5- QOS - ETH-OAM

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Ethernet QOS,E-OAM

Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page2

Upon completion of this course, you will be able to:

Understand QoS model Understand QoS functional module Understand QoS advance feature Understand QoS typical application


Chapter 1 QoS ModelsChapter 1 QoS Models

Chapter 2 QoS TechnologiesChapter 2 QoS Technologies

Chapter 3 Advanced QoS Chapter 3 Advanced QoS TechnologiesTechnologies

Chapter 4 QoS Technologies ApplicationChapter 4 QoS Technologies Application


Traditional QoS Model Best Effort Model

Using FIFO queue Without QoS function

InterServ Model Application requests a specific kind of QoS service, through RSVP signaling

protocol Complex to use Fine grain, providing strict QoS Difficult to support with a large number of RSVP connections

DiffServ Model Qos is provided by differential treatment to each packet or class of packets This model is appropriate for aggregate flows No explicit signaling from the application Coarse grain, not strict QoS

Three QoS ModelThree QoS Model


DiffServ System Architecture

The contents of DiffServ system architecture ： Traffic Condition at the edge

Traffic Policy Coloring Traffic Shaping

Per-hop Behaviors scheduling in the core ： Queuing Scheduling Dropping

DiffServ ArchitectureDiffServ Architecture


QoS Mapping Between IP Network and MPLS Network

Mapping relationship between IP DSCP and MPLS EXP ：QoS MappingQoS Mapping

Service Type DSCP Domain EXP Domain

Reserved 111000(CS7) 7

Reserved 110000(CS6) 6

Service Type 1( real-time service)

101110(EF) 5

Service Type 2 (fulfil SLS) 011010(AF31) 4

Service Type 2(non-fulfil SLS) 011100(AF32)011110(AF33)

3

Service Type 3(fulfil SLS) 001010(AF11) 2

Service Type 3(non-fulfil SLS) 001100(AF12)001110(AF13)

1

Service Type 4(best-effort) 0(default) 0


QOS Model------IntServ Model

Provide controllable end-to-end service. Network units support QoS control mechanism. The application applies to NM for specific QoS service. Signaling protocol deploys in network according to QoS request. RSVP is most frequently used.

I want a bandwidth of 2Mbps

OK ！

I want a

bandwidth

of 2Mbps



OK ！ OK ！OK ！


DiffServ Model

DiffServ Network

User’s network

DiffServ Network

Traffic control

SLA/TCA

Border node

Internal node

Border node

Border node

Internal node Border

node

On network borders.1 Service classification2 Traffic regulation(Measuring/ Marking/Dropping . Shaping)

Different DS domains have different PHBs for realizing different services. They provide cross-domain service via coordination of SLA and TCA. .

User’s network

DS domain service provides strategic PHB decision..


Chapter 1 QoS Models

Chapter 2 QoS Technologies

Chapter 3 Advanced QoS Chapter 3 Advanced QoS TechnologiesTechnologies

Chapter 4 QoS Technologies ApplicationChapter 4 QoS Technologies Application


Basic of QoS---Traffic Classification

ACL IP address

(Source/Destination) Protocol Type TCP/UDP Port (in/out) MAC Address Interface Index

Marking IP Precedence DSCP EXP (MPLS) 802.1p (LAN Switch)

Frame Relay DLCI(PIPQ)

ATM UBR, CBR, VBR-rt, VBR-

nrt

Voice Data Service

VOD Service VPN Service

Bandwidth Assure

Low Delay and Jitter

Bandwidth Assure

Normal Delay and Jitter

No Bandwidth Assure

Higher Delay and Jitter

EF

AF

BE

VOIP signal


DiffServ Signaling -- DSCP and IP Precedence

DSCP and IP Precedence are two standards used in the industry DSCP is designed to be compatible to IP precedence, by defining code-points 'xxx000' as the

Class Selector code-points and the respective priority rules

IDID OffsetOffset TTLTTL ProtoProto FCSFCS IP-SAIP-SA IP-DAIP-DA DataDataLenLenToSToS1 Byte1 Byte

DSCP

IP Precedence

currently unused

ToS

IP Packet Header

currently unused

RFC2474

0 1 2 3 4 5 6 7

RFC1122 RFC1349

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7 •remark dscp dscp-value

IP Precedence DSCP

Data length 3 bits 6 bits

Purpose Define Service Class Define the PHB (Per Hop Behavior) a packet experiences at each node

Compatibility

IPv4 only IPv4/IPv6

7

VersionVersionLengthLength


DSCP, EXP, and Priority Mapping

EXP Service Color EXP Service Color

0 be green

4 af4 green

1 af1 green

5 ef green

2 af2 green

6/7 Network Control

green

3 af3 green

green

802.1P

Service

Color 802.1P

Service

Color

0 be green 4 af4 green

1 af1 green 5 ef green

2 af2 green 6 cs6 green

3 af3 green 7 Cs7 green

MPLS EXP 0 1 2

802.1P 0 1 2

LabelLabel EXPEXP SS TTLTTL

TPIDTPID(tag protocol ID)(tag protocol ID)PriorityPriority CFICFI VLAN IDVLAN ID


Introduction to QoS On the conventional IP-based network, all packets are processed

according to the first in first out (FIFO) and best effort strategies.

