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Cisco IOS Software Releases 12.0 Special and Early Deployments

Fast EtherChannel Enhancements for Cisco 7200 Routers

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Table of Contents

Fast EtherChannel Enhancements on Cisco 7200 Series Routers
 Feature Overview
 Supported Platforms
 Supported Standards, MIBs, and RFCs
 Configuration Tasks
 Configuration Examples
 Command Reference
 channel-group
 clear counters
 clear interface
 interface port-channel
 show interfaces port-channel
 Glossary

Fast EtherChannel Enhancements on Cisco 7200 Series Routers

The Fast EtherChannel feature allows multiple Fast Ethernet point-to-point links to be bundled into one logical link to provide bidirectional bandwidth of up to 800 Mbps. Fast EtherChannel builds on standards-based 802.3 full-duplex Fast Ethernet to provide fault-tolerant, high-speed links between switches, routers, and servers. This feature can be configured between Cisco 7200 series routers, Cisco 7500 series routers and Cisco 7000 series routers with the 7000 Series Route Switch Processor (RSP7000) and 7000 Series Chassis Interface (RSP7000CI) or between a Cisco 7500 series router or a Cisco 7000 series router with the RSP7000 and RSP700CI and a Catalyst 5000 switch.

Note   Using the Fast EtherChannel feature on a Catalyst 5000 switch requires a hardware upgrade. Contact your local sales representative for upgrade details.

This feature module describes the Fast EtherChannel feature.

This document includes the following sections:

Feature Overview

Fast EtherChannel provides higher bidirectional bandwidth, redundancy, and load sharing. Up to four Fast Ethernet interfaces can be bundled in a port-channel, and the router or switch can support up to four port-channels. The Fast EtherChannel feature is capable of load balancing traffic across the Fast Ethernet links. Unicast, broadcast, and multicast traffic is distributed across the links providing higher performance and redundant parallel paths. In the event of a link failure, traffic is redirected to remaining links within the Fast EtherChannel without user intervention.

In this release of the Fast EtherChannel feature, IP traffic is distributed over the port-channel interface while traffic from other routing protocols is sent over a single link. Bridged traffic is distributed based on the Layer 3 information in the packet. If the Layer 3 information does not exist in the packet, the traffic is sent over the first link.

Fast EtherChannel supports all features currently supported on the Fast Ethernet interface. You must configure these features on the port-channel interface rather than on the individual Fast Ethernet interfaces. Fast EtherChannel connections are fully compatible with Cisco IOS virtual LAN (VLAN) and routing technologies. The Inter-Switch Link (ISL) VLAN trunking protocol can carry multiple VLANs across a Fast EtherChannel, and routers attached to Fast EtherChannel links can provide full multiprotocol routing with support for host standby using Host Standby Router Protocol (HSRP).

The port-channel (consisting of up to four Fast Ethernet interfaces) is treated as a single interface. Port-channel is used in the Cisco IOS software to maintain compatibility with existing commands on the Catalyst 5000 switch. You create the Fast EtherChannel by using the interface port-channel interface configuration command. You can assign up to four Fast Ethernet interfaces to a port-channel by using the channel-group interface configuration command.

Benefits

Fast EtherChannel provides the following benefits and features:

  • Logical aggregation of bandwidth
  • Load balancing
  • Fault tolerance
  • Supports all features currently supported on the Fast Ethernet interface
  • Fully compatible with Cisco IOS virtual LAN (VLAN) and routing technologies
  • Support for host standby using Host Standby Router Protocol (HSRP)—available in Cisco IOS Release 11.1(19)CA and Release 11.1(20)CC
  • Support for Cisco Express Forwarding (CEF) and distributed CEF (dCEF)—available in Cisco IOS Release 11.1(20)CC

Restrictions

If you are using the Fast EtherChannel feature in Cisco IOS Release 11.1 CA or Release 11.1(19)CC (or earlier), you must disable distributing switching on the router.

Supported Platforms

  • Cisco 7200 series
  • Cisco 7500 series
  • Cisco 7000 series routers with the RSP7000 and RSP7000CI
  • Catalyst 5000 switch

Supported Standards, MIBs, and RFCs

Standards
  • No new or modified standards are supported by this feature.
MIBs
  • No new or modified MIBs are supported by this feature.

