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H3C S9500 Series Routing Switches
Operation Manual
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Manual Version: T2-081655-20080530-C-2.03
Product Version: S9500-CMW520-R2132
Copyright © 2007-2008, Hangzhou H3C Technologies Co., Ltd. and its licensors
All Rights Reserved
No part of this manual may be reproduced or transmitted in any form or by any means
without prior written consent of Hangzhou H3C Technologies Co., Ltd.
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3
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2
G, V
n
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HUASAN are trademarks of Hangzhou H3C Technologies Co., Ltd.
All other trademarks that may be mentioned in this manual are the property of their
respective owners.
Notice
The information in this document is subject to change without notice. Every effort has
been made in the preparation of this document to ensure accuracy of the contents, but
all statements, information, and recommendations in this document do not constitute
the warranty of any kind, express or implied.
To obtain the latest information, please access:
http://www.h3c.com
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About This Manual
Related Documentation
In addition to this manual, each H3C S9500 Series Routing Switches documentation
set includes the following:
Manual Description
H3C S9500 Series Routing Switches
Installation Manual
It introduces the installation procedure,
commissioning, maintenance and
monitoring of the S9500 series routing
switches.
H3C S9500 Series Routing Switches
Command Manual
It includes Feature List and Command
Index, Access Volume, IP Service
Volume, IP Routing Volume, IP Multicast
Volume, MPLS VPN Volume, QoS ACL
Volume, Security Volume, System
Volume, and unsupported commands.
Organization
H3C Configuration Manual is organized as follows:
Part Contents
00 Product Overview
includes Obtaining the Documentation, Product
Features, and Features.
01 Access Volume
includes Ethernet Interface Configuration, POS
Interface Configuration, GVRP Configuration, Link
Aggregation Configuration, Port Mirroring
Configuration, RPR Configuration, Ethernet OAM
Configuration MSTP Configuration, VLAN
Configuration, QinQ Configuration, BPDU Tunneling
Configuration, and Port Isolation Configuration.
02 IP Services Volume
includes ARP Configuration, DHCP Configuration,
DNS Configuration, IP Addressing Configuration, IP
Performance Configuration, UDP Helper Configuration
IPv6 Basics Configuration, Dual Stack Configuration,
Tunneling Configuration, and Adjacency Table
Configuration.
Part Contents
03 IP Routing Volume
includes IP Routing Overview, BGP Configuration,
IS-IS Configuration, OSPF Configuration, RIP
Configuration, Routing Policy Configuration, Static
Routing Configuration, IPv6 BGP Configuration, IPv6
IS-IS Configuration, IPv6 OSPFv3 Configuration, IPv6
RIPng Configuration, and IPv6 Static Routing
Configuration.
04 IP Multicast Volume
includes Multicast Overview, Multicast Routing and
Forwarding Configuration, IGMP Snooping
Configuration, IGMP Configuration, PIM Configuration,
MSDP Configuration, IPv6 Multicast Routing and
Forwarding Configuration, MLD Snooping
Configuration, MLD Configuration, IPv6 PIM
Configuration, and Multicast VLAN Configuration.
05 MPLS VPN Volume
includes MPLS Basics Configuration, MPLS TE
Configuration, VPLS Configuration, MPLS L2VPN
Configuration, MPLS L3VPN Configuration, MPLS
Hybrid Insertion Configuration, and GRE Configuration.
06 QoS ACL Volume includes QoS Configuration and ACL Configuration.
07 Security Volume
includes 802.1x Configuration, AAA RADIUS
HWTACACS Configuration, MAC Authentication
Configuration, L3+NAT Configuration, Password
Control Configuration, SSH2.0 Configuration, and
Portal Configuration.
08 System Volume
includes GR Configuration, VRRP Configuration, HA
Configuration, Device Management Configuration,
NQA Configuration, NetStream Configuration, NTP
Configuration, RMON Configuration, SNMP
Configuration, File System Management Configuration,
System Maintaining and Debugging Configuration,
Basic System Configuration, Information Center
Configuration, User Interface Configuration, MAC
Address Table Management Configuration, PoE
Configuration, and Clock Monitoring Configuration.
