Configuring Interface Characteristics

Information About Interface Characteristics

The following sections provide information about interface characteristics.

Interface Types

This section describes the different types of interfaces supported by the device. The rest of the chapter describes configuration procedures for physical interface characteristics.


Note

The stack ports on the rear of the stacking-capable devices are not Ethernet ports and cannot be configured.

Port-Based VLANs

A VLAN is a switched network that is logically segmented by function, team, or application, without regard to the physical location of the users. Packets received on a port are forwarded only to ports that belong to the same VLAN as the receiving port. Network devices in different VLANs cannot communicate with one another without a Layer 3 device to route traffic between the VLANs.

VLAN partitions provide hard firewalls for traffic in the VLAN, and each VLAN has its own MAC address table. A VLAN comes into existence when a local port is configured to be associated with the VLAN, when the VLAN Trunking Protocol (VTP) learns of its existence from a neighbor on a trunk, or when a user creates a VLAN. VLANs can be formed with ports across the stack.

To configure VLANs, use the vlan vlan-id global configuration command to enter VLAN configuration mode. The VLAN configurations for normal-range VLANs (VLAN IDs 1 to 1005) are saved in the VLAN database. If VTP is version 1 or 2, to configure extended-range VLANs (VLAN IDs 1006 to 4094), you must first set VTP mode to transparent. Extended-range VLANs created in transparent mode are not added to the VLAN database but are saved in the running configuration. With VTP version 3, you can create extended-range VLANs in client or server mode in addition to transparent mode. These VLANs are saved in the VLAN database.

In a switch stack, the VLAN database is downloaded to all switches in a stack, and all switches in the stack build the same VLAN database. The running configuration and the saved configuration are the same for all switches in a stack.

Add ports to a VLAN by using the switchport command in interface configuration mode.

  • Identify the interface.

  • For a trunk port, set trunk characteristics, and, if desired, define the VLANs to which it can belong.

  • For an access port, set and define the VLAN to which it belongs.

Switch Ports

Switch ports are Layer 2-only interfaces associated with a physical port. Switch ports belong to one or more VLANs. A switch port can be an access port or a trunk port. You can configure a port as an access port or trunk port or let the Dynamic Trunking Protocol (DTP) operate on a per-port basis to set the switchport mode by negotiating with the port on the other end of the link. Switch ports are used for managing the physical interface and associated Layer 2 protocols and do not handle routing or bridging.

Configure switch ports by using the switchport interface configuration commands.

Access Ports

An access port belongs to and carries the traffic of only one VLAN (unless it is configured as a voice VLAN port). Traffic is received and sent in native formats with no VLAN tagging. Traffic arriving on an access port is assumed to belong to the VLAN assigned to the port. If an access port receives a tagged packet (Inter-Switch Link [ISL] or IEEE 802.1Q tagged), the packet is dropped, and the source address is not learned.

The types of access ports supported are:

  • Static access ports are manually assigned to a VLAN (or through a RADIUS server for use with IEEE 802.1x.

You can also configure an access port with an attached Cisco IP Phone to use one VLAN for voice traffic and another VLAN for data traffic from a device attached to the phone.

Trunk Ports

A trunk port carries the traffic of multiple VLANs and by default is a member of all VLANs in the VLAN database. The IEEE 802.1Q trunk port type is supported. An IEEE 802.1Q trunk port supports simultaneous tagged and untagged traffic. An IEEE 802.1Q trunk port is assigned a default port VLAN ID (PVID), and all untagged traffic travels on the port default PVID. All untagged traffic and tagged traffic with a NULL VLAN ID are assumed to belong to the port default PVID. A packet with a VLAN ID equal to the outgoing port default PVID is sent untagged. All other traffic is sent with a VLAN tag.

Although by default, a trunk port is a member of every VLAN known to the VTP, you can limit VLAN membership by configuring an allowed list of VLANs for each trunk port. The list of allowed VLANs does not affect any other port but the associated trunk port. By default, all possible VLANs (VLAN ID 1 to 4094) are in the allowed list. A trunk port can become a member of a VLAN only if VTP knows of the VLAN and if the VLAN is in the enabled state. If VTP learns of a new, enabled VLAN and the VLAN is in the allowed list for a trunk port, the trunk port automatically becomes a member of that VLAN and traffic is forwarded to and from the trunk port for that VLAN. If VTP learns of a new, enabled VLAN that is not in the allowed list for a trunk port, the port does not become a member of the VLAN, and no traffic for the VLAN is forwarded to or from the port.

Tunnel Ports

Tunnel ports are used in IEEE 802.1Q tunneling to segregate the traffic of customers in a service-provider network from other customers who are using the same VLAN number. You configure an asymmetric link from a tunnel port on a service-provider edge switch to an IEEE 802.1Q trunk port on the customer switch. Packets entering the tunnel port on the edge switch, already IEEE 802.1Q-tagged with the customer VLANs, are encapsulated with another layer of an IEEE 802.1Q tag (called the metro tag), containing a VLAN ID unique in the service-provider network, for each customer. The double-tagged packets go through the service-provider network keeping the original customer VLANs separate from those of other customers. At the outbound interface, also a tunnel port, the metro tag is removed, and the original VLAN numbers from the customer network are retrieved.

Tunnel ports cannot be trunk ports or access ports and must belong to a VLAN unique to each customer.

Routed Ports

A routed port is a physical port that acts like a port on a router; it does not have to be connected to a router. A routed port is not associated with a particular VLAN, as is an access port. A routed port behaves like a regular router interface, except that it does not support VLAN subinterfaces. Routed ports can be configured with a Layer 3 routing protocol. A routed port is a Layer 3 interface only and does not support Layer 2 protocols, such as DTP and STP.

Configure routed ports by putting the interface into Layer 3 mode with the no switchport interface configuration command. Then assign an IP address to the port, enable routing, and assign routing protocol characteristics by using the ip routing and router protocol global configuration commands.


Note

Entering a no switchport interface configuration command shuts down the interface and then re-enables it, which might generate messages on the device to which the interface is connected. When you put an interface that is in Layer 2 mode into Layer 3 mode, the previous configuration information related to the affected interface might be lost.


