igmp access-limit

Function

The igmp access-limit command sets the maximum number of IGMP group memberships that can be created on an interface.

The undo igmp access-limit command cancels the setting.

By default, the maximum number of IGMP group memberships on an interface is not configured.

Format

igmp access-limit number except { acl-number | acl-name acl-name }

igmp access-limit number

undo igmp access-limit

Parameters

Parameter	Description	Value
number	Specifies the maximum number of IGMP entries that can be created on an interface.	The value is an integer ranging from 1 to 16384.
acl-number	Specifies the number of a basic or an advanced ACL.	The value is an integer. The value ranging from 2000 to 2999 specifies a basic ACL. A basic ACL filters group addresses, without distinguishing between (*, G) and (S, G) entries. The value ranging from 3000 to 3999 specifies an advanced ACL. An advanced ACL filters only (S, G) entries on an interface.
acl-name acl-name	Specifies the name of a named ACL.	The value is a string of 1 to 64 case-sensitive characters without spaces. The value must start with a letter (a to z or A to Z, case sensitive).

Parameter

Description

Value

number

Specifies the maximum number of IGMP entries that can be created on an interface.

The value is an integer ranging from 1 to 16384.

acl-number

Specifies the number of a basic or an advanced ACL.

The value is an integer.

The value ranging from 2000 to 2999 specifies a basic ACL. A basic ACL filters group addresses, without distinguishing between (*, G) and (S, G) entries.
The value ranging from 3000 to 3999 specifies an advanced ACL. An advanced ACL filters only (S, G) entries on an interface.

acl-name acl-name

Specifies the name of a named ACL.

The value is a string of 1 to 64 case-sensitive characters without spaces. The value must start with a letter (a to z or A to Z, case sensitive).

Views

100ge sub-interface view, 100GE interface view, 10GE sub-interface view, 10GE interface view, 200GE sub-interface view, 25GE sub-interface view, 25GE interface view, 400GE sub-interface view, 400GE interface view, 40GE sub-interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk sub-interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE sub-interface view, GE interface view, GE electrical interface view, Global VE sub-interface view, PW-VE sub-interface view, VBDIF interface view, VE sub-interface view, VLANIF interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
igmp	write

Usage Guidelines

Usage Scenario

When a large number of multicast users request multiple programs simultaneously, excessive bandwidth resources will be exhausted, and the Router's performance will be degraded, deteriorating the multicast service quality. To prevent this issue, run the igmp access-limit command on a Router interface to limit the number of IGMP entries. When receiving an IGMP Join message from a user, the Router interface first checks whether the configured maximum number of IGMP entries is reached. If the maximum number is reached, the Router interface discards the IGMP Join message and rejects the user. If the maximum number is not reached, the Router interface sets up an IGMP membership and forwards data flows of the requested multicast group to the user. This mechanism enables users who have successfully joined multicast groups to enjoy smoother multicast services.

The principles of counting the number of IGMP entries are as follows:

Each (*, G) entry is counted as one entry on an interface, and each (S, G) is counted as one entry on an interface.
SSM-mapping (*, G) entries are not counted as entries on an interface, and each (S, G) entry mapped using the SSM-mapping mechanism is counted as one entry on an interface.

Prerequisites

The multicast routing function has been enabled using the multicast routing-enable command.

Precautions

To use except, an ACL must be configured to filter IGMP Join messages received by an interface. If except is specified, the maximum number of IGMP entries is not effective for multicast groups that match the specified ACL. If except is not specified, the maximum number is effective for all multicast groups, including source-specific groups.

The igmp access-limit command requires an ACL configured using the acl (basic ACL) or acl (advanced ACL) command. To use a numbered ACL, perform either of the following operations to configure an ACL rule:

In the basic ACL view, specify the source parameter in the rule command to set the range of multicast groups whose IGMP entries are not limited.
In the advanced ACL view, specify the source parameter in the rule command to set the range of sources that are allowed to send multicast data to multicast groups. Specify the destination parameter in the rule command to set the range of multicast groups whose IGMP entries are not limited.
If the igmp access-limit command is run more than once, the latest configuration overrides the previous one.

Example

# Create a named ACL myacl, and configure a rule for the named ACL to allow hosts to receive messages sent by multicast source 1.1.1.1 to multicast group 232.0.0.0/16. Specify 1024 as the maximum number of IGMP entries that can be created on GE 0/1/0, and exclude IGMP entries with the multicast group address 232.0.0.0/16 from this maximum number limit.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] acl name myacl
[*HUAWEI-acl4-advance-myacl] rule permit ip source 1.1.1.1 0 destination 232.0.0.0 0.0.255.255
[*HUAWEI-acl4-advance-myacl] quit
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] igmp access-limit 1024 except acl-name myacl

# Specify 1024 as the maximum number of IGMP entries that can be created on GE 0/1/0.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] igmp access-limit 1024