09 OAA Volume
includes OAP Module Configuration and ACSEI
Configuration.
10 Acronyms Offers the acronyms used in this manual.
Conventions
The manual uses the following conventions:
I. Command conventions
Convention Description
Boldface
The keywords of a command line are in Boldface.
italic
Command arguments are in italic.
[ ]
Items (keywords or arguments) in square brackets [ ] are
optional.
{ x | y | ... }
Alternative items are grouped in braces and separated by
vertical bars. One is selected.
[ x | y | ... ]
Optional alternative items are grouped in square brackets
and separated by vertical bars. One or none is selected.
{ x | y | ... } *
Alternative items are grouped in braces and separated by
vertical bars. A minimum of one or a maximum of all can be
selected.
[ x | y | ... ] *
Optional alternative items are grouped in square brackets
and separated by vertical bars. Many or none can be
selected.
&<1-n>
The argument(s) before the ampersand (&) sign can be
entered 1 to n times.
# A line starting with the # sign is comments.
II. GUI conventions
Convention Description
< >
Button names are inside angle brackets. For example, click
<OK>.
[ ]
Window names, menu items, data table and field names
are inside square brackets. For example, pop up the [New
User] window.
/
Multi-level menus are separated by forward slashes. For
example, [File/Create/Folder].
III. Symbols
Convention Description
Warning
Means reader be extremely careful. Improper operation
may cause bodily injury.
Caution
Means reader be careful. Improper operation may cause
data loss or damage to equipment.
Note Means a complementary description.
Operation Manual
H3C S9500 Series Routing Switches QoS ACL Volume Organization
Manual Version
T2-081655-20080530-C-2.03
Product Version
S9500-CMW520-R2132
Organization
The QoS ACL Volume is organized as follows:
Features (operation
manual)
Description
QoS
The volume describes:
z QoS overview
z Traffic classification and traffic shaping configuration
z QoS policy configuration
z Hardware-based congestion management configuration
z Priority mapping configuration
z Congestion avoidance configuration
z Aggregation CAR configuration
z VLAN policy configuration
z Traffic mirroring configuration
z EACL configuration
z Outbound traffic accounting configuration
ACL
Access Control Lists (ACLs) are used to filter packets
passing through network devices. The volume describes:
z ACL overview and ACL types
z ACL configuration
Operation Manual – QoS
H3C S9500 Series Routing Switches Table of Contents
i
Table of Contents
Chapter 1 QoS Overview .............................................................................................................. 1-1
1.1 Introduction........................................................................................................................1-1
1.2 Traditional Packets Forwarding Application ......................................................................1-1
1.3 New Requirements Caused by New Applications.............................................................1-1
1.4 Congestion: Causes, Impact, and Countermeasures........................................................1-2
1.4.1 Causes....................................................................................................................1-2
1.4.2 Impact......................................................................................................................1-3
1.4.3 Countermeasure......................................................................................................1-3
1.5 Traffic Management Technologies ....................................................................................1-3
Chapter 2 Traffic Classification and Traffic Shaping Configuration........................................2-1
2.1 Traffic Classification Overview...........................................................................................2-1
2.1.1 Traffic classification.................................................................................................2-1
2.1.2 Priority.....................................................................................................................2-2
2.2 Traffic Shaping Overview...................................................................................................2-2
2.3 Traffic Evaluation and Token Bucket.................................................................................2-2
2.4 Traffic Shaping Configuration............................................................................................2-5
Chapter 3 QoS Policy Configuration...........................................................................................3-1
3.1 QoS Policy Overview.........................................................................................................3-1
3.2 QoS Policy Configuration Procedure.................................................................................3-1
3.3 Configuring QoS Policy......................................................................................................3-2
3.3.1 Configuration Prerequisites.....................................................................................3-2
3.3.2 Defining a Class......................................................................................................3-2
3.3.3 Defining a Traffic Behavior......................................................................................3-3
3.3.4 Defining a Policy......................................................................................................3-6
3.3.5 Applying a Policy.....................................................................................................3-7
3.4 Implementing QoS in an MPLS Network...........................................................................3-9
3.4.1 Mapping Dot1p to EXP in L2VPN .........................................................................3-10
3.4.2 Implementing QoS in an MPLS Network ..............................................................3-10
3.5 Displaying and Maintaining QoS Policies........................................................................3-14
Chapter 4 Hardware-based Congestion Management Configuration......................................4-1