Note

A port configured as a switchport does not support MAC address configuration. It does not support the mac-address x.x.x command.

The number of routed ports that you can configure is not limited by software. However, the interrelationship between this number and the number of other features being configured might impact CPU performance because of hardware limitations.

Switch Virtual Interfaces

A switch virtual interface (SVI) represents a VLAN of switch ports as one interface to the routing function in the system. You can associate only one SVI with a VLAN. You configure an SVI for a VLAN only to route between VLANs or to provide IP host connectivity to the device. By default, an SVI is created for the default VLAN (VLAN 1) to permit remote device administration. Additional SVIs must be explicitly configured.


Note

You cannot delete interface VLAN 1.

SVIs provide IP host connectivity only to the system. SVIs are created the first time that you enter the vlan interface configuration command for a VLAN interface. The VLAN corresponds to the VLAN tag associated with data frames on an ISL or IEEE 802.1Q encapsulated trunk or the VLAN ID configured for an access port. Configure a VLAN interface for each VLAN for which you want to route traffic, and assign it an IP address.

You can also use the interface range command to configure existing VLAN SVIs within the range. The commands entered under the interface range command are applied to all existing VLAN SVIs within the range. You can enter the command interface range create vlan x - y to create all VLANs in the specified range that do not already exist. When the VLAN interface is created, interface range vlan id can be used to configure the VLAN interface.

Although the device stack or standalone device supports a total of 1005 VLANs and SVIs, the interrelationship between the number of SVIs and routed ports and the number of other features being configured might impact CPU performance because of hardware limitations.

When you create an SVI, it does not become active until it is associated with a physical port.

EtherChannel Port Groups

EtherChannel port groups treat multiple switch ports as one switch port. These port groups act as a single logical port for high-bandwidth connections between devices or between devices and servers. An EtherChannel balances the traffic load across the links in the channel. If a link within the EtherChannel fails, traffic previously carried over the failed link changes to the remaining links. You can group multiple trunk ports into one logical trunk port, group multiple access ports into one logical access port, group multiple tunnel ports into one logical tunnel port, or group multiple routed ports into one logical routed port. Most protocols operate over either single ports or aggregated switch ports and do not recognize the physical ports within the port group. Exceptions are the DTP, the Cisco Discovery Protocol (CDP), and the Port Aggregation Protocol (PAgP), which operate only on physical ports.

When you configure an EtherChannel, you create a port-channel logical interface and assign an interface to the EtherChannel. For Layer 3 interfaces, you manually create the logical interface by using the interface port-channel global configuration command. Then you manually assign an interface to the EtherChannel by using the channel-group interface configuration command. For Layer 2 interfaces, use the channel-group interface configuration command to dynamically create the port-channel logical interface. This command binds the physical and logical ports together.

Uplink Ports

A supervisor module has 10 uplink ports, named 1 to 10. The first eight uplink ports, 1 to 8, use Small Form-Factor Pluggable (SFP) transceivers or SFP+ transceivers and uplink ports 9 and 10 use Quad Small Form-Factor Pluggable (QSFP) transceivers. Ports 1 to 8 are 10-Gigabit Ethernet ports that support both 10G and 1G transceivers. Ports 9 and 10 are the QSFP ports that support 40-Gigabit Ethernet uplinks. Additionally, Supervisor1XL25 supports 25-Gigabit Ethernet uplinks on ports 1 and 5. These ports 1 and 5 on Supervisor1XL25 use SFP28 transceivers to support 25-Gigabit mode.

By default, the 10-Gigabit Ethernet ports 1 to 8 are enabled.

Uplink Ports on Cisco Catalyst 9400 Series Supervisor1XL25 Module

The 10 uplink ports on Supervisor XL25 are grouped into two groups to support different speed configurations.

Port Group 1 supports 10G on ports 1 to 4; 25G on port 1 and 40G on port 9.

Port Group 2 supports 10G on ports 5 to 8; 25G on port 5 and 40G on port 10.

See the following table for port groupings and configurable speeds for Supervisor1XL25.

Table 1. Port Groupings on Cisco Catalyst 9400 Series Supervisor1XL25

Port Group

Port

Speed

Port Group 1

(ports 1,2,3,4,9)

1

10G or 25G

2 - 4

10G

9

40G

Port Group 2

(ports 5,6,7,8,10)

5

10G or 25G

6 - 8

10G

10

40G

Speeds 10G, 25G and 40G are mutually exclusive per port group. You can enable any one speed on a port group, at any given time.

For example, if you enable 25G on port 1, all the other speeds in Port Group 1 are disabled. If you configure 40G on port 10, 25G and 10G are disabled on the remaining ports in Port Group 2.


Note

In a dual supervisor configuration (High Availability scenario), the ports in Port Group 2 are inactive. Only the ports in Port Group 1 are active.

Examples

The following examples are commands on Supervisor1XL25 Module fitted on a 10-slot chassis.

The following command enables 25G on port 1:
Switch(config)# interface TwentyFiveGigE5/0/1
Switch(config-if)# enable
Switch(config-if)#
The following command disables 25G on port 1:
Switch(config)# interface TwentyFiveGigE5/0/1
Switch(config-if)# no enable
*Jun  4 11:55:54.316: %TRANSCEIVER-6-REMOVED: R0/0: iomd: Transceiver module removed from TwentyfiveGigabitEthernet5/0/1
The following command throws an error because it tries to configure 40G on port 9 when 25G is already configured on port 1:
Switch(config)# interface FortyGigabitE5/0/9
Switch(config-if)# enable
Twe5/0/1 currently configured with enable command - remove this before enabling on FortyGigabitE5/0/9
Uplink Ports on Cisco Catalyst 9400 Series Supervisor2XL Module

The 8 uplink ports on Supervisor2XL are grouped into four groups to support different speed configurations.

Port Group 1 supports 25G on ports 1 to 4, and 100G on port 5, which is shared by ports 1 to 4.

Port Groups 2 to 4 supports 100G on ports 6 to 8.

In a redundant setup, ports 1 to 6 are used, and ports 7 and 8 are inactivate.

