odd010010 ip backbone network planning issue 1_2

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ODD010010 IP Backbone Network Planning

ISSUE 1.2

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With telecom services transferred to the IP network, the IP network bears more and more services. It is obviously more and more important to build a stable IP core network that can bear multiple services and ensure the Quality of Service (QoS).



This course helps you to:

[Learn the backbone network architecture of the current main operators.

[Master the traffic models of backbone network.

[Master major points of backbone networking planning.

[Learn typical IP backbone network networking instances.



Chapter 1 Overview of Backbone Network Chapter 1 Overview of Backbone Network PlanningPlanning

Chapter 2 Backbone Network Architecture Chapter 2 Backbone Network Architecture

Chapter 3 Backbone Network Planning Chapter 3 Backbone Network Planning

Chapter 4 Typical Case Analysis for Chapter 4 Typical Case Analysis for Backbone NetworkBackbone Network



Overview of Backbone Network

l The IP backbone network, as the core of the whole network and upper-level network of the metropolitan area network (MAN), serves as the egress for the MAN to visit external networks and the hinge for interworking between MANs.

l Because the IP network bears more and more services, the networktraffic is becoming large and the network is becoming more and more important. In addition to the traditional Internet access service, large operators are actively engaged in developing value-added services such as NGN services, 3G service, and key account interconnection. To bear the value-added services, some operators start to build a second backbone network such as CN2 of China Telecom, IP private network of China Mobile, and CRNET Stage 2 of China Tietong.

Introduction to Backbone Network Introduction to Backbone Network



Backbone Network Planning Principles

l High reliability

[ The reliability of backbone network devices is the key for the whole network to

run reliably. Therefore, the network architecture must be designed properly and

reliable network backup strategies must be developed to ensure that the network can recover by itself upon failure.

l Flexibility and scalability

[ Based on the requirements of future network service development, capacity

can be expanded smoothly and the network can be upgraded easily so as to

reduce the impact of network architecture adjustment.

l Flat

[ Decrease the network hierarchy and hops and facilitate network management.

Backbone Network Planning Principles Backbone Network Planning Principles



Backbone Network Planning Principles (Continued)

l Proper QoS planning

[The services borne by the current IP network cover not only the pure Internet access service but also VoIP service, video service, key account service, and other services. These services have high requirements for the QoS. Therefore, the support for QoS is a necessary condition for network transition from the telecom network to IP network. The QoS must be properly planned.

l Operability and manageability

[Monitor the network on an integrated basis, manage the network based on authority, and allocate bandwidth resources on a uniform basis so that the network can be in the management scope.

Backbone Network Planning Principles Backbone Network Planning Principles




Chapter 2 Backbone Network ArchitectureChapter 2 Backbone Network Architecture





Network Architecture of Backbone Network

l The architecture of the backbone network falls into:

[ Plane hierarchical structure

[ Plane and space hierarchical structure

l The traditional backbone network often uses the plane hierarchical structure, that is, build a network using the hierarchy structure, for example, the current core layer and convergence layer structure. This network structure enables subscribers to access networks quickly and stably.

l The difference of the plane and space hierarchical structure from the above structure is that the backbone network is divided into multiple planes (two planes in most cases). The planes are still in the hierarchical structure and run services of their own. When the network is faulty, the planes can serve as backup devices of each other.

Network Architecture of Backbone Network Network Architecture of Backbone Network



VoIP, Video, BT, QQ, or MPLS VPN

Local IDC visit (news, games, or downloading) Access of local network IDC by external networks

External network traffic

Internal network traffic

BR BR ARAR

AR access router BR - core router/transit router

link link link

Core layer/transit layer

Access layerAccess layerIP provincial

network IP backbone network

National and international Internet access, or international VoIP

Longitudinal traffic

Transverse traffic

12

3

4

IP Backbone Network Traffic Model Analysis

IP provincialnetwork




BR BR ARAR

link link link

12

3

4

Plane Hierarchical Structure Model



Transverse traffic

Access layer Access layerCore layer/transit layer

IP backbone network





AR access router BR - core router/transit routerNational and international Internet access,

or international VoIP



XA

CD

WH

SY

NJSHGZ

BJ

GZ egress

GZ IDC

SH egress

SH IDCBJ IDC

BJ egress

Provincial IP network Region/City IP network

National backbone IP networkNational backbone IP network

Plane Hierarchical Structure Model



Plane Hierarchical Structure

l The plane hierarchical network is common in early backbone network.

l At present, most national operators use this network. The network consists of the core backbone layer, core convergence layer, and core access layer.

l The core backbone layer is divided into the regional centers based on regions. Regional centers are all connected or partially connected to make the network more robust.

l The dual-homing mode is used for networking of the core convergence layer. Two uplinks are connected to the backbone devices of the regional center or to different backbone devices of two regional centers.