All packets to be transmitted through this interface enter the FIFO queue according to the sequence of their arrival at the interface. The interface transmits these packets from the head of the queue. The packets are not differentiated during the transmission, and the quality of packet transmission is not guaranteed. This method cannot meet the special requirements of the new services for bandwidth, delay, and delay jitter. Hence, the QoS technology is developed to solve the problem.


Introduction to QoS

After packets arrive at an interface, packets are classified and then enter the queues that correspond to the classes of packets. The interface transmits the packets in the queue of a higher priority first, and then the packets in the queue of a lower priority. In this manner, the packets in the queue of a higher priority are always transmitted first. Hence, these packets have a low delay, and in the case of network congestion, their performances including packet loss ratio and delay jitter are also ensured.


Basic Concepts of QoS Flow classification: According to certain rules, packets are divided into different

flows for different QoS operations. The flow classification is a prerequisite for the QoS operation.

Committed access rate (CAR): The CAR is used to supervise the rate of traffic and thus to ensure that the rate of traffic does not exceed the committed rate. If the traffic of a connection exceeds the committed access rate, the traffic policing function discards certain packets or re-set packet priorities.

Class of service (CoS): The CoS function classifies packets and schedules them to queues of different priorities. Then, the packets are processed according to their queue priorities. In this case, the packets have different QoS operations in terms of delay and bandwidth.

Traffic shaping: The traffic shaping function restricts the traffic and bursts of a connection on a network. Thus, packets are transmitted at an even rate.

Egress scheduling: Based on traffic shaping and CoS, the egress scheduling function ensures the queue scheduling in terms of priority, probability, and bandwidth.


ContentsIntroduction to QoSWorking Principles of QoSPlanning Guide to QoSConfiguration Guide to QoS


Major Technologies of QoS Classification and marking technologies:

Differentiated Services Code Point (DSCP), VLAN priority, port, port+CVLAN, and port+SVLAN

Congestion management mechanism: First In First Out (FIFO), Strict-Priority Queue (SP), Weighted Round Robin (WRR), and SP+WRR

Congestion adjustment mechanism: policing, shaping, line rate (LR)


Packet Classification and Marking

Packet classification and marking is the basis of QoS execution. It is classified into simple traffic classification and complex traffic classification.

Packet classification technologies include DSCP, VLAN priority, port, port+CVLAN, and port+SVLAN.

Packets are sent to other modules for processing or marking for the core network according to the classification results.

ACL, IP priority


Traffic Monitoring

drop

Token bucket

Traffic classification

Committed Access Rate (CAR) Token bucket algorithm Traffic control

Shaping is to enable the traffic output rate to comply with the traffic model specifications.

Dropping is to discard packets according to specific rules. Marking is to modify forwarding queues.


Example of Traffic Policing

Without Without traffic traffic policingpolicing

With traffic With traffic policing policing

bpsbps

TimeTime

bpsbps

TimeTime

Rate LimitRate Limit



Traffic Shaping

QueueTraffic classification

Token bucket

256 Kbps

128 Kbps

FRFR

128 Kbps

Generic Traffic Shaping (GTS): solves the unmatched interface rates on both sides of a link.

Limit packet traffic and cache the packets exceeding the committed traffic. Traffic shaping may increase the delay.

Token


Examples of Traffic Shaping

Without Without traffic traffic shapingshaping

With traffic With traffic shapingshaping

bpsbps

TimeTime

bpsbps

TimeTime




Total Rate Limit of the Physical Interface

LR: Limits the total rate of packet sending (including emergency packets) on a physical interface.

LR uses the token bucket for traffic control. All packets must be processed by the token bucket of the LR before being sent through the interface.

Abundant QoS queues are used for caching packets.

Traffic classificatio

n

Token bucket

256 Kbps 128

Kbps

QoS queue


Congestion Management

When a network is congested, the QoS (including delay and bandwidth) of packets is determined according to their priorities.

Packets with different priorities are added to different queues. Different scheduling priorities, probabilities, or bandwidths are guaranteed for different queues.

Algorithms: FIFO SP WRR SP+WRR

Output queue

Traffic classification


FIFO

FIFO: The algorithm is simple and implements fast packet forwarding. All packets comply with the first-in-first-out rule. It is the queuing policy used by the default service mode (namely, Best-Effort) of

Internet.

Forward packets


SP

SP: It guarantees the QoS of the queues with higher priority. There are eight port queues, namely, queues 7, 6, 5, 4, 3, 2, 1, and 0

following a descending order. The queue with higher priority is scheduled preferentially.

drop

Traffic classificati

on

Queue 7Queue 6Queue 1Queue 0

……

……


WRR

WRR: Each queue is configured with a weighted value to ensure at least a certain proportion of bandwidth for each queue.

