B Commands

bandwidth (interface)

To set the inherited and received bandwidth values for an interface, use the bandwidth command. To restore the default values, use the no form of this command.

bandwidth { kbps | inherit [kbps] }

no bandwidth { kbps | inherit [kbps] }

Syntax Description

kbps

Informational bandwidth in kilobits per second. Valid values are from 1 to 10000000.

inherit

(Optional) Specifies that the bandwidth be inherited from the parent interface.

Command Default

1000000 kbps

Command Modes

Interface configuration mode

Subinterface configuration mode

Command History

Release

Modification

6.0(2)N1(1)

This command was introduced.

Usage Guidelines

The bandwidth command sets an informational parameter to communicate only the current bandwidth to the higher-level protocols; you cannot adjust the actual bandwidth of an interface using this command.

The bandwidth inherit command controls how a subinterface inherits the bandwidth of its main interface.

The no bandwidth inherit command enables all subinterfaces to inherit the default bandwidth of the main interface, regardless of the configured bandwidth. If a bandwidth is not configured on a subinterface, and you use the bandwidth inherit command, all subinterfaces will inherit the current bandwidth of the main interface. If you configure a new bandwidth on the main interface, all subinterfaces will use this new value.

If you do not configure a bandwidth on the subinterface and you configure the bandwidth inherit command on the main interface, the subinterfaces will inherit the specified bandwidth.

In all cases, if an interface has an explicit bandwidth setting configured, then that interface will use that setting, regardless of whether the bandwidth inheritance setting is in effect.

Examples

This example shows how to configure the badwidth for a Layer 2 interface: 

switch(config)# interface ethernet 1/5 
switch(config-if)# bandwidth 1000
switch(config-if)#

This example shows how to configure subinterfaces to inherit the bandwidth from the parent routed interface: 

switch(config)# interface ethernet 1/5 
switch(config-if)# no switchport
switch(config-if)# bandwidth inherit 30000
switch(config-if)# interface ethernet 1/1.1
switch(config-subif)#

Related Commands

Command

Description

show interface

Displays the interface configuration information.

beacon (interface)

To turn on the beacon LED for a port of an interface, use the beacon command. To turn off the beacon LED for the interface, use the no form of this command.

beacon

no beacon

Syntax Description

This command has no arguments or keywords.

Command Default

None

Command Modes

Interface configuration mode

Command History

Release

Modification

6.0(2)N1(1)

This command was introduced.

Usage Guidelines

Use the beacon command to toggle the port LED of an interface to easily identify each time a beacon is sent to check for pending packets on the interface.

Examples

This example shows how to turn on the locator beacon LED for a specific interface: 

switch(config)#interface ethernet 2/1
switch(config-if)#beacon

This example shows how to turn off the locator beacon LED for a specific interface: 

switch(config)#interface ethernet 2/1
switch(config-if)#no beacon

Related Commands

Command

Description

show interface

Displays configuration information for an interface.

bfd authentication

To configure SHA-1 authentication for all Bidirectional Forwarding Detection (BFD) sessions on the interface, use the bfd authentication command. To disable SHA-1 authentication on the interface, use the no form of the command.

bfd [fabricpath] authentication keyed-SHA1 key-id id { hex-key hex-key | key ascii-key }

no bfd [fabricpath] authentication

Syntax Description

fabricpath

(Optional) Enables BFD authentication for the fabricpath session.

key-id

Specifies the key ID to use in BFD frames.

id

Key ID value. The range is from 1 to 255.

hex-key

Specifies the HEX binary SHA1 secret.

hex-key

HEX binary SHA1 secret. A hex-key can be any case-sensitive, alphanumeric string up to 40 characters.

key

Specifies the ASCII SHA1 secret.

ascii-key

SHA1 secret value. An ASCII key can be any case-sensitive, alphanumeric string up to 20 characters.

Command Default

None

Command Modes

Interface configuration mode

Command History

Release

Modification

7.0(0)N1(1)

The fabricpath keyword was added.

6.0(2)N2(1)

This command was introduced.

Usage Guidelines

Configures SHA-1 authentication for all BFD sessions on the interface. The ascii_key string is a secret key shared among BFD peers. The id value, a number between 0 and 255, is assigned to this particular ascii_key. BFD packets specify the key by ID, allowing the use of multiple active keys.

Use the optional fabricpath keyword to configure SHA-1 authentication for fabricpath BFD sessions.

Examples

This example shows how to configure SHA-1 authentication for all BFD sessions on the interface: 

switch#configure terminal
switch(config)#interface ethernet 3/1
switch(config-if)#bfd authentication keyed-SHA1 key-id 23 key cisco123
switch(config-if)#

Related Commands

Command

Description

feature bfd

Enables the BFD feature.

bfd fabricpath

To enable a Bidirectional Forwarding Detection (BFD) fabricpath session on a specific interface, use the bfd fabricpath command. To disable the setting, use the no form of the command.

bfd fabricpath

no bfd fabricpath

Syntax Description

This command has no arguments or keywords.

