring
• Simplest topology with
redundant paths
 Interconnected Rings
 Mesh
• More efficient routes
 Mesh with Switching
• Efficient routing
• Flexibility in demand
management
IP over Intelligent Optical Networks:
Summary
 Application traffic predominantly IP-based
• Perhaps including voice in the near future
 Intelligent optical networks: physical layer of all highbandwidth networks
 IP over intelligent optical networks is the natural evolution
• Incorporate QoS functionality of ATM in IP
• Incorporate reliability functions of SDH within DWDM
 IP protocols (OSPF, MPLS) basis for intelligent algorithms
in optical networks
• OSPF for autodiscovery
• OSPF for routing circuits
• MPLS for signalling circuit setup