4.1 Congestion Management Overview...................................................................................4-1
4.1.1 SP Queuing.............................................................................................................4-1
4.1.2 WRR Queuing.........................................................................................................4-2
4.2 Configuring SP Queues.....................................................................................................4-3
4.2.1 Configuration Procedure.........................................................................................4-3
4.2.2 Configuration Examples..........................................................................................4-3
4.3 Configuring Group-based WRR Queues...........................................................................4-3
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H3C S9500 Series Routing Switches Table of Contents
ii
4.3.1 Configuration Procedure.........................................................................................4-4
4.3.2 Configuration Examples..........................................................................................4-4
Chapter 5 Priority Mapping .......................................................................................................... 5-1
5.1 Priority Mapping Overview.................................................................................................5-1
5.2 Configuring a Priority Mapping Table................................................................................5-2
5.2.1 Configuration Prerequisites.....................................................................................5-3
5.2.2 Configuration Procedure.........................................................................................5-3
5.2.3 Configuration Examples..........................................................................................5-4
5.3 Configuring Port Priority.....................................................................................................5-5
5.3.1 Configuration Prerequisites.....................................................................................5-5
5.3.2 Configuration Procedure.........................................................................................5-6
5.3.3 Configuration Examples..........................................................................................5-6
5.4 Configuring to Trust Packet Priority...................................................................................5-7
5.4.1 Configuration Procedure.........................................................................................5-8
5.4.2 Configuration Examples..........................................................................................5-8
Chapter 6 Congestion Avoidance................................................................................................6-1
6.1 Congestion Avoidance Overview.......................................................................................6-1
6.2 Configuring WRED ............................................................................................................6-3
6.2.1 Description on WRED Parameters..........................................................................6-3
6.2.2 Configuration Procedure.........................................................................................6-4
6.3 Displaying and Maintaining WRED....................................................................................6-5
6.4 WRED Configuration Examples.........................................................................................6-5
Chapter 7 Aggregation CAR Configuration................................................................................ 7-1
7.1 Aggregation CAR Overview...............................................................................................7-1
7.2 Referencing Aggregation CAR in Traffic Behaviors..........................................................7-1
7.2.1 Configuration Prerequisites.....................................................................................7-1
7.2.2 Configuration Procedure.........................................................................................7-1
7.2.3 Configuration Examples..........................................................................................7-2
7.3 Displaying and Maintaining Aggregation CAR................................................................... 7-2
Chapter 8 VLAN Policy Configuration.........................................................................................8-1
8.1 VLAN Policy Overview....................................................................................................... 8-1
8.2 Configuring a VLAN Policy ................................................................................................8-2
8.2.1 Configuration Prerequisites.....................................................................................8-2
8.2.2 Configuration Procedure.........................................................................................8-2
8.3 Displaying and Maintaining VLAN Policies........................................................................8-2
8.4 VLAN Policy Configuration Examples................................................................................8-2
8.4.1 Network Requirements............................................................................................8-2
8.4.2 Configuration Procedure.........................................................................................8-3
Chapter 9 Traffic Mirroring Configuration ..................................................................................9-1
9.1 Traffic Mirroring Overview..................................................................................................9-1
9.2 Configuring Traffic Mirroring..............................................................................................9-1
Operation Manual – QoS
H3C S9500 Series Routing Switches Table of Contents
iii
9.2.1 Mirroring Traffic to a Port ........................................................................................9-1
9.2.2 Mirroring Traffic to the CPU ....................................................................................9-2