For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs
  • No new or modified RFCs are supported by this feature.

Configuration Tasks

Configuring a Fast EtherChannel consists of the following required steps:

1. Create a port-channel interface and assign an IP address.

2. Assign the Fast Ethernet interfaces (up to four) to the port-channel interface.

For information on other configuration tasks for the Fast EtherChannel, refer to the "Configure an Ethernet or Fast Ethernet Interface" section in the "Configuring Interfaces" chapter of the Configuration Fundamentals Configuration Guide.

For information on other commands that can be used by the Fast EtherChannel, refer to the Cisco IOS Release 11.1 configuration guides.

Configuring the Port-Channel Interface

To configure the port-channel interface, perform the following tasks beginning in global configuration mode:

Command Purpose
Step 1 

Router(config)# interface port-channel channel-number

 

Create the port-channel interface and enter interface configuration mode. The channel-number can be 1 to 4.
Step 2 

Router(config-if)# ip address ip-address mask

Assign an IP address and subnet mask to the Fast EtherChannel.
Step 3 

Router(config-if)# mac-address ieee-address

 

Optionally, assign a static MAC address to the Fast EtherChannel.
Step 4 

Router(config-if)# end

Optionally, enable other supported interface commands to meet your needs and exit when you have finished.
Step 5 

Router# show interface port-channel

Verify the configuration.

Note   If you configure ISL, you must assign the IP address to the subinterface (for example, interface port-channel 1.1—an IP address per VLAN), and you must specify the encapsulation with the VLAN number under that subinterface (for example, encapsulation isl 100) for ISL to work.
Note   Currently, if you want to use the Cisco Discovery Protocol (CDP), you must configure it only on the port-channel interface and not on the physical Fast Ethernet interface.
Note   If you do not assign a static MAC address on the port-channel interface, the Cisco IOS software automatically assigns a MAC address. If you assign a static MAC address and then later remove it, the Cisco IOS software automatically assigns a MAC address.
Caution   With Release 11.1(20)CC, Fast EtherChannel supports CEF/dCEF. We recommend that you clear all explicit ip route-cache distributed commands from the Fast Ethernet interfaces before enabling dCEF on the port-channel interface. Doing this gives the port-channel interface proper control of its physical Fast Ethernet links. When you enable CEF/dCEF globally, all interfaces that support CEF/dCEF are enabled. When CEF/dCEF is enabled on the port-channel interface, it is automatically enabled on each of the Fast Ethernet interfaces in the channel group. However, if you have previously disabled CEF/dCEF on the Fast Ethernet interface, CEF/dCEF is not automatically enabled. In this case, you must enable CEF/dCEF on the Fast Ethernet interface.

Configuring the Fast Ethernet Interfaces

To assign the Fast Ethernet interfaces to the Fast EtherChannel, perform the following tasks beginning in global configuration mode:

Command Purpose
Step 1 

Router(config)# interface fastethernet slot/port-adapter/port
(Cisco 7500 series and Cisco 7000 series routers with the RSP7000)

Router(config)# interface fastethernet slot/port (Cisco 7200 series routers)

Create or modify an existing Fast Ethernet interface and enter interface configuration mode.
Step 2 

Router(config-if)# no ip address

 

If the Fast Ethernet interface already exists and has an IP address assigned, disable the IP address before performing the next step.
Step 3 

Router(config-if)# channel-group channel-number

 

Assign the Fast Ethernet interfaces to the Fast EtherChannel. The channel-number is the same as the channel-number you specified when you created the port-channel interface.
Step 4 

Router(config-if)# exit

Exit interface configuration mode and repeat Step 1 through Step 4 to add up to four Fast Ethernet interfaces to the Fast EtherChannel.
Step 5 

Router(config)# end

Exit when you have finished.
Step 6 

Router# show interface port-channel

Verify the configuration.

Caution   The port-channel interface is the routed interface. Do not enable Layer 3 addresses on the physical Fast Ethernet interfaces. Do not assign bridge groups on the physical Fast Ethernet interfaces because it creates loops. Also, you must disable spanning tree.