See the following table for port groupings and configurable speeds for Supervisor2XL.

Table 2. Port Groupings on Cisco Catalyst 9400 Series Supervisor2XL

Port Group

Port

Speed

Port Group 1

(ports 1,2,3,4,5)

1 - 4

25G

5

100G

Port Group 2

(port 6)

6

100G

Port Group 3

(port 7)

7

100G

Port Group 4

(port 8)

8

100G

There are a total of 4 port groups operating at 100G speed, where ports 1 to 4 operating at 25G and port 5 operating at 100G are mutually exclusive.

Examples

The following examples are commands on Supervisor2 and Supervisor2XL module fitted on a 10-slot chassis.

The following command enables 100G on port 5 and disables port 1 to 4:
Switch(config)# interface HundredGigE5/0/5
Switch(config-if)# enable
Switch(config-if)#
May 25 11:18:01.586 PDT: %TRANSCEIVER-6-REMOVED: C5/0: iomd: Transceiver module removed from TwentyFiveGigE5/0/1
May 25 11:18:01.590 PDT: %TRANSCEIVER-6-REMOVED: C5/0: iomd: Transceiver module removed from TwentyFiveGigE5/0/2
May 25 11:18:01.593 PDT: %TRANSCEIVER-6-REMOVED: C5/0: iomd: Transceiver module removed from TwentyFiveGigE5/0/3
May 25 11:18:01.596 PDT: %TRANSCEIVER-6-REMOVED: C5/0: iomd: Transceiver module removed from TwentyFiveGigE5/0/4
May 25 11:18:05.767 PDT: %TRANSCEIVER-6-INSERTED: C5/0: iomd: transceiver module inserted in HundredGigE5/0/5
The following command disables 100G on port 5 and enables port 1 to 4:
Switch(config)# interface HundredGigE5/0/5
Switch(config-if)# no enable
May 25 11:18:29.832 PDT: %TRANSCEIVER-6-REMOVED: C5/0: iomd: Transceiver module removed from HundredGigE5/0/5
May 25 11:18:31.011 PDT: %TRANSCEIVER-6-INSERTED: C5/0: iomd: transceiver module inserted in TwentyFiveGigE5/0/1
May 25 11:18:31.015 PDT: %TRANSCEIVER-6-INSERTED: C5/0: iomd: transceiver module inserted in TwentyFiveGigE5/0/2
May 25 11:18:31.019 PDT: %TRANSCEIVER-6-INSERTED: C5/0: iomd: transceiver module inserted in TwentyFiveGigE5/0/3
May 25 11:18:31.022 PDT: %TRANSCEIVER-6-INSERTED: C5/0: iomd: transceiver module inserted in TwentyFiveGigE5/0/4
Power over Ethernet

The Power over Ethernet (PoE) technology allows PoE (802.3af standard), PoE+ (802.3at), and PoE++ (802.3bt) ports to supply power for the operation of a device.

Cisco Universal Power Over Ethernet (Cisco UPoE) extends the IEEE PoE+ standard to double the power per port to 60 watts.

Cisco Universal Power Over Ethernet Plus (Cisco UPoE+) combines the new IEEE 802.3bt standard and Cisco UPoE to increase the power per port to 90 watts. The 802.3bt-compliant Type 4 powered devices support up to 90watts.

For more information, see the Configuring PoE section of this guide.

Using the Switch USB Ports

The has two USB ports on the front panel — a USB mini-Type B console port and a USB Type A port.

USB Mini-Type B Console Port

The device has the following console ports:

  • USB mini-Type B console connection

  • RJ-45 console port

Console output appears on devices connected to both ports, but console input is active on only one port at a time. By default, the USB connector takes precedence over the RJ-45 connector.


Note
Windows PCs require a driver for the USB port. See the hardware installation guide for driver installation instructions.

Use the supplied USB Type A-to-USB mini-Type B cable to connect a PC or other device to the device. The connected device must include a terminal emulation application. When the device detects a valid USB connection to a powered-on device that supports host functionality (such as a PC), input from the RJ-45 console is immediately disabled, and input from the USB console is enabled. Removing the USB connection immediately reenables input from the RJ-45 console connection. An LED on the device shows which console connection is in use.

Console Port Change Logs

At software startup, a log shows whether the USB or the RJ-45 console is active. Every device always first displays the RJ-45 media type.

In the sample output, device 1 has a connected USB console cable. Because the bootloader did not change to the USB console, the first log from the device shows the RJ-45 console. A short time later, the console changes and the USB console log appears.

When the USB cable is removed or the PC de-activates the USB connection, the hardware automatically changes to the RJ-45 console interface:

You can configure the console type to always be RJ-45, and you can configure an inactivity timeout for the USB connector.

USB Type A Port

The USB Type A port provides access to external USB flash devices, also known as thumb drives or USB keys. The port supports Cisco USB flash drives, USB 2.0 and USB 3.0, with capacities from 128 MB to 16 GB (USB devices with port densities of 128 MB, 256 MB, 1 GB, 4 GB, 8 GB, and 16 GB are supported). USB 3.0 is also called SuperSpeed USB, used for higher file transfer rates. You can use standard Cisco IOS command- line interface (CLI) commands to read, write, erase, and copy to or from the flash device. You can also configure the devices to boot from the USB flash drive.

USB 2.0 Host Port

The USB 2.0 host port provides access to external USB flash devices, also known as thumb drives or USB keys. The port supports Cisco USB flash drives with capacities from 128 MB to 16 GB (USB devices with port densities of 128 MB, 256 MB, 1 GB, 4 GB, 8 GB, and 16 GB are supported). You can use standard Cisco IOS command-line interface (CLI) commands to read, write, erase, and copy to or from the flash device. You can also configure the device to boot from the USB flash drive.

Disabling USB Ports

From Cisco IOS XE Bengaluru 17.5.x, all the USB ports in a standalone or stacked device can be disabled using the platform usb disable command. To reenable the USB ports, use the no platform usb disable command.

When a USB port is disabled, no system messages are generated if a USB is inserted.


