- Information About Ethernet Interfaces
- Configuring Ethernet Interfaces
- Configuring the UDLD Mode
- Changing an Interface Port Mode
- Configuring Interface Speed
- Disabling Link Negotiation
- Disabling SVI Autostate
- Configuring the CDP Characteristics
- Enabling or Disabling CDP
- Enabling the Error-Disabled Detection
- Enabling the Error-Disabled Recovery
- Configuring the Error-Disabled Recovery Interval
- Configuring the Description Parameter
- Disabling and Restarting Ethernet Interfaces
- Displaying Interface Information
- Default Physical Ethernet Settings
- MIBs for Layer 2 Interfaces
Configuring Layer 2 Interfaces
This chapter contains the following sections:
- Information About Ethernet Interfaces
- Configuring Ethernet Interfaces
- Displaying Interface Information
- Default Physical Ethernet Settings
- MIBs for Layer 2 Interfaces
Information About Ethernet Interfaces
The Ethernet ports can operate as standard Ethernet interfaces connected to servers or to a LAN.
The Ethernet interfaces are enabled by default.
- About the Interface Command
- About the Unidirectional Link Detection Parameter
- SVI Autostate
- About the Cisco Discovery Protocol
- About the Error-Disabled State
- About MTU Configuration
About the Interface Command
You can enable the various capabilities of the Ethernet interfaces on a per-interface basis using the interface command. When you enter the interface command, you specify the following information:
- Interface type—All physical Ethernet interfaces use the ethernet keyword.
- Slot number
- Port number— Port number within the group.
The interface numbering convention is extended to support use with a Cisco Nexus Fabric Extender as follows:
switch(config)# interface ethernet [chassis/]slot/port
About the Unidirectional Link Detection Parameter
The Cisco-proprietary Unidirectional Link Detection (UDLD) protocol allows ports that are connected through fiber optics or copper (for example, Category 5 cabling) Ethernet cables to monitor the physical configuration of the cables and detect when a unidirectional link exists. When the switch detects a unidirectional link, UDLD shuts down the affected LAN port and alerts the user. Unidirectional links can cause a variety of problems, including spanning tree topology loops.
UDLD is a Layer 2 protocol that works with the Layer 1 protocols to determine the physical status of a link. At Layer 1, autonegotiation takes care of physical signaling and fault detection. UDLD performs tasks that autonegotiation cannot perform, such as detecting the identities of neighbors and shutting down misconnected LAN ports. When you enable both autonegotiation and UDLD, Layer 1 and Layer 2 detections work together to prevent physical and logical unidirectional connections and the malfunctioning of other protocols.
A unidirectional link occurs whenever traffic transmitted by the local device over a link is received by the neighbor but traffic transmitted from the neighbor is not received by the local device. If one of the fiber strands in a pair is disconnected, as long as autonegotiation is active, the link does not stay up. In this case, the logical link is undetermined, and UDLD does not take any action. If both fibers are working normally at Layer 1, then UDLD at Layer 2 determines whether those fibers are connected correctly and whether traffic is flowing bidirectionally between the correct neighbors. This check cannot be performed by autonegotiation, because autonegotiation operates at Layer 1.
A Cisco Nexus device periodically transmits UDLD frames to neighbor devices on LAN ports with UDLD enabled. If the frames are echoed back within a specific time frame and they lack a specific acknowledgment (echo), the link is flagged as unidirectional and the LAN port is shut down. Devices on both ends of the link must support UDLD in order for the protocol to successfully identify and disable unidirectional links.
Note |
By default, UDLD is locally disabled on copper LAN ports to avoid sending unnecessary control traffic on this type of media. |
The following figure shows an example of a unidirectional link condition. Device B successfully receives traffic from Device A on the port. However, Device A does not receive traffic from Device B on the same port. UDLD detects the problem and disables the port.
Default UDLD Configuration
The following table shows the default UDLD configuration.
Feature |
Default Value |
---|---|
UDLD global enable state |
Globally disabled |
UDLD aggressive mode |
Disabled |
UDLD per-port enable state for fiber-optic media |
Enabled on all Ethernet fiber-optic LAN ports |
UDLD per-port enable state for twisted-pair (copper) media |
Disabled on all Ethernet 10/100 and 1000BASE-TX LAN ports |
UDLD Aggressive and Nonaggressive Modes
UDLD aggressive mode is disabled by default. You can configure UDLD aggressive mode only on point-to-point links between network devices that support UDLD aggressive mode. If UDLD aggressive mode is enabled, when a port on a bidirectional link that has a UDLD neighbor relationship established stops receiving UDLD frames, UDLD tries to reestablish the connection with the neighbor. After eight failed retries, the port is disabled.