WRR supports a maximum of 8 queues. Each queue complies with the configured bandwidth

proportion. It gets rid of the disadvantage of the SP algorithm, that is,

the queues with low priority may not be served for a long time.

drop


n

…… Queue 7Queue 6Queue 5Queue 0

……


SP+WRR

SP+WRR: The algorithm ensures that the packets in high-priority queues are sent preferentially, and the service time of WRR queues is allocated by the weighted value. WRR queues must be continuous, that is, no SP queues are

inserted between WRR queues. All WRR queues can be treated as an SP queue. For example, Queue 7 and Queue 0 are SP queues, whereas Queue

6 to Queue 1 are WRR queues.

drop


n

…… Queue 7Queue 6Queue 5Queue 0

……


ContentsIntroduction to QoSWorking Principles of QoSPlanning Guide to QoS

QoS Features and Functions of the OptiX RTN 900 V1R2

QoS Planning Principles of the OptiX RTN 900

Configuration Guide to QoS


QoS Features and Functions of the RTN 900 V1R2 As an end-to-end QoS control model, the DiffServ can be simply realized and easily extended. In a DiffServ model, a packet represents its QoS level through the carried QoS information. The

DiffServ model provides differentiated services for collections of packets that have different QoS levels. Based on the DiffServ model, a network is divided into several DiffServ domains (also referred to as DS domains). A DS domain consists of a group of network nodes (DS nodes) that provide the same service policy and realize the same per-hop behavior (PHB). The DS nodes can be classified into two types, namely, DS edge nodes and DS interior nodes.

In the DS domain as shown in the above Figure ， the DS edge node identifies the QoS information (VLAN priority and DSCP value) carried by the packets that enter the DS domain. After that, the DS edge node aggregates the packets that are at the same QoS level. A collection of the aggregated packets is called a behavior aggregate (BA). The DS edge node controls the traffic of the BA based on the configured PHB service level, and forwards the BA to the DS interior node. The DS interior node controls the traffic of the BA based on the PHB service level and then forwards the BA to the DS edge node of the next hop.


QoS Features and Functions of the RTN 900 V1R2 The PHB service level indicates the forwarding action performed

by the DS node on the BA. The forwarding action can meet a specified requirement. PHB service levels provide eight types of QoS, namely, BE, AF1, AF2, AF3, AF4, EF, CS6, and CS7. The mapping relation between the priority (C-VLAN priority, S-VLAN priority, and DSCP value) of a packet in the DS domain and the eight PHB service levels can be configured. A default DS domain is available on the OptiX RTN equipment. Before the configuration, all the ports are in this domain. The default DS domain cannot be modified or deleted.

In this default DS domain, a default mapping relation is defined.


QoS Features and Functions of the RTN 900 V1R2

CVLAN Priority SVLAN Priority DSCP ( Decimal) PHB Service Level

0 0 0 BE

1 1 8 ， 10 ， 12 ， 14 AF1

2 2 16 ， 18 ， 20 ， 22 AF2

3 3 24 ， 26 ， 28 ， 30 AF3

4 4 32 ， 34 ， 36 ， 38 AF4

5 5 40 ， 46 EF

6 6 48 CS6

7 7 56 CS7

Default mapping relations between the priorities of ingress packets and PHB service levels

•The packet that carries the C-VLAN priority, S-VLAN priority, or DSCP value is trusted by the OptiX RTN 900 V1R2. The untrusted packet is mapped to the BE service level by default and forwarded in best effort mode. •If the DS domain is defined by the user, the DSCP value that is not mapped to the AF1-CS7 service levels is mapped to the BE service level by default and forwarded in best effort mode.



PHB Service Level CVLAN Priority SVLAN Priority DSCP ( Decimal)

BE 0 0 0

AF1 1 1 8 ， 12 ， 14

AF2 2 2 16 ， 20 ， 22

AF3 3 3 24 ， 28 ， 30

AF4 4 4 32 ， 36 ， 38

EF 5 5 40

CS6 6 6 48

CS7 7 7 56

Default mapping relations between the priorities of ingress packets and PHB service levels


QoS Features and Functions of the RTN 900 V1R2 The OptiX RTN 900 supports the QoS model based on ports.



Application

Point of the QoS

Policy Adopted QoS Technology

Ingress Port policy Complex traffic classification (specific service being classified according to

the C-VLAN/S-VLAN ID, C-VLAN/S-VLAN priority, or DSCP value)

CAR

DiffServ policy Simple traffic classification (ingress packets being classified into flows at

different PHB service levels according to their priorities)

Egress DiffServ policy Forwarding the flows at different PHB service levels into corresponding port

queues, and remarking packet priorities according to PHB service levels

Port policy Shaping (based on queues corresponding to PHB service levels) Running the queue scheduling algorithm (SP, WRR, or SP+WRR) for the

queues at different PHB service levels after the queue policy is set

Port shaping Shaping (based on egress ports)

QoS model



The OptiX RTN 900 V1R2 supports two traffic classification methods, namely, simple traffic classification and complex traffic classification.

Simple Traffic Classification The simple traffic classification is based on the DS domain. In the case of the simple

traffic classification, different services on specified ports are mapped to different PHB service classes according their carried QoS information.

Classification technologies ： CVlan Pri 、 SVlan Pri 、 DSCP 。 Ingress packets being classified into flows at different PHB service levels according

to their priorities. Remarking the packet CVLAN PRI, SVLAN PRI and DSCP according to the egress

direction mapping relation table. The OptiX RTN 900 V1R2 supports Color Blindness only. The BE, AF1, AF2, AF3, AF4,

EF, CS6, and CS7 service classes respectively map eight queuing entities. The AF1 is classified into three sub service classes, namely, AF11, AF12, and AF13, only one of which is valid. It is the same case with the AF2, AF3, and AF4. 。


QoS Features and Functions of the RTN 900 V1R2 Complex Traffic Classification

In the case of the complex traffic classification, specified services are classified according to the C-VLAN/S-VLAN ID, C-VLAN/S-VLAN priority, or DSCP value. The flow type is based on the associated Ethernet service type of the traffic.