Note

The platform usb disable command does not disable Bluetooth dongles connected to USB ports.

This command works on a device configured with Cisco StackWise Virtual.

Interface Connections

Devices within a single VLAN can communicate directly through any switch. Ports in different VLANs cannot exchange data without going through a routing device. With a standard Layer 2 device, ports in different VLANs have to exchange information through a router. By using the device with routing enabled, when you configure both VLAN 20 and VLAN 30 with an SVI to which an IP address is assigned, packets can be sent from Host A to Host B directly through the device with no need for an external router.

Figure 1. Connecting VLANs with a Switch

When the Network Advantage license is used on the device or the active device, the device uses the routing method to forward traffic between interfaces. If the Network Essentials license is used on the device or the active device, only basic routing (static routing and RIP) is supported. Whenever possible, to maintain high performance, forwarding is done by the device hardware. However, only IPv4 packets with Ethernet II encapsulation are routed in hardware.

The routing function can be enabled on all SVIs and routed ports. The device routes only IP traffic. When IP routing protocol parameters and address configuration are added to an SVI or routed port, any IP traffic received from these ports is routed.

Interface Configuration Mode

The device supports these interface types:

  • Physical ports: Device ports and routed ports

  • VLANs: Switch virtual interfaces

  • Port channels: EtherChannel interfaces

You can also configure a range of interfaces.

To configure a physical interface (port), specify the interface type, stack member number (only stacking-capable switches), module number, and device port number, and enter interface configuration mode.

  • Type: Gigabit Ethernet (GigabitEthernet or gi) for 10/100/1000 Mbps Ethernet ports, 2.5-Gigabit Ethernet (TwoGigabitEthernet or tw) for 2.5 Gbps, 5-Gigabit Ethernet (FiveGigabitEthernet or fi) for 5 Gbps, 10-Gigabit Ethernet (TenGigabitEthernet or te) for 10 Gbps, 25-Gigabit Ethernet (TwentyFiveGigE or twe) for 25 Gbps, small form-factor pluggable (SFP) module Gigabit Ethernet and 10-Gigabit Ethernet interfaces and quad small-form-factor pluggable (QSFP) module 40-Gigabit Ethernet (FortyGigabitEthernet or fo) for 40 Gbps, and 100-Gigabit Ethernet (HundredGigE or hu) for 100 Gbps.

  • Switch number: The number that identifies the given device. The number range is assigned the first time the device initializes.

    Stack member number: The number that identifies the device within the stack. The device number range is 1 to 8 and is assigned the first time the device initializes. The default device number, before it is integrated into a device stack, is 1. When a device has been assigned a stack member number, it keeps that number until another is assigned to it.

  • Module number: The module or slot number on the device: switch (downlink) ports are 0, and uplink ports are 1.

  • On a device with SFP uplink ports, the module number is 1 and the port numbers restart. For example, if the device has 24 10/100/1000 ports, the SFP module ports are GigabitEthernet1/1/1 through GigabitEthernet1/1/4 or TenGigabitEthernet1/1/1 through TenGigabitEthernet1/1/4.

You can identify physical interfaces by physically checking the interface location on the device. You can also use the show privileged EXEC commands to display information about a specific interface or all the interfaces on the switch. The remainder of this chapter primarily provides physical interface configuration procedures.

    Default Ethernet Interface Configuration

    To configure Layer 2 parameters, if the interface is in Layer 3 mode, you must enter the switchport interface configuration command without any parameters to put the interface into Layer 2 mode. This shuts down the interface and then re-enables it, which might generate messages on the device to which the interface is connected. When you put an interface that is in Layer 3 mode into Layer 2 mode, the previous configuration information related to the affected interface might be lost, and the interface is returned to its default configuration.

    This table shows the Ethernet interface default configuration, including some features that apply only to Layer 2 interfaces.

    Table 3. Default Layer 2 Ethernet Interface Configuration

    Feature

    Default Setting

    Operating mode

    Layer 2 or switching mode (switchport command).

    Allowed VLAN range

    VLANs 1 to 4094.

    Default VLAN (for access ports)

    VLAN 1 (Layer 2 interfaces only).

    Native VLAN (for IEEE 802.1Q trunks)

    VLAN 1 (Layer 2 interfaces only).

    VLAN trunking

    Switchport mode dynamic auto (supports DTP) (Layer 2 interfaces only).

    Port enable state

    All ports are enabled.

    Port description

    None defined.

    Speed

    Autonegotiate. (Not supported on the 25-Gigabit, 40-Gigabit, and 100-Gigabit interfaces.)

    Duplex mode

    Autonegotiate. (Not supported on the 25-Gigabit, 40-Gigabit, and 100-Gigabit interfaces.)

    Flow control

    Flow control is set to receive: on . It is always off for sent packets.

    EtherChannel (PAgP)

    Disabled on all Ethernet ports.

    Port blocking (unknown multicast and unknown unicast traffic)

    Disabled (not blocked) (Layer 2 interfaces only).

    Broadcast, multicast, and unicast storm control

    Disabled.

    Protected port

    Disabled (Layer 2 interfaces only).

    Port security

    Disabled (Layer 2 interfaces only).

    Port Fast

    Disabled.

    Auto-MDIX

    Enabled.

    Note

     

    The switch might not support a pre-standard powered device, such as Cisco IP phones and access points that do not fully support IEEE 802.3af, if that powered device is connected to the switch through a crossover cable. This is regardless of whether auto-MIDX is enabled on the switch port.

    Power over Ethernet (PoE)

    Enabled (auto).

    Interface Speed and Duplex Mode

    Ethernet interfaces on the switch operate at 10, 100, 1000 Mbps, 2.5 Gbps, 5 Gbps, 10 Gbps and in either full-duplex or half-duplex mode. In full-duplex mode, two stations can send and receive traffic at the same time. Normally, 10-Mbps ports operate in half-duplex mode, which means that stations can either receive or send traffic.