To remove a Fast Ethernet interface from a Fast EtherChannel, perform the following tasks beginning in global configuration mode

Command Purpose
Step 1 

Router(config)# interface fastethernet slot/port-adapter/port
(Cisco 7500 series and Cisco 7000 series routers with the RSP7000)
 
Router(config)# interface fastethernet slot/port (Cisco 7200 series routers)

Specify the Fast Ethernet interface and enter interface configuration mode.
Step 2 

Router(config-if)# no channel-group

Remove the Fast Ethernet interface from the channel group.
Step 3 

Router(config)# end

Exit when you have finished.

:

The Cisco IOS software automatically removes a Fast Ethernet interface from the Fast EtherChannel if the interface goes down, and the software automatically adds the Fast Ethernet interface to the Fast EtherChannel when the interface is back up.

Currently, Fast EtherChannel relies on keepalives to detect whether the line protocol is up or down. Keepalives are enabled by default on the Fast Ethernet interfaces. If the line protocol on the interface goes down because it did not receive a keepalive signal, the Fast EtherChannel detects that the line protocol is down and removes the interface from the Fast EtherChannel. However, if the line protocol remains up because keepalives are disabled on the Fast Ethernet interface, the Fast EtherChannel cannot detect this link failure (other than a cable disconnect) and does not remove the interface from the Fast EtherChannel even if the line protocol goes down. This can result in unpredictable behavior. The implementation of the Port Aggregation Protocol (PAgP) in a subsequent release of this feature will remove the dependency on keepalives.

See the section "Configuration Examples", later in this document, for configuration examples.

You can monitor the status of the Fast EtherChannel interface by using the show interfaces port-channel EXEC command.

Verifying Port-Channel Interface

Enter the show interfaces port-channel command from interface configuration mode. This output shows port-channel session information. Confirm that the port-channel is UP.

Router# show interfaces port-channel 1
Port-channel1 is up, line protocol is up
Hardware is FEChannel, address is 0000.0ca8.6220 (bia 0000.0000.0000)
MTU 1500 bytes, BW 400000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive not set, fdx
ARP type: ARPA, ARP Timeout 04:00:00
No. of active members in this channel: 4
Member 0 : FastEthernet1/0/0
Member 1 : FastEthernet1/1/0
Member 2 : FastEthernet4/0/0
Member 3 : FastEthernet4/1/0
Last input 01:22:13, output never, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
223 packets input, 11462 bytes, 0 no buffer
Received 1 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 watchdog, 0 multicast
0 input packets with dribble condition detected
192 packets output, 13232 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

Configuration Examples

Figure 1 shows four point-to-point Fast Ethernet interfaces that are aggregated into a single Fast EtherChannel interface.


Figure 1   Fast Ethernet Interfaces Aggregated into a Fast EtherChannel

Following is an example of how to create a Fast EtherChannel (port-channel interface) with four Fast Ethernet interfaces. In this example, ISL is enabled on the Fast EtherChannel, and an IP address is assigned to the subinterface.

router# configure terminal
router(config)# interface port-channel 1
router(config-if)# no shutdown
router(config-if)# exit
router(config)# interface port-channel 1.1
router(config-if)# ip address 1.1.1.10 255.255.255.0
router(config-if)# encapsulation isl 100
router(config-if)# exit
router(config)# interface fastethernet 0/0/0
router(config-if)# no ip address
router(config-if)# channel-group 1
Fast Ethernet 0/0 added as member-1 to port-channel1.
router(config-if)# exit
router(config)# interface fastethernet 0/1/0
router(config-if)# no ip address
router(config-if)# channel-group 1
Fast Ethernet 0/1 added as member-2 to port-channel1.
router(config-if)# exit
router(config)# interface fastethernet 1/0/0
router(config-if)# no ip address
router(config-if)# channel-group 1
Fast Ethernet 1/0 added as member-3 to port-channel1.
router(config-if)# exit
router(config)# interface fastethernet 1/1/0
router(config-if)# no ip address
router(config-if)# channel-group 1
Fast Ethernet 1/1 added as member-4 to port-channel1.
router(config-if)# exit
router(config)# exit
router#

The following is a partial example of a configuration file. The MAC address is automatically added to the Fast Ethernet interface when the interfaces are added to the Fast EtherChannel.

Note   If you do not assign a static MAC address on the port-channel interface, the Cisco IOS software automatically assigns a MAC address. If you assign a static MAC address and then later remove it, the Cisco IOS software automatically assigns a MAC address.
interface Port-channel1
 ip address 1.1.1.10 255.255.255.0
!
interface Port-channel1.1
 encapsulation isl 100
!
interface FastEthernet0/0/0
 mac-address 00e0.1476.7600
 no ip address
 channel-group 1
!
interface FastEthernet0/1/0
 mac-address 00e0.1476.7600
 no ip address
 channel-group 1
!
interface FastEthernet1/0/0
 mac-address 00e0.1476.7600
 no ip address
 channel-group 1
!
interface FastEthernet1/1/0
 mac-address 00e0.1476.7600
 no ip address
 channel-group 1

Command Reference

This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release <<x.x>> command reference publications.

In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.

To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:

command | {begin | include | exclude} regular-expression

Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:

show atm vc | begin PeakRate

For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.

channel-group

To assign a Fast Ethernet interface to a Fast EtherChannel group, use the channel-group interface command. To remove a Fast Ethernet interface from a Fast EtherChannel group, use the no form of the command.

channel-group channel-number
no channel-group channel-number

Syntax Description Syntax Description

channel-number

Port-channel number previously assigned to the port-channel interface when using the interface port-channel global configuration command. Range is 1 to 4.

Defaults

No default behavior or values.

Command Modes

Interface configuration

Command History

Release Modification

Cisco IOS Release 11.1 CA.

This command was introduced.

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1 CA.

Before you assign a Fast Ethernet interface to a Fast EtherChannel group, you must first create a port-channel interface. To create a port-channel interface, use the interface port-channel global configuration command.

If the Fast Ethernet interface has an IP address assigned, you must disable it before adding the Fast Ethernet interface to the Fast EtherChannel. To disable an existing IP address on the Fast Ethernet interface, use the no ip address interface configuration command.

The Fast EtherChannel feature allows multiple Fast Ethernet point-to-point links to be bundled into one logical link to provide bidirectional bandwidth of up to 800 Mbps. Fast EtherChannel can be configured between Cisco 7500 series routers and Cisco 7000 series routers with the 7000 Series Route Switch Processor (RSP7000) and 7000 Series Chassis Interface (RSP7000CI) or between a Cisco 7500 series router or a Cisco 7000 series router with the RSP7000 and RSP700CI and a Catalyst 5000 switch.

Up to four Fast Ethernet interfaces can be added to a Fast EtherChannel group.

Caution   The port-channel interface is the routed interface. Do not enable Layer 3 addresses on the physical Fast Ethernet interfaces. Do not assign bridge groups on the physical Fast Ethernet interfaces because it creates loops. Also, you must disable spanning tree.

To display information about the Fast EtherChannel, use the show interfaces port-channel EXEC command.

Examples

The following example adds Fast Ethernet 1/0 to the Fast EtherChannel group specified by port-channel 1:

Router(config)# interface port-channel 1
Router(config-if)# ip address 1.1.1.10 255.255.255.0
Router(config)# interface fastethernet 1/0/0
Router(config-if)# channel-group 1

Related Commands Related Commands

Command Description

interface port-channel

Specifies a Fast EtherChannel and enters interface configuration mode.

show interfaces port-channel

Displays the information about the Fast EtherChannel.

clear counters

To clear the interface counters, use the clear counters EXEC command.

clear counters [type number]

Syntax Description

type

(Optional) Interface type; one of the keywords listed in Usage Guidelines.

number

(Optional) Port number.

Command Modes

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

This command was modified in Cisco IOS Release 11.1 CA to include the port-channel interface type keyword.

This command clears all the current interface counters from the interface unless the optional arguments type and number are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on).

Note   This command will not clear counters retrieved using SNMP, but only those seen with the show interface EXEC command.