9.3 Displaying and Maintaining Traffic Mirroring .....................................................................9-3
9.4 Traffic Mirroring Configuration Examples..........................................................................9-3
Chapter 10 EACL Configuration ................................................................................................10-1
10.1 EACL Overview..............................................................................................................10-1
10.2 EACL Configuration Task List........................................................................................10-1
10.2.1 Configuring a Reflexive ACL Policy ....................................................................10-1
10.2.2 Configuring BT Traffic Limiting............................................................................10-3
10.2.3 Configuring a QoS Policy....................................................................................10-5
10.3 EACL Configuration Examples......................................................................................10-7
10.3.1 Reflexive ACL Configuration Examples.............................................................. 10-7
10.3.2 BT Traffic Limiting Configuration Examples........................................................10-8
10.4 Troubleshooting EACL.................................................................................................10-10
Chapter 11 Outbound Traffic Accounting Configuration........................................................11-1
11.1 Outbound Traffic Accounting Overview.........................................................................11-1
11.2 Configuring Outbound Traffic Accounting......................................................................11-1
11.3 Displaying and Maintaining Outbound Traffic Accounting.............................................11-2
Operation Manual – QoS
H3C S9500 Series Routing Switches Chapter 1 QoS Overview
1-1
Chapter 1 QoS Overview
When configuring QoS, go to these sections for information you are interested in:
z Introduction
z Traditional Packets Forwarding Application
z New Requirements Caused by New Applications
z Congestion: Causes, Impact, and Countermeasures
z Traffic Management Technologies
1.1 Introduction
Quality of Service (QoS) measures the service performance of service providers in
terms of client satisfaction. Instead of giving accurate marks, QoS emphasizes
analyzing what good or imperfect services are, and they come in what kind of
circumstances, so as to provide a cutting edge improvement.
In the Internet, QoS evaluates service performance for network packet forwarding. Due
to various services offered by the network, the evaluation for QoS will be based on
different aspects accordingly. Generally, QoS evaluates the service performance for
those network core requirements during packet forwarding process, such as delay, jitter
and packet loss ratio.
1.2 Traditional Packets Forwarding Application
On traditional IP networks, the devices treat all packets identically and handle them
with the first in, first out (FIFO) policy, assigning forwarding resources by arrival
sequence of packets. All the packets share the resources of the network devices. How
many resources the packets can obtain will completely depend on the time they arrive.
This service policy is called Best-effort, which delivers the packets to their destination
as it can, without any assurance and guarantee for delivery delay, jitter, packet loss
ratio, reliability and so on for packet forwarding.
The traditional Best-Effort service policy is only suitable for applications insensitive to
bandwidth and delay, such as WWW, file transfer and E-mail.
1.3 New Requirements Caused by New Applications
With the fast development of the network, more and more networks access the Internet.
The Internet has been expanded in terms of its scale, coverage and users quantities.
More and more users use Internet as their data transmission platform to implement
various applications.
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H3C S9500 Series Routing Switches Chapter 1 QoS Overview
1-2
Apart from traditional applications of WWW, E-mail and FTP, network users try to
expand some new applications, such as tele-education, telemedicine, video telephone,
videoconference and Video-on-Demand (VoD), on the Internet. And the enterprise
users expect to connect their regional branches together to develop some operational
applications through VPN technology, for instance, to access the database of the
company or monitor their remote equipment via Telnet.
Those new applications have one thing in common, i.e. high requirements for
bandwidth, delay, and jitter. For instance, videoconference and VOD need the
assurance of wide bandwidth, low delay and jitter. As for mission-critical applications,
such as transaction and Telnet, they may not require wide bandwidth but do require
lower delay and be handled by priority during congestion.
The new emerging applications demand higher service performance of IP network.
Better network services during packets forwarding are required other than simply
delivering the packets to their destination, such as providing user-specific bandwidth,
reducing packet loss ratio, avoiding congestion, regulating network traffic, setting
priority of the packets. To meet those requirements, the network should be provided
with better service capability.
1.4 Congestion: Causes, Impact, and Countermeasures
Network congestion occurs when inadequate resources are available for traffic. It can
degrade forwarding performance, introduce undesired delays, and hence degraded
service quality.
1.4.1 Causes
Congestion will easily occur in complex packet switching circumstances in the Internet,
with two cases illustrated in the following figure:
Figure 1-1 Traffic congestion causes
1) The packet streams enter a device from a high speed link and are forwarded via a
low speed link;
2) The packet streams enter a device from several interfaces with a same speed and
are forwarded through an interface with the same speed as well.
Operation Manual – QoS
H3C S9500 Series Routing Switches Chapter 1 QoS Overview
1-3
When traffic arrives at wire speed, congestion may occur for network resource
bottleneck.