    Speed and Duplex Configuration Guidelines

    When configuring an interface speed and duplex mode, note these guidelines:

    • Ethernet (10/100/1000-Mb/s) ports and multigigabit ethernet ports (2.5 Gb/s, 5Gb/s, 10 Gb/s) support all speed options and all duplex options (auto, half, and full). However, Gigabit Ethernet ports operating at 1000 Mb/s and above do not support half-duplex mode.

    • If both ends of the line support autonegotiation, we highly recommend the default setting of auto negotiation.

    • If one interface supports autonegotiation and the other end does not, configure duplex and speed on both interfaces; do not use the auto setting on the supported side.

    • When STP is enabled and a port is reconfigured, the device can take up to 30 seconds to check for loops. The port LED is amber while STP reconfigures. As best practice, we suggest configuring the speed and duplex options on a link to auto or to fixed on both the ends. If one side of the link is configured to auto and the other side is configured to fixed, the link may or may not be up and this is expected.


    Caution

    Changing the interface speed and duplex mode configuration might shut down and re-enable the interface during the reconfiguration.

    IEEE 802.3x Flow Control

    Flow control enables connected Ethernet ports to control traffic rates during congestion by allowing congested nodes to pause link operation at the other end. If one port experiences congestion and cannot receive any more traffic, it notifies the other port by sending a pause frame to stop sending until the condition clears. Upon receipt of a pause frame, the sending device stops sending any data packets, which prevents any loss of data packets during the congestion period.


    Note

    The switch ports can receive, but not send, pause frames.

    You use the flowcontrol interface configuration command to set the interface’s ability to receive pause frames to on, off, or desired . The default state is off.

    When set to desired, an interface can operate with an attached device that is required to send flow-control packets or with an attached device that is not required to but can send flow-control packets.

    These rules apply to flow control settings on the device:

    • receive on (or desired ): The port cannot send pause frames but can operate with an attached device that is required to or can send pause frames; the port can receive pause frames.

    • receive off : Flow control does not operate in either direction. In case of congestion, no indication is given to the link partner, and no pause frames are sent or received by either device.


    Note

    For details on the command settings and the resulting flow control resolution on local and remote ports, see the flowcontrol interface configuration command in the command reference for this release.

    Layer 3 Interfaces

    The device supports these types of Layer 3 interfaces:

    • SVIs: You should configure SVIs for any VLANs for which you want to route traffic. SVIs are created when you enter a VLAN ID following the interface vlan global configuration command. To delete an SVI, use the no interface vlan global configuration command. You cannot delete interface VLAN 1.


      Note

      When you create an SVI, it does not become active until it is associated with a physical port.

      When configuring SVIs, you can use the switchport autostate exclude command on a port to exclude that port from being included in determining SVI line-state. To disable autostate on the SVI, use the no autostate command on the SVI.

    • Routed ports: Routed ports are physical ports configured to be in Layer 3 mode by using the no switchport interface configuration command. A routed port supports VLAN subinterfaces.

      VLAN subinterface: A 802.1Q VLAN subinterface is a virtual Cisco IOS interface that is associated with a VLAN id on a routed physical interface. The parent interface is a physical port. Subinterfaces can be created only on Layer 3 physical interfaces. A subinterface can be associated with different functionalities such as IP addressing, forwarding policies, Quality of Service (QoS) policies, and security policies. Subinterfaces divide the parent interface into two or more virtual interfaces on which you can assign unique Layer 3 parameters such as IP addresses and dynamic routing protocols. The IP address for each subinterface should be in a different subnet from any other subinterface on the parent interface.

    • Layer 3 EtherChannel ports: EtherChannel interfaces made up of routed ports.

    A Layer 3 device can have an IP address assigned to each routed port and SVI.

    There is no defined limit to the number of SVIs and routed ports that can be configured in a device or in a device stack. However, the interrelationship between the number of SVIs and routed ports and the number of other features being configured might have an impact on CPU usage because of hardware limitations. If the device is using its maximum hardware resources, attempts to create a routed port or SVI have these results:

    • If you try to create a new routed port, the device generates a message that there are not enough resources to convert the interface to a routed port, and the interface remains as a switchport.

    • If you try to create an extended-range VLAN, an error message is generated, and the extended-range VLAN is rejected.

    • If the device is notified by VLAN Trunking Protocol (VTP) of a new VLAN, it sends a message that there are not enough hardware resources available and shuts down the VLAN. The output of the show vlan user EXEC command shows the VLAN in a suspended state.

    • If the device attempts to boot up with a configuration that has more VLANs and routed ports than hardware can support, the VLANs are created, but the routed ports are shut down, and the device sends a message that this was due to insufficient hardware resources.


    Note

    All Layer 3 interfaces require an IP address to route traffic. This procedure shows how to configure an interface as a Layer 3 interface and how to assign an IP address to an interface:

    If the physical port is in Layer 2 mode (the default), you must enter the no switchport interface configuration command to put the interface into Layer 3 mode. Entering a no switchport command disables and then re-enables the interface, which might generate messages on the device to which the interface is connected. Furthermore, when you put an interface that is in Layer 2 mode into Layer 3 mode, the previous configuration information related to the affected interface might be lost, and the interface is returned to its default configuration.

    How to Configure Interface Characteristics

    The following sections provide information about the various tasks that comprise the procedure to configure interface characteristics.

    Configuring an Interface

    These general instructions apply to all interface configuration processes.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface

    Example:

    
Device(config)# interface gigabitethernet1/0/1
Device(config-if)#

    Identifies the interface type, and the number of the connector.

    Note

     

    You do not need to add a space between the interface type and the interface number. For example, in the preceding line, you can specify either gigabitethernet 1/0/1 , gigabitethernet1/0/1 , gi 1/0/1 , or gi1/0/1 .

    Step 4

    Follow each interface command with the interface configuration commands that the interface requires.

    Defines the protocols and applications that will run on the interface. The commands are collected and applied to the interface when you enter another interface command or enter end to return to privileged EXEC mode.

    Step 5

    interface range or interface range macro

    (Optional) Configures a range of interfaces.

    Note

     

    Interfaces configured in a range must be the same type and must be configured with the same feature options.

    Step 6

    show interfaces

    Displays a list of all interfaces on or configured for the switch. A report is provided for each interface that the device supports or for the specified interface.