To prevent spanning tree loops, nonaggressive UDLD with the default interval of 15 seconds is fast enough to shut down a unidirectional link before a blocking port transitions to the forwarding state (with default spanning tree parameters).
When you enable the UDLD aggressive mode, the following occurs:
- One side of a link has a port stuck (both transmission and receive)
- One side of a link remains up while the other side of the link is down
In these cases, the UDLD aggressive mode disables one of the ports on the link, which prevents traffic from being discarded.
SVI Autostate
The Switch Virtual Interface (SVI) represents a logical interface between the bridging function and the routing function of a VLAN in the device. By default, when a VLAN interface has multiple ports in the VLAN, the SVI goes to the down state when all the ports in the VLAN go down.
Autostate behavior is the operational state of an interface that is governed by the state of the various ports in its corresponding vlan. In other words a SVI interface on a VLAN comes up when there is at least one port in that vlan that is in STP forwarding state. Similarly, this interface goes down when the last STP forwarding port goes down or goes to another STP state.
By default, Autostate calculation is enabled. You can disable Autostate calculation for a SVI interface and change the default value.
About the Cisco Discovery Protocol
The Cisco Discovery Protocol (CDP) is a device discovery protocol that runs over Layer 2 (the data link layer) on all Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows network management applications to discover Cisco devices that are neighbors of already known devices. With CDP, network management applications can learn the device type and the Simple Network Management Protocol (SNMP) agent address of neighboring devices running lower-layer, transparent protocols. This feature enables applications to send SNMP queries to neighboring devices.
CDP runs on all media that support Subnetwork Access Protocol (SNAP). Because CDP runs over the data-link layer only, two systems that support different network-layer protocols can learn about each other.
Each CDP-configured device sends periodic messages to a multicast address, advertising at least one address at which it can receive SNMP messages. The advertisements also contain time-to-live, or holdtime information, which is the length of time a receiving device holds CDP information before discarding it. Each device also listens to the messages sent by other devices to learn about neighboring devices.
The switch supports both CDP Version 1 and Version 2.
Default CDP Configuration
The following table shows the default CDP configuration.
Feature |
Default Setting |
---|---|
CDP interface state |
Enabled |
CDP timer (packet update frequency) |
60 seconds |
CDP holdtime (before discarding) |
180 seconds |
CDP Version-2 advertisements |
Enabled |
About the Error-Disabled State
An interface is in the error-disabled (err-disabled) state when the inteface is enabled administratively (using the no shutdown command) but disabled at runtime by any process. For example, if UDLD detects a unidirectional link, the interface is shut down at runtime. However, because the interface is administratively enabled, the interface status displays as err-disabled. Once an interface goes into the err-disabled state, you must manually reenable it or you can configure an automatic timeout recovery value. The err-disabled detection is enabled by default for all causes. The automatic recovery is not configured by default.
When an interface is in the err-disabled state, use the errdisable detect cause command to find information about the error.
You can configure the automatic err-disabled recovery timeout for a particular err-disabled cause by changing the time variable.
The errdisable recovery cause command provides automatic recovery after 300 seconds. To change the recovery period, use the errdisable recovery interval command to specify the timeout period. You can specify 30 to 65535 seconds.
If you do not enable the err-disabled recovery for the cause, the interface stays in the err-disabled state until you enter the shutdown and no shutdown commands. If the recovery is enabled for a cause, the interface is brought out of the err-disabled state and allowed to retry operation once all the causes have timed out. Use the show interface status err-disabled command to display the reason behind the error.
About MTU Configuration
The Cisco Nexus device switch does not fragment frames. As a result, the switch cannot have two ports in the same Layer 2 domain with different maximum transmission units (MTUs). A per-physical Ethernet interface MTU is not supported. Instead, the MTU is set according to the QoS classes. You modify the MTU by setting class and policy maps.