Besides the bottleneck of link bandwidth, congestion will also be caused by resources
deficiency in normal packet forwarding, such as the deficiency of assignable processor
time, buffer and memory. In addition, congestion may occur if the arrival traffic is not
managed efficiently and the assignable network resources are inadequate.
1.4.2 Impact
Congestion may cause the following negative effects:
z Increase the delay and jitter of packet transmission
z Packet re-transmission caused by high delay
z Decrease the efficient throughput of network and lower the utilization of network
resources
z Intensified congestion can occupy too many network resources (especially in
memory), and the irrational assignment of resources even can lead to resource
block and breakdown for the system
It is obvious that congestion will make the traffics unable to obtain the resources in time
and degrade the service performance accordingly. No one wants congestion, but it
occurs frequently in complex environments where packet switching and multi-users
applications coexist. So it needs to be treated cautiously.
1.4.3 Countermeasure
A direct way to solve resources deficiency problem is to increase the bandwidth of
network; however, it cannot resolve all the problems caused by congestion.
A more effective method to solve the problem of QoS is to enhance the functions of
traffic control and resource allocation in the network, and to provide differentiated
services for applications with different service requirement in order to allocate and use
resources rightly. During the process of resources allocation and traffic control, the
direct or indirect factors that might cause network congestion should be controlled with
best effort to reduce the probability of congestion. As congestion occurs, resource
allocation should be balanced according to features and demands of applications, to
minimize the effects on QoS by congestion.
1.5 Traffic Management Technologies
Traffic classification, traffic policing, traffic shaping, congestion management, and
congestion avoidance are common traffic management techniques. They deliver the
following functions:
z Traffic classification: It is a prerequisite for differentiated service, to identify the
interested objects based on a certain matching rule.
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H3C S9500 Series Routing Switches Chapter 1 QoS Overview
1-4
z Traffic policing: polices the specification of particular traffics entering the switch.
When the traffics exceed the specification, then some restriction or punishment
measures can be taken to protect the commercial benefits of carriers and to
prevent network resources from being damaged.
z Traffic shaping: A traffic control measure of actively adjusting the output speed of
traffics, generally it can enable the traffic to adapt to the network resources
supplied by the downstream switch, to prevent the unwanted packet dropping and
congestion. Same as traffic policing, traffic shaping is implemented at the IP layer.
z Congestion management: handles resource competition during network
congestion. Generally, it stores the packets in the queue first, and then takes a
dispatching algorithm to assign the forwarding sequence of packets.
z Congestion avoidance: Exceeding congestion consumes network resources.
Congestion avoidance can monitor the usage status of network resources, and as
congestion becomes worse, actively take the policy of dropping packets through
adjusting traffic to resolve the overloading of the network.
Among those traffic management technologies, traffic classification is the basis. It is a
prerequisite for differentiated services, which identifies the interested packets with
certain matching rule. As for traffic policing, traffic shaping, congestion management
and congestion avoidance, they implement management to network traffic and
allocated resources from different aspects respectively to realize the differentiated
service.
Normally, QoS provides the following functions:
z Traffic classification
z Access control
z Traffic policing and shaping
z Congestion management
z Congestion avoidance
Operation Manual – QoS
H3C S9500 Series Routing Switches
Chapter 2 Traffic Classification and Traffic
Shaping Configuration
2-1
Chapter 2 Traffic Classification and Traffic
Shaping Configuration
When configuring traffic classification and traffic shaping, go to these sections for
information you are interested in:
z Traffic Classification Overview
z Traffic Shaping Overview
z Traffic Evaluation and Token Bucket
z Traffic Shaping Configuration
2.1 Traffic Classification Overview
2.1.1 Traffic classification
Traffic classification is the prerequisite and foundation for differentiated services, which
uses certain rules to identify the packets with certain features.
To discriminate flows, you can set traffic classification rules using the priority bits of ToS
(type of service) field in the IP packet header. Alternatively, the network administrator
may define a traffic classification policy, for instance, integrating information such as
source IP address, destination IP address, MAC address, IP protocol, or port number of
the applications to classify the traffic. In general, it can be a narrow range defined by a
quintuple (source IP address, source port number, destination IP address, destination
port number and the Transport Protocol), or can be all packets to a network segment.