    Adding a Description for an Interface

    Follow these steps to add a description for an interface.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface interface-id

    Example:

    
Device(config)# interface gigabitethernet1/0/2

    Specifies the interface for which you are adding a description, and enter interface configuration mode.

    Step 4

    description string

    Example:

    
Device(config-if)# description Connects to Marketing

    Adds a description for an interface.

    Step 5

    end

    Example:

    
Device(config-if)# end

    Returns to privileged EXEC mode.

    Step 6

    show interfaces interface-id description

    Verifies your entry.

    Step 7

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Configuring a Range of Interfaces

    To configure multiple interfaces with the same configuration parameters, use the interface range global configuration command. When you enter the interface-range configuration mode, all command parameters that you enter are attributed to all interfaces within that range until you exit this mode.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface range {port-range | macro macro_name}

    Example:

    
Device(config)# interface range macro

    Specifies the range of interfaces (VLANs or physical ports) to be configured, and enter interface-range configuration mode.

    • You can use the interface range command to configure up to five port ranges or a previously defined macro.

    • The macro variable is explained in Configuring and Using Interface Range Macros.

    • In a comma-separated port-range , you must enter the interface type for each entry and enter spaces before and after the comma.

    • In a hyphen-separated port-range , you do not need to re-enter the interface type, but you must enter a space before the hyphen.

    Note

     

    Use the normal configuration commands to apply the configuration parameters to all interfaces in the range. Each command is executed as it is entered.

    Step 4

    end

    Example:

    
Device(config)# end

    Returns to privileged EXEC mode.

    Step 5

    show interfaces [interface-id]

    Example:

    
Device# show interfaces

    Verifies the configuration of the interfaces in the range.

    Step 6

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Configuring and Using Interface Range Macros

    You can create an interface range macro to automatically select a range of interfaces for configuration. Before you can use the macro keyword in the interface range macro global configuration command string, you must use the define interface-range global configuration command to define the macro.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    define interface-range macro_name interface-range

    Example:

    Defines the interface-range macro, and saves it in NVRAM.

    • The macro_name is a 32-character maximum character string.

    • A macro can contain up to five comma-separated interface ranges.

    • Each interface-range must consist of the same port type.

    Note

     

    Before you can use the macro keyword in the interface range macro global configuration command string, you must use the define interface-range global configuration command to define the macro.

    Step 4

    interface range macro macro_name

    Example:

    
Device(config)# interface range macro enet_list

    Selects the interface range to be configured using the values saved in the interface-range macro called macro_name .

    You can now use the normal configuration commands to apply the configuration to all interfaces in the defined macro.

    Step 5

    end

    Example:

    
Device(config)# end

    Returns to privileged EXEC mode.

    Step 6

    show running-config | include define

    Example:

    
Device# show running-config | include define

    Shows the defined interface range macro configuration.

    Step 7

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Setting the Interface Speed and Duplex Parameters

    Follow these steps to configure the interface speed and duplex parameters.


    Note

    SFP+ modules operate only at 10G speed and full duplex. You can't configure the speed and duplex parameters for SFP+ modules.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface interface-id

    Example:

    
Device(config)# interface gigabitethernet1/0/3

    Specifies the physical interface to be configured, and enters interface configuration mode.

    Step 4

    speed {10 | 100 | 1000 | auto [10 | 100 | 1000 | 10000] | nonegotiate}

    Example:

    
Device(config-if)# speed 10

    Enters the appropriate speed parameter for the interface:

    • Enter 10 , 100 , 1000 , or 10000 to set a specific speed for the interface.

    • Enter auto to enable the interface to autonegotiate speed with the connected device. If you specify a speed and also set the auto keyword, the port autonegotiates only at the specified speeds.

    • The nonegotiate keyword is available only for SFP module ports. SFP module ports operate only at 1000 Mb/s but can be configured to not negotiate if connected to a device that does not support autonegotiation.

    Step 5

    duplex {auto | full | half}

    Example:

    
Device(config-if)# duplex half

    Enters the duplex parameter for the interface.

    Enables half-duplex mode (for interfaces operating only at 10 or 100 Mb/s). Half duplex is not supported on multi-Gigabit Ethernet ports configured for speed of 1000 Mb/s.

    You can configure the duplex setting when the speed is set to auto .

    Step 6

    end

    Example:

    
Device(config-if)# end

    Returns to privileged EXEC mode.

    Step 7

    show interfaces interface-id

    Example:

    
Device# show interfaces gigabitethernet1/0/3

    Displays the interface speed and duplex mode configuration.

    Step 8

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Configuring the IEEE 802.3x Flow Control

    Follow these steps to configure the IEEE 802.3x flow control.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode

    Step 3

    interface interface-id

    Example:

    
Device(config)# interface gigabitethernet1/0/1

    Specifies the physical interface to be configured, and enters interface configuration mode.

    Step 4

    flowcontrol {receive} {on | off | desired}

    Example:

    
Device(config-if)# flowcontrol receive on

    Configures the flow control mode for the port.

    Step 5

    end

    Example:

    
Device(config-if)# end

    Returns to privileged EXEC mode.

    Step 6

    show flowcontrol interface interface-id

    Example:

    
Device# show flowcontrol interface GigabitEthernet1/0/1

    Verifies the specified interface flow control settings.

    Step 7

    show flowcontrol module slot

    Example:

    
Device# show flowcontrol module 1

    Verifies the interface flow control settings on the module.

    Step 8

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Configuring a Layer 3 Interface

    Follow these steps to configure a layer 3 interface.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface {gigabitethernet interface-id} | {vlan vlan-id} | {port-channel port-channel-number}

    Example:

    
Device(config)# interface gigabitethernet1/0/2

    Specifies the interface to be configured as a Layer 3 interface, and enters interface configuration mode.

    Step 4

    no switchport

    Example:

    
Device(config-if)# no switchport

    (For physical ports only) Enters Layer 3 mode.

    Step 5

    ip address ip_address subnet_mask

    Example:

    
Device(config-if)# ip address 192.20.135.21 255.255.255.0

    Configures the IP address and IP subnet.