Note |
When you show the interface settings, a default MTU of 1500 is displayed for physical Ethernet interfaces. |
Configuring Ethernet Interfaces
The section includes the following topics:
- Configuring the UDLD Mode
- Changing an Interface Port Mode
- Configuring Interface Speed
- Disabling Link Negotiation
- Disabling SVI Autostate
- Configuring the CDP Characteristics
- Enabling or Disabling CDP
- Enabling the Error-Disabled Detection
- Enabling the Error-Disabled Recovery
- Configuring the Error-Disabled Recovery Interval
- Configuring the Description Parameter
- Disabling and Restarting Ethernet Interfaces
Configuring the UDLD Mode
You can configure normal or aggressive unidirectional link detection (UDLD) modes for Ethernet interfaces on devices configured to run UDLD. Before you can enable a UDLD mode for an interface, you must make sure that UDLD is already enabled on the device that includes the interface. UDLD must also be enabled on the other linked interface and its device.
To use the normal UDLD mode, you must configure one of the ports for normal mode and configure the other port for the normal or aggressive mode. To use the aggressive UDLD mode, you must configure both ports for the aggressive mode.
Note |
Before you begin, UDLD must be enabled for the other linked port and its device. |
This example shows how to enable the UDLD for the switch:
switch# configure terminal switch(config)# feature udld
This example shows how to enable the normal UDLD mode for an Ethernet port:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# udld enable
This example shows how to enable the aggressive UDLD mode for an Ethernet port:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# udld aggressive
This example shows how to disable UDLD for an Ethernet port:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# udld disable
This example shows how to disable UDLD for the switch:
switch# configure terminal switch(config)# no feature udld
Changing an Interface Port Mode
You can configure a Quad small form-factor pluggable (QSFP+) port by using the hardware profile portmode command. To restore the defaults, use the no form of this command.
This example shows how to change the port mode to 48x10g+4x40g for QSFP+ ports:
switch# configure terminal switch(config) copy running-config bootflash:my-config.cfg switch(config)# write erase switch(config)# reload WARNING: This command will reboot the system Do you want to continue? (y/n) [n] y switch(config)# hardware profile portmode 48x10g+4x40g Warning: This command will take effect only after saving the configuration and reload! Port configurations could get lost when port mode is changed! switch(config)# copy running-config startup-config switch(config)# reload WARNING: This command will reboot the system Do you want to continue? (y/n) [n] y
This example shows how to change the port mode to 48x10g+4x40g for QSFP+ ports and verify the changes:
switch# configure terminal switch(config)# hardware profile portmode 48x10g+4x40g Warning: This command will take effect only after saving the configuration and r eload! Port configurations could get lost when port mode is changed! switch(config)# show running-config !Command: show running-config !Time: Thu Aug 25 07:39:37 2011 version 5.0(3)U2(1) feature telnet no feature ssh feature lldp username admin password 5 $1$OOV4MdOM$BAB5RkD22YanT4empqqSM0 role network-admin ip domain-lookup switchname BLR-QG-5 ip access-list my-acl 10 deny ip any 10.0.0.1/32 20 deny ip 10.1.1.1/32 any class-map type control-plane match-any copp-arp class-map type control-plane match-any copp-bpdu : : control-plane service-policy input copp-system-policy hardware profile tcam region arpacl 128 hardware profile tcam region ifacl 256 hardware profile tcam region racl 256 hardware profile tcam region vacl 512 hardware profile portmode 48x10G+4x40G snmp-server user admin network-admin auth md5 0xdd1d21ee42e93106836cdefd1a60e062 <--Output truncated--> switch#
This example shows how to restore the default port mode for QSFP+ ports:
switch# configure terminal switch(config)# no hardware profile portmode Warning: This command will take effect only after saving the configuration and r eload! Port configurations could get lost when port mode is changed! switch(config)#
Configuring Interface Speed
Note |
If the interface and transceiver speed is mismatched, the SFP validation failed message is displayed when you enter the show interface ethernet slot/port command. For example, if you insert a 1-Gigabit SFP transceiver into a port without configuring the speed 1000 command, you will get this error. By default, all ports are 10 Gigabits. |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters configuration mode. |
Step 2 | switch(config)# interface type slot/port |
Enters interface configuration mode for the specified interface. This interface must have a 1-Gigabit Ethernet SFP transceiver inserted into it. |
Step 3 | switch(config-if)# speed speed |
Sets the speed on the interface. |
This example shows how to set the speed for a 1-Gigabit Ethernet port:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# speed 1000
Disabling Link Negotiation
You can disable link negotiation using the no negotiate auto command. By default, auto-negotiation is enabled on 1-Gigabit ports and disabled on 10-Gigabit ports. By default, auto-negotiation is enabled on the Cisco Nexus 3064 and 3064-X switches and disabled on the Cisco Nexus 3048 switch.