Plane Hierarchical Structure Plane Hierarchical Structure



Typical Plane Hierarchical Network China CRC CRNET Stage 2



BR BR ARAR

link link link

12

3

4

Plane and Space Hierarchical Structure Model 1 (External Network/Internal Network)



Transverse traffic





IP backbone network









BR BR ARAR

link link link

1

23

4

Plane and Space Hierarchical Structure Model 2 (Longitudinal/Transverse)



Transverse traffic



IP backbone network







Provincial IP network Municipal IP network

XA

CD

WH

SY

NJGZ

BJ

GZ IDC

GZ egress

SH egress

SH IDC

BJ IDCBJ egress

BJGZ

SH

National Backbone IP Network National Backbone IP Network

SH

Plane and Space Hierarchical Network



Plane Hierarchical Network Structure

l For the plane and space hierarchical structure, the plane is divided during hierarchy. Different planes bear different services.

l In normal cases, the services in two planes do not affect each other. When one plane is faulty, the other plane serves as the backup device of the plane.

l Based on network design, each plane can bear all service volume by design.

l When multiple services need to be borne currently, the plane hierarchical network model shows its advantages of clear structure, good backup function, and high security.

Plane Hierarchical Structure Plane Hierarchical Structure



IP MAN Dual-Plane Structure

MANMAN

B: carrierB: carrier--class class service plane service plane

A: Internet service A: Internet service plane plane

1+1>21+1>2

Backbone network 2(carrier-class service)

Backbone network 1(network access and data services)



IP Bearer Network in T Office of China Mobile

SH1

XA1

XA2

BJ1

BJ2

WH1

SY2

NJ1

NJ2

SH2

GZ2

GZ1CD1

CD2

WH2

A forwarding plane

B forwarding plane

CR1

AR

SY1





Chapter 3 Backbone Network PlanningChapter 3 Backbone Network Planning





3.1 IP Address Planning 3.1 IP Address Planning

3.2 Routing Protocol Planning3.2 Routing Protocol Planning

3.3 MPLS VPN Planning 3.3 MPLS VPN Planning

3.4 QoS Planning 3.4 QoS Planning



IP Address Planning

l Proper IP address planning is an important part in the network design. IP addresses must be planned and implemented on a uniform basis for large networks.

l IP address planning affects the efficiency of network protocol algorithm, network performances, network scalability, network management, and further development of network application.

IP Address Planning IP Address Planning



IP Address Planning Principles

l Unique:

[ In an IP network, the same IP address cannot be set for two hosts. Do not set the same IP address for different hosts even if the MPLS/VPN technology that supports address overlapping is used.

l Continuous:

[ Continuous addresses facilitate path overlapping in the hierarchical network, thus cutting the size of the routing table and improving the efficiency of routing algorithms.

l Scalable:

[ Excessive addresses must be reserved for each layer so as to meet requirements of network expansion.

l Meaningful:

[ Each IP address shall have concrete meaning, and it is easy to find the device of an IP address.

IP Address Planning Principles IP Address Planning Principles



Routing Protocol Planning

l Routing protocol planning directly affects network stability, recovery duration upon network failure, and workload of network maintenance. Therefore, routing protocol planning is the key of network planning.

l Routing protocol planning covers Interior Gateway Protocol (IGP)and Exterior Gateway Protocol (EGP).

l In dynamic protocols of IGP, the protocols that are open and cansupport large networks include OSPF and IS-IS.

l BGP4 and MP-BGP are commonly used as the EGP currently.

