H Commands
This chapter describes the Cisco NX-OS commands that begin with H that are used to manage a Cisco Nexus 2000 Series Fabric Extender from a Cisco Nexus 5500 switch.
hardware buffer-threshold
To limit the amount of input hardware buffer usage for each Fabric Extender, use the hardware buffer-threshold command. To revert to the default and allow a Fabric Extender to use all available hardware buffer space, use the no form of this command.
hardware fex_card_typ buffer-threshold buffer-limit
no hardware fex_card_typ buffer-threshold
Syntax Description
Command Default
Command Modes
Fabric extender configuration mode
Command History
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Usage Guidelines
Note This command is supported only on a Cisco Nexus 2148T Fabric Extender.
The Cisco Nexus 2148T Fabric Extender has four 10-Gigabit Ethernet fabric interfaces for its uplink connection to the parent Cisco Nexus 5500 Series switch and 48 1000BASE-T (1-Gigabit) Ethernet host interfaces for its downlink connection to servers or hosts.
The buffer-threshold keyword sets the consumption level of input buffers before an indication is sent to the egress queue to start observing the tail drop threshold. If the buffer usage is lower than the configured buffer threshold, the tail drop threshold is ignored.
Examples
This example shows how to configure the hardware buffer threshold limit on a Cisco Nexus 2148T Fabric Extender:
This example shows how to remove the hardware buffer threshold configured on a Cisco Nexus 2148T Fabric Extender:
Related Commands
hardware N2248PQ uplink-load-balance-mode
To enable the load balancing queues for the Cisco Nexus 2248PQ Fabric Extender, use the hardware N2248PQ uplink-load-balance-mode command. To disable load balancing queues,use the no form of this command.
hardware N2248PQ uplink-load-balance-mode
no hardware N2248PQ uplink-load-balance-mode
Syntax Description
Command Default
Command Modes
Fabric extender configuration mode
Command History
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Usage Guidelines
Note This command is supported only on a Cisco Nexus 2248PQ Fabric Extender.
The Cisco Nexus 2248PQ has 48 10-Gigabit Ethernet host interfaces with SFP+ interface adapters and 16 10-Gigabit Ethernet fabric interfaces corresponding to 4 QSFP interface adapters for its uplink connection to the parent switch.
Examples
This example shows how to enable the load balancing queues for a Cisco Nexus 2248PQ Fabric Extender:
This example shows how to disable the load balancing queues for a Cisco Nexus 2248PQ Fabric Extender:
hardware queue-limit
To control the egress queue tail drop threshold level on a Fabric Extender, use the hardware queue-limit command. To disable the drop threshold and allow a Fabric Extender to use all available hardware buffer space, use the no form of this command.
hardware fex_card_typ queue-limit [ queue-limit ] [ rx | tx ]
no hardware fex_card_typ queue-limit [ rx | tx ]
Syntax Description
Command Default
The default queue-limit for rx (ingress) on a Cisco Nexus 2248TP-E Fabric Extender is 1MB.
The default queue-limit for tx (egress) on a Cisco Nexus 2248TP-E Fabric Extender is 4MB.
Command Modes
Fabric extender configuration mode
Command History
Usage Guidelines
You can use a lower queue limit value on the Fabric Extender to prevent one blocked receiver from affecting traffic being sent to other noncongested receivers (head-of-line blocking); however, this will increase burst absorption on the ingress traffic. A higher queue limit value provides better burst absorption and less head-of-line blocking protection.
The following Cisco Nexus 2000 Series Fabric Extenders was introduced on a Cisco Nexus 5500 Series switch that runs a Cisco NX-OS release 5.1(3)N1(1):
- Cisco Nexus N2248TP-E Fabric Extender—It has four 10-Gigabit Ethernet fabric interfaces for its uplink connection to the parent Cisco Nexus 5500 Series switch and 48 1000BASE-T (1-Gigabit) Ethernet host interfaces with small form-factor pluggable (SFP+) interface adapters for its downlink connection to servers or hosts.
- Cisco Nexus 2248PQ Fabric Extender—It has 48 10-Gigabit Ethernet host interfaces with SFP+ interface adapters and 16 10-Gigabit Ethernet fabric interfaces corresponding to 4 QSFP interface adapters for its uplink connection to the parent switch.
Examples
This example shows how to configure the hardware buffer queue limit on a Cisco Nexus 2248T Fabric Extender:
This example shows how to remove the hardware buffer queue limit configured on a Cisco Nexus 2248T Fabric Extender:
Related Commands
hardware shared-buffer-size
To configure the shared buffer size for a Cisco Nexus 2000 Series Fabric Extender, use the hardware shared-buffer-size command. To revert to the default setting, use the no form of this command.
hardware fex_card_type shared-buffer-size [ buffer-size ]
no hardware fex_card_type shared-buffer-size [ buffer-size ]
Syntax Description
Command Default
Command Modes
Fabric Extender configuration mode
Command History
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Usage Guidelines
Note This command is supported only on a Cisco Nexus 2248TP-E Fabric Extender.
The Cisco Nexus N2248TP-E Fabric Extender has four 10-Gigabit Ethernet fabric interfaces for its uplink connection to the parent Cisco Nexus 5500 Series switch and 48 1000BASE-T (1-Gigabit) Ethernet host interfaces with small form-factor pluggable (SFP+) interface adapters for its downlink connection to servers or hosts.
The total available buffer is 32MB which is shared in both direction (ingress, egress).
The default size of the shared buffer is 25392KB. However, when configuring an Ethernet-based pause no-drop class, the shared buffer size changes to 10800KB. This change is required to increase the dedicated buffer that supports the pause no-drop class. The pause no-drop class does not use buffer space from the shared-pool.
Examples
This example shows how to configure the hardware buffer size on a Cisco Nexus 2248TP-E Fabric Extender:
This example shows how to remove the hardware pause no-drop configuration between a Cisco Nexus 2248TTP-E Fabric Extender and a switch:
Related Commands
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Creates a Fabric Extender and enters fabric extender configuration mode. |
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Displays all configured Fabric Extender chassis connected to the switch. |
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hardware uplink-pause-no-drop
To configure a pause no-drop class up to a distance of 3000 meters between the Cisco Nexus 2000 Series Fabric Extender and a Cisco Nexus 5500 switch, use the hardware uplink-pause-no-drop command. To revert to the default setting, use the no form of this command.
hardware fex_card_type uplink-pause-no-drop distance [ distance-value ]
no hardware fex_card_type uplink-pause-no-drop distance [ distance-value ]
Syntax Description
Command Default
The default distance between a Fabric Extender and the switch is 300 meters.
Command Modes
Fabric Extender configuration mode
Command History
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Usage Guidelines
Note This command is supported only on a Cisco Nexus 2248TP-E Fabric Extender.
The Cisco Nexus N2248TP-E Fabric Extender has four 10-Gigabit Ethernet fabric interfaces for its uplink connection to the parent Cisco Nexus 5500 Series switch and 48 1000BASE-T (1-Gigabit) Ethernet host interfaces with small form-factor pluggable (SFP+) interface adapters for its downlink connection to servers or hosts.
Examples
This example shows how to configure the hardware pause no-drop class up to a distance of 3000 meters between a Cisco Nexus 2248TTP-E Fabric Extender and a switch:
This example shows how to remove the hardware pause no-drop configuration between a Cisco Nexus 2248TTP-E Fabric Extender and a switch:
Related Commands
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Creates a Fabric Extender and enters fabric extender configuration mode. |
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Displays all configured Fabric Extender chassis connected to the switch. |
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