A study of IP Over WDM

1
A study of IP Over WDM

• Partha Goswami
• 22/07/05

2
Topics

• Motivations for IP over WDM
• IP Traffic Over WDM
• MPLS approch for IP over WDM
• GMPLS Control Plane
• Optical Internetworking and Signaling across
  Network Boundary

3
Motivation for IP over WDM

• The volume of the Data traffic exceeds the Voice
  traffic.
• Long Haul Optical network follows SONET/SDH
  transmission standard
• with time fame of 125 µ sec.
• Most of the data traffics are due to IP traffic
  where existing transmission technique in the
  Fiber backbone is not giving Optimal
  Multiplexing.
• Several alternative are in Consideration
• IP over Fiber
• PPP to replace SONET
• Lightweight SONET

Reference 14 Acute need to increase the data
bandwidth
Reference 16 Exponential Growth of Internet
4
.
Motivation for IP over WDM Continued..

• Inflexibility in bandwidth granularity
• Each traffic source must use a fixed multiple of
  OC1 (51.84 Mbps) rate, for example, OC-3
  (155Mbps), OC-12 (622Mbps), OC-48 (2.4Gbps), and
  OC-192 (9.9Gbps).
• High overhead
• SONET frame require a minimum of 3 overhead for
  framing, status monitoring, and management.
• Other Protocol overhead, Here
• IP Over PPP over SDH

How present network look like.
5
Motivation for IP over WDM Continued

• Advent of wavelength division multiplexing (WDM)
  technology that allows multiple wavelengths on a
  single fiber, the "IP over fiber" issue takes on
  a new dimension.
• End stations (traffic sources) and routers
  (traffic switches) have a choice of wavelengths
  on which to direct their traffic.
• High capacity of WDM and exponential growth of IP
  traffic is the perfect match of the need and
  technology

Reference 15, Ch 2, Page 14 Thousand fold
capacity enhancement for Submarine cable system
Reference 15, Ch 1, Page 2 Introduction of high
capacity WDM
6
Challenges of IP over WDM

• IP over WDM domain, attempts to address issues
  like
• Light path selection and network routing
• Support for various classes of service
• Algorithms for network restorations and
  protection scheme
• Integration with existing technology
• Standardization of Signaling and protocol
• The future optical component technology may
  allow full optical switching of IP packets.
• The Optical switching can be classified as
  follows
• Optical Circuit switching (OCS)
• Optical Burst Switching (OBS)
• Optical Packet Switching (OPS)

7
Three Generation of Digital Transport Network

• First Generation T1 , E1
• Second Generation SONET , SDH
• Third Generation Optical Transport network
• Suitable for Voice, Video, Data, QOS, BOD
• Multiplexing and Switching scheme WDM/O/O/O
• Capacity Tbps
• Payload Fixed or Variable length
• Protocol support PPP, IP, ATM, MPLS
• Commercial Availability Full feature 3rd
  Generation yet to
• arrive due to lack of mass scale commercial
  deployment O/O/O

Reference 1, Page 1-4
8
IP Traffic Over WDM network

• IP Traffic Over WDM is the Correct Choice for
  Next Generation Internet backbone.
• OCS technology is matured.
• Network node will use Wavelength Routing Switch
  and IP router.
• Nodes are connected by fiber to form physical
  topology
• Any two IP router will be connected by all-
  Optical WDM Channel called light path
• The set of lightpath termed as Virtual topology.
• Multihop approach

WRS
Wave length Routed Network
?1
?1,?2, ?3,?4
?1,?2, ?3,?4
?1,?2, ?3,?4
?1,?2, ?3,?4
?1,?2, ?3,?4
Reconfigurable Wavelength Routing node
Reference 17
9
IP/WDM network Model

• IP Routers are Network element of IP Layer
• WXC, WADM are Network element of WDM Layer
• Overlay model IP layer and optical layer are
  managed and controlled independently
• IP-NCM, WDM-NCM, UNI
• Integrated IP/WDM Functionality of both IP and
  WDM are integrated at each node.