This command is equivalent to the Cisco IOS speed non-negotiate command.
Note |
ERROR: Ethernet1/40: Configuration does not match the port capability |
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
||
Step 2 | switch(config)# interface ethernet slot/port | Selects the interface and enters interface mode. |
||
Step 3 | switch(config-if)# no negotiate auto | Disables link negotiation on the selected Ethernet interface (1-Gigabit port). |
||
Step 4 | switch(config-if)# negotiate auto | (Optional) Enables link negotiation on the selected Ethernet interface. The default for 1-Gigabit ports is enabled.
|
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# negotiate auto switch(config-if)#
Disabling SVI Autostate
You can configure a SVI to remain active even if no interfaces are up in the corresponding VLAN. This enhancement is called Autostate Disable.
When you enable or disable autostate behavior it is applied to all the SVIs in the switch unless you configure autostate per SVI .
Note |
Autostate behavior is enabled by default. |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# feature interface-vlan | Enables the interface-vlan feature. |
Step 3 | switch(config)# system default interface-vlan [no] autostate | Configures the system to enable or disable the Autostate default behavior. |
Step 4 | switch(config)# interface vlan interface-vlan-number | (Optional) Creates a VLAN interface. The number range is from 1 to 4094. |
Step 5 | switch(config-if)# [no] autostate | (Optional) Enables or disables Autostate behavior per SVI. |
Step 6 | switch(config)# show interface-vlan interface-vlan | (Optional) Displays the enabled or disabled Autostate behavior of the SVI. |
Step 7 | switch(config)# copy running-config startup-config | (Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration. |
This example shows how to disable the systems Autostate default for all the SVIs on the switch:
switch# configure terminal switch(config)# feature interface-vlan switch(config)# system default interface-vlan no autostate switch(config)# interface vlan 50 switch(config-if)# no autostate switch(config)# copy running-config startup-config
This example shows enabled autostate configuration:
switch(config)# show interface-vlan 2 Vlan2 is down, line protocol is down, autostate enabled Hardware is EtherSVI, address is 547f.ee40.a17c MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec
Configuring the CDP Characteristics
You can configure the frequency of Cisco Discovery Protocol (CDP) updates, the amount of time to hold the information before discarding it, and whether or not to send Version-2 advertisements.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# [no] cdp advertise {v1 | v2 } |
(Optional) Configures the version to use to send CDP advertisements. Version-2 is the default state. Use the no form of the command to return to its default setting. |
Step 3 | switch(config)# [no] cdp format device-id {mac-address | serial-number | system-name} |
(Optional) Configures the format of the CDP device ID. The default is the system name, which can be expressed as a fully qualified domain name. Use the no form of the command to return to its default setting. |
Step 4 | switch(config)# [no] cdp holdtime seconds |
(Optional) Specifies the amount of time a receiving device should hold the information sent by your device before discarding it. The range is 10 to 255 seconds; the default is 180 seconds. Use the no form of the command to return to its default setting. |
Step 5 | switch(config)# [no] cdp timer seconds |
(Optional) Sets the transmission frequency of CDP updates in seconds. The range is 5 to 254; the default is 60 seconds. Use the no form of the command to return to its default setting. |
This example shows how to configure CDP characteristics:
switch# configure terminal switch(config)# cdp timer 50 switch(config)# cdp holdtime 120 switch(config)# cdp advertise v2
Enabling or Disabling CDP
You can enable or disable CDP for Ethernet interfaces. This protocol works only when you have it enabled on both interfaces on the same link.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# interface type slot/port |
Enters interface configuration mode for the specified interface. |
Step 3 | switch(config-if)# cdp enable |
Enables CDP for the interface. To work correctly, this parameter must be enabled for both interfaces on the same link. |
Step 4 | switch(config-if)# no cdp enable |
Disables CDP for the interface. |
This example shows how to enable CDP for an Ethernet port:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# cdp enable
This command can only be applied to a physical Ethernet interface.