Traffic classification tenologies ： CVlan ID 、 SVlan ID 、 CVlan Pri 、 SVlan Pri 、 DSCP 、 CVlan ID + CVlan Pri 、 SVlan ID + SVlan Pri 。

A complex flow supports the following QoS processing operations: The flow is passed or discarded based on the ACL. The flow is mapped to a new PHB service class. In the ingress direction, the rate of the flow is restricted through the CAR

mechanism. In the egress direction, traffic shaping is performed on the flow.


QoS Features and Functions of the RTN 900 V1R2Each port supports eight queues at the egress port.supports three queue scheduling methods: strict-priority (SP), weighted round robin (WRR) SP+WRR.Queues SHAPING ： Support traffic shaping for complex flows, and for egress queues

and egress ports corresponding to PHB service classes.


Planning Guidelines on DiffServ

As a basis and condition for QoS implementation, DiffServ (namely, simple traffic classification) helps to map service flows into different PHB service classes based on the VLAN priorities or DSCP values carried by the service packets. The RTN 900 can perform corresponding queue scheduling and traffic shaping operations based on PHB service.

Consider the following points when you plan DiffServ: ： A default DiffServ is available on the OptiX RTN 900. Therefore, all the Ethernet ports

use the policies of the default DiffServ if another DiffServ is not configured. The default DiffServ cannot be modified or deleted. If the user-defined DiffServ needs to be used, create a DiffServ based on the planning information and apply the rules of the new DiffServ to the desired ports.

When the OptiX RTN 900 receives services and identifies service types based on VLAN priorities, the trusted packets at a UNI port must carry C-VLAN priorities, and the trusted packets at an NNI port must carry S-VLAN priorities. When the OptiX RTN 950 receives services and identifies service types based on DSCP values, the trusted packets at a port must carry DSCP values.

When service packets are mapped to PHB service classes, do not use the CS7 and CS6 queues if possible. This is because that an NE may use the CS7 and CS6 queues to transmit Ethernet protocol packets or inband DCN packets.



All the nodes in a DS domain must use consistent DiffServ rules. A DS interior node generally uses only the DiffServ.

When the OptiX RTN 900 receives 3G backhaul services (Ethernet services), it is recommended that you allocate VLAN priorities or DSCP values to services transmitted from base stations at the BTS/BSC or NodeB/RNC. In this manner, the OptiX RTN 900 can map the services to different PHB service classes based on the VLAN priorities or DSCP values carried by the services. The following tables list the mapping relationships between priorities of typical Ethernet services from base stations and PHB service classes.



PHB Service

Level

DSCP VLAN

Priority

Corresponding Service Type

CS7 56 7 -

CS6 48 6 -

EF 40 5 Real-time voice service and signaling service (R99

conversational and R99 streaming services)

AF4 32 4 -

AF3 24 3 Real-time OM and HSDPA services (OM streaming and

HSPA streaming services)

AF2 16 2 Non-real-time R99 service (R99 interactive and R99

background services)

AF1 8 1 -

BE 0 0 HSDPA data service （ HSPA Interactive, Backgroun

d ）

•Service class and PHB service class


Planning Guidelines on Complex Traffic Classification The OptiX RTN 900 can classify traffic at a specified port into flows based

on the VLAN ID, VLAN priority, DSCP value, or combination of the VLAN ID and VLAN priority.

A complex flow supports one or several QoS operations: The flow is passed or discarded based on the ACL. The flow is mapped to a new PHB service class. In the ingress direction, the rate of the flow is restricted through the

CAR mechanism. In the egress direction, traffic shaping is performed on the flow.


Planning Guidelines on Complex Traffic Classification Adhere to the following principles when you plan complex traffic

classification: Complex traffic classification is supplementary to DiffServ. Specially,

use complex traffic classification only when DiffServ fails to implement required QoS functions.

Generally, apply complex traffic classification to a DS edge node. The traffic at a UNI port can be classified based on the C-VLAN ID, C-

VLAN priority, DSCP value, or combination of the C-VLAN ID and C-VLAN priority. The traffic at an NNI port can be classified based on the S-VLAN ID, S-VLAN priority, DSCP value, or combination of the S-VLAN ID and S-VLAN priority.


Planning Guidelines on ACL Use the ACL function if you need to prohibit the access of a

certain service flow. Consider the following points when you plan ACL:

Enable ACL only at the access point of a service flow. By using complex traffic classification, classify the service

flow whose access is prohibited.


Planning Guidelines on CAR Use the CAR function if you need to restrict the traffic of a complex flow that is transmitted

into. Adhere to the following principles when you plan the CAR function: Generally, apply the CAR function to a DS edge node. By using complex traffic classification, classify the service flow whose traffic is

restricted. After the CAR function is enabled, packet loss occurs if the traffic that is transmitted

into is more than the committed traffic. Therefore, do not apply the CAR function to services that are sensitive to packet loss.

It is recommended that you set the value of the CIR equal to the committed service bandwidth and the value of the PIR one and half times to two times of the value of the CIR.

It is recommended that you set the value of the CBS/PBS equal to the traffic at the CIR/PIR in 50 to 200 ms, as the value of the CBS/PBS is proportional to the value of the CIR/PIR.

You can make settings so that yellow packets can be passed, discarded, or downgraded in the PHB service class.

