HUAWEI OptiX OSN 8800 T64/T32 Intelligent Optical Transport Platform. Product Description - part 25
Figure 7-1 Huawei ASON model
Network management
system
Contol plane supported by
OptiX GCP/GSP software
ASON composed
of OSN series
equipment
Currently, Huawei can provide the integral ASON metropolitan transport solution formed by
the OptiX OSN 8800 and OptiX OSN 6800, as shown in the Figure 7-2. The mesh network can
be used in the short long-haul to perform the flexible service grooming. For the ASON products
for different layers, refer to the Table 7-1.
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Figure 7-2 ASON metropolitan solution (OTN networking)
Area
backbones
OptiX OSN 8800 T64
OptiX OSN 8800 T32
Short long-hual
OptiX OSN 8800 T16
OptiX OSN 6800
Local networks and
metropolitan core layers
ASON NE
Internet data center
Multi-tenant building
Enterprise
Banks and financial institutions
Intelligent residential community
Table 7-1 ASON WDM NE in the OptiX OSN series products
ASON NE
Remarks
OptiX OSN 8800 T64 and
ASON NE in short long-haul
OptiX OSN 8800 T32
OptiX OSN 8800 T16 and
ASON NE in local network and metropolitan core layers
OptiX OSN 6800
NOTE
In the actual networking of the ASON WDM series products, the reconfigurable optical add/drop
multiplexer board (such as ROAM, WSMD2, RMU9, WSD9, WSM9, WSMD9 and WSMD4) needs to
be configured to implement the automatic rerouting and restoration of WDM ASON OCh trail.
7.1.4 Huawei OCS ASON Solution
Huawei provides detailed OCS ASON solutions for different layers.
The OCS ASON solution provided by Huawei involves the following products:
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l Control plane software: OptiX GSP
l Network management software: iManager U2000
l Equipment on the transport plane: OptiX OSN series equipment
Figure 7-3 illustrates the relation among them.
Figure 7-3 Huawei ASON model
Network management
system
Contol plane supported by
OptiX GCP/GSP software
ASON composed
of OSN series
equipment
The OptiX OSN 8800 can be networked with the NG SDH/PTN equipment or data
communication equipment to provide a complete transport solution. This solution is mainly
applied to OCS networking, as shown in Figure 7-4.
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Figure 7-4 ASON transport solution (OCS networking)
OptiX OSN 9500
OptiX OSN 8800
OptiX OSN 9500
Backbone layer
OptiX OSN 3500
OptiX OSN 3500
Convergence layer
OptiX OSN 1500
OptiX OSN 2500
Access layer
GSM/CDMA/
PSTN
Ethernet . . .
ATM
DDN
WCDMA
Table 7-2 OptiX OSN series products
ASON NE
Applied at
OptiX OSN 8800
Backbone layer
OptiX OSN 9500
Backbone layer
OptiX OSN 7500
Backbone layer
OptiX OSN 3500
Convergence layer
OptiX OSN 3500 II
Convergence layer
OptiX OSN 2500
Access layer
OptiX OSN 1500
Access layer
7.1.5 Introduction and Development of the OTN ASON
The concepts and standards of the ASON appear on the premise that the traditional SDH
transmission system is widely used. The reasonable introduction schemes are necessary.
Introduction Scheme
Two basic introduction schemes are described as follows.
l To create an ASON network:
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When the backbone network and MAN need to expand the capacity, you can consider
creating the ASON network.
l To upgrade a traditional WDM network to an ASON network:
If Huawei OptiX OSN series products are deployed in existing network, new software can
be loaded to upgrade the network to an ASON network. If NEs on the existing network can
be used to deploy ASON features, this scheme does not require new equipment and the
network can be smoothly upgraded. If NEs on the existing network cannot be used to deploy
ASON features, the network needs to be reconstructed and then upgraded.
Interconnection between ASON and WDM networks
A great number of WDM networks are currently in service. Hence, for the development of the
ASON, the interconnection between ASON and WDM networks becomes a key factor.
The ASON and WDM networks share the same service granularities, such as ODU2, and ODU1.
Hence, the interconnection between ASON and WDM networks is not a problem from the
viewpoint of service.
The ASON and WDM networks can be uniformly managed only if the equipment in the network
is the Huawei OptiX series equipment.
7.1.6 Introduction and Development of the OCS ASON
The concepts and standards of the ASON appears on the premise that the SDH fiber transmission
system is widely used. The reasonable introduction schemes and development schemes are
necessary. As the ASON concepts and standards continue to develop, and as considerable SDH
fiber transmission systems already exist, the introduction schemes and development schemes
become very important.