Routing Protocol PlanningRouting Protocol Planning



Routing Protocol Planning Principles

l Shortest path: Try to make the shortest path of IGP be the shorttransmission distance because the end-to-end delay comes from transmission delay in the backbone network. Try to use the second shortest transmission distance as other backup paths to reduce the delay jitter caused by active/standby switchover.

l Fast convergence: Detect faults quickly and respond to them so that the system can recover as soon as possible and black hole routes and route loop can be avoided.

l Controllable and predictable routes: Use clear, specific, and simple routing strategies to avoid possible difficulties in operation and deployment.

l Reliability: Judge network faults correctly and avoid frequent route calculation and update. Load sharing: Improve network resource utilization and system reliability.

Routing Protocol Planning Principles Routing Protocol Planning Principles



Selection of IGP Routing Protocol

l Both OSPF and IS-IS are used in the current large networks.

l To select a routing protocol of IGP, take the following into account:

[Features of protocols

[Application degree

[Technology continuity

Selection of IGP Routing Protocol Selection of IGP Routing Protocol



Selection of IGP Routing Protocol (Continued)

l The OSPF protocol is based on the IP layer and can support the IP network only. The IS-IS protocol is running in the link layer directly and can support multiple types of network.

l Both OSPF and IS-IS cover the concepts of hierarchy and area. The OSPF has the backbone area 0 and branch areas. The IS-IS has two levels: level 1 and level 2. When visiting other networks, level 1 uses the nearest routerL2. In this case, routes need to be optimized. The route penetration must be used to solve this problem.

l The OSPF protocol, based on interface, is very flexible. It supports all types of network and is mature. The IS-IS is precise in structure and runs stably. The IS-IS router can belong to one area only and does not support networks such as FR, ATM, and X.25 network.

l The IS-IS protocol is more scalable because it is based on TLV.

In terms of protocol featuresIn terms of protocol features




l The OSPF is widely used in the MAN, and early network

maintenance personnel are familiar with this protocol.

l In recent years, the IS-IS protocol is frequently used in the

backbone networks of large operators. However, network

maintenance personnel are less familiar with this protocol, which

may affect subsequent network maintenance.

In terms of application degree In terms of application degree




l When selecting a protocol, you need to check the protocol that

is running in the original network. For example, some operators

use the IS-IS protocol in the core layer and the OSPF protocol

in the MAN. To protect network continuity, you must take the

cases into account when selecting a protocol.

In terms of technology continuity In terms of technology continuity



IGP Selection Principle

l Backbone network

[ In the backbone network, focus on stability of protocols and convergence speed. In the backbone network, the IGP needs to bear loopback addresses and interconnection addresses of the backbone network only. There are no special networking requirements, and the size of network is large. It is recommended to use the IS-IS protocol.

l MAN

[ In the MAN, focus on the flexibility of protocols and networking and whether a large number of user demands can be satisfied. The OSPF protocol can meet the requirements. It is recommended to use this protocol.

IGP Selection Principle IGP Selection Principle



OSPF Routing Protocol Planning

l Router id

[ It is unique in the OSPF area. It is recommended to use loopback addresses.

l Area division

[Division of areas is of great significance in the OSPF design.

[ It is recommended that no more than 50 routers are running in each area.

[ If the OSPF protocol is used in the backbone network, use area 0 by preference.

[ If a non-backbone area needs to be used, divide the area based on physical area.

Major Points of OSPF Planning Major Points of OSPF Planning



OSPF Routing Protocol Planning (Continued)

l Area type

[ The areas of OSPF can be divided into common area, Stub area, Totally Stub area, and NSSA area.

[ Stub: It is not allowed to introduce external routes of AS. Set a default route for the area.

[ Totally Stub: External routes of AS and the area are not introduced. Set a default route for the area.

[ NSSA: External routes are introduced during running. Others are the same as that of the Stub.

l The above three special areas are used to decrease the number of routes and reduce the performance requirements on equipment. Common backbone networks are used to transfer routes of interconnected links only. Therefore, the areas are not used in most cases.