NOTE: The working principle of yellow packet discarding is to perform CAR processing with only the CIR and CBS used.


Planning Guidelines on Traffic Shaping Use the traffic shaping function if you need to reduce occurrence of packet loss that results from

traffic fluctuation. Adhere to the following principles when you plan traffic shaping: After the traffic shaping function is used, service delay occurs in the case of traffic fluctuation.

Therefore, do not apply the traffic shaping function to services that are sensitive to delay. The RTN 900 can perform traffic shaping for complex flows, and for egress queues and egress

ports corresponding to PHB service classes. Select appropriate objects to which traffic shaping is applied as required.

In the case of Hybrid radio links, the RTN 900 can restrict the bandwidth at the air interface that the Ethernet service occupies, based on the permissible air interface capacity specified in the license file on the IF board. In addition, after the AM function is enabled on a Hybrid radio link, port shaping is performed based on the current Ethernet service bandwidth if the IF board supports a lower Ethernet service bandwidth than the permissible air interface capacity specified in the license file.

It is recommended that you set the value of the CIR 100% to 120% of the average traffic in peak hours. When the value of the CIR is higher than the average traffic, delay resulting from fluctuation can decrease. It is recommended that the value of the CIR be equal to the value of the CIR (if traffic shaping is performed on egress queues or ports) or one and half or two times of the value of the CIR (if traffic shaping is performed on flows).

It is recommended that you set the value of the CBS/PBS equal to the traffic at the CIR/PIR in 50 to 200 ms, as the value of the CBS/PBS is proportional to the value of the CIR/PIR.


Planning Guidelines on Queue Scheduling Based on a certain algorithm, queue scheduling is performed on egress

queues corresponding to different PHB service classes. Queue scheduling is a key operation in QoS processing. In the case of packets in higher-priority queues, queue scheduling helps to prevent or reduce occurrence of delay, jitter, or packet loss in the case of network congestion.

Adhere to the following principles when you plan queue scheduling: Egress queue scheduling is applicable to egress queues. In the case of

packets in higher-priority queues, queue scheduling helps to prevent or reduce occurrence of delay, jitter, or packet loss in the case of network congestion. The RTN 900 supports three queue scheduling algorithms: SP, WRR, and SP+WRR. It is recommended that you use the SP+WRR algorithm to perform egress queue scheduling.


Planning Guidelines on Queue Scheduling Consider the following points when you use the SP algorithm to perform queue scheduling:

All the ports in a DS domain use the same queue scheduling method. The RTN 900 supports the SP, WRR, and SP+WRR algorithms. Their benefits and

disadvantages are as follows: The SP algorithm makes most efforts to guaranteeing scheduling of higher-priority

services. If the traffic of higher-priority services is large, lower-priority services, however, may fail to be processed for a long time.

The WRR algorithm ensures a certain bandwidth for lower-priority services, but fails to make most efforts to guaranteeing scheduling of higher-priority services.

The SP+WRR algorithm combines the advantages of the SP and WRR algorithms. On the RTN 900, each Ethernet port adopts the default queue scheduling algorithm

SP+WRR, in which AF1 to AF4 are WRR queues. When you manually set the SP+WRR algorithm, WRR queues and SP queues cannot interleave except in the case of default settings. That is, the scheduling algorithms corresponding to queues with priorities in a descending order (CS7 to BE) can change only from SP to WRR except in the case of default settings.


ContentsIntroduction to QoSWorking Principles of QoSPlanning Guide to QoSConfiguration Guide to QoS


Procedure for Configuring the DiffServ Fields

Start

Apply to ports

Egress mapping table (PHB)

Ingress mapping table (BA)

End

Select packet type

Packets are classified into CVlan Pri packets, SVlan Pri packets, and IP-DSCP packets. If the packet type is set to CVlan Pri or SVlan Pri, it must be consistent with the port type.

Map the packets to different queues according to the configuration of the ingress mapping table.

Change types (CVlan Pri, SVlan Pri, and IP-DSCP) of packets in queues according to the configuration of the egress mapping table.


QoS Configuration Procedure

Start

Create a policy

Configure COS queue

management

Set the queue type to WRR

Configure traffic classification and related

actions

End

Start of COS queue management configuration

Set queue type to SP

or WRR

End of COS queue management configuration

Set rate limit parameters: CIR,

PIR, CBS, and PBS

Set the queue type to SP

Set the weights of

WRR queues

Need queue rate?

WRRSP

Y

N

Figure 1 shows the general configuration process. Figure 2 and Figure 3 show the sub-processes.

Apply to ports

Figure 1

Figure 2


QoS Configuration ProcessStart of traffic

classification and action configuration

Need rate limit in outgoing

direction?

Set rate limit parameters: CIR, PIR, CBS, and PBS

Y

Figure 3

End of traffic classification and action

configuration

Configure traffic matching rule

Configure the ACL of a flow

Configure flow queues

Set CAR parameters: CIR,

PIR, CBS, and PBS

Need rate limit in the incoming

direction?

Configure marking


Ethernet Service OAM (802.1ag, 802.3ah)

Background Networks are evolving to IP-based networks. Ethernet services do not support powerful

operation, management, and maintenance capabilities as SDH services. No effective fault locating methods or tools are available if a service link becomes faulty.