WRS
Over Lay Model
WRS control
Reference 18Ch 9, Page 347-351
Integrated Model
10
Optical Packet switching

• Large gap between IP route processing and the
  capacity of WDM because of
• Electrically Store and forwarding technique
• One possibility is packet switching in optical
  domain instead of electrical domain
• Statistical Multiplexing
• Hardware cost
• Premature state
• Other Possible solutions in electrical domain are
• Fast lookup
• Parallelism of the forwarding
• Label switching Technique

• Format of an optical Packet
• Header encoded at lower speed
• Payload duration is fixed
• Payload Variable bit rate up to 10 Gb/s
• Header and payload at the same wavelength
• Guard time to take care of delay variation
• Sync bit used for packet synch

A Generic Optical Packet switching node structure
Reference 18Ch 9, Page 365-366 Reference 19,20
11
Optical Burst Switching

• It Combines the advantages of OCS and OPS
• No buffering and Electronic Processing
• High bandwidth utilization
• Burst is aggregating a no of IP datagram destined
  for same egress router in the ingress router
• Control burst and Data Burst
• Node Architecture

?0
Fiber 1
Optical Burst Switching node Architecture
Reference 18Ch 9, Page 351-355 Reference 21
12
MPLS approach in WDM network
MPLS Back bone for IP network
IP Over MPLS Over WDM

• MPLS is the backbone for IP network.
• MPLS approach for OCS is Known as LOCS or MP?S
• MPLS approach is suitable for OBS and OPS using
  LOBS and LOPS respectively
• If Label of the MPLS is mapped with ? of the
  WDM network, then IP-MPLS frame work enables
  direct integration of IP and WDM

Reference 22,23
13
MPLS and Optical Network

• MPLS is the key components for 3rd generation
  Transport networks.
• MPLS Architecture is defined in RFC 3031 .
• Operations of Label switch router (LSR), Label
  assignments, and Label swapping.
• What is label switching and how it is different
  than traditional internets ?
• Correlations between MPLS label value and optical
  wavelength

Reference 1, Chapter 9
14
Advantage of Label Switching

• Speed, delay and jitter Faster than traditional
  IP forwarding
• Scalability Large no IP address can be
  associated with few labels
• Resource consumption Less resource for control
  mechanism to establish Label switch Path (LSP)
• Route control More efficient route control than
  destination based routing
• Traffic Engineering Allows network provider to
  engineer the link and nodes in the network to
  support different kind of traffic considering
  different constraints.
• Labels and Lambdas Wave length can be used for
  Label and optical router capable of O/O/O can
  forward the traffic with out any processing delay

Reference 1, Ch 9
15
The forwarding Equivalence Class (FEC)

• What is FEC?
• It associates an FEC value with destination
  address and a class of traffic.
• The class of traffic is associated with a
  destination TCP/UDP port no and/or protocol ID
  field in the IP datagram header.
• Advantages of FEC
• Grouping of packet into classes
• For different FEC we can set different priorities
• Can be used for efficient QOS operation

Reference 1, Ch 9, page 151
16
Types of MPLS nodes

• Ingress LSR
• User Traffic classifies into FEC.
• It generate MPLS header and assign it an initial
  label.
• If QOS is implemented then LSR will condition the
  traffic
• Transit LSR
• Uses the MPLS header for forwarding decision
• It also performs label swapping
• Not concerned with IP header
• Egress LSR
• It removes MPLS header

The MPLS nodes
Reference 1, Ch 9, page 152
17
Label Distribution and Binding

• MPLS control plane perform the followings
• Advertising a range of Label values that that an
  LSR want to use.
• Advertising of those IP address which are
  associated with Labels
• Advertising of QOS performance parameter and
  suggested routes
• Label Distribution Protocol (LDP) developed for
  MPLS by IETF
• Constraint based LDP ( CR-LDP) is an extension of
  LDP which emulates circuit switched networks and
  also support Traffic Engineering operations.
• RSVP Path and RESV message of RSVP-TE(extension
  of RSVP) also support Label binding and
  distributions.
• Extension to BGP is also another method.
• Generalized MPLS extended the RSVP and and LDP
  for optical network.

