ip optical
TRANSCRIPT
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IP-optical Integration
Peter Sjdin
KTH TSLab, Kista, Sweden
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Layered Communication Model
Modular design with well-defined interfaces
Independent layers
Duplicated functionality
Connection management
Error control
Flow control Quality of service
Each layer requires its ownmanagement
From B. A. Forouzan: Data Communications and Networking, 4th ed, McGraw-Hill
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End-to-end Arguments
End-to-end arguments in system design, by J.H.Saltzer, D.P. Reed and D.D. Clark, 1981.
A function or service should be carried out within anetwork layer only if
it is needed by all clients of that layer,
and it can be completely implemented in that layer. Result is that protocol operations shift towards the
network end-points
Dumb network, smart terminals
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SONET/SDH Networks
TDM circuit switching
Packet switching overSONET/SDH
ATM infrastructure ontop
IP routers connected
to ATM switches
Regenerationof optical signal
Combination of
multiple signalson a path
Adding signals into
(dropping signalsfrom) a path
From B. A. Forouzan: Data Communications and Networking, 3rd ed, McGraw-Hill
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SONET/SDH Control
Three individual control planes
IP, ATM and SDH
Redundancy between IP andATM in particular
Both are packet (cell)switched networks
Routing, addressing Flow control, error control
Fragmentation and reassembly
SONET/SDH
Fiber Optics
IP
ATM
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ATM, MPLS Switching and IP Routing
Simplify by introducing yet another protocol layer!
MPLS (Multi-Protocol Label Switching)
Unites IP and ATM
Use control information from IP to set up MPLS LSPs(Label Switch Paths)
IP routing, RSVP, etc
LSP
IP pktl=xIP pkt
l=yIP pkt
l=zIP pkt
l=vIP pkt
IP pkt
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Control of SONET/SDH Networks
Replace ATM control by MPLS
SONET/SDH
Fiber Optics
ATM data plane
IP
MPLS
SONET/SDH
Fiber Optics
IP
ATM
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WDMWavelength Division
Multiplexing
Cost-efficient solution compared to SONET/SDH
Singlewavelength
Multi-wavelength
Singlewavelength
Mult iplexer Demult iplexer
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WDM System
Add/drop and cross-connectconfiguration
M u l t i p l e x e r D e m u l t i p l e x e r
Nx N
T r a n s p o n d e r s
T r a n s p o n d e r s
A d d ed w a v el en g t h s
D r o p p ed w a v el en g t h s
Transponders
Combine receive/transmit ondifferent wavelengths
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Control of WDM Networks
SDH/SONET are for setting up synchronous circuits
IP control protocols (routing protocols, RSVP, etc) are
for controlling packet switches Manual configuration and/or proprietary control
protocols for controlling WDM networks
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Enters Generalized MPLS (GMPLS)
MPLS switching generalized to control different kinds of switching
Packet switching
TDM
Time slots
TSI switches between time slots
Cross Connects (space division multiplexing)
Switches between ports (fibers)
Wavelength (lambda) switching Switches between wavelengths
IETF MPLS and CCAMP (Common Control and Measurement Plane) working groups
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GMPLS Rationale
Unified control plane for IP over optical networks
SONET/SDH
Fiber Optics
ATM data plane
IP
MPLS
Fiber Optics
IP
GMPLS
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Generalized Label Request
Generalized labels is superset of MPLS labels
Wavelength, time slot, ATM VCI/VPI, generic MPLS labels (shim),
Switching type Payload identifierLSP encoding type
Type of label
Packet
SONET/SDH
Wavelength
Swit ch capabilities
Packet switch
Time slot switch
Wavelength switch
Fiber (port) switch
Virtual Tributary
ATM
Ethernet
Type of payload
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Hierarchical LSPs
LSPs can be organized into hierarchies
From a (link state) routing point of view, each LSP is a link
Link bundling allows several LSPs with similar attributes to be treated as a single link
Fiber LSPWavelength LSP
Time slot LSP
Packet LSP
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Using IP to Control Cross Connects
BGP, RSVP, etc. are forcontrolling routers
Next hop routing based on IP
addresses
An optical cross connectswitches lightpaths, not packets
Still, it needs to appear as a
router IP addresses
Wavelengths, fibers, are links
Nx N
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GMPLS over Ethernet
MPLS treats an Ethernet as a single link
One hop in an LSP
Even if the LSP goes through multiple Ethernet switches But with GMPLS, couldnt we control Ethernet switches
as well?
In analogy with how we deal with optical switches Yes, but:
We need to decide what is a generalised label in Ethernet
Ethernet switches need to recognize and switch betweengeneralised labels
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Conclusions
Large benefit from an operational point of view if we canuse IP for controlling the network Even if it is not a packet switched network
GMPLS is emerging as an important way of controllingoptical networks from IP Requires a generalization of the label concept from MPLS to be
applicable to non-packet networks Optical switches need to appear as IP routers, even
though they do not forward IP packets
If we want to use GMPLS to control different switches,
we need to define new generalized switching models For Ethernet, for instance
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Thank You For Listening!