    Step 6

    no shutdown

    Example:

    
Device(config-if)# no shutdown

    Enables the interface.

    Step 7

    end

    Example:

    
Device(config-if)# end

    Returns to privileged EXEC mode.

    Step 8

    show interfaces [interface-id]

    Verifies the configuration.

    Step 9

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Configuring a Logical Layer 3 GRE Tunnel Interface

    Before you begin

    Generic Routing Encapsulation (GRE) is a tunneling protocol used to encapsulate network layer protocols inside virtual point-to-point links. A GRE tunnel only provides encapsulation and not encryption.


    Note

    • GRE tunnels are supported on the hardware on Cisco Catalyst 9000 switches. When GRE is configured without tunnel options, packets are hardware-switched. When GRE is configured with tunnel options (such as key, checksum, and so on), packets are switched in the software. A maximum of 1000 GRE tunnels are supported.

    • Other features such as Access Control Lists (ACL) and Quality of Service (QoS) are not supported for the GRE tunnels.

    • The tunnel path-mtu-discovery command is not supported for GRE tunnels. To avoid fragmentation, you can set the maximum transmission unit (MTU) of both ends of the GRE tunnel to the lowest value by using the ip mtu 256 command.

    To configure a GRE tunnel, perform this task:

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface tunnel number

    Example:

    Device(config)#interface tunnel 2

    Enables tunneling on the interface.

    Step 4

    ip address ip_addresssubnet_mask

    Example:

    Device(config)#ip address 100.1.1.1 255.255.255.0

    Configures the IP address and IP subnet.

    Step 5

    tunnel source {ip_address | type_number}

    Example:

    Device(config)#tunnel source 10.10.10.1

    Configures the tunnel source.

    Step 6

    tunnel destination {host_name | ip_address}

    Example:

    Device(config)#tunnel destination 10.10.10.2

    Configures the tunnel destination.

    Step 7

    tunnel mode gre ip

    Example:

    Device(config)#tunnel mode gre ip

    Configures the tunnel mode.

    Step 8

    end

    Example:

    Device(config)#end

    Exits configuration mode.

    Configuring SVI Autostate Exclude

    Follow these steps to exclude SVI autostate.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface interface-id

    Example:

    
Device(config)# interface gigabitethernet1/0/2

    Specifies a Layer 2 interface (physical port or port channel), and enters interface configuration mode.

    Step 4

    switchport autostate exclude

    Example:

    
Device(config-if)# switchport autostate exclude

    Excludes the access or trunk port when defining the status of an SVI line state (up or down)

    Step 5

    end

    Example:

    
Device(config-if)# end

    Returns to privileged EXEC mode.

    Step 6

    show running config interface interface-id

    (Optional) Shows the running configuration.

    Verifies the configuration.

    Step 7

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Shutting Down and Restarting an Interface

    Shutting down an interface disables all functions on the specified interface and marks the interface as unavailable on all monitoring command displays. This information is communicated to other network servers through all dynamic routing protocols. The interface is not mentioned in any routing updates.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    interface {vlan vlan-id} | { gigabitethernet interface-id} | {port-channel port-channel-number}

    Example:

    
Device(config)# interface gigabitethernet1/0/2

    Selects the interface to be configured.

    Step 4

    shutdown

    Example:

    
Device(config-if)# shutdown

    Shuts down an interface.

    Step 5

    no shutdown

    Example:

    
Device(config-if)# no shutdown

    Restarts an interface.

    Step 6

    end

    Example:

    
Device(config-if)# end

    Returns to privileged EXEC mode.

    Step 7

    show running-config

    Example:

    
Device# show running-config

    Verifies your entries.

    Configuring USB Inactivity Timeout

    The configurable inactivity timeout reactivates the RJ-45 console port if the USB console port is activated but no input activity occurs on it for a specified time period. When the USB console port is deactivated due to a timeout, you can restore its operation by disconnecting and reconnecting the USB cable.


    Note

    The configured inactivity timeout applies to all device in a stack. However, a timeout on one device does not cause a timeout on other device in the stack.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    line console 0

    Example:

    
Device(config)# line console 0

    Configures the console and enters line configuration mode.

    Step 4

    usb-inactivity-timeout switch switch_number timeout-minutes

    Example:

    
Device(config-line)# usb-inactivity-timeout switch 1 30

    Specifies an inactivity timeout for the console port. The range is 1 to 240 minutes. The default is to have no timeout configured.

    Step 5

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Disabling USB Ports

    To disable all USB ports, peform this procedure.

    Procedure

      Command or Action Purpose

    Step 1

    enable

    Example:

    
Device> enable

    Enables privileged EXEC mode.

    Enter your password, if prompted.

    Step 2

    configure terminal

    Example:

    
Device# configure terminal

    Enters global configuration mode.

    Step 3

    [no] platform usb disable

    Example:

    
Device(config)# platform usb disable

    Disables all the USB ports on the device.

    Use the no platform usb disable command to reenable the USB ports.

    Step 4

    exit

    Example:

    
Device(config)# exit

    Exits to privileged EXEC mode.

    Step 5

    copy running-config startup-config

    Example:

    
Device# copy running-config startup-config

    (Optional) Saves your entries in the configuration file.

    Monitoring Interface Characteristics

    The following sections provide information about monitoring interface characteristics.

    Monitoring Interface Status

    Commands entered at the privileged EXEC prompt display information about the interface, including the versions of the software and the hardware, the configuration, and statistics about the interfaces.