Point-to-point Ethernet links between two directly-connected devices (in the first mile) raise requirements for detecting a link fault or monitoring performance.

A 605D

CORE AccessAccessME MEB C

IEEE 802.1agIEEE 802.3ah IEEE 802.3ah

IEEE 802.1ag: (1) Continuity check (CC): This method can check the link status in real time and is used to check unidirectional continuity. (2) Loopback (LB): This method can locate or detect a fault at one end. LB is used to check bidirectional connectivity. (3) Link trace (LT): This method is used to locate a fault on site. IEEE 802.3ah: This method focuses on performance monitoring and fault locating for the physical links in the first mile.

RNC

Description of scenarios


Application of the 802.3ah OAM and the 802.1ag OAM in the Network

The IEEE 802.1ag OAM focuses on the maintenance of end-to-end Ethernet links. Its application is based on services.

The IEEE 802.3ah OAM focuses on the maintenance of point-to-point Ethernet links between two directly-connected devices in the first mile. Its application is not specific to services.


Contents

IntroductionEnd-to-End 802.1ag OAMPoint-to-Point 802.3ah OAM


Contents End-to-End 802.1ag OAM

Overview Basic Concepts Basic Functions CC LB LT OAM Ping


Overview of the IEEE 802.1ag OAM Implements the OAM of end-to-end Ethernet links (which can

cross multiple bridge nodes). Based on services, realizes end-to-end detection in the unit of

"maintenance domain". Differentiates the VLAN OAMs. Major functions:

CC LB LT OAM Ping


Data Units of the IEEE 802.1ag

OAM Mac Destination Address: indicates the MAC address of the sink MP.OAM Mac Source Address: Indicates the MAC address of the source MP. Ether Type(VLAN): indicates the type of Ethernet data, such as 0x8100. VLAN tag: indicates the VLAN value of the service traffic. Ether Type(OAM): The type of the IEEE 802.1ag OAM packet is 0x8809. OAM Type: specifies how an MP differs and responds to various OAM operations according to the types of OAM packets.


Basic Concepts of the IEEE 802.1ag OAM—MD Maintenance Domain (MD)

An MD indicates a network that requires the OAM. Multiple MAs can be configured under an MD.

Attributes of an MD: MD Name: uniquely identifies an MD. Therefore, MD names in

one network cannot be the same. Level (optional. The default value is 0. The greater the value

is, the higher the level is.)


Basic Concepts of the IEEE 802.1ag OAM—MA

Maintenance Association (MA) The MA is used to detect the internal continuity of the MD. An MA

is a part of an MD. An MD can be divided into one MA or multiple MAs. An MA name must be unique in one MD. MA names in different MDs can be the same. On the network of a carrier, a VLAN is corresponding to a service instance. On the equipment, a VLAN is corresponding to an MA or multiple MAs. By classifying MAs, you can detect the connectivity faults of a network that transmits a certain service instance.

The CCM interval can be configured inside an MA to specify the CCM sending frequency of all the MEPs inside the MA. The CCM sending frequency of all the MEPs inside one MA must be the same.

Attributes of an MA: MA Name QinQ CCM Interval An MA inherits all attributes of the corresponding MD.


Basic Concepts of the IEEE 802.1ag OAM—MP

A maintenance point (MP) is a functional entity of the IEEE 802.1ag OAM. It consists of one or more maintenance end points (MEPs) and maintenance intermediate point (MIPs). Each MP has a maintenance point identification (MPID). This ID is unique in the entire maintenance association (MA). The information about the MP is recorded in the MAC address table, MP table, and routing table. The service type, service ID, and VLAN tag are key contents in the MP configuration information. Once the MP is created successfully, the protocol packet carrying the information about this MP is broadcast to other MPs that are associated with services. Then, these MPs receive the protocol packet and record the information for future use. The MEP initiates all the OAM operations and the MIP does not initiate any OAM operation or send any OAM packet.


Basic Concepts of the IEEE 802.1ag OAM—MEP/MIP

MPs are classified into the MEP and MIP: MEP It defines the start position of an MA. MEPs are the

originating and terminating points of OAM packets. MEPs are directional and related to services. All OAM operations and OAM packets are initiated by MEPs.

MIP The MIP cannot initiate an OAM packet. The MIP can

respond to and forward an LB or LT packet, and can only forward a CC packet.


Logical Relationship Inside an MD

Hierarchy: customer ME > service provider ME > operator ME. The dashed lines in the diagram show the logic channels where IEEE 802.1ag OAM packets

pass through. The MPs at different levels process the OAM protocol packets as follows: In the case of the OAM protocol packets whose level is higher, the maintenance points transparently transmit them. In the case of the OAM protocol packets whose layer level is lower, the MPs discard them directly. In the case of the OAM protocol packets whose level is the same, the maintenance points respond to or end the packets according to the messages types of the OAM protocol packets.


Contents End-to-End 802.1ag OAM

Overview Basic Concepts Basic Functions

CC

LB

LTOAM Ping


CORE AccessAccessMEPA

Basic Functions of the IEEE 802.1ag OAM—CC

Is the link from MEP A to MEP B in normal state?

MEPB

Count CC packets.

CC_LOC Alarm!

Requirements of the scenario:(1) Ethernet services are configured between devices.(2) The link status is checked in real time.

