A quality of service (QoS) policy is a mechanism for mitigating network traffic congestion. You can use QoS policies to specify appropriate data transmission priorities for the communication traffic of various services in the network. For example, you can use QoS policies to define different priorities for different services. This ensures that high-priority services can preferentially obtain the required bandwidth and run as expected.
The QoS policy feature is in invitational preview. To try this feature out, contact your Alibaba Cloud account manager to apply for the qualification.
Prerequisites
Billing is enabled for the outbound data transfer feature. For more information, see Outbound data transfer fees.
The resource to be associated with a QoS policy is a dedicated Express Connect circuit. You cannot associate a QoS policy with a shared Express Connect circuit or a virtual border router (VBR).
Billing
The QoS policy feature is in invitational preview. You can use the QoS policy feature free of charge.
Overview
You can use a QoS policy of Express Connect to create two types of priority queues: high-priority queues and standard queues. One or more traffic classification rules can be added to each type of priority queue. QoS policies divide traffic to match priority queues and schedule traffic based on priorities. High-priority traffic is preferentially scheduled and forwarded.
The following table describes the key terms that are used in QoS policies.
Term | Description |
high-priority queue | High-priority queues preferentially allocate bandwidth to high-priority services to ensure traffic forwarding for high-priority services. |
standard queue | Standard queues allocate the bandwidth that is not occupied by high-priority queues based on the specified bandwidth percentage. Standard queues can use the idle bandwidth of each other to maximize the bandwidth utilization. |
traffic classification rule | A traffic classification rule is an identifier that is used to identify and classify data in a network. In a QoS policy, you can create a traffic classification rule by configuring a six-tuple. The six-tuple consists of the following elements:
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Scenarios
Audio and video calls
In Voice over IP (VoIP) and real-time video conferencing scenarios, high-quality audio and image transmission critically depends on low latency and minimal packet loss. Latency or packet loss may lead to dropped calls or blurred images. You can use a QoS policy to configure queue priorities and traffic classification rules to manage bandwidth usage. This way, you can prevent excessive bandwidth consumption by other services to ensure the stable transmission of real-time traffic.
Streaming media services
When you use online streaming media services, you want videos or music to be continuously played without buffering or interruptions caused by network issues. To achieve this, you can configure a QoS policy to increase the priority of the packets of the online streaming media services to allocate sufficient bandwidth to the packets.
Office
When offshore employees connect to the corporate intranet over a VPN, they require a stable network connection to maintain work efficiency. You can configure a QoS policy to ensure that remote connections to the corporate intranet are not interrupted by other traffic in the local network.
Critical data transmission and backup
For enterprises, regular data backups are critical to ensure service continuity. Transmission of large amounts of data consumes significant network bandwidth and necessitates a low packet loss rate. You can configure a QoS policy to preferentially allocate sufficient bandwidth for these data backups to reduce packet loss due to congestion from burst traffic.
Limits
You can create only one high-priority queue in each QoS policy.
Each dedicated Express Connect circuit can be associated with only one QoS policy.
Quotas
Quota | Description | Default value | Adjustable |
ec_max_qos_num | The maximum number of QoS policies that a user can create. | 5 | Yes Note To increase the quota, contact your account manager. |
ec_max_qos_queue_num | The maximum number of queues that can be created in a QoS policy. | 3 | |
ec_max_qos_queue_rule_num | The maximum number of traffic classification rules that can be created for each queue. | 5 |
Flowchart
Create a QoS policy
Log on to the Express Connect console.
In the top navigation bar, select a region based on your business requirements.
In the left-side navigation pane, click QoS Policies.
On the QoS Policies page, click Create QoS Policy.
On the Create QoS Policy page, configure the parameters that are described in the following table and click OK.
Parameter
Description
Policy Name
The name of the QoS policy.
Policy Description
The description of the QoS policy.
Queue Information
Queue Name: the name of the queue.
Queue Priority: the priority of the queue. Valid values:
High-priority: You can create only one high-priority queue in a QoS policy.
Standard: By default, you can create up to two standard queues in a QoS policy.
Allocated Bandwidth: the percentage of bandwidth allocated to a standard queue. The total percentage of bandwidth allocated to standard queues cannot exceed 100%.
Queue Description: the description of the queue.
Traffic Classification Rules
The traffic classification rule to be created for the queue. To create a traffic classification rule, configure the following parameters:
Rule Name: the name of the traffic classification rule.
Priority: the priority of the traffic classification rule. The greater the value, the higher the priority. The priority of a traffic classification rule must be unique within the same QoS policy. Valid values: 1 to 9000.
Protocol Type: the type of the protocol. The supported protocols provided in this topic are for reference only. The actual protocols supported in the console prevail.
CIDR Block Type: the type of the CIDR block. Valid values:
IPv4
IPv6
Source CIDR Block: the CIDR block from which data packets are sent.
Destination CIDR Block: the CIDR block to which data packets are sent.
Source Port: the port from which data packets are sent.
Valid values: 1 to 65535 and -1.