Command Default

Enabled for fabricpath core ports.

Disabled for non-fabricpath ports.

Command Modes

Interface configuration mode

Command History

Release

Modification

7.0(0)N1(1)

This command was introduced.

Usage Guidelines

If the command is disabled, all sessions matching the address family on the interface will be put into admit down state. The session will be maintained and client requests for the session on the interface will be accepted.

Examples

This example shows how to enable a BFD fabricpath for an interface: 

switch#configure terminal
switch(config)#interface ethernet 3/1
switch(config-if)#bfd fabricpath

Related Commands

Command

Description

feature bfd

Enables the BFD feature.

bfd fabricpath encap-ce

To select the encapsulation mode for L2BFD frames on a per-session basis, use the [no] bfd fabricpath encap-ce command.

bfd fabricpath encap-ce

[no] bfd fabricpath encap-ce

Syntax Description

encap-ce

To select the encapsulation mode for L2BFD frames on a per-session basis. On enabling, a L2BFD frame is sent out with Ethernet encapsulation and by default it is sent with fabricpath encapsulation. The encapsulation mode cannot be changed once the session has been initiated.

Command Default

Default mode

Command Modes

Interface configuration mode

Command History

Release

Modification

7.2(0)N1(1)

This command was introduced.

Usage Guidelines

This command is mandatory for interoperability with Cisco Nexus 7000 Series switch and is optional for interoperability with other Cisco Nexus 5000 Series and Cisco Nexus 6000 Series switches.

Examples

This example shows how to enable a BFD fabricpath encapsulation for an interface: 

switch#configure terminal
switch(config)#interface int-if
switch(config-if)#bfd fabricpath encap-ce
switch(config-if)#fabricpath isis bfd

Related Commands

Command

Description

bfd fabricpath

To enable a Bidirectional Forwarding Detection (BFD) fabricpath session on a specific interface.

bfd interval

To configure Bidirectional Forwarding Detection (BFD) session parameters, use the bfd interval command. To return to the default setting, use the no form of the command.

bfd [fabricpath] interval mintx min_rx msec multiplier value

no bfd [fabricpath] interval

Syntax Description

fabricpath

(Optional) Configures BFD session parameters for the fabricpath session.

mintx

Rate at which BFD control packets are sent to BFD neighbors. The configurable range is from 250 to 999.

min_rx msec

Specifies the rate at which BFD control packets are expected to be received from BFD neighbors. The range is from 250 to 999.

multiplier value

Specifies the number of consecutive BFD control packets that must be missed from a BFD neighbor before BFD declares that the neighbor is unavailable and the BFD neighbor is informed of the failure. The range is from 3 to 50.

Command Default

BFD interval: 250 milliseconds

min_rx: 250 milliseconds

multiplier: 3

Command Modes

Global configuration mode

Interface configuration mode

Command History

Release

Modification

7.0(0)N1(1)

The fabricpath keyword was added.

6.0(2)N2(1)

This command was introduced.

Usage Guidelines

BFD session parameters configured at the interface level take precedence over the globally configured BFD session parameters.

Use the optional fabricpath keyword to configure the global parameters for fabricpath BFD sessions.


Note
The bfd fabricpath interval command cannot be enabled on a non-fabricpath port.

Examples

This example shows how to set the BFD session parameters for an interface: 

switch#configure terminal
switch(config)#interface ethernet 3/1
switch(config-if)#bfd fabricpath interval 50 min_rx 20 multiplier 3

Related Commands

Command

Description

feature bfd

Enables the BFD feature.

bfd slow-timer

To configure the Bidirectional Forwarding Detection (BFD) slow timer value, use the bfd slow-timer command. To return to the default setting, use the no form of this command.

bfd [fabricpath] slow-timer milliseconds

no bfd [fabricpath] slow-timer

Syntax Description

fabricpath

(Optional) Configures the slow timer in milliseconds, used in the echo function for the fabricpath session.

milliseconds

BFD slow timer value, in milliseconds. The range is from 1000 to 30000.

Command Default

2000 milliseconds

Command Modes

Interface configuration mode

Command History

Release

Modification

7.0(0)N1(1)

The fabricpath keyword was added.

6.0(2)N2(1)

This command was introduced.

Usage Guidelines

Configures the slow timer used in the echo function.

This value determines how fast BFD starts up a new session and at what speed the asynchronous sessions use for BFD control packets when the echo function is enabled. The slow-timer value is used as the new control packet interval, while the echo packets use the configured BFD intervals. The echo packets are used for link failure detection, while the control packets at the slower rate maintain the BFD session.

Examples

This example shows how to configure the BFD slow timer value to 14,000 milliseconds for fabricpath sessions on an interface: 

switch#configure terminal
switch(config)#interface ethernet 2/1
switch(config-if)#bfd fabricpath slow-timer 14000
switch(config-if)#

Related Commands

Command

Description

feature bfd

Enables the BFD feature.