Enabling the Error-Disabled Detection
You can enable error-disable (err-disabled) detection in an application. As a result, when a cause is detected on an interface, the interface is placed in an err-disabled state, which is an operational state that is similar to the link-down state.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# errdisable detect cause {all | link-flap | loopback} | Specifies a condition under which to place the interface in an err-disabled state. The default is enabled. |
Step 3 | switch(config)# shutdown | Brings the interface down administratively. To manually recover the interface from the err-disabled state, enter this command first. |
Step 4 | switch(config)# no shutdown | Brings the interface up administratively and enables the interface to recover manually from the err-disabled state. |
Step 5 | switch(config)# show interface status err-disabled | Displays information about err-disabled interfaces. |
Step 6 | switch(config)# copy running-config startup-config | (Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration. |
This example shows how to enable the err-disabled detection in all cases:
switch# configure terminal switch(config)# errdisable detect cause all switch(config)# shutdown switch(config)# no shutdown switch(config)# show interface status err-disabled switch(config)# copy running-config startup-config
Enabling the Error-Disabled Recovery
You can specify the application to bring the interface out of the error-disabled (err-disabled) state and retry coming up. It retries after 300 seconds, unless you configure the recovery timer (see the errdisable recovery interval command).
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# errdisable recovery cause {all | udld | bpduguard | link-flap | failed-port-state | pause-rate-limit} | Specifies a condition under which the interface automatically recovers from the err-disabled state, and the device retries bringing the interface up. The device waits 300 seconds to retry. The default is disabled. |
Step 3 | switch(config)# show interface status err-disabled | Displays information about err-disabled interfaces. |
Step 4 | switch(config)# copy running-config startup-config | (Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration. |
This example shows how to enable err-disabled recovery under all conditions:
switch# configure terminal switch(config)# errdisable recovery cause all switch(config)# show interface status err-disabled switch(config)# copy running-config startup-config
Configuring the Error-Disabled Recovery Interval
You can use this procedure to configure the err-disabled recovery timer value. The range is from 30 to 65535 seconds. The default is 300 seconds.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | errdisable recovery interval interval |
Specifies the interval for the interface to recover from the err-disabled state. The range is from 30 to 65535 seconds. The default is 300 seconds. |
Step 3 | show interface status err-disabled |
Displays information about err-disabled interfaces. |
Step 4 | switch(config)# copy running-config startup-config | (Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration. |
This example shows how to enable err-disabled recovery under all conditions:
switch# configure terminal switch(config)# errdisable recovery interval 32 switch(config)# show interface status err-disabled switch(config)# copy running-config startup-config
Configuring the Description Parameter
You can provide textual interface descriptions for the Ethernet ports.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# interface type slot/port |
Enters interface configuration mode for the specified interface. |
Step 3 | switch(config-if)# description test |
Specifies the description for the interface. |
This example shows how to set the interface description to Server 3 Interface:
switch# configure terminal switch(config)# interface ethernet 1/3 switch(config-if)# description Server 3 Interface
Disabling and Restarting Ethernet Interfaces
You can shut down and restart an Ethernet interface. This action disables all of the interface functions and marks the interface as being down on all monitoring displays. This information is communicated to other network servers through all dynamic routing protocols. When shut down, the interface is not included in any routing updates.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
Step 2 | switch(config)# interface type slot/port |
Enters interface configuration mode for the specified interface. |
Step 3 | switch(config-if)# shutdown |
Disables the interface. |
Step 4 | switch(config-if)# no shutdown |
Restarts the interface. |
This example shows how to disable an Ethernet port:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# shutdown
This example shows how to restart an Ethernet interface:
switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# no shutdown
Displaying Interface Information
To view configuration information about the defined interfaces, perform one of these tasks:
Command |
Purpose |
---|---|
switch# show interface type slot/port | Displays the detailed configuration of the specified interface. |
switch# show interface type slot/port capabilities | Displays detailed information about the capabilities of the specified interface. This option is only available for physical interfaces |
switch# show interface type slot/port transceiver | Displays detailed information about the transceiver connected to the specified interface. This option is only available for physical interfaces. |
switch# show interface brief | Displays the status of all interfaces. |
switch# show interface flowcontrol | Displays the detailed listing of the flow control settings on all interfaces. |
The show interface command is invoked from EXEC mode and displays the interface configurations. Without any arguments, this command displays the information for all the configured interfaces in the switch.