Reference 1, Ch 9, page 153
18
Label swapping and Traffic forwarding

• LSR forwarding table map the Incoming Label and
  interface to an Outgoing Label and interface.
• An LSR may explicitly request a Label binding for
  an FEC from the next hop.
• Ingress LSR analyzes the FEC field and correlate
  the FEC with a Label, encapsulate the datagram.
• The Transit LSR process only label header based
  on the LSR forwarding table.

Destination Network
Label 3
Request
Request
Label 2
Request
Label 1
Source network
Label allocation and MPLS forwarding
Reference 1, Ch 9, Page 154 and Reference 2, Ch
5, Page 151
19
MPLS Support of Virtual Private Network

• MPLS can be used to support VPN customers with
  very simple arrangement.
• It is possible by label stacking Placing of
  more than one Label in the MPLS header.
• This concept allows certain Label to be processed
  by the node while others are ignored.
• VPN backbone can accommodate all traffic with
  one set of Labels for the LSP in the back bone.
• The customers Labels are pushed down and are not
  examined in the through the MPLS tunnel.
• When the packet arrive at the end of the VPN
  backbone LSP then the LSR pops the Labels.
• Assumptions
• Customers at the same ends of the MPLS end to end
  path.
• Customers have the same QOS requirements and FEC
  parameters

VPN
Label Stacking in VPN
Reference 1, Ch 9, page 155
20
MPLS Traffic Engineering

• It deals with Performance of network.
• High performance required for Customers QOS
  need.
• Methodologies are Measurement of Traffic and
  Control of Traffic.
• RFC 2702 specify the requirement of TE over MPLS.
• Objective of TE are Traffic Oriented and Resource
  Oriented performance enhancement.
• Traffic oriented performance objective are
  minimizing Traffic loss, minimizing delay,
  maximizing throughput and enforcement of SLAs.
• Resource oriented performance objective deals
  with Communication Links, Routers and Servers.
• Efficient management of the available bandwidth
  is the essence of TE

Reference 1, Ch 9, page 156-157
21
MPLS Traffic Engineering Continued

• TrunksAggregation of Traffic flow of the same
  class which are place inside an LSP
• MPLS TE concerns with mapping of Traffic trunk
  on to physical links of a network through Label
  switched path.
• MPLS TE is getting extended from Label switched
  path (LSP) to Optical switched path( OSP) for 3rd
  generation Transport network.
• LDP,CR-LDP, RSVP-TE and OSPF (Extension) have
  been developed to provide signaling capabilities
  for MPLS.

22
Multi Protocol Lambda switching (MP?S)

• MP?S is the framework for inter working Optical
  networks and MPLS.
• MPLS and Optical network both have control plane
  to Manage the user traffic.
• MPLS Control Plane deals with Label distribution
  and binding an end to end LSP
• Optical Control Plane deals with setting up
  wavelength, optical coding scheme (SDH/SONET),
  transfer rates, Protection switching options.
• Reference 3 and 4 discussed about adapting the
  MPLS TE Control Plane for optical Cross Connect.

The MPLS and Optical Control Plane
MPLS network over WDM network
Reference 1, Ch 9, page 158
23
Relationship of OXC and LSR operations
MPLS and Optical network Layered model
Reference 1, Ch 9, page 159
24
MPLS and MP?S Correlation
Processing of user Traffic in the MP?S
Reference 1, Ch 9, page 160
25
MPLS and Optical TE similarities

• MPLS term Traffic trunk Optical Layer Term
  Optical Channel trail
• Attributes of Traffic for MPLS TE
• Traffic Parameters Indicate BW requirement of
  traffic trunk
• Adaptive attributes Sensitivity and Possibility
  of re-routing of trunk
• Priority attribute Priority of path selection
  and path placement for trunk
• Preemption attribute Whether a traffic trunk can
  preempt an existing trunk
• Resilience attribute Survivability requirement
  of Traffic trunk
• Resource class affinity attribute Restrict route
  selection to specific subset of resources

Reference 1, Ch 9, page 162
26
Possibilities for the MP?S Network

• Following work remain in Reference 4 which
  needs to be done to complete the MP?S Network
• Concept of link bundling.
• Distribution of OTN topology , available
  bandwidth, available channels and other OTN
  topology state using extension of IS-IS or OSPF
• Exploring the possibilities of fiber termination
  in the same device which perform the role of OXC
  and IP router.
• Uniform Control Plane for LSR and PXC as close
  interaction are needed between Control and Data
  plane for the interwork of Label and wavelength.
• How to increase the utilization of the optical
  Channel trail in case traffic in the LSP mapped
  with Optical channel is low.

Reference 1, Ch 9, page 163-165
27
IP, MPLS and Optical Control Plane

• 3rd Generation transport networks encompasses
  three Control plane.
• All the above control plane need to be
  coordinated to take the benefit of the
  followings
• Route discovery of IP control Plane
• Routing protocol advertises and discover address
  as well as routes
• Traffic Engineering capability of MPLS control
  plane
• MPLS Label distribution protocol will bind the IP
  address with Label
• Forwarding speed of optical data plane
• MPLS Label will be mapped with wavelength
• Optical node can perform PXC based O/O/O
  operation
• O/E/O based Label label swapping will not be
  needed.
• Ideally same wavelength can be used on each OSP
  segment.

Inter working of three Control Plane
Reference 1, Ch 10, page 170
28
Optical Control Plane

• The requirement of Optical Control Plane as
  specified in Reference 5
• Permanent Optical channel setup by NMS by network
  management protocol
• Soft permanent optical channel by NMS using
  network generated signaling and routing protocol
• Switched Optical Channel which can be setup by
  customer on demand using signaling and Routing
  protocol
• The Optical Node consist of OXC and Optical
  network control plane
• Between two neighboring node there is pre
  configured control channel which may In band
  or Out of band.
• Switching function is done by OXC but it is
• based on how cross connect table is configured

Optical Node Model
Reference 1, Ch 10, page 169 and Reference 6, Ch
14, page 427
29
A Frame work for IP Over Optical

• Optical network control plane should utilize IP
  based protocol for dynamic provisioning and
  restoration of light path with in and across
  Optical sub-network
• Two general model discussed in Reference 7.
• Unified Service model
• IP and Optical Network are treated as a single
  integrated network from a control plane view.
• Edge router can create a lightpath with specified
  attributes, or delete and modify lightpath
• When a router are attached to a single optical
  network. A remote router could compute an end to
  end path across the optical internetwork.
• Once lightpath is established forwarding
  adjacency between the router is developed.
• Domain Services model
• Standardized signaling like RSVP-TE or LDP across
  the UNI is used
• for the following four services LightPath
  creation, Lightpath deletion, Lightpath
  modification and Lightpath status enquiry
• The protocol for neighbor and service discovery
  are separate like LMP

Reference 1, Ch 10, page 173-174
30
Interconnections for IP over Optical

• Transport of IP datagram over optical network
• Peer model
• Single control plane runs over over both IP and
  Optical domain
• Common routing protocol like OSPF or IS-IS with
  appropriate extension can be used for the
  distribution of topology information
• Opaque LSA for OSPF and Extended TLV for IS-IS
  can be used.
• Overlay model
• Supported by Optical domain service interconnect
  (ODSI)
• IP domain routing, topology distribution and
  signaling protocol are independent of Optical
  domain routing, topology distribution and
  signaling protocol
• Interconnection between signaling and routing are
  accomplished UNI defined procedures.
• Augmented model
• Separate routing instances in the IP and Optical
  domains but information from one routing
  instances is passed through the other routing
  instances.

Reference 1, Ch 10, page 175
31
Generalized MPLS use in optical network

• Purpose of GMPLS development (Reference 8)
• To support MPLS operation in optical network with
  ability to use the optical technologies as
• Time division ( SONET ADM)
• Wavelength
• Spatial switching( Incoming Fiber to out going
  fiber)
• GMPLS assume that forwarding decision based on
  time slot , wavelength and physical ports.
• GMPLS Terminology
• Packet switch capable (PXC) Process traffic
  based on packet/cell/frame boundaries
• Time division Multiplex capable (TDM) Process
  Traffic based on a TDM boundary,
  
  such as SONET/SDH node.
• Lambda-switch capable (LSC) Process traffic
  based on the Optical wavelength
• Fiber switch capable (FSC) Process traffic based
  on the physical interface.