Introduction Scheme
Two basic introduction schemes are described as follows.
l To create an ASON network:
When the backbone network and MAN need to expand the capacity, you can consider
creating the ASON network.
l To upgrade a traditional SDH network to an ASON network:
If Huawei OptiX OSN series products are deployed in existing network, new software can
be loaded to upgrade the network to an ASON network. If NEs on the existing network can
be used to deploy ASON features, this scheme does not require new equipment and the
network can be smoothly upgraded. If NEs on the existing network cannot be used to deploy
ASON features, the network needs to be reconstructed and then upgraded.
Interconnection between ASON and SDH
A great number of SDH networks are currently in service. Hence, for the development of the
ASON, the interconnection between ASON and SDH networks becomes a key factor.
The ASON and SDH networks share the same service granularities such as VC-4, VC-3 and
VC-12. Hence, the interconnection between ASON and SDH networks is not a problem from
the viewpoint of service.
The ASON and SDH networks can be uniformly managed only if the equipment in the network
is the Huawei OptiX series equipment.
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7.2 ASON Software and ASON Functions
Huawei provides the software on the ASON control plane, which implements the functions such
as network callings and connections and dynamic control of the transport plane through signaling
switching.
7.2.1 Basic Concepts of ASON
The basic concepts related to the ASON are the label switched path (LSP) and rerouting.
ASON
ASON is a new generation optical network that has the following features:
l Customers launch a service request dynamically.
l Routes are selected automatically.
l Signaling controls the creation and removal of connections.
l Network connections are automatically and dynamically completed.
l Switching and transmission are integrated into one system.
LSP
Label switched path (LSP) is the path ASON services pass through. In an ASON, to create ASON
services is to create LSPs. On U2000, LSP is also called ASON Trail.
WDM ASON Trail
WDM ASON Trail is classified into WDM ASON OCh Trail and WDM ASON ODUk Trail.
See Figure 7-5.
l The WDM ASON OCh trail can be created when there are sufficient OCh TE link resources.
l The WDM ASON ODUk trail can be created when there are sufficient TE link resources
where the payload type is ODUk.
Figure 7-5 WDM ASON Trail
ODUk trail
OCh trail
OTU
OM
OA
OA
OD
OTU
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NOTE
The OptiX OSN 8800 does not support the WDM ASON client route.
Rerouting
Rerouting is a means of resuming services. For a non-revertive service, when an LSP is
disconnected, the source node queries and finds the best route to resume services. Then, the
initial node creates a new LSP to transmit the service. After creating a new LSP, the source node
deletes the original LSP.
NOTE
After a revertive service is rerouted, the original LSP is not deleted.
NOTE
For more information on service restoration, refer to 7.2.10 ASON Network Protection and
Restoration.
Rerouting Lockout
In some cases, rerouting is not required after failure of LSP. Then you need to set rerouting
lockout.
Rerouting Policy
Diamond and silver services all support the several rerouting polices. You can flexibly choose
a rerouting policy and properly use network resources according to different network conditions.
l Overlapping policy
During rerouting, the route of the new LSP overlaps the original route whenever possible.
This policy helps save network resources. When bandwidth resources are insufficient, the
service gets more chances to reroute successfully.
l Separating policy
During rerouting, the route of the new LSP is separated from the original route whenever
possible. This policy is applicable to a network with sufficient link resources.
l Best route policy
During rerouting, the best route is computed for the new LSP. Whether the new or old route
resources are utilized again is not considered. This policy chooses a route with the minimum
cost as the new route after rerouting according to network conditions.
l Simulated span restoration policy
During rerouting, the services must reuse the original routes without involving faulty spans.
End-to-end rerouting is enabled only when rerouting on the faulty spans fails, and thus
service route can be controlled and managed more easily.
NOTE
The rerouting policy can be set on the U2000 according to actual conditions.
7.2.2 Structure of the ASON Transmission Network
the ASON has three planes: the control plane, the transport plane, and the management plane.
The most outstanding feature of the ASON compared with the traditional optical network lies
in the introduction of an independent control plane to the transport network. The control plane
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brings the revolutionary change to the entire optical network and enables the latter to have the
ability to automatically implement network bandwidth allocation and dynamically configure
trails.
Functions of the three planes of the ASON are as follows:
l Control plane
The control plane mainly controls callings and connections of the network and dynamically
controls the transport plane through signaling exchange (involving setup, release,
monitoring, and maintenance of connections, and provision of protection restoration in case
of a connection failure).
l Transport plane
The traditional WDM network is the transport plane. It transmits optical signals, configures
cross-connection and protection switching for optical signals, and guarantees the reliability
of all optical signals. The switching operations on the transport plane are performed under
the control of the management plane and control plane.
l Management plane
The management plane is a complement to the control plane. It maintains the transport
plane, the control plane and the entire system. On this plane, the end-to-end configuration
can be supported. Its functions include performance management, fault management,
configuration management and security management. The functions of the management
plane are coordinated with the functions of the control plane and transport plane.