Keyword Interface Type

async

Asynchronous interface

bri

Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI)

dialer

Dialer interface

ethernet

Ethernet interface

fast-ethernet

Fast Ethernet interface

fddi

Fiber Distributed Data Interface (FDDI)

hssi

High-Speed Serial Interface (HSSI)

lex

LAN Extender interface

loopback

Loopback interface

null

Null interface

port-channel

Fast EtherChannel interface

pos

Packet OC-3 interface

serial

Synchronous serial interface

tokenring

Token Ring interface

tunnel

Tunnel interface

vg-anylan

100VG-AnyLAN port adapter

Example

The following example clears the interface counters on a Fast Etherchannel interface:

Router# show interface port-channel 1
Port-channel1 is up, line protocol is up
Hardware is FEChannel, address is 0060.83d8.4420 (bia 0000.0000.0000)
Internet address is 64.1.1.3/24
...
No. of active members in this channel: 4
Member 0: FastEthernet1/0/0
Member 1: FastEthernet4/0/0
Member 2: FastEthernet10/0/0
Member 3: FastEthernet11/0/0
Last input 00:00:00, output never, output hang never
Last clearing of "show interface" counters 11w2d
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/300, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
2295286 packets input, 142305812 bytes, 0 no buffer
Received 2294327 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 watchdog, 0 multicast
0 input packets with dribble condition detected
2420593 packets output, 184050286 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffers copied, 0 interrupts, 0 failures
Router# clear counter port-channel 1
Clear "show interface" counters on all interfaces [confirm]
%CLEAR-5-COUNTERS: Clear counter on all interfaces by console 1
Router# show interface port-channel 1
Port-channel1 is up, line protocol is up
Hardware is FEChannel, address is 0060.83d8.4420 (bia 0000.0000.0000)
Internet address is 64.1.1.3/24
MTU 1500 bytes, BW 400000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec), fdx
ARP type: ARPA, ARP Timeout 04:00:00
No. of active members in this channel: 4
Member 0: FastEthernet1/0/0
Member 1: FastEthernet4/0/0
Member 2: FastEthernet10/0/0
Member 3: FastEthernet11/0/0
Last input 00:00:01, output never, output hang never
Last clearing of "show interface" counters 00:00:03
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/300, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1 packets input, 62 bytes, 0 no buffer
Received 1 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 watchdog, 0 multicast
0 input packets with dribble condition detected
1 packets output, 62 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffers copied, 0 interrupts, 0 failures

Related Commands Related Command

Command Description

show interfaces port-channel

Displays the information about the Fast EtherChannel.

clear interface

To reset the hardware logic on an interface, use the clear interface EXEC command.

clear interface type number

Syntax Description

type

Interface type; one of the keywords listed in Usage Guidelines.

number

Port number.

Command Modes

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

This command was modified in Cisco IOS Release 11.1 CA to include the port-channel interface type keyword.

Under normal circumstances, you do not need to clear the hardware logic on interfaces.

Keyword Interface Type

async

Async interface

atm

Asynchronous Transfer Mode (ATM) interface

bri

Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI)

ethernet

Ethernet interface

fddi

Fiber Distributed Data Interface (FDDI)

hssi

High-Speed Serial Interface (HSSI)

loopback

Loopback interface

null

Null interface

port-channel

Fast EtherChannel interface

pos

Packet OC-3 Interface Processor

serial

Synchronous serial interface

tokenring

Token Ring interface

tunnel

Tunnel interface

vg-anylan

100VG-AnyLAN port adapter

Examples

The following example resets the interface logic on Fast Etherchannel interface 1:

Router# clear interface port-channel 1

interface port-channel

To specify a Fast EtherChannel and enter interface configuration mode, use the interface port-channel global configuration command.

interface port-channel channel-number

Syntax Description Syntax Description

channel-number

Channel number assigned to this port-channel interface. Range is 1 to 4.

Defaults

None

Command Modes

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1 CA.

The Fast EtherChannel feature allows multiple Fast Ethernet point-to-point links to be bundled into one logical link to provide bidirectional bandwidth of up to 800 Mbps. Fast EtherChannel can be configured between Cisco 7500 series routers and Cisco 7000 series routers with the 7000 Series Route Switch Processor (RSP7000) and 7000 Series Chassis Interface (RSP7000CI) or between a Cisco 7500 series router or a Cisco 7000 series router with the RSP7000 and RSP700CI and a Catalyst 5000 switch.

You can configure the port-channel interface as you would do to any Fast Ethernet interface.