This example shows how to display the physical Ethernet interface:
switch# show interface ethernet 1/1 Ethernet1/1 is up Hardware is 1000/10000 Ethernet, address is 000d.eca3.5f08 (bia 000d.eca3.5f08) MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec, reliability 255/255, txload 190/255, rxload 192/255 Encapsulation ARPA Port mode is trunk full-duplex, 10 Gb/s, media type is 1/10g Input flow-control is off, output flow-control is off Auto-mdix is turned on Rate mode is dedicated Switchport monitor is off Last clearing of "show interface" counters never 5 minute input rate 942201806 bytes/sec, 14721892 packets/sec 5 minute output rate 935840313 bytes/sec, 14622492 packets/sec Rx 129141483840 input packets 0 unicast packets 129141483847 multicast packets 0 broadcast packets 0 jumbo packets 0 storm suppression packets 8265054965824 bytes 0 No buffer 0 runt 0 Overrun 0 crc 0 Ignored 0 Bad etype drop 0 Bad proto drop Tx 119038487241 output packets 119038487245 multicast packets 0 broadcast packets 0 jumbo packets 7618463256471 bytes 0 output CRC 0 ecc 0 underrun 0 if down drop 0 output error 0 collision 0 deferred 0 late collision 0 lost carrier 0 no carrier 0 babble 0 Rx pause 8031547972 Tx pause 0 reset
This example shows how to display the physical Ethernet capabilities:
switch# show interface ethernet 1/1 capabilities Ethernet1/1 Model: 734510033 Type: 10Gbase-(unknown) Speed: 1000,10000 Duplex: full Trunk encap. type: 802.1Q Channel: yes Broadcast suppression: percentage(0-100) Flowcontrol: rx-(off/on),tx-(off/on) Rate mode: none QOS scheduling: rx-(6q1t),tx-(1p6q0t) CoS rewrite: no ToS rewrite: no SPAN: yes UDLD: yes MDIX: no FEX Fabric: yes
This example shows how to display the physical Ethernet transceiver:
switch# show interface ethernet 1/1 transceiver Ethernet1/1 sfp is present name is CISCO-EXCELIGHT part number is SPP5101SR-C1 revision is A serial number is ECL120901AV nominal bitrate is 10300 MBits/sec Link length supported for 50/125mm fiber is 82 m(s) Link length supported for 62.5/125mm fiber is 26 m(s) cisco id is -- cisco extended id number is 4
This example shows how to display a brief interface status (some of the output has been removed for brevity):
switch# show interface brief -------------------------------------------------------------------------------- Ethernet VLAN Type Mode Status Reason Speed Port Interface Ch # -------------------------------------------------------------------------------- Eth1/1 200 eth trunk up none 10G(D) -- Eth1/2 1 eth trunk up none 10G(D) -- Eth1/3 300 eth access down SFP not inserted 10G(D) -- Eth1/4 300 eth access down SFP not inserted 10G(D) -- Eth1/5 300 eth access down Link not connected 1000(D) -- Eth1/6 20 eth access down Link not connected 10G(D) -- Eth1/7 300 eth access down SFP not inserted 10G(D) -- ...
This example shows how to display the CDP neighbors:
switch# show cdp neighbors Capability Codes: R - Router, T - Trans-Bridge, B - Source-Route-Bridge S - Switch, H - Host, I - IGMP, r - Repeater, V - VoIP-Phone, D - Remotely-Managed-Device, s - Supports-STP-Dispute Device ID Local Intrfce Hldtme Capability Platform Port ID d13-dist-1 mgmt0 148 S I WS-C2960-24TC Fas0/9 n5k(FLC12080012) Eth1/5 8 S I s N5K-C5020P-BA Eth1/5
Default Physical Ethernet Settings
The following table lists the default settings for all physical Ethernet interfaces:
Parameter |
Default Setting |
---|---|
Duplex |
Auto (full-duplex) |
Encapsulation |
ARPA |
MTU1 |
1500 bytes |
Port Mode |
Access |
Speed |
Auto (10000) |
MIBs for Layer 2 Interfaces
MIB |
MIB Link |
---|---|
IF-MIB |
To locate and download MIBs, go to the following URL: http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml |
MAU-MIB |