Major Points of OSPF Planning Major Points of OSPF Planning



OSPF Routing Protocol Planning (Continued)

l COST

To ensure that the router selects the best path, the value of COST must be set uniformly. At present, the value is set in the following ways:

[ 1. Set this value according to the bandwidth of links: Select a reference bandwidth and compare the actual link bandwidth with the reference bandwidth. COST = reference value / actual link bandwidth (if the maximum bandwidth GE is selected)

40 GE links COST = 1

10 GE links COST = 4

GE links COST = 40

FE links COST = 400COST

155 M links COST = 258 2

[ 2. Set the value of COST based on the designed traffic model so as to control routing:

Major Points of OSPF PlanningMajor Points of OSPF Planning



IS-IS Routing Protocol Planning

l Network hierarchy

[The IS-IS is designed with L2 and L1. Therefore, the router in the IS-IS domain can play the roles of L1, L2, and L1/L2. Considering scalability, it is recommended that the IS-IS equipment is placed in L2 in the backbone network. L2 of the IS-IS must be continuous. At the border of the backbone network, you can set the router to L1/L2 so as to facilitate subsequent expansion of the IS-IS domain.

l Area division

[ IS-IS, the concept of area is almost the same as that in the OSPF. Currently, the OSPF protocol is used for L2 in most cases, but areas do not play an important role. Only when routers L1 and L1/L2 exist, areas can restrict routes and traffic. If areas are identified through the local telephone area codes, they must be planned uniformly.

Major Points of ISMajor Points of IS--IS Planning IS Planning



IS-IS Routing Protocol Planning (Continued)

l NET (network entity ID)

[ NET, converted by the NSAP by setting NSEL to 0, is used to identify an IS device in the IP network. Its structure is as follows:

l AFI: AFI can be applied officially or be set to the private value 49. The value plays the role of identification in the IP network only.

AREA ID: It is planned in advance. For the backbone network, you can set this parameter to a local telephone area code or the AS No. of the system.

System ID: ID of a device in an area. It is unique in an area. This parameter is often set to an MAC address or IP address. It is recommended to set this parameter to the loopback address of equipment.

NSEL: It is set to the fixed value 00.


AFI Variable Length Area Address System ID NSEL1 byte 1~12 bytes 6 bytes 1 byte

Area ID Sys ID NESL



NET Planning Example

l Suppose the area of a device is 49.0001 and the loopback address is 192.168.3.25, the NET can be in the following forms:

NET Planning Example NET Planning Example

192.168.003.025

1921.6800.3025 : System ID

49.0001.1921.6800.3025.00: NET

192.168.3.25



IS-IS Routing Protocol Planning (Continued)

l Metric

[Metric The functions and settings of Metric are the same as those of COST of the OSPF. Metric is used to control the shortest path of a route. IS-IS Metric consists of basic Metric and extended Metric. In Huawei, it is set to basic Metric by default. In large networks,extended Metric is used frequently. The value ranges of Metric are as follows:

Basic Metric: 1 63

Extended Metric: 1 - 16777215




BGP Routing Protocol Planning

l The BGP is the most widely used and complicated protocol in the backbone network. The major points of BGP route planning are as follows:

[AS Number

AS numbers consist of public numbers and private numbers. Public AS numbers are allocated by CNNIC and need not be planned. Private AS numbers are in the range 64512 to 65535. Private AS numbers can be used inside operators, and the numbers can be filtered at the egress of network.

[ IBGP & EBGP

BGP neighbor covers IBGP and EBGP. The EBGP is running between operators and other networks, and the IBGP is used internally.

Major Points of BGP Planning Major Points of BGP Planning AS Number & BGP NeighborAS Number & BGP Neighbor



BGP Routing Protocol Planning (Continued)

l RR

[ In an AS, IBGP neighbors must be fully connected. Because the number of IBGP neighbors is large, the router reflector (RR) is used for networking.

Major Points of BGP Planning Major Points of BGP Planning RR Planning RR Planning

A: RR B: RR

Client Client

Cluster

RR RR RR RR

RR RR




l Select an independent RR to ensure stability of the RR.

l If an independent RR cannot be selected, choose the router in the core position as the RR and ensure that the router can meet performance requirements.

l Use the RR redundancy configuration, that is, configure two RRs in a cluster and run the two RRs on the client.

l Set the same cluster-id for multiple RRs in a same cluster to avoid loop. It is recommended to select the bigger router id of RR as the cluster-id.

l If the network is large and is in the regular 2-level structure, use multi-level RR form to plan the RR.