RNC

CC

As shown in the figure, after the CC is activated, MEPA sends a CCM according to the Ethernet service trail. After identifying the first CCM, MEPB in the same MD starts a timer for reception of the CCMs from MEPA. If the link is faulty and the MEPB does not receive the CCM within the period 3.5 times the timeout duration, MEPB reports the ETH_CFM_LOC alarm until the link recovers to normal.

The frequency of sending CCMs can be 1s, 10s, 1 min, or 10 min.


CORE AccessAccessRNC

MEPA

Basic Functions of the IEEE 802.1ag OAM—LB

Is the link from MEP A to MEP

B in normal state?

MEPB

LBM LBR

Successful LB

Does the loopback return (LBR) from MEP

B time out?LBM

Failed LB

Requirements of the scenario:(1) Ethernet services are configured between devices.(2)The fault is located by performing loopbacks point by

point.

A loopback test is based on bidirectional services. The source MEP constructs a Loopback Message (LBM) packet, fills the ID of the sink MP (MIP or MEP), transmits the packet, and starts the timer.

After receiving the LBM packets, the sink MP constructs the LBR packets and transmits them back to the source MEP. In this case, the loopback test is successful. If the source MEP timer times out and fails to receive the LBR from the sink MP, the loopback test fails. As shown in the figure, MEPA sends LBM packets to the sink MEPB. After receiving the packets, MIPC and MIPD in the same MD find that the sink MPID in the packets are different from their MPIDs, and thus transmit the packets transparently. After receiving the packets, the sink MEP4 transmits the LBR packets back to the source MEP1. At this moment, the loopback test is complete. Only MEPs can initiate loopback tests, and MEPs and MIPs can serve as the receiving end of the detection.

MIPC MIPD


Basic Functions of the IEEE 802.1ag OAM—LT

Application Scenario

Requirements of the scenario: (1) Ethernet services are configured between devices. (2) The fault is located at one time.

A 605D CORE AccessAccess

LTM

ME ME

LTR

The LTM cannot reach D because of a link failure between C and D.

A does not receive the LTR and A reports the unavailability to D.

B C

Node B: normal LTM

LTRNode C: normal

Node D: faulty

LTM

RNC

The source MEP constructs a Link Trace Message (LTM) packet, fills the D of the sink MEP in the packet, transmits the packet, and starts the timer. All MIPs on the link in the same MD continue to transmit the received LTM packet to the sink MEP and return an LTR packet to the source MEP. After the sink MEP receives the LTM packets, the packet transmission is complete. Then, the sink MEP transmits LTR packets back to the sink. In this case, the link trace test is successful. If the source MEP fails to receive the LTR packet from the sink MEP until its timer expires, the LT test fails.


Basic Functions of the IEEE 802.1ag OAM—OAM PingOAM ping test: MPID-Ping: When the Ethernet service processing boards of the Huawei equipment at both ends support the IEEE 802.1ag OAM, the MP on the Ethernet service processing board at one end initiates ping tests to the MP on the Ethernet service processing board at the other end. When the equipment at both ends supports the ARP and ICMP protocols, only Huawei equipment can initiate a ping test and Huawei equipment does not respond to a request for a ping test from the opposite equipment.


Contents

IntroductionEnd-to-End 802.1ag OAMPoint-to-Point 802.3ah OAM


Contents Point-to-Point 802.3ah OAM

Overview Basic Concepts Basic Functions

Auto-discovery

Link performance monitoring Remote fault detection Remote loopback Self-loop check


Overview of the IEEE 802.3ah OAM The IEEE 802.3ah OAM focuses on the maintenance of

Ethernet physical links between two devices in the last mile.

Major functions:Auto-discoveryLink performance monitoringRemote fault detectionRemote loopbackSelf-loop check

The IEEE 802.3ah OAM does not implement the functions irrelevant to a single link, for example, node position management, protection switching, and bandwidth reservation and allocation.


Overview of the IEEE 802.3ah OAM

The MAC destination address of an 802.3ah protocol packet is a fixed multicast address.

The IEEE 802.3ah protocol is a slow protocol. The packet sending frequency is 1s.

The 802.3ah protocol packets cannot be forwarded by the network bridge. No matter whether the IEEE 802.3ah OAM function is available or is activated, 802.3ah protocol packets cannot be forwarded across hops.

The IEEE 802.3ah protocol specifies that 802.3ah handshake packets are sent between the equipment at both ends to keep the handshake state.


Ethernet Port OAM—IEEE 802.3ah OAM

Microwave/Optical ring

RNC

2 When a fault at the local end is detected, the remote equipment can be notified.

1 When the bit error performance (error frame or error

signal) is detected on the receive link at the local end, the remote equipment can be notified.

3 A fault can be located.

Values and Features

4 The loopback on the port and the intra-board loopback can

be detected.

Error frames or bit errors

are detected./A fault on the local

segment is detected.

Initiate Loopbac

k at Local

Respond to a

loopback.

Check the alarms that are reported when a loopback is performed on the port.

Requirements of the scenario:(1) The status of the physical link is checked.

Description of scenarios:(1) The service performance

of the link is monitored in real time.

(2) The fault at the remote end is monitored in real time.

(3)The fault is located on site.(4)The self-loop is detected.


802.3ah Protocol Data Unit (OAMPDU)

Indicates the slow protocol multicast address. It is fixed as 0x01-80-C2-00-00-02.Indicates the MAC address of a port.

Indicates the data part of an OAM PDU.

