Performance Evaluation of Optical Label Switched Path Routing
Automatically Switched Optical Network
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Transcript of Automatically Switched Optical Network
Automatic Switched Optical Network
2nd WDM Hungarian Workshop Budapest, March 27th 2001
Automatic Switched Optical Networks: functionality and architectural components
Roberto ClementeGiuseppe Ferraris
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Optical transport network evolution
è Transparent transport of different optical clientsè Interconnection of different administrative domainsèOptical channel networking and protectionèPerformance monitoring and alarm supervisionèNetwork management
OTNOTNWDMWDM
Main functionality provided by an OTN
Point-to-point systems
yesterdayyesterday
Pre-OTN: OADM ring and point-to-point
systems
todaytoday
Meshed/ring networksInterconnection of
OTN domains
tomorrowtomorrow
Introduction
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
New requirements for OTN4Fast and automatic end-to-end provisioning4Fast and efficient re-routing4Support of different clients, but optimized for IP4Dynamic set up of connections4Support of Optical Virtual Private Networks (OVPNs)4Support of different levels of quality of service
Automatically Switched Optical Network (ASON)Automatically Switched Optical Network (ASON)More generally, the same requirements can be
applied to any transport network (SDH too)Automatically Switched Transport Networks (ASTN)Automatically Switched Transport Networks (ASTN)
Introduction
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
An example of SLAWhy ASON?
4 I need to permanently connect my sites (“always on” connection)…
4 I need other connections based on my traffic demands (per usage connections…)
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Optical Transport Network
Node ANode B
Node C
“Always on” connectionsPermanent connections
Client equipment are connected to the transport network
The transport network operator sets up the “always on” connections
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Without ASON, when traffic grows…Why ASON?
Optical Transport Network
Node ANode B
Node C
WarningToo many packets to
node B
Traffic Traffic grows…grows…
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…the customer analyses traffic reports…
Why ASON?
Optical Transport Network
Node ANode B
Node C
A new connection to B is needed
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…he contacts the network provider…Why ASON?
Optical Transport Network
Node ANode B
Node C
Connect ports Am and Bn A customer request…
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…the job order moves on…Why ASON?
Optical Transport Network
Node ANode B
Node C
Connect ports Am and Bn
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…the operator looks for a route…Why ASON?
Optical Transport Network
Node ANode B
Node C
What route?
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Why ASON?
Node ANode B
Node C
…the operator looks for a route…What route?
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Why ASON?
Node ANode B
Node C
…the route is found
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…the route is found and the network is re-configured…
Why ASON?
Node ANode B
Node C
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…the new connection is operational!Why ASON?
Optical Transport Network
Node ANode B
Node C
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Node ANode B
Node C
With ASON…Why ASON?
Signaling between transport equipment for network discovery
Each network element knows the network topology
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…when traffic grows…Why ASON?
Optical Transport Network
Node ANode B
Node C
WarningToo many packets to
node B
Traffic Traffic grows…grows…
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…connection-request through the UNI…Why ASON?
Optical Transport Network
Node ANode B
Node C
Connection set up request (A,2,B,4…)
User NetworkInterface
The client equipment request the establishment
of a new connection…
The client equipment request the establishment
of a new connection…
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…connection-request is sent…Why ASON?
Node ANode B
Node C
Connection set up request (W,i,X,j,Y,k,…)
…and sends a connection setup request…
…and sends a connection setup request…
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…setup request is acknowledged…Why ASON?
Node ANode B
Node C
Setup acknowledgment (W,i,X,j,Y,k,…)
…each switching matrix is configured and the
connection is established
…each switching matrix is configured and the
connection is established
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
…the new connection is established!Why ASON?
