bgp instance

Function

The bgp instance command enables BGP and enter the BGP multi-instance view.

The undo bgp instance command disables BGP.

By default, the BGP is disabled.

Format

bgp as-number instance instance-name

undo bgp as-number instance instance-name

Parameters

Parameter	Description	Value
as-number	Specifies a destination AS number.	For an integral AS number, the value is an integer ranging from 1 to 4294967295. For an AS number in dotted notation, the value is in the format of x.y, where x and y are integers ranging from 1 to 65535 and from 0 to 65535, respectively.
instance instance-name	Specifies the name of a BGP multi-instance.	The value is a string of 1 to 31 case-sensitive characters, spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string.

Parameter

Description

Value

as-number

Specifies a destination AS number.

For an integral AS number, the value is an integer ranging from 1 to 4294967295.

For an AS number in dotted notation, the value is in the format of x.y, where x and y are integers ranging from 1 to 65535 and from 0 to 65535, respectively.

instance instance-name

Specifies the name of a BGP multi-instance.

The value is a string of 1 to 31 case-sensitive characters, spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string.

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bgp	write

Usage Guidelines

Usage Scenario

BGP is an inter-AS dynamic routing protocol. BGP is called Internal BGP (IBGP) when it runs within an AS and called External BGP (EBGP) when it runs between ASs.

BGP transmits routes between ASs; however, it may not be required in some situations.

BGP is used only when at least one of the following conditions is met:

An AS allows packets to traverse it to reach other ASs.
An AS has multiple external connections to multiple ISPs and multiple connections to the Internet.
Data flows entering or leaving an AS must be controlled.

BGP is not required in the following situations:

Users are connected to only one ISP.
The ISP does not need to provide Internet routes for users.
ASs are connected using default routes.

Configuration Impact

After the bgp command is run, BGP is enabled.

Follow-up Procedure

Run the peer as-number command to establish BGP peer relationships between devices on a BGP network.

Precautions

Each device runs in only one AS; therefore, each device can be specified with only one local AS number.

By default, an AS number must be specified when you run the undo bgp command. If the re-confirmation function is disabled for undo commands using the configuration prevent-misoperation disable command, an AS number is optional when you run the undo bgp command.

Exercise caution when using the undo bgp command because it will delete all BGP configurations from a device.

Example

# Enable BGP and enter the BGP multi-instance view.

<HUAWEI> system-view
[~HUAWEI] bgp 100 instance instance100