RR Planning Principles RR Planning Principles



RR Networking Instances

Beijin

Level-1 RR1

Level-1 RR2

Level-1 RR1

Level-1 RR2

...

Level-1 RR1 Level-1 RR2

...

.

..Shang

hai

ZONE 3

Xian

Wuhan Nanjin

Guangzhou

ZONE 1

Level-2 RR1

City ECityD

City CCity BCity A

Province A1

Province A2Level-2 RR2

ZONE 2

City A

City A

CityA

City A

CityA

City B

City B

City B

City B

City BCity C City C

City C

City C

City C

CityD

City D

CityD

CityD

City D

City E

City E

City E

City E

City E

Level-2 RR1

Level-2 RR1

Level-2 RR1

Level-2 RR1

Level-2 RR1

Province A1

Province A1

Province A1

Province A1

Province A1

Province A2

Province A2

Province A2

Province A2

Province A2

Level-2 RR2

Level-2 RR2

Level-2 RR2

Level-2 RR2

Level-2 RR2




l The major feature of the BGP is the route attribute. Planning ofthe BGP covers:

[Local-preference

[MED

[AS-Path

[Community

[Load-balancing

Major Points of BGP Planning Major Points of BGP Planning Route Attributes and Strategy Route Attributes and Strategy



Local-preference

l Local Preference

[ To control the router in the AS to select outgoing routes, set the parameter local-preference. By default, this parameter is set to 100. The bigger value indicates higher priority. Local-preference is often used in the backbone network to boot outgoing traffic. It must be set during networking planning.

LocalLocal--preferencepreference

A B

C

10.0.0.1 /24 Pre:100 10.0.0.1 /24 Pre:200RRRR

RR



MED

l MED is used to control the direction of incoming traffic of the AS. It is set to 0 by default. The smaller value indicates higher priority. To make the MED value indicate the internal topology of AS, replicate the COST value of IGP routes in the next hop of IBGP routes to the MED in EBGP routes. However, it needs support of devices.

MEDMED

A B

C

10.0.0.1 /24 MED:100

10.0.0.1 /24 MED:200

RR

RR RR



AS-Path

l As-Path is used to prevent loops and control routing (that is, modify the length of As-Path through the AS-Path Prepend mode to implement routing). As-Path differs from MED in that the MED helps control incoming traffic of neighbor Ass, whereas the Prepend can control routing of remote ASs.

ASAS--PathPath

AS 100

Import route10.0.0.0/24AS 200

AS 300AS 400

AS 500

As-p: 200 100

As-p: 400 300 100



Community

l Community attribute

[You can apply a group of strategies to a group of neighbors so as to simplify configuration. Through the community attribute, a group of strategies can be applied to a group of routes to control routes. In large networks, the community attribute is planned uniformly to identify and control some types of route.

[Known community attribute:

no-export: not inform the EBGP peer entity

no-advertise: not inform any peer entity

CommunityCommunity



Load-Balancing

l Load sharing mode 1:

[Use the command Balance BGP to change the preference strategy and form the equal-cost route.

LoadLoad--BalancingBalancing

RR RR

RR RR

Router A Router B

Router C Router D

1.1.1.1 2.1.1.1

3.1.1.1

3.1.1.2

AS100

AS200

Serial2/0/0 2.1.1.2

Serial1/0/0 1.1.1.2



Load-Balancing

l Load sharing mode 2:

[There are many routes between ASBRs. Use the loopback interface to create EBGP connections and share load for BGP routes throughiteration of the IGP equal-cost route of loopback.

LoadLoad--BalancingBalancing

RR RRAS 100 AS 200

Loopback130.0.0.1/8

Loopback130.0.0.1/8

Loopback030.0.0.1/8

Loopback030.0.0.1/8

Ethemet1/0/010.0.0.1/8

Ethemet2/0/020.0.0.1/8

Ethemet2/0/020.0.0.2/8

Ethemet1/0/010.0.0.2/8

Router A Router B



MPLS VPN Planning

l VPN demand analysis

[Number of VPNs and VPN service types

[Determine the network scope of VPNs, number of subscribers, and number of routes.

[Determine VPN mutual visit demands and networking structure.

