Transcript A study of IP Over WDM

A study of “IP Over WDM”
Partha Goswami
22/07/05
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
2
Motivation for IP over WDM
Worldwide Network Demand
•The volume of the Data traffic exceeds the
Voice traffic.
30000
25000
Gb/s
20000
Data
15000
Voice
10000
5000
0
1996
1997
1998
1999
2000
2001
2002
Year
Reference 14: Acute need to increase the data bandwidth
•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 16: Exponential Growth of Internet
3
Motivation for IP over
. WDM Continued..
Inflexibility in bandwidth granularity
Access ring
•
National Ring
ADM
Each traffic source must use a fixed
multiple of OC1 (51.84 Mbps) rate,
for example, OC-3 (155Mbps), OC12 (622Mbps), OC-48 (2.4Gbps),
and OC-192 (9.9Gbps).
SDH-DWDM
Metro ring
PBX
Regional ring
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
OLT
OLT
PBX
How present network look like.
4
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 1, Page 2
Introduction of high capacity WDM
Reference 15, Ch 2, Page 14
5
Thousand fold capacity enhancement for Submarine cable system
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)
6
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
7
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 allOptical WDM Channel called light path
•
The set of lightpath termed as Virtual topology.
•
Multihop approach
WRS
Wave length Routed Network
λ1
λ1,λ2, λ3,λ4
λ1,λ2, λ3,λ4
λ2
λ1,λ2, λ3,λ4
λ1,λ2, λ3,λ4
λ1,λ2, λ3,λ4
λ3
λ1,λ2, λ3,λ4
λ4
8
Reconfigurable Wavelength Routing node
Reference 17
IP/WDM network Model
IP NCM
WDM NCM
•
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
IP NCM
Over Lay Model
WRS
+ control
Integrated Model
Reference 18:Ch 9, Page 347-351
9
Optical Packet switching
•
Header
Sync
Header
•
Guard
Payload
Sync
Payload
Guard
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
Demux
Large gap between IP route
processing and the capacity of
WDM because of
•
•
One possibility is packet
switching in optical domain
instead of electrical domain
Mux
FDL
Synchronizer
O/E
Header
Delineation
O/E
Payload
Position
Switch
Control
Unit
Header
Recovery
•
•
•
Signal
Regenerator
Switching
Fabric
Payload
Delineation
Header
updating
Electrically Store and
forwarding technique
•
Statistical Multiplexing
Hardware cost
Premature state
Other Possible solutions in
electrical domain are
–
–
–
Fast lookup
Parallelism of the forwarding
Label switching Technique
A Generic Optical Packet switching node structure
Reference 18:Ch 9, Page 365-366
Reference 19,20
10
Optical Burst Switching
Core Router
Edge Router
Access
Network
• It Combines the advantages of
OCS and OPS
Access
Network
• No buffering and Electronic
Processing
Access
Network
λ0
Control Channel
• High bandwidth utilization
λ1
Data Channel 1
λ2
Data Channel 2
λ0
λ1
λ2
λ1
λ2
Fiber 1
λ0
λ1
FDL
λ1
FDL
λ2
λ1
λ2
λ2
FDL
Optical
Switching
Network
λ0
λ1
λ2
λ0
λ1
λ2
λ0
λ1
λ2
FDL
Fiber 2
Mux
Demux
λ0
IM
λ0
Optical Burst Switching node
Architecture
IM
Control
Burst
Processing
Routing
Table
OM
OM
Buffer
And
Scheduler
λ0
• Burst is aggregating a no of IP
datagram destined for same
egress router in the ingress
router
• Control burst and Data Burst
• Node Architecture
Reference 18:Ch 9, Page 351-355
Reference 21
11
MPLS approach in WDM network
IP network
MPLS Network
WRS
IP 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 MPλS
• MPLS approach is suitable for OBS and OPS using LOBS and LOPS
respectively
• If Label of the MPLS is mapped with λ of the WDM network, then IP-MPLS
frame work enables direct integration of IP and WDM
Reference 22,23
12
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
13
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
14
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
15
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
Reference 1, Ch 9, page 152
Ingress
LSR
Transit
LSR
Egress
LSR
The MPLS nodes
16
Label swapping and Traffic forwarding
• LSR forwarding table map the
Incoming Label and interface to
an Outgoing Label and interface.
• 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.
Reference 1, Ch 9, Page 154 and Reference 2, Ch 5, Page 151
IP L2
• An LSR may explicitly request a
Label binding for an FEC from
the next hop.
Destination Network
Source network
Label allocation and MPLS forwarding
18
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.
IP 33 34
Customer 1
IP 33 35
IP 32 34
IP 32 35
IP 31
IP
IP
Customer 2
LSR A
Customer 1
31
34
LSR B
IP 32
Assumptions:
– Customers at the same ends of the MPLS
end to end path.
– Customers have the same QOS
requirements and FEC parameters
IP 31
35
Cust 2
LSR C
IP 32
VPN
IP 33
Customer 3
When the packet arrive at the end of the VPN
backbone LSP then the LSR pops the Labels.
31
IP 33
Customer 3
Label Stacking in VPN
Reference 1, Ch 9, page 155
19
MPLS Traffic Engineering
•
It deals with Performance of network.
•
High performance required for Customer’s 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
20
Multi Protocol Lambda switching (MPλS)
•
MPλS is the framework for inter working
Optical networks and MPLS.
Label Mgt
MPLS Control Plane
•
MPLS and Optical network both have
control plane to Manage the user traffic.
LSP
Cross Connect table
λ Mgt
•
•
•
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.
Optical Control Plane
OSP
Cross Connect Table
The MPLS and Optical Control Plane
WDM
network
MPLS network
MPLS network over WDM network
Reference 1, Ch 9, page 158
22
Relationship of OXC and LSR operations
Data Transfer
Control Plane
Label Switch Router
(LSR)
Optical Cross Connect
(OXC)
Label Swapping
operation to transfer
labeled packet from an
Input port to an Output
port
Connect optical Channel
of one Input port to an
Output port
Discovery,distribute
and maintain relevant
state information
related with MPLS.
Discovery,distribute and
maintain relevant state
information related with
optical Transport
network (OTN)
Forwarding
information
Forwarding information
Label is appended with
Data Packet
Forwarding information
is implied in the data
Channel.
Storage of
switching
information
Input - output relation
is maintained in Next
hop label forwarding
entry (NHLFE)
Input - output relation is
maintained by
Wavelength forwarding
information base
Reference 1, Ch 9, page 159
Sending
Node
Receiving
Node
USER
USER
MPLS
MPLS
Optical
Optical
MPLS and Optical network Layered model
23
MPLS and MPλS Correlation
MPLS
MPλS
Map Label to
Wavelength
Key aspect
Label Value
Optical Wavelength
Ingress Node
Role of Ingress Node on
the user Traffic, termed
as Ingress LSR
MPLS Label is
correlated with
appropriate wavelength,
termed as LSR/OXC
Core node
Path
Termed as Transit LSR
Termed as Label switch
Path (LSP)
Termed as Transit PXC,
used to process the
wavelength to make the
routing decisions.
Termed as Optical
switched path(OSP)
User
Ingress
LSR/OXC
Process
λ
Transit
PXC
User
Map wavelength
to Label
Egress
LSR/OXC
Processing of user Traffic in the MPλS
Reference 1, Ch 9, page 160
24
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
25
Possibilities for the MPλS Network
•
Following work remain in Reference 4 which needs to be done to complete
the MPλS 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
26
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:
IP Control Plane
(Routing Layer)
Mapping of
IP Address
to MPLS Label
– Route discovery of IP control Plane
MPLS Control Plane
(Binding Layer)
• 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.
Reference 1, Ch 10, page 170
Data Plane
(Forwarding)
Mapping of
MPLS Label
to wavelength
Data Plane
(Forwarding)
Optical Control Plane
(λ Mapping Layer)
Data Plane
(λ Mapping Layer)
User Payload IP Header
Label
Header
Inter working of three Control Plane
27
Optical Control Plane
•
The requirement of Optical Control Plane as
specified in Reference 5
•
Permanent Optical channel setup by NMS
by network management protocol
Control
•
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
Reference 1, Ch 10, page 169 and Reference 6, Ch 14, page 427
Control
Control
Data
OXC
OXC
Optical Network Node
Optical Network Node
Optical Node Model
28
Generalized MPLS use in optical network
•
Purpose of GMPLS development: (Reference 8)
•
•
•
1.