In general, while packets being classified on the network border, the precedence bits in
the ToS byte of IP header are set so that IP precedence can be used as a direct packet
classification standard within the network. The queuing technologies can use IP
precedence to handle the packets. Downstream network can receive the packets
classification results from upstream network selectively, or re-classify the packets with
its own standard.
Traffic classification is used to provide differentiated service, so it must be associated
with certain kinds of traffic policing or resource-assignment mechanisms. To adopt what
kind of traffic policing action will depend on the current stage and load status of the
network. For example, to police the packets according to the committed rate when they
enter the network, to make traffic shaping before they flow out the nodes, to perform
queuing management in the event of congestion and to employ congestion avoidance
when congestion becomes worse.
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H3C S9500 Series Routing Switches
Chapter 2 Traffic Classification and Traffic
Shaping Configuration
2-2
2.1.2 Priority
Several priorities are described as follows:
Figure 2-1 DS field and ToS byte
As shown in
Figure 2-1, the ToS byte of IP header contains 8 bits: the first three bits (0
to 2) indicates IP precedence, valued in the range 0 to 7; the following 4 bits (3 to 6)
indicates ToS priority, valued in the range 0 to 15. In RFC2474, the ToS field of IP
packet header is redefined as DS field, where the DiffServ code point (DSCP) priority is
indicated by the first 6 bits (0 to 5), valued in the range 0 to 63. The remaining 2 bits (6
and 7) are reserved.
2.2 Traffic Shaping Overview
If no restrictions are imposed on the traffics from the users, bursting data sent by mass
users continuously will make the network become more congested. Thus for more
efficient network function and better network service for more users, the traffics from
the users must be restricted, for example, to restrict a traffic can only acquire the
specific assigned resources in certain time interval so as to prevent the network
congestion caused by excess burst.
Traffic shaping is a traffic monitoring policy to restrict the traffic and resources through
comparing with the traffic specification. To know whether the traffic exceeds the
specification or not is a prerequisite for traffic shaping. Then based upon the evaluation
result you can implement a regulation policy. Usually, Token Bucket is used to value the
traffic specification.
2.3 Traffic Evaluation and Token Bucket
I. Token bucket features
Token Bucket can be regarded as a container holding a number of tokens. The system
will put Tokens into the Bucket at a defined rate. In case the Bucket is full, the extra
Tokens will overflow and no more Tokens will be added.
Operation Manual – QoS
H3C S9500 Series Routing Switches
Chapter 2 Traffic Classification and Traffic
Shaping Configuration
2-3
Figure 2-2 Measuring the traffic with a token bucket
II. Measuring the traffic with Token Bucket
Whether or not the token quantity of the Token Bucket can satisfy the packets
forwarding is the basis for Token Bucket to measure the traffic specification. If enough
tokens are available for forwarding packets, traffic is regarded conforming the
specification (generally, one token is associated to the forwarding ability of one bit),
otherwise, non-conform or excess.
When measuring the traffic with Token Bucket, these parameters are included:
z Mean rate: The rate of putting Token into Bucket, i.e. average rate of the
permitting traffic. Generally set as CIR (Committed Information Rate).
z Burst size: Token Bucket’s capability, i.e. the maximum traffic size of every burst.
Generally, it is set as CBS (Committed Burst Size), and the bursting size must be
greater than the maximum packets size.
A new evaluation will be made when a new packet arrives. If there are enough tokens in
bucket for each evaluation, it shows that traffics are within the bound, and at this time
the amount of tokens appropriate for the packets forwarding rights, need to be taken
out. Otherwise, it shows that too many tokens have been used, and traffic
specifications are exceeded.
III. Complicated evaluation
Two Token Buckets can be configured to evaluate conditions that are more complex
and to implement more flexible regulation policy. For example, traffic policing has four
parameters, as follows:
z CIR (Committed information rate)
z CBS (Committed burst size)
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Chapter 2 Traffic Classification and Traffic
Shaping Configuration
2-4
z PIR (Peak information rate)
z EBS (Excess burst size)
It uses two token buckets, with the token-putting rate of every bucket set as CIR and
PIR and the capability of every bucket set as CBS and EBS (CBS < EBS, called C
bucket and E bucket), which represents different bursting class permitted. In each
evaluation, you may use different traffic control policies for different situations, such as
"C bucket has enough tokens”; "Tokens of C bucket are deficient, but those of E bucket
are enough”; "Tokens of C bucket and E bucket are all deficient”.