    Table 4. show Commands for Interfaces

    Command

    Purpose

    show interfaces interface-number downshift [module module-number]

    Displays the downshift status details of the specified interfaces and modules.

    show interfaces interface-id status [err-disabled]

    Displays interface status or a list of interfaces in the error-disabled state.

    show interfaces [interface-id] switchport

    Displays administrative and operational status of switching (nonrouting) ports. You can use this command to find out if a port is in routing or in switching mode.

    show interfaces [interface-id] description

    Displays the description configured on an interface or all interfaces and the interface status.

    show ip interface [interface-id]

    Displays the usability status of all interfaces configured for IP routing or the specified interface.

    show interface [interface-id] stats

    Displays the input and output packets by the switching path for the interface.

    show interface [interface-id] link[module number]

    Displays the up time and down time of an interface or all interfaces.

    show interfaces interface-id

    (Optional) Displays speed and duplex on the interface.

    show interfaces transceiver dom-supported-list

    (Optional) Displays Digital Optical Monitoring (DOM) status on the connect SFP modules.

    show interfaces transceiver properties

    (Optional) Displays temperature, voltage, or amount of current on the interface.

    show interfaces [interface-id] [{transceiver properties | detail}] module number]

    Displays physical and operational status about an SFP module.

    show running-config interface [interface-id]

    Displays the running configuration in RAM for the interface.

    show version

    Displays the hardware configuration, software version, the names and sources of configuration files, and the boot images.

    show controllers ethernet-controller interface-id phy

    Displays the operational state of the auto-MDIX feature on the interface.

    Clearing and Resetting Interfaces and Counters

    Table 5. clear Commands for Interfaces

    Command

    Purpose

    clear counters [interface-id]

    Clears interface counters.

    clear interface interface-id

    Resets the hardware logic on an interface.

    clear line [number | console 0 | vty number]

    Resets the hardware logic on an asynchronous serial line.

    Note

    The clear counters privileged EXEC command does not clear counters retrieved by using Simple Network Management Protocol (SNMP), but only those seen with the show interface privileged EXEC command.

    Configuration Examples for Interface Characteristics

    The following sections provide examples of interface characteristics configurations.

    Example: Adding a Description to an Interface

    The following example shows how to add a description to an interface:

    
Device# configure terminal
Enter configuration commands, one per line. End with CNTRL/Z.
Device(config)# interface gigabitethernet1/0/2
Device(config-if)# description Connects to Marketing
Device(config-if)# end
Device# show interfaces gigabitethernet1/0/2 description
Interface Status         Protocol Description
Gi1/0/2   admin down     down     Connects to Marketing

    Example: Configuring a Range of Interfaces


    Note
    If you enter multiple configuration commands while you are in interface-range mode, each command is executed as it is entered. The commands are not batched and executed after you exit interface-range mode. If you exit interface-range configuration mode while the commands are being executed, some commands might not be executed on all interfaces in the range. Wait until the command prompt reappears before exiting interface-range configuration mode.

    Example: Configuring and Using Interface Range Macros

    The following example shows how to enter interface-range configuration mode for the interface-range macro enet_list: 

    
Device# configure terminal
Device(config)# interface range macro enet_list
Device(config-if-range)#

    The following example shows how to delete the interface-range macro enet_list and to verify that it was deleted: 

    
Device# configure terminal
Device(config)# no define interface-range enet_list 
Device(config)# end
Device# show run | include define
Device#

    Example: Setting Interface Speed and Duplex Mode

    The following example shows how to set the interface speed to 10 Mbps and the duplex mode to full, on a 10/100/1000 Mbps port:

    
Device# configure terminal
Device(config)# interface gigabitethernet1/0/3
Device(config-if)# speed 10
Device(config-if)# duplex full

    The following example shows how to set the interface speed to 100 Mbps on a 10/100/1000 Mbps port:

    
Device# configure terminal
Device(config)# interface gigabitethernet1/0/2
Device(config-if)# speed 100

    Example: Configuring a Layer 3 Interface

    The following example shows how to configure a Layer 3 interface:

    
Device# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Device(config)# interface gigabitethernet1/0/2
Device(config-if)# no switchport
Device(config-if)# ip address 192.20.135.21 255.255.255.0
Device(config-if)# no shutdown

    Example: Configuring USB Inactivity Timeout

    The following example shows how to configure the inactivity timeout to 30 minutes:

    
Device# configure terminal
Device(config)# line console 0
Device(config-line)# usb-inactivity-timeout switch 1 30

    The following example shows how to disable the configuration:

    
Device# configure terminal
Device(config)# line console 0
Device(config-line)# no usb-inactivity-timeout switch 1

    If there is no (input) activity on a USB console port for the configured number of minutes, the inactivity timeout setting applies to the RJ-45 port, and a log shows this occurrence: 

    
*Mar  1 00:47:25.625: %USB_CONSOLE-6-INACTIVITY_DISABLE: Console media-type USB disabled due to inactivity, media-type reverted to RJ45.

    At this point, the only way to reactivate the USB console port is to disconnect and reconnect the cable.

    When the USB cable on a switch is disconnected and reconnected, a log, which is similar to this, appears:

    
*Mar  1 00:48:28.640: %USB_CONSOLE-6-MEDIA_USB: Console media-type is USB.

    Additional References for Configuring Interface Characteristics

    Related Documents

    Related Topic Document Title

    For complete syntax and usage information for the commands used in this chapter.

    See the Interface and Hardware Commands section in the Command Reference (Catalyst 9400 Series Switches) .

    Feature History for Configuring Interface Characteristics

    This table provides release and related information for the features explained in this module.

    These features are available in all the releases subsequent to the one they were introduced in, unless noted otherwise.

    Release

    Feature

    Feature Information

    Cisco IOS XE Everest 16.6.1

    Interface Characteristics

    Interface Characteristics includes interface types, connections, configuration modes, speed, and other aspects of configuring a physical interface on a device.

    Cisco IOS XE Everest 16.6.4

    IEEE 802.3x Flow Control

    The default value for flowcontrol interface configuration command was modified to on on all the models of the series.

    Cisco IOS XE Amsterdam 17.2.1

    Downlink support for Multi-Gigabit Ethernet Interfaces

    Support to view downlink status of multi-gigabit ethernet interfaces was introduced.

    Cisco IOS XE Bengaluru 17.5.1

    Disabling USB interfaces

    Support to disable all USB ports on a standalone or stacked device was introduced.

    Cisco IOS XE Cupertino 17.7.1

    Interface Characteristics

    This feature was implemented on supervisor modules C9400X-SUP-2 and C9400X-SUP-2XL, which were introduced in this release.

    Use the Cisco Feature Navigator to find information about platform and software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn.