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Table Of Contents
Using Interface Configuration Mode
Procedures for Configuring Interfaces
Configuring a Range of Interfaces
Configuring and Using Interface Range Macros
Using the Ethernet Management Port
Understanding the Ethernet Management Port
Supported Features on the Ethernet Management Port
Configuring the Ethernet Management Port
TFTP and the Ethernet Management Port
Configuring Ethernet Interfaces
Default Ethernet Interface Configuration
Configuring Interface Speed and Duplex Mode
Speed and Duplex Configuration Guidelines
Setting the Interface Speed and Duplex Parameters
Configuring IEEE 802.3x Flow Control
Configuring Auto-MDIX on an Interface
Adding a Description for an Interface
Configuring Layer 3 Interfaces
Monitoring and Maintaining the Interfaces
Clearing and Resetting Interfaces and Counters
Shutting Down and Restarting the Interface
Configuring Interfaces
This chapter defines the types of interfaces on the Cisco ME 3800X and ME 3600X switches and describes how to configure them.
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Understanding Interface Types
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Understanding Interface Types
This section describes the different types of interfaces supported by the switch with references to chapters that contain more detailed information about configuring these interface types. The rest of the chapter describes configuration procedures for physical interface characteristics.
NNI Port Type
All Cisco ME 3800X and 3600X ports are network node interfaces (NNIs), which are typically connected to a router or to another switch. The default status for an NNI is administratively up to allow a service provider remote access to the switch during initial configuration.
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. For more information about VLANs, see Chapter 11 "Configuring VLANs." 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 associated with the VLAN ID or when a user creates te VLAN ID.
To configure VLANs, use the vlan vlan-id global configuration command to enter VLAN configuration mode. The VLAN configurations for VLAN IDs 1 to 1005 are saved in the VLAN database. Extended-range VLANs (VLAN IDs 1006 to 4094) are not added to the VLAN database. VLAN configuration is saved in the switch running configuration, and you can save it in the switch startup configuration file by entering the copy running-config startup-config privileged EXEC command.
Add ports to a VLAN by using the switchport interface configuration commands:
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To isolate VLANs of different customers in a service-provider network, Cisco ME switches use UNI VLANs. Local switching does not occur among user network interfaces (UNIs) and enhanced network interfaces (ENIs) on the switch that belong to the same UNI isolated VLAN. Local switching is allowed among ports that belong to a UNI community VLAN. Because all ports on the ME 3800X and 3600X switches are NNIs, UNI VLAN configuration has no effect. Local switching is allowed between NNIs.
Switch Ports
Switch ports are Layer 2 only interfaces associated with a physical port. Switch ports belong to one or more VLANs. You can configure a port as an access port or trunk port. 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. Use the switchport command with no keywords to put an interface that is in Layer 3 mode into Layer 2 mode.
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For detailed information about configuring access port and trunk port characteristics, see Chapter 11 "Configuring VLANs."
Access Ports
An access port belongs to and carries the traffic of only one VLAN. 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 an IEEE 802.1Q tagged packet, the packet is dropped, and the source address is not learned. IEEE 802.1x can also be used for VLAN assignment.
You manually assign static access ports to a VLAN.
Trunk Ports
An IEEE 802.1Q trunk port carries the traffic of multiple VLANs and by default is a member of all VLANs in the VLAN database. A 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 multiple VLANs, 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 the VLAN is in the enabled state.
For more information about trunk ports, see Chapter 11 "Configuring VLANs."
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 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.
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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. See the "Configuring Layer 3 Interfaces" section for information about what happens when hardware resource limitations are reached.
For more information about IP unicast and multicast routing and routing protocols, see Chapter 37 "Configuring IP Unicast Routing" and Chapter 44 "Configuring IP Multicast Routing."
Ethernet Management Port
The Ethernet management port, also referred to as the Gi0 or gigabitethernet0 port, is a Layer 3 host port to which you can connect a PC. You can use the Ethernet management port instead of the switch console port for network management.
See the "Using the Ethernet Management Port" section for more information.
Switch Virtual Interfaces
A switch virtual interface (SVI) represents a VLAN of switch ports as one interface to the routing or bridging function in the system. Only one SVI can be associated with a VLAN, but you need to configure an SVI for a VLAN only when you wish to route between VLANs or to provide IP host connectivity to the switch. By default, an SVI is created for the default VLAN (VLAN 1) to permit remote switch administration. Additional SVIs must be explicitly configured.
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SVIs provide IP host connectivity only to the system; in Layer 3 mode, you can configure routing across SVIs.
Although the switch 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. See the "Configuring Layer 3 Interfaces" section for information about what happens when hardware resource limitations are reached.
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 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. For more information, see the "Manually Assigning IP Information" section.
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SVIs support routing protocols. For more information about configuring IP routing, see Chapter 37 "Configuring IP Unicast Routing," and Chapter 44 "Configuring IP Multicast Routing."
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 switches or between switches 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, 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 Cisco Discovery Protocol (CDP), Link Aggregation Control Protocol (LACP), and the Port Aggregation Protocol (PAgP), which operate only on physical NNI or ENI 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. For more information, see Chapter 36 "Configuring EtherChannels."
Ethernet Flow Points
An Ethernet Flow Point (EFP) is a logical interface that connects an Ethernet Virtual Connection (EVC) bridge domain to a physical port in a switch. Configuring a service instance on an interface creates a pseudoport or EFP on which you configure EVC features.
You can configure EFP service instances only on Layer 2 ports. You can configure an EtherChannel with a service instance, but you cannot add an interface to a channel group if it has a service instance configured on it. EFPs do not support routing. EFPs do not support switchport commands.
Switch interfaces configured with service instances support a different range of features than interfaces that do not have service instances. For more information on EVCs, see Chapter 12 "Configuring Ethernet Virtual Connections (EVCs)."
Connecting Interfaces
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 switch, ports in different VLANs have to exchange information through a router. By using the switch 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 switch with no need for an external router (Figure 10-1).
Figure 10-1 Connecting VLANs with the Switch
You can enable routing on all SVIs and routed ports on the switch. Whenever possible, to maintain high performance, forwarding is done by the switch hardware. However, only IP Version 4 packets with Ethernet II encapsulation can be routed in hardware. The switch 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. For more information, see Chapter 37 "Configuring IP Unicast Routing" and Chapter 44 "Configuring IP Multicast Routing."
Using Interface Configuration Mode
The switch supports these interface types:
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You can also configure a range of interfaces (see the "Configuring a Range of Interfaces" section).
To configure a physical interface (port), specify the interface type, the module number, and the switch port number, and enter interface configuration mode.
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You can identify physical interfaces by physically checking the interface location on the switch. 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.
Procedures for Configuring Interfaces
These general instructions apply to all interface configuration processes.
Step 1
Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)#Step 2
Switch(config)# interface gigabitethernet0/1Switch(config-if)#
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You can also configure a range of interfaces by using the interface range or interface range macro global configuration commands. Interfaces configured in a range must be the same type and must be configured with the same feature options.
Step 4
Enter the show interfaces privileged EXEC command to see 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.
Configuring a Range of Interfaces
You can use the interface range global configuration command to configure multiple interfaces with the same configuration parameters. 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.
Beginning in privileged EXEC mode, follow these steps to configure a range of interfaces with the same parameters:
When using the interface range global configuration command, note these guidelines:
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This example shows how to use the interface range global configuration command to set the speed on ports 1 and 2 to 100 Mb/s:
Switch# configure terminalSwitch(config)# interface range gigabitethernet0/1 - 2Switch(config-if-range)# speed 100This example shows how to use a comma to add different interface type strings to the range to enable Fast Ethernet ports 1 to 3 and Gigabit Ethernet ports 1 and 2 to receive IEEE 802.3x flow control pause frames:
Switch# configure terminalSwitch(config)# interface range gigabitethernet0/1 - 3 , gigabitethernet0/5 - 6Switch(config-if-range)# flowcontrol receive onIf 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 together 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.
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.
Beginning in privileged EXEC mode, follow these steps to define an interface range macro:
Use the no define interface-range macro_name global configuration command to delete a macro.
When using the define interface-range global configuration command, note these guidelines:
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This example shows how to define an interface-range named enet_list to include ports 1 and 2 and to verify the macro configuration:
Switch# configure terminalSwitch(config)# define interface-range enet_list gigabitethernet0/1 - 2Switch(config)# endSwitch# show running-config | include definedefine interface-range enet_list GigabitEthernet0/1 - 2This example shows how to create a multiple-interface macro named macro1 and assign all of the interfaces in the range to a VLAN:
Switch# configure terminalSwitch(config)# define interface-range macro1 gigabitethernet0/1 - 2, gigabitethernet0/5 - 6Switch(config)# interface range macro macro1Switch(config-if-range)# switchport access vlan 20Switch(config-if-range)# endThis example shows how to enter interface range configuration mode for the interface-range macro enet_list:
Switch# configure terminalSwitch(config)# interface range macro enet_listSwitch(config-if-range)#This example shows how to delete the interface-range macro enet_list and to verify that it was deleted.
Switch# configure terminalSwitch(config)# no define interface-range enet_listSwitch(config)# endSwitch# show run | include defineSwitch#Using the Ethernet Management Port
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Understanding the Ethernet Management Port
The Ethernet management port is port Gi0 or gigabitethernet0, a Layer 3 host port to which you can connect a PC. You can use the Ethernet management port instead of the switch console port for network management.
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When connecting a PC to the Ethernet management port, you must assign an IP address. Connect the Ethernet management port to the PC as shown in Figure 10-2.
Figure 10-2 Connecting a Switch to a PC
By default, the Ethernet management port is enabled. The switch cannot route packets from the Ethernet management port to a network port or receive routed packets from a network port.
Even though the Ethernet management port does not support routing, you might need to enable routing protocols on the port. For example, in Figure 10-3, you must enable routing protocols on the Ethernet management port when the PC is two or more hops away from the switch and the packets must pass through two or more Layer 3 devices to reach the PC.
Figure 10-3 Network Example with Routing Protocols Enabled
In Figure 10-3, if the Ethernet management port and the network ports are associated with the same routing process, the routes are propagated in this manner:
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Because routing is not supported between the Ethernet management port and the network ports, traffic cannot be sent or received between these ports. If traffic is sent or received, data packet loops occur between the ports, which disrupts the switch and network operation. Configure route filters to avoid routes between the Ethernet management port and the network ports and to prevent the loops.
Supported Features on the Ethernet Management Port
The Ethernet management port supports these features:
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Configuring the Ethernet Management Port
To specify the Ethernet management port in the CLI, enter gigabitethernet0.
To disable the port, use the shutdown interface configuration command. To enable the port, use the no shutdown interface configuration command.
You can monitor the Ethernet management port LED to determine the link status to the PC. The LED is green (on) when the link is active, and the LED is off when the link is down. The LED is amber when there is a POST failure.
To display the link status, use the show interfaces gigabitethernet 0 privileged EXEC command.
TFTP and the Ethernet Management Port
Use the commands in Table 1 when using TFTP to download or upload a configuration file to the boot loader.
Table 1 Boot Loader Commands
arp [ip_address]
Displays the currently cached ARP1 table when this command is entered without the ip_address parameter.
Enables ARP to associate a MAC address with the specified IP address when this command is entered with the ip_address parameter.
mgmt_clr
Clears the statistics for the Ethernet management port.
mgmt_init
Starts the Ethernet management port.
mgmt_show
Displays the statistics for the Ethernet management port.
ping host_ip_address
Sends ICMP ECHO_REQUEST packets to the specified network host.
boot tftp:/file-url ...