[Determine the demands of VPNs to access public networks.

[Determine VPN cross-domain demands and implementation basis.

l Selection of device roles

[Determine devices P, PE, and CE. In the backbone network, most devices serve as the device P, and device P must support basic protocols such as MBGP, MPLS, and LDP.

MPLS VPN Planning Clue MPLS VPN Planning Clue



MPLS VPN Planning (Continued)

l Planning of VPN-Instance, RD, and RT

[The above parameters are planned and implemented on the device PE.

l MBGP Planning

[The planning of MBGP is basically the same as that of common BGP. It is recommended to use an independent RR that is different from common BGP devices for the MBGP. Do not overlap the RR and ASBR.

l PE-CE Protocol Planning

[Currently, the commonly used protocols include RIP, static protocols, OSPF, and EBGP. Select a protocol based on the network conditions and support of devices.

MPLS VPN Planning Clue MPLS VPN Planning Clue



MPLS VPN Planning (Continued)

l Inter-AS implementation mode

l The cross-AS MPLS VPN can be implemented in the following modes:

[VRF-to-VRF

[MP-EBGP

[Multi-Hop MP-EBGP

MPLS VPN Planning ClueMPLS VPN Planning Clue



Inter-AS implementation mode

l VRF-to-VRF

[ Advantage: The MPLS need not be running between ASBRs.

[ Disadvantage: Each VPN site must be bound with a sub-interface, and the ASBR needs to maintain vpn routes.

l MP-EBGP

[ Advantage: It is unnecessary to configure a sub-interface for each VPN site at the ASBR.

[ Disadvantage: VPN routes must be maintained at the ASBR. A complete LSP is required between the PE ingress and PE egress, and ASBRs need mutual trust.

l Multi-Hop MP-EBGP

[ Advantage: It is easy to expand, and VPN routes need not be maintained by the ASBR. It is suitable for large networks.

[ Disadvantage: The PEs of both ASs need to know the PE host address of peer AS, which may cause security problems.

CrossCross--ASAS MPLS VPNMPLS VPN



IP QoS Planning

l IntServ model: Services request specific QoS service from the network through signaling messages, and the network reserves resources within the range defined by the traffic parameter.

IP QoS IP QoS IntServ Model IntServ Model

l The IntServ model requires that end-to-end devices support this protocol. Network units save status information for each application. This model is not easy to expand, and the overhead of protocol messages is large due to regular information exchange with neighbor units. This model is not suitable for large networks.

I want to reserve 20 Mbps of bandwidth.

OKOK OK OK

I want to re

serve

20 Mbps o

f bandwidt

h.I want to reserve 20 Mbps of bandwidth.

I want to re

serve

20 Mbps o

f bandwidt

h.



l DiffServ model: When the network is congested, remove congestion by controlling the traffic and forwarding according to different QoS levels.

l For the DiffServ model, multiple service streams are converged into a Behavior Aggregate (BA), and the same PHB is used in network units for forwarding, thus simplifying service processing and storage. This model is easy to be expanded. Currently, the QoS is implemented based on the DiffServ model in most cases.

IP QoS Planning (Continued) IP QoS IP QoS DiffServ model DiffServ model

DiffServ network

User network

Traffic control

SLA/TCA

Border node

Internal node

Border node

Border node

Internal node Border

node

DiffServ network

User network



MPLS QoS Planning

l At the LER, map the IP DS bytes to the EXP bit of the MPLS Label and indicate the packet QoS requirement for the LSR through the EXP bit. In this case, an LSP can support up to eight service levels. The LSR dispatches queues for packets based on label and EXP and discards messages based on EXP. The packets in the same LSP may be dispatched to different queues. E-LSP is a common LSP created through the LDP.

MPLS QoSMPLS QoSEE--LSPLSP

E-LSPLSR

EFAF1

LERLER



MPLS QoS Planning (Continued)

l At the LER, map the IP DS bytes to an LSP and indicate the packet QoS requirement for the LSR through the label and EXP bit. The LSR dispatches queues for packets based on the label and discards messages based on EXP. The packets in a same LSP are dispatched to a same queue.