Reference 1, Ch 10, page 177
32
Generalized MPLS use in optical network continued

• GMPLS Extension of MPLS to support various
  switching technology (RFC 3945)
• Following switching technology is considered
• Packet switching Forwarding capability packet
  based, IP Router
• Layer2 switching Forwarding data on cell or
  frame Ethernet, ATM
• TDM or Time slot switching Forwarding data based
  on time slot SONET,DCS, ADM
• Lambda switching Performed by OXC
• Fiber switching Performed by Fiber switch
  capable OXC
• GMPLS control plane focus on full range of
  switching technology
• Natural Hierarchy of Label stacking in GMPLS
• Packet LSP over Layer 2 LSP over over Time slot
  LSP over ?-switching LSP over Fiber switching LSP

Packet LSP
Layer 2 LSP
Time slot LSP
?- LSP
Fiber LSP
GMPLS Label stacking LSP
Reference 26, 27
33
GMPLS Control Plane

• Optical network is becoming the Transport network
  for IP traffic
• (IP over Optical)
• IP centric optical control plane is the best
  choice
• GMPLS control plane for Optical network contains
  Routing, Signaling and Restoration Management

GMPLS Control Plane for Optical Network
Reference 6, Ch 14, page 428
34
Resource Discovery and Link-state Information
Dissemination

• Each Optical node need to know the Global
  topology and resource information, which is
  possible by broadcasting local resource use and
• neighbor connectivity information by each
  optical node.
• It can be done the OSPF (Reference 9) and its
  extension ( Reference 10)
• It can also be done by IS-IS (Reference 11) and
  its extension (Reference 12)
• Here neighbor discover require inband
  communication which is possible for
• Opaque OXC with SONET termination.
• For Transparent OXC neighbor discovery generally
  utilizes a separate protocol such as Link
  management protocol ( Reference 13)
• Issues Scalability problem for link addressing
  and Link state advertisement
• Solutions
• Unnumbered links Globally unique end node ID (
  LSR ID) plus local selector ID
• Link Bundling The link attribute of multiple
  wavelength channel of similar characteristics can
  aggregated.

Reference 6, Ch 14, page 428-429
35
CSPF Path computation

• CSPF SPF resource constraint policy
  constraint To achieve the MPLS TE objective
  RFC 2702
• Such path computation is NP complete and
  Heurestic have to be used.
• The objective of path computation in optical
  network is to minimize the resource required for
  routing light paths for a given SLA.
• For optical network CSPF algorithm needs to be
  modified for the following reason
• Link Bundling and Restoration Path Computation
• The Solution is Shared Risk Link Group (SRLG)
  Administrative group associated with some optical
  Resources that probably share common
  vulnerability to a Single Failure.
• Example Fiber in the same conduit can be
  assigned with one SRLG

36
Wavelength Assignment
Fiber 1
?1 ?2 ?3

• Wave length Continuity constrained for
  Transparent OXC
• Opaque OXC and wave length Conversion
• Wave Length Assignment Problem is constrained to
  the CSPF algorithm
• Wave length assignment
• At the Source
• Random wave length assignment
• Dynamic wavelength Reservation

1
Reference 6, Ch14, Page 430 Reference 24,25
3
2
Light Path Demand set in a ring
37
Restoration Management

• Difference between Optical Layer protection with
  IP layer MPLS Layer.
• Management and co-ordination among multiple layer
  is an important issue.
• Optical Protection mechanism can be classified as
  follows
• Path Protection
• Link Protection
• Path Protection classified as follows
• Disjoint Path Protection 11 , 11 and MN
• Link-dependent Path protection
• Restoration Management Failure detection,
  Failure notification and Failure restoration.
• Detection by lower layer impairments, higher
  layer link probing.
• Time for restoration is due to restoration path
  computation and traffic rerouting from primary
  path to restoration path

Reference 6, Ch14, Page 431
38
Signaling

• Signaling is distributed path establishment
  operation across Optical network
• Major Operation of Light Path signaling are
  Light Path setup, Teardown and Abort
• Light Path Setup SETUP, SETUP ACK, SETUP NAK
• Light Path commitment Phase ABORT
• Light Path Teardown TEARDOWN and TEARDOWN ACK
• Addressing Issue due to High no of entity in
  Optical network Unique IP to OXC and other
  resources through Selector
• Each node will Maintain a Light Path table
• to record the Lightpath ID, Incoming/ Out going
  Port no, SRLG so on..

DST
INT_A
INT_B
SRC
SETUP
SETUP
SETUP
SETIP ACK
Time
SETIP ACK
SETIP ACK
Reference 6, Ch14, Page 432-435
39
GMPLS Signaling Functional Requirements

• Same switching functionality for both end LSR
• GMPLS extends MPLS Signaling in many aspect
• Generalized label is defined with enough
  flexibility to represent Label for different
  switching type.
• Label suggestion capability by the upstream node
  will reduce the LSP setup delay.
• Label set Upstream restrict the label selection
  of the down stream to acceptable limit.
• GMPLS support Bi-directional LSP setup.
• Explicit Label label selection offers capability
  of explicit label selection on a specific on an
  explicit route
• GMPLS data channel and control channel may be
  separate.
• GMPLS signaling for fault handling should
  minimize the packet loss.

Reference 6, Ch14, Page 435-436
40
GMPLS Traffic Engineering Extension

• MPLS-TE has two metrics
• Regular link metric used in traditional IP
  routing
• Traffic Engineering link metric used for
  constrained based routing
• GMPLS Traffic Engineering Link is Logical Link
  with Traffic Engineering properties.
• The Management of Traffic Engineering link is
  conducted by LMP
• For GMPLS LSP may be taken as TE link but routing
  adjacency need not to be established directly
  between the two end node of the LSP
• For GMPLS link bundle can be advertised as TE
  link

Reference 6, Ch14, Page 436
41
GMPLS Adjacencies

• Three types of adjacencies
• Routing Neighbors of the routing protocol
• Signaling Peering relationship of two nodes
  established by signaling
• ForwardingTE link that transit three or more
  GMPLS nodes in the same instance.
• If Signaling adjacency is established over TE
  link then TE link is used as tunnel to establish
  LSP over it.

Reference 6, Ch14, Page 436-437
42
IP Centric Control Plane
Receive incoming message Process the request with
the help of other module Initializing the control
Plane
IP Network
UNI
Optical Network
Main Module
(MM)
Connection Module
Resource Management Module (RMM)
Protection/ Restoration Module (PRM)
(CM)

• Light Path Signaling
• Maintenance

• Survivability
• Fault Monitoring
• Fast Protection/
• Restoration

• Routing and wavelength Assignment (RWA)
• Topology and Resource Discovery
• QOS support

Reference 6, Ch14, Page 461-469 Reference 28
43
Connection Module (CM)

• Connection Request Message Contents
• Light Path ID
• Light Path Type (Primary/ Protection)
• Routing Path
• Assigned wave Length
• QOS type
• SRLG list of Primary Path
• At each hop, request Message is processed
• Destination node send ACK along the same path
• If there is resource conflict NAK is sent back

LightPath Table
44
Connection Module (CM) Continued
Reserved
1
Creating
5
Processing of Lightpath signaling
2
4
6
Deleted
Resource Reservation/ Release
Active
Lightpath State Transfer
3
Determination of Input/ Output port from the LT
QOS Protection Sensitive If it is Primary
Path and wavelength status available change
the status to Used Preemptible If it is
Protection LightPath and wavelength status
available Set the status to Reserved Else
Check the SRLG list
NAK
If Assigned wavelength is available Set the
wavelength status Used Preemptible
QOS best Effort
QOS Mission Critical If Assigned Wavelength is
available Change the status to to Used and
Non-perrmptible Else abort the existing
lightpath on this wavelength. Then Change the
status to to Used and Non-perrmptible