Loads and boots an executable image from the TFTP server and enters the command-line interface.
For more details, see the command reference for this release.
copy tftp:/source-file-url filesystem:/destination-file-url
Copies a Cisco IOS image from the TFTP server to the specified location.
For more details, see the command reference for this release.
1 ARP = Address Resolution Protocol.
Configuring Ethernet Interfaces
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Default Ethernet Interface Configuration
Table 10-2 shows the Ethernet interface default configuration. For more details on the VLAN parameters listed in the table, see Chapter 11 "Configuring VLANs." For details on controlling traffic to the port, see Chapter 24 "Configuring Traffic Control."
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Table 10-2 Default Ethernet Configuration
Operating mode
Layer 2 or switching mode (switchport command).
Allowed VLAN range
VLANs 1- 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 access (Layer 2 interfaces only).
Port enable state
Enabled.
Port description
None defined.
Speed
Autonegotiate.
Duplex mode
Autonegotiate.
IEEE 802.3x flow control
Flow control is set to receive: off. It is always off for sent packets.
EtherChannel
Disabled on all Ethernet ports. See Chapter 36 "Configuring EtherChannels."
Broadcast, multicast, and unicast storm control
Disabled. See the "Default Storm Control Configuration" section.
Port Fast
Disabled. See the "Default Optional Spanning-Tree Configuration" section.
Auto-MDIX
Enabled.
Cisco Discovery Protocol (CDP)
Enabled.
Configuring Interface Speed and Duplex Mode
Ethernet interfaces on the switch operate at 10, 100, or 1000 Mb/s or and in either full- or half-duplex mode. In full-duplex mode, two stations can send and receive traffic at the same time. Normally, 10-Mb/s ports operate in half-duplex mode, which means that stations can either receive or send traffic.
Switch models include combinations Gigabit Ethernet (10/100/1000-Mb/s) ports and small form-factor pluggable (SFP) module slots supporting SFP modules.
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Speed and Duplex Configuration Guidelines
When configuring an interface speed and duplex mode, note these guidelines:
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The exception is when a 1000BASE-T SFP module is in the SFP module slot, you can configure speed as 10, 100, or 1000 Mb/s, or auto, but not as nonegotiate.
On a 100BASE-FX SFP module, you cannot configure the speed as nonegotiate.
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Setting the Interface Speed and Duplex Parameters
Beginning in privileged EXEC mode, follow these steps to set the speed and duplex mode for a physical interface.
Use the no speed and no duplex interface configuration commands to return the interface to the default speed and duplex settings (autonegotiate). To return all interface settings to the defaults, use the default interface interface-id interface configuration command.
This example shows how to set the interface speed to 10 Mb/s and the duplex mode to half:
Switch# configure terminalSwitch(config)# interface gigabitethernet0/3Switch(config-if)# speed 10Switch(config-if)# duplex halfThis example shows how to set the interface speed to 100 Mb/s on a 10/100/1000 Mb/s port:
Switch# configure terminalSwitch(config)# interface gigabitethernet0/2Switch(config-if)# speed 100Configuring IEEE 802.3x Flow Control
IEEE 802.3x 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.
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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 IEEE 802.3x flow control settings on the device:
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Beginning in privileged EXEC mode, follow these steps to configure IEEE 802.3x flow control on an interface:
To disable IEEE 802.3x flow control, use the flowcontrol receive off interface configuration command.
This example shows how to enable IEEE 802.3x flow control on a port:
Switch# configure terminalSwitch(config)# interface gigabitethernet0/1Switch(config-if)# flowcontrol receive onSwitch(config-if)# endConfiguring Auto-MDIX on an Interface
When automatic medium-dependent interface crossover (auto-MDIX) is enabled on an interface, the interface automatically detects the required cable connection type (straight through or crossover) and configures the connection appropriately. When connecting switches without the auto-MDIX feature, you must use straight-through cables to connect to devices such as servers, workstations, or routers and crossover cables to connect to other switches or repeaters. With auto-MDIX enabled, you can use either type of cable to connect to other devices, and the interface automatically corrects for any incorrect cabling. For more information about cabling requirements, see the hardware installation guide.