Set the source port range in one of the following formats: 1/200 and 80/80. A value of -1/-1 specifies all ports.
Destination Port: the port to which data packets are sent.
Valid values: 1 to 65535 and -1.
Set the destination port range in one of the following formats: 1/200 and 80/80. A value of -1/-1 specifies all ports.
DSCP Value: the DSCP value of traffic.
Valid values: 0 to 63. Default value: -1, which specifies no limits on the DSCP value.
Remark DSCP: Specifies whether to remark your traffic with a new DSCP value. If you enable Remark DSCP, you can modify the DSCP value of your traffic.
Rule Description: the description of the traffic classification rule.
Create a queue in a QoS policy
Log on to the Express Connect console.
In the top navigation bar, select a region based on your business requirements.
In the left-side navigation pane, click QoS Policies.
On the QoS Policies page, click the ID of the QoS policy that you want to manage to go to the details page of the QoS policy.
On the details page of the QoS policy, click the Queue tab. On the Queue tab, click Create Queue.
In the Create Queue dialog box, configure the parameters that are described in the following table and click OK.
Parameter
Description
Queue Name
The name of the queue.
Queue Priority
The priority of the queue. Valid values:
High-priority
Standard
NoteIf you have created a high-priority queue in the QoS policy, you cannot set this parameter to High-priority.
Allocated Bandwidth
The percentage of bandwidth allocated to a standard queue. The total percentage of bandwidth allocated to standard queues cannot exceed 100%.
NoteThis parameter is required if you set the Queue Priority parameter to Standard.
Queue Description
The description of the queue.
Create a traffic classification rule for a queue
To create a traffic classification rule for a high-priority queue or standard queue, perform the following operations:
Log on to the Express Connect console.
In the top navigation bar, select a region based on your business requirements.
In the left-side navigation pane, click QoS Policies.
On the QoS Policies page, click the ID of the QoS policy that you want to manage to go to the details page of the QoS policy.
On the details page of the QoS policy, click the Queue tab. On the Queue tab, click the ID of the queue for which you want to create a traffic classification rule. In the Traffic Classification Rules section, click Create Rule.
In the Create Rule dialog box, configure the parameters that are described in the following table and click OK.
Rule Name
The name of the traffic classification rule.
Priority
The priority of the traffic classification rule. The greater the value, the higher the priority. The priority of a traffic classification rule must be unique within the same QoS policy. Valid values: 1 to 9000.
Protocol Type
The type of the protocol. The supported protocols provided in this topic are for reference only. The actual protocols supported in the console prevail.
CIDR Block Type
The type of the CIDR block. Valid values:
IPv4
IPv6
Source CIDR Block
The CIDR block from which data packets are sent.
Destination CIDR Block
The CIDR block to which data packets are sent.
Source Port
The port from which data packets are sent. Valid values: 1 to 65535 and -1.
Set the source port range in one of the following formats: 1/200 and 80/80. A value of -1/-1 specifies all ports.
Destination Port
The port to which data packets are sent. Valid values: 1 to 65535 and -1.
Set the destination port range in one of the following formats: 1/200 and 80/80. A value of -1/-1 specifies all ports.
DSCP Value
The DSCP value of traffic. Valid values: 0 to 63. Default value: -1, which specifies no limits on the DSCP value.
Remark DSCP
Specifies whether to remark your traffic with a new DSCP value. If you enable Remark DSCP, you can modify the DSCP value of your traffic.
Rule Description
The description of the traffic classification rule.
Associate an Express Connect circuit with a QoS policy
Log on to the Express Connect console.
In the top navigation bar, select a region based on your business requirements.
In the left-side navigation pane, click QoS Policies.
On the QoS Policies page, find the QoS policy that you want to manage. You can use one of the following methods to associate an Express Connect circuit with the QoS policy:
Method 1:
Click Add Instance in the Actions column of the QoS policy.
On the Associate Instance page, select the Express Connect circuit that you want to associate with the QoS policy and click OK.
Method 2:
Click the ID of the QoS policy that you want to manage to go to the details page of the QoS policy. On the details page of the QoS policy, click the Associated Instances tab.
On the Associated Instances tab, click Associate Instance.
On the Associate Instance page, select the Express Connect circuit that you want to associate with the QoS policy and click OK.
What to do next
Disassociate an Express Connect circuit from a QoS policy
Log on to the Express Connect console.
In the top navigation bar, select a region based on your business requirements.
In the left-side navigation pane, click QoS Policies.
On the QoS Policies page, click the ID of the QoS policy that you want to manage to go to the details page of the QoS policy.
On the Associated Instances tab, find the Express Connect circuit that you want to disassociate from the QoS policy and click Disassociate in the Actions column.
Delete a QoS policy
Log on to the Express Connect console.
In the top navigation bar, select a region based on your business requirements.
In the left-side navigation pane, click QoS Policies.
On the QoS Policies page, find the QoS policy that you want to delete and click Delete in the Actions column.
In the message that appears, click OK.