Optical Transport Network
Node ANode B
Node C
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Generic requirements for an ASON
4Dynamic and fast provisioning of OCh connections through the optical network
4Different OCh services with different quality degrees
4Client-independent solution4Automate the rules of enforcing SLA
Generic requirements
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Two alternative approaches for switched OChs
44Client server (overlay) modelClient server (overlay) modelThe client network (IP, ATM, …) or customer device requests resources (OCh connections) to the optical network (server), but has no knowledge about its internal structure
l ITU G.ASON “Automatic Switched Optical Network”l OIFl ODSIl IETF G-MPLS “Generalized Multi Protocol Label Switching”
44PeerPeer--toto--peer modelpeer modelThe client is only IP and the control plane of the optical network is integrated with the IP control plane
l IETF G-MPLS “Generalized Multi Protocol Label Switching”
Alternative approaches
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
ASON architecture (logical view)
Optical switch
Transport plane
PI
OCC Control plane
NNI
CCI
Client equipment (IP router, ATM switch, …)
OCC
Optical switch
PI
UNI
NMI-T
NMI-A
Optical switch
OCC
EM/NM
Management plane
CCI: Connection Control InterfaceNMI-A: Network Management Interface for the ASON Control PlaneNMI-T: Network Management Interface for the Transport NetworkNNI: Network to Network Interface
OCC: Optical Connection ControllerPI: Physical InterfaceUNI: User to Network Interface
ASON is an Optical Transport Network (OTN) capable to ASON is an Optical Transport Network (OTN) capable to switch automatically Optical Channelsswitch automatically Optical Channels
General architecture
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Supported optical transport services
44Permanent Permanent OChOCh – setup from the management system by means of the configuration of all the involved equipment (possible today)
44Soft permanentSoft permanent OChOCh – setup from the management system using routing capability embedded in the network; it requires routing and signaling at the NNI to establish connections
44Switched Switched OChOCh – setup by the customer/client layer using signaling at the UNI
44Optical Virtual Private NetworkOptical Virtual Private Network44Lambda Lambda TrunkingTrunking
Optical transport services
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Control plane
4It carries signaling messages4It represents the transport infrastructure for
control traffic 4It can be either in-band or out-of-band4Its topology can be different from the transport
network topology
Internet developed protocols seem to be the most likely candidates to accomplish the functions
needed to automate the OTNFASHION still have a short look at other protocols
as well (e.g. PNNI)
Control plane
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Basic functionality
4Network topology discovery (resource discovery)
4Signaling, routing, address assignment4Connection set-up/tear-down4Connection protection/restoration4Traffic engineering4Wavelength assignment
Functionality
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Network topology discovery
4Control plane topology (signaling or control channel network) and transport network topology can be different
4ASON requires both logical and physical topology information
4The discovery can be done by using currently available IP protocols, like OSPF or MPLS, with some extensions
Topology discovery
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Network topology discovery (II)
4Physical topology information refers toèNode addressèPort number (or address)èPort connectivity (to both
end devices and neighbor nodes)
è Inside node interconnection scheme
èNumber of portsèBandwidth of each portèLink ID, fiber ID, trunk IDèTrench IDèGrooming channel ID
4Logical topology information refers toèEnd-to-end path
information like working paths, protection/ /restoration paths
èOptical VPNè Information related to TE
(attributes TE) like available bandwidth, quality of service, policy routing information, …
Topology discovery
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Switched OCh Resilience
44ProtectionProtection – resources for an alternative route are reserved before a failure occurs
44RestorationRestoration – resources for an alternative route are not reserved before a failure occurs and are found after a failure has occurred (automatic re-rerouting)
Resilience
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Basic operations
44SetSet--up up OChsOChs44Modify Modify OChsOChs44Release Release OChsOChs
Connection provisioning
4Example of parameters associated to the set-up OChs operationèEnd pointsèScheduled serviceèScheduled durationèResilienceèPre-emption (priority)
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Provisioning options
4Slow vs. fast4On-demand vs. pre-ordered4Guaranteed vs. best-effort
Connection provisioning
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Routing and signaling
Internet developed protocols seem to be the most likely candidates
4Routing protocols based on OSPF (or perhaps IS-IS)
4Constraint-based routing4Signaling protocols based on MPLS (LDP, CR-
LDP, RSVP)
Routing and signaling
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Several open issues are addressed
4Adaptation of IP developed protocol to ASON
4Transparency (wavelength conversion, monitoring, management, …)
4Sub-rate bandwidth provisioning and traffic aggregation
4Traffic engineering
Open issues under study
2nd WDM Hungarian Workshop Budapest, March 27th 2001 [email protected]
Conclusions
4ASON is client independent and it has its own control plane
4All the information required by the client layer are exchanged through the signaling at the UNI
4The signaling and routing protocols allow fast and automatic configuration of the network for provisioning and re-routing purposes
Conclusions