IV. Traffic policing
Typically, traffic policing is used to monitor the specification of certain traffic entering the
network and keep it within a reasonable bound, or it will make “penalty” on the
exceeding traffic so as to protect network resources and profits of carriers. For example,
it can restrict HTTP packets to occupy network bandwidth of no more than 50%. Once
finding the traffic of a connection exceeds, it may drop the packets or reset the
precedence of packets.
Traffic policing allows you to define match rules based on IP precedence or DiffServ
code point (DSCP). It is widely used by ISP to police the network traffic. Traffic policing
also includes the traffic classification service for the policed traffics, and depending
upon the different evaluation results, it will implement the pre-configured policing
actions, which are described as the following:
z Forward: For example, continue to forward the packets evaluated as “conform”.
z Drop: For example, dropping the packets evaluated as “not conform”.
V. Traffic shaping
Traffic shaping is an active way to adjust the traffic output rate.
The main difference between traffic shaping and traffic policing is: the packets to be
dropped in traffic policing will be stored during traffic shaping — generally they will be
put into buffer or queues, as shown in
Figure 2-3. Once there are enough tokens in
token bucket, those stored packets will be evenly sent. Another difference is that traffic
shaping may intensify delay, yet traffic policing seldom does so.
Operation Manual – QoS
H3C S9500 Series Routing Switches
Chapter 2 Traffic Classification and Traffic
Shaping Configuration
2-5
Figure 2-3 Traffic shaping diagram
For example, Switch A sends packets to Switch B. Switch B implements traffic policing
on those packets, and directly drops exceeding traffic.
To reduce unnecessary packet drop, GTS can be applied to the packets on the egress
interface of Switch A. The packets beyond the traffic specifications of GTS are stored in
Switch A. While sending the next set of packets, GTS takes out those packets from
buffer queues and sends them. Thus, all the packets sent to Switch B accord with the
traffic specification of Switch B.
Note:
z Traffic shaping cannot be configured on ports with even port numbers on XP4CA
and XP4B boards, and traffic shaping configured on a port with an odd port number
takes effect on the incoming packets of both the port with the odd port number and
the port with the even port number (the odd port number plus one).
z Traffic shaping is not available to POS interfaces.
2.4 Traffic Shaping Configuration
Traffic shaping includes the following two types:
z Queue-based traffic shaping: set traffic shaping parameters for packets in a
queue.
z Traffic shaping applicable to all the traffic: set traffic shaping parameters for all the
traffic.
Operation Manual – QoS
H3C S9500 Series Routing Switches
Chapter 2 Traffic Classification and Traffic
Shaping Configuration
2-6
I. Configuring queue-based traffic shaping
Follow these steps to configure queue-based traffic shaping:
To do… Use the command… Remarks
Enter system view
system-view
—
Enter
Ethernet
interface
view
interface interface-type
interface-number
Enter
Ethernet
interface
view or
port
group
view
Enter
port
group
view
port-group { manual
port-group-name | aggregation
agg-id }
Use either the command
Configured in Ethernet
interface view, the
setting is effective on the
current interface only;
configured in port group
view, the setting is
effective on all the ports
in the port group.
Configure traffic
shaping on the
specific port or
ports in the specific
port group
qos gts queue queue-number cir
committed-information-rate [ cbs
committed-burst-size ]
Required
Display the traffic
shaping
configuration
information
display qos gts interface
[ interface-type interface-number ]
Optional
Available in any view
Note:
z In traffic shaping configuration, the outgoing ports of XP4CA, XP4B, XP4DB,
GV48D, and GP48D boards support four queues, that is, the queue-number
argument is in the range of 0 to 3; this argument is in the range of 0 to 7 for the other
boards.
z For the description on the default value of CBS, refer to the related part in QoS
Commands.
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