2.
3.
4.
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.
31
Reference 1, Ch 10, page 177
Generalized MPLS use in optical network continued…
•
GMPLS = Extension of MPLS to support various
switching technology (RFC 3945)
Packet LSP
•
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 λswitching LSP over Fiber switching LSP
Reference 26, 27
Layer 2 LSP
Time slot LSP
λ- LSP
Fiber LSP
GMPLS Label stacking LSP
32
GMPLS Control Plane
• Optical network is
becoming the Transport
network for IP traffic
(IP over Optical)
Routing protocol
Resource discovery and dissemination
CSPF path computation
Wave length Assignment
• IP centric optical control
plane is the best choice
• GMPLS control plane for
Optical network contains
Routing, Signaling and
Restoration Management
Signaling
Restoration
Management
GMPLS Control Plane for Optical Network
33
Reference 6, Ch 14, page 428
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.
34
Reference 6, Ch 14, page 428-429
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
35
Wavelength Assignment
Fiber 1
• Wave length Continuity constrained for
Transparent OXC
λ1
λ2
λ3
• Opaque OXC and wave length
Conversion
λ1
λ2
λ3
Fiber 1
λ1
λ2
λ3
λ1
λ2
λ3
Fiber 2
Fiber 2
Transparent OXC
• Wave Length Assignment Problem is
constrained to the CSPF algorithm
• Wave length assignment
• At the Source
• Random wave length assignment
• Dynamic wavelength
Reservation
Reference 6, Ch14, Page 430
Reference 24,25
λ1
λ2
λ3
λ1
λ2
λ3
λ4
λ5
λ6
λ4
λ5
λ6
Fiber 1
Fiber 1
Opaque OXC
1
2
3
Light Path Demand set in a ring
36
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: 1+1 , 1:1 and M:N
• 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
37
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
DST
SRC
INT_A
INT_B
SETUP
SETUP
•
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..
SETUP
SETIP ACK
SETIP ACK
SETIP ACK
Reference 6, Ch14, Page 432-435
38
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
39
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
(CM)
Resource
Management
Module
(RMM)
Protection/
Restoration
Module
(PRM)
•Light Path Signaling
•Maintenance
•Routing and wavelength Assignment (RWA)
•Topology and Resource Discovery
•QOS support
Reference 6, Ch14, Page 461-469
Reference 28
•Survivability
•Fault Monitoring
•Fast Protection/
Restoration
42
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
IP Network
UNI
Optical
Network
•At each hop, request Message is processed
•Destination node send ACK along the same path
•If there is resource conflict NAK is sent back
Light Path ID
Status
SRC
DEST SEQ
NODE NODE NUM
ID
ID
(Creating/
Reserved/
Active/
Deleted)
QOS
Type
Input
Port
ID
Output
Port
ID
λ ID
43
Connection Module (CM) Continued……
1
Creating
Processing of Lightpath signaling
Resource Reservation/
Release
QOS = best Effort
If Assigned wavelength is available
Set the wavelength status
“ Used Preemptible”
5
4
2
6
Lightpath State Transfer
Deleted
Active
3
Determination of Input/ Output port
from the LT
NAK
Reserved
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
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”
1.
2.
3.
4.
5.
6.
Protection Path: Reservation Ack
Failure on Primary path
Tear Down abort
NAK
44
Primary Path : Setup ACK
Tear Down Abort
Resource Management Module
•
•
•
•
•
IP Network
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)
• “λi 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”
• “λi SRLG list” stores the SRLG information of
the primary path whose protection path has
reserved the wavelength (λi status = Reserved)
UNI
Optical
Network
Port
no
Peering
Node
ID
λ1 status
λ2 status
λ1 SRLG list
λ2 SRLG list
Local Resource Table (LRT)
45
…
Resource Management Module Continued….
• Each node build its own Topology
connectivity Matrix (TCM) with N
nodes.
Optical
Network
• 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
Node
1
Node
2
Node
3
Node
4
Node
5
Node
1
Node
2
Node
3
Node
4
Node
5
Node
6
Topology Connectivity Matrix 46
Node
6
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.
Connection Request
NAK/ACK
Control Plane of Node A
(MM)
(CM)
(MM)
(RMM) (PRM)
Control
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.
Control Plane of Node A
(CM)
Control
(RMM) (PRM)
Control
Data
OXC
OXC
Optical Network Node A
Optical Network Node B
47
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
48
Signaling across NNI
Reference 6, Ch14, Page 459-461
ISP
ISP
ISP
ISP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ESP
ISP
ISP
ESP
ISP
ESP
ISP
ISP
ISP
ESP
ISP
ESP
ISP
ISP
ISP
ESP
ISP
ESP
ISP
ISP
ISP
ESP
ISP
ESP
ISP
ISP
ISP
ESP
ISP
ESP
ISP
ISP
49
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.
50
References
1.
2.
Optical Networks, Third Generation Transport Systems by Uyless Black
Optical Network Control Architecture, Protocols, and Standards by Greg Bernstein
3.
Multiprotocol Lambda Switching:Combining MPLS Traffic Engineering Control with
Optical Crossconnects by Daniel Awduche, Movaz NetworksYakov Rekhter, Juniper
Networks , IEEE Communications Magazine • March 2001
4.
Multi-Protocol Lambda Switching: Combining MPLS Traffic Engineering Control With
Optical Crossconnects draft-awduche-mpls-te-optical-03.txt
5.
Considerations on the development of an Optical Control Plane, Internet Draft
Document: draft-freeland-octrl-cons-01.txt by IP-Optical Working Group
6.
IP Over WDM: Building the next Generation Optical Internet, Edited by Sudhir Dixit
7.
IP over Optical Networks: A Framework: draft-ietf-ipo-framework-00.txt by Bala
Rajagopalan
8.
Generalized MPLS - Signaling Functional Description: draft-ietf-mpls-generalized-signaling05.txt by Network Working Group
9.
OSPF Version 2: RFC 2328
51
Reference Continued….
10. OSPF Extensions in Support of Generalized MPLS: draft-ietf-ccamp-ospf-gmpls-extensions-00.txt
11. Use of OSI ISIS for Routing in TCP/IP and Dual Environments: RFC 1195
12. IS-IS Extensions in Support of Generalized MPLS: draft-ietf-isis-gmpls-extensions-04.txt
13. Link Management Protocol (LMP) : draft-ietf-ccamp-lmp-10.txt
14. http://www.cs.columbia.edu/~hgs/internet/traffic.html
15. WDM Technologies, Volume III - Optical Networks - 2004 - (By A.K.Dutta)
16. http://bgp.potaroo.net/
17. Design of Logical Topologies for Wavelength-Routed Optical Networks, Rajiv Ramaswami,
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 14, NO. 5, JUNE 1996
18. WDM Optical Networks: Concept, Design and Algorithm by C. Siva Ram Murthy
19. Transparent Optical Packet Switching: The European ACTS KEOPS Project Approach,
JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 16, NO. 12, DECEMBER 1998
20. High-capacity Multi-service optical label switching for the next generation Internet,
IEEE Optical Communications * May 2004
21. Choices, Features and Issues in Optical Burst Switching, Optical Network Magazine, Vol.1, no.2, pp 36-44, April 2000
52
Reference Continued….
22. On IP-over-WDM Integration, IEEE Communications Magazine • March 2000
23.
Labeled Optical Burst Switching for I P-over-W DM Integration, IEEE Communications Magazine
September 2000
24.
Efficient Distributed Control Protocols for WDM All-Optical Networks*Computer Communications and
Networks, 1997. Proceedings
25.
Lightpath Communications: An Approach to High Bandwidth Optical WDM’s by Imrich
Chlamtac, IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 40, NO. 7. JULY 1992
26.
Generalized Multiprotocol Label Switching: An Overview of Routing and Management
Enhancements, IEEE Communications Magazine • January 2001
27.
Generalized Multi-Protocol Label Switching (GMPLS) Architecture, RFC 3945
28.
On an IP-Centric Optical Control Plane, IEEE Communications Magazine September 2001
53