• Protection Path Reservation Ack
• Failure on Primary path
• Tear Down abort
• NAK
• Primary Path Setup ACK
• Tear Down Abort

45
Resource Management Module

• Functionality Resource Discovery, Maintenance,
  QOS support, RWA
• Neighbor discovery mechanism by sending Hello
  Message on all out going link.
• Local Connectivity Vector (LCV) Store the cost
  of the Adjacent Node.
• If LCV is updated , it is broadcasted to the
  network
• Local resource availability stored in Local
  Resource Table (LRT)
• ?i status indicate state of ith wavelength in
  the fiber attached to the port
• Possible states are used and preemptable ,
  used and non-preemptable , Reserved,
  Available and Faulty
• ?i SRLG list stores the SRLG information of
  the primary path whose protection path has
  reserved the wavelength (?i status Reserved)

IP Network
UNI
Optical Network
Local Resource Table (LRT)
46
Resource Management Module Continued.

• Each node build its own Topology connectivity
  Matrix (TCM) with N nodes.
• Each row of TCM is the LCV of the node I plus a
  time stamp.
• RMM also maintain a Global Resource Table (GRT)
  consisting of LRT of all nodes.
• RMM utilize different RWA algorithm to support
  QOS.
• QOS support
• Best-effort service
• Mission critical service
• Protection Sensitive Matrix

Topology Connectivity Matrix
47
Protection and Restoration Module

• Functions Setup Co-ordination of Primary and
  protection Light Path, Fault detection,
• and notification.
• Fault can be detected by as follows
• Low level impairments
• Higher layer link probing
• Failure can happen for Control Plane or OXC.
• Failure indication Signal (FIS) send to the
  source node.
• If Qos requirement is Restoration the restoration
  Path will be calculated.
• If Qos requirement is Protection then source node
  will invoke the setup signal for the Lightpath
  previously reserved.
• For Mission critical destination node detect the
  failure of the primary Lightpath and turn to
  protection path.

Connection Request
NAK/ACK
Control Plane of Node A
Control Plane of Node A
Control
Data
Optical Network Node B
Optical Network Node A
48
Optical Internetworking and Signaling across
Network Boundary

• Need for Inter-domain Optical network
• Need for standard
• Addressing scheme to identify light path end
  points
• Routing Protocol
• Standard signaling protocol across Network to
  Network interface
• Restoration procedure
• Policies that affect the flow of Control
  Information
• Solution is by implementing
• External Signaling Protocol (ESP) Used for
  Signaling across NNI
• Internal Signaling protocol( ISP) May be
  different for different network
• Possibility of BGP extension is being studied for
  Routing .
• Possibility of CR-LDP or RSVP-TE extension is
  being studied for Signaling across the network
  boundary.

NNI
NNI
49
Signaling across NNI
Reference 6, Ch14, Page 459-461
ISP
ISP
50
Conclusion

• Development and implementation of GMPSL over the
  existing technology can only bring the reality of
  IP over WDM
• Performance of GMPLS in the hybrid scenario
  should be simulated.

51
References

• Optical Networks, Third Generation Transport
  Systems by Uyless Black
• 2. Optical Network Control Architecture,
  Protocols, and Standards by Greg Bernstein
• Multiprotocol Lambda SwitchingCombining MPLS
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• 5. Considerations on the development of an
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• Document draft-freeland-octrl-cons-01.txt by
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• OSPF Version 2 RFC 2328

52
Reference Continued.

• 10. OSPF Extensions in Support of Generalized
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• 11. Use of OSI ISIS for Routing in TCP/IP and
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• 13. Link Management Protocol (LMP)
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53
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• 22. On IP-over-WDM Integration, IEEE
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• Generalized Multiprotocol Label Switching An
  Overview of Routing and Management Enhancements,
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• Generalized Multi-Protocol Label Switching
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• On an IP-Centric Optical Control Plane, IEEE
  Communications Magazine September 2001
•  
•  
•