MPLS QoSMPLS QoSLL--LSPLSP

L-LSPLSRLER LER

EFAF1



MPLS QoS Planning (Continued)

l Selection of E-LSP or L-LSP depends on the number of service types, packet discard value, and MPLS running mode (frame mode or cell mode) planned by the network.

l When the cell mode is used as the MPLS running mode, the label corresponds to VPI/VCI. In this case, only L-LSP can be used. Map the EXP of label to the CLP of cells.

l When the frame mode is used as the MPLS running mode, E-LSP or L-LSP can be used. Currently, most operators use up to four service levels (voice, video, VPN and high-quality network access, and common network access). Therefore, E-LSP can meet requirements of application and implement interworking with IP Precedence and 802.1p. It is recommend to use the E-LSP mode.

Selection of ESelection of E--LSP&LLSP&L--LSP LSP



MPLS TE

l MPLS TE helps optimize network resources of the backbone network and avoid congestion or idleness of some nodes.

l By extending the IGP routing protocol (OSPF or IS-IS), the MPLS TE enables the IGP to collect network traffic information (including maximum link bandwidth, maximum reserved bandwidth, currently reserved bandwidth, and link types) and stores the information in the traffic database (TED). Each TE router obtains displayed routes based on its TED and route calculation according to strategies. The finally displayed routes are deployed through the signaling protocol CR-LDP or extension of RSVP. The MPLS TE technology is not used in a large scale because its deployment is complicated and need support of devices.

MPLS TEMPLS TE



QoS Planning Service Analysis

l Currently, the requirements on the network quality fall into the following categories:

[ The delay, jitter, packet loss ratio are low, and the bandwidth can be ensured. The typical services for these requirements include NGN voice services and video services.

[ The bandwidth can be ensured, and the real-time requirement is not high. The typical services for these requirements include key account service and NM service.

[ The requirements for real-time performance and bandwidth are not high. The typical service for these requirements is the common network access service.

l In the current backbone network, the QoS models frequently used are DifferServ and MPLS E-LSP. Based on the above analysis, the EF stream is for the first type of service, the AF stream for the second type of service, and BE stream for the third type of service.

Service AnalysisService Analysis



QoS Planning Service Levels

Service levelService level

WRED00b000000BEInternet access

WRED10b001xxxAF1Key account VPN (bronze medal), Vnet low priority, 3G data services

WRED20b010xxxAF2Key account VPN (silver medal), Vnet high priority

WRED40b100xxxAF4Key account VPN (gold medal)

None 50b101110EFReal-time video service

None 60b110xxxEF3G/NGN voice stream

None 70b111xxxHighest Control management

Congestion avoidance

MPLS EXP codeDSCP code Priority Service type



Typical Cases of T Office of China Mobile

l T office of China Mobile is the IP private backbone network that bears the softswitch service and VPN service especially.

l Beijing, Shanghai, Guangzhou, Wuhan, Nanjing, Shenyang, Xi an, and Chengdu are eight transit nodes, used to converge traffic of the areas.

Guangzhou

Shanghai

Xian

Wuhan

Tianjin

Shijiazhuang

Zhengzhou

HhhotTaiyuan

Haerbing

Changchun

Hangzhou

Nanjing 2

Fuzhou

Guangzhou 1

Shanghai2

Jinan

Hefei

NanchangChengdu

Haikou Changsha

Chongqing

Lanzhou

Urumchi

Yinchuan

Sining

Nanling

Kunming

Lasa

Beijing

Shenyang2

Beijing 2

Nanjing

Wuhan 1

Chengdu2

Xian 2

Shenyang

1

Shenyang1

Shanghai1

Nanjing 1

Wuhan 2Guangzhou 2

Chengdu1

Xian 1

National network management center



Typical Cases of T Office of China Mobile

l The backbone network of T office is divided into two planes: A and B. Each plane can bear all data traffic by design.

l In normal cases, plane A is responsible for the softswitch services, and plane B bears the key account VPN service. When a plane is faulty, the traffic in the plane will be switched to the other plane.

Forwarding plane A

Forwarding plane B


www.huawei.com

Thank You


odd010010 ip backbone network planning issue 1_2

Documents

backbone network pdf

backbone network introduction

network hierarchy

network management

ip network bears

upperlevel network

stable ip core network

metropolitan area network