As shown in Figure 7-6, the three planes are independent but they interact with each other
through interfaces and defined functions. The management plane communicates with the control
plane and the transport plane through network management interfaces (NMIs). The control plane
communicates with the transport plane through connection control interfaces (CCIs).
Figure 7-6 Three planes of the ASON
NMI
Control plane
Management
CCI
plane
NMI
Transmission plane
7.2.3 Location of ASON Software
The ASON software is included in the NE software.
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Figure 7-7 shows where ASON software is located in the whole product software system. The
ASON software and NE software run on the SCC board, whereas the board software and network
management (NM) software run on the boards and NM computer respectively, to implement
corresponding functions. The structure of the software for all the OptiX OSN series products is
the same. You can upgrade traditional versions to ASON by loading the NE software that
contains ASON software. Some boards should be upgraded.
Figure 7-7 Software structure of the OptiX OSN series
NM software
NE software
ASON software
Board software
7.2.4 Structure of ASON Software
The ASON software is formed by several modules. Each module implements different functions.
According to ITU-T recommendations, ASON has three planes: a control plane, a management
plane, and a transport plane. The management plane refers to the NM layer, and the transport
plane refers to the WDM network. ASON software is used in the control plane, using LMP,
OSPF-TE, and RSVP-TE.
Table 7-3 Acronyms and abbreviations
Acronym
Full Spelling
RSVP-TE
Resource Reservation Protocol-Traffic Engineering
OSPF-TE
Open Shortest Path First-Traffic Engineering
LMP
Link Management Protocol
CSPF
Constrained Shortest Path First
Figure 7-8 shows the structure of the ASON software, which consists of a signaling module, a
routing module and a cross-connection management module.
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Figure 7-8 Structure of ASON software
ASON software
NMS
Signaling
module
NE
Cross-connection
software
management
module
Routing module
Link management module
Link Management Module
The link management module uses the LMP protocol to perform the following functions.
l Creates and maintains the control channels
l Checks component links and TE links
Signaling Module
The signaling module uses the RSVP-TE protocol to create or remove services according to the
requests from users, and synchronizes and restores services as needed.
Routing Module
The routing module uses the OSPF-TE protocol to perform the following functions.
l Collects and floods TE link information.
l Collects and floods control link information.
l Calculates control route.
The routing module mainly uses the CSPF protocol to perform the following function:
Compute service routes based on information about network-wide TE links
Cross-connection Management Module
The cross-connection management module performs the following functions.
l Creates/Deletes cross-connections.
l Reports link state and alarms.
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7.2.5 ASON Protocol
Huawei ASON applies the link management protocol (LMP) as the link management protocol,
OSPF-TE as the routing protocol, and RSVP-TE as the signaling protocol.
The following sections describe the functions of these protocols in an ASON network.
LMP
The LMP performs the following functions in an ASON network.
l Creating and maintaining the control channels between adjacent nodes.
The following is the procedure of creating control channels.
- See Figure 7-9. When two adjacent ASON NEs start up, the LMP uses the OTN
overheads or the DCC channels of the OSC to transmit messages. Node 1 transmits
messages to Node 2, which performs the check to the received messages. If the messages
pass the check, Node 2 returns messages to Node 1. If the messages do not pass the
check, Node 2 returns a message to Node 1, indicating that the messages fail to pass the
check. In this way, Node 2 waits for another check. Hence, a control channel between
the two adjacent nodes is created.
- After the control channel is created, the two nodes store the information about the control
channel and identify the control channel according to the ID.
Figure 7-9 Creating control channels
LMP
LMP
Message
Node 1
Node 2
Message
l Verifying component links and TE links.
The following is the procedure of verifying component links and TE Links.
- After the control channels are configured, an attribute consistency check is performed
to the TE links to see if the information is identical at both ends of dynamically
discovered or manually configured TE links. If the check succeeds, the OSPF protocol
is used to flood the information of the TE links to the entire network.
- As shown in Figure 7-10, Node 1 transmits messages and the content to be checked to
Node 2, which checks if it has the same information and returns the check result to Node
1.
- On the OCS network, after a logical board is created for an ASON NE, the ASON
software creates component links for the optical interfaces of the board. Then, the
attributes of component links are configured according to the attributes of the optical
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