Indicates the slow protocol type. It is always set to 0x8809.Is always set to 0x03, indicating the IEEE 802.3ah OAM subtype.Indicates the status information, such as link fault, critical fault, and emergency event.Identifies IEEE 802.3ah OAM protocol packets of different types.

Indicates the frame check sequence.


Basic Concepts of the IEEE 802.3ah OAM—OAM Mode

OAM Mode Active: Link discovery and remote loopback can be

initiated actively in this mode. Passive: Link discovery and remote loopback cannot

be initiated actively in passive mode. Other processing methods are the same as those in active mode.


Basic Functions of the IEEE 802.3ah OAM—Auto-Discovery

ActivePassive

NE1 NE2

NE1 initiates discovery actively and transmits a

packet carrying its OAM information.

After receiving a packet from NE1, NE2 checks whether the

setting in the packet is consistent with the local

setting, and then sends an OAM packet that carries the

settings of NE1 and NE2.

After receiving an OAM packet from NE2, NE1 updates the setting of NE2 at the local end, and checks

whether the settings are consistent. After that, the OAM packets transmitted by NE1 carry the

settings of NE1 and NE2. 802.3ah packet sent by NE1

802.3ah packet sent by NE2

By exchanging the information OAM protocol data unit (OAMPDU) periodically, the equipment at local end is informed whether the opposite end supports the IEEE 802.3ah OAM protocol. OAM auto-discovery is a prerequisite to realizing the link performance monitoring and remote loopback. The discovery procedure can be initiated by only the active end. The equipment at both ends can be in active mode at the same time, or one is in active mode and the other is in passive mode. The equipment at both ends cannot be in passive mode at the same time.

The packet sending frequency is 1s during the discovery procedure.

The contents to be negotiated during the discovery procedure include whether the remote loopback is supported, whether the error frame detection and bit error detection are supported, and whether the fast test (not specified by the protocol) is supported. The discovery procedure ends only after the contents at both ends are negotiated successfully.

The handshake procedure starts immediately after the discovery procedure.


IEEE 802.3ah OAM Handshake Phase

In the handshake phase, handshake packets are continuously sent at a frequency of 1s.

All 3AH packets including normal handshake packets, fault notification packets, and loopback packets can be kept in handshake state.

If no 3AH packet is received within 5s, it is considered that the link is faulty and the process goes back to the discovery phase.

If the negotiation fails due to the configuration modification at either end during the handshake phase, the process goes back to the discovery phase.


Basic Functions of the IEEE 802.3ah OAM—Link Performance Monitoring The link performance monitoring method monitors the bit error performance

(error frames or error signals) of a link. On detecting that bit errors exceed the threshold, the local end sends the specific bit error event to the opposite end through the event notification OAMPDU. In this case, the opposite end reports the alarm accordingly. The standard fault notification events are as follows:

Error frame event: The number of error frames in the time unit exceeds the preset threshold.

Error frame second event: The number of seconds in which error frames occur within the specified m seconds exceeds the preset threshold.

Error bit event: The number of error bits in the time unit exceeds the preset threshold.

When the IEEE 802.3ah OAM protocol is enabled at a port, the protocol queries the RMON statistic count on the hardware chip periodically to obtain the information such as the number of correct packets and the number of error packets. After the information is processed, you can find out whether the preceding three performance events occur or not. If a certain performance event occurs, the peer equipment is notified through an OAMPDU. After receiving the notification, the peer equipment reports an ETHOAM_RMT_SD alarm.


Basic Functions of the IEEE 802.3ah OAM—Remote Fault Detection If the traffic is interrupted due to the equipment fault or

equipment unavailability, a notification is sent to the peer equipment through the flag field in the OAMPDU. Fault Symptom: Link Fault: This fault is sent when the local port is shut

down. Dying Gasp: This fault is sent upon reboot or reset. Critical Event: This fault is sent when a fault is received

from the OAM manager.


Basic Functions of the IEEE 802.3ah OAM—Remote Loopback

Active Passive

NE1 NE2

NE1 actively initiates a remote loopback

request.

After receiving a loopback request packet from NE1, NE2

enters loopback state, and then sends a loopback response

packet to NE1.

After receiving a loopback response packet from NE2, NE1 enters loopback initiate

state.

Loopback request packet sent by NE1

Loopback response packet sent by NE2

Only the active end can initiate a remote loopback request. If the equipment at both ends initiates the remote loopback request at the same time, the equipment with the larger MAC address enters loopback state.

After entering loopback state, NE2 returns the packets (except OAM packets) received on the loopback port to NE1.

NE1 sends test packets to detect the link. The MAC address, packet length, and packet quantity can be specified. NE2 returns the test packets to NE1 without any change. NE1 then counts the packet loss.

The loopback cancellation process is similar to the loopback request process.


Basic Functions of the IEEE 802.3ah OAM—Self-Loop Check This function can detect the self-loop from the transmit end of a port

to the receive end of the local port and the intra-board loopback between two ports.

After the self-loop check is enabled on each port of the equipment, the self-loop can be detected, and an ETHOAM_SELF_LOOP or ETHOAM_VCG_SELF_LOOP alarm is reported.

The self-loop check function is developed by Huawei in compliance with the IEEE 802.3ah protocol. With this function, port loop problems can be solved by detecting and blocking self-loop ports.

Thank youwww.huawei.com

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