Auto-MDIX is enabled by default. When you enable auto-MDIX, you must also set the speed and duplex on the interface to auto so that the feature operates correctly. Auto-MDIX is supported on all 10/100 and 10/100/1000 Mb/s interfaces and on Cisco 10/100/1000 BASE-T/TX SFP module interfaces. It is not supported on 1000 BASE-SX or -LX SFP module interfaces.
Table 10-3 shows the link states that result from auto-MDIX settings and correct and incorrect cabling.
Beginning in privileged EXEC mode, follow these steps to configure auto-MDIX on an interface:
To disable auto-MDIX, use the no mdix auto interface configuration command.
This example shows how to enable auto-MDIX on a port:
Switch# configure terminalSwitch(config)# interface gigabitethernet0/1Switch(config-if)# speed autoSwitch(config-if)# duplex autoSwitch(config-if)# mdix autoSwitch(config-if)# endAdding a Description for an Interface
You can add a description about an interface to help you remember its function. The description appears in the output of these privileged EXEC commands: show configuration, show running-config, and show interfaces.
Beginning in privileged EXEC mode, follow these steps to add a description for an interface:
Use the no description interface configuration command to delete the description.
This example shows how to add a description on a port and how to verify the description:
Switch# config terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# interface gigabitethernet0/2Switch(config-if)# description Connects to MarketingSwitch(config-if)# endSwitch# show interfaces gigabitethernet0/2 descriptionInterface Status Protocol DescriptionGi 0/2 admin down down Connects to MarketingConfiguring Layer 3 Interfaces
The switch supports these types of Layer 3 interfaces:
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EtherChannel port interfaces are described in Chapter 36 "Configuring EtherChannels."
A Layer 3 switch 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 switch. 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 switch is using maximum hardware resources, attempts to create a routed port or SVI have these results:
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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.
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Beginning in privileged EXEC mode, follow these steps to configure a Layer 3 interface:
To remove an IP address from an interface, use the no ip address interface configuration command.
This example shows how to configure a port as a routed port and to assign it an IP address:
Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# interface gigabitethernet0/2Switch(config-if)# no switchportSwitch(config-if)# ip address 192.20.135.21 255.255.255.0Configuring the Interface MTU
You can configure the maximum transmission unit (MTU) size on an interface to determine the packet size that can be received on the interface. Because the switch does not fragment Layer 2 packets, it drops switched Layer 2 packets larger than the packet size supported on the egress interface.
Beginning in privileged EXEC mode, follow these steps to change the MTU size on an interface:
This example shows how to set the maximum packet size for a Gigabit Ethernet port to 1800 bytes:
Switch(config)# interface gigabitethernet0/3Switch(config-if)# mtu 1800Switch(config)# exitMonitoring and Maintaining the Interfaces
These sections contain interface monitoring and maintenance information:
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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 10-4 lists some of these interface monitoring commands. (You can display the full list of show commands by using the show ? command at the privileged EXEC prompt.) These commands are fully described in the Cisco IOS Interface Command Reference, Release 15.x.
Clearing and Resetting Interfaces and Counters
Table 10-5 lists the privileged EXEC mode clear commands that you can use to clear counters and reset interfaces.
To clear the interface counters shown by the show interfaces privileged EXEC command, use the clear counters privileged EXEC command. The clear counters command clears all current interface counters from the interface unless you specify optional arguments that clear only a specific interface type from a specific interface number.
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Shutting Down and Restarting the 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.
Beginning in privileged EXEC mode, follow these steps to shut down an interface:
Use the no shutdown interface configuration command to enable an interface.
To verify that an interface is disabled, enter the show interfaces privileged EXEC command. A disabled interface is shown as administratively down in the display.