After you create a port-channel interface, you assign Fast Ethernet interfaces (up to four) to it. For information on how to assign a Fast Ethernet interface to a port-channel interface, refer to the channel-group interface configuration command.

Caution   The port-channel interface is the routed interface. Do not enable Layer 3 addresses on the physical Fast Ethernet interfaces. Do not assign bridge groups on the physical Fast Ethernet interfaces because it creates loops. Also, you must disable spanning tree.
Note   If you configure ISL, you must assign the IP address to the subinterface (for example, interface port-channel 1.1—an IP address per VLAN), and you must specify the encapsulation with the VLAN number under that subinterface (for example, encapsulation isl 100) for ISL to work.
Note   Currently, if you want to use the Cisco Discovery Protocol (CDP), you must configure it only on the port-channel interface and not on the physical Fast Ethernet interface.
Note   If you do not assign a static MAC address on the port-channel interface, the Cisco IOS software automatically assigns a MAC address. If you assign a static MAC address and then later remove it, the Cisco IOS software automatically assigns a MAC address.
Caution   With Release 11.1(20)CC, the Fast EtherChannel supports CEF/dCEF. We recommend that you clear all explicit ip route-cache distributed commands from the Fast Ethernet interfaces before enabling dCEF on the port-channel interface. Doing this gives the port-channel interface proper control of its physical Fast Ethernet links. When you enable CEF/dCEF globally, all interfaces that support CEF/dCEF are enabled. When CEF/dCEF is enabled on the port-channel interface, it is automatically enabled on each of the Fast Ethernet interfaces in the channel group. However, if you have previously disabled CEF/dCEF on the Fast Ethernet interface, CEF/dCEF is not automatically enabled. In this case, you must enable CEF/dCEF on the Fast Ethernet interface.

Examples

The following example creates a port-channel interface with a channel group number of 1 and adds three Fast Ethernet interfaces to port-channel 1:

Router(config)# interface port-channel 1
Router(config-if)# ip address 1.1.1.10 255.255.255.0
Router(config)# interface fastethernet 1/0/0
Router(config-if)# channel-group 1
Router(config)# interface fastethernet 4/0/0
Router(config-if)# channel-group 1
Router(config)# interface fastethernet 5/0/0
Router(config-if)# channel-group 1

Related Commands Related Commands

Command Description

channel-group

Defines the timeslots that belong to each T1 and E1 circuit.

show interfaces port-channel

Displays the information about the Fast EtherChannel.

show interfaces port-channel

To display the information about the Fast EtherChannel on Cisco 7200 series routers, Cisco 7500 series routers and Cisco 7000 series routers with the RSP7000 and RSP7000CI, use the show interfaces port-channel EXEC command.

show interfaces port-channel [channel-number]

Syntax Description

channel-number

(Optional) Port channel number. Range is 1 to 4.

Command Modes

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1 CA.

Examples

The following is sample output from the show interfaces port-channel command:

Router# show interfaces port-channel 1
Port-channel1 is up, line protocol is up
Hardware is FEChannel, address is 0000.0ca8.6220 (bia 0000.0000.0000)
MTU 1500 bytes, BW 400000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive not set, fdx
ARP type: ARPA, ARP Timeout 04:00:00
No. of active members in this channel: 4
Member 0 : FastEthernet1/0/0
Member 1 : FastEthernet1/1/0
Member 2 : FastEthernet4/0/0
Member 3 : FastEthernet4/1/0
Last input 01:22:13, output never, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
223 packets input, 11462 bytes, 0 no buffer
Received 1 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 watchdog, 0 multicast
0 input packets with dribble condition detected
192 packets output, 13232 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

The following table describes significant fields in this output.

Field Description

Port-channel1 is up, line protocol is up

Indicates if the interface hardware is currently active and can transmit and receive or if it has been taken down by an administrator.

Hardware is

Hardware type (Fast EtherChannel).

address is

Address being used by the interface.

MTU

Maximum transmission unit of the interface.

BW

Bandwidth of the interface in kilobits per second.

DLY

Delay of the interface in microseconds.

rely

Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.

load

Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. The calculation uses the value from the bandwidth interface configuration command.

Encapsulation

Encapsulation method assigned to the interface.

loopback

Indicates if loopbacks are set.

keepalive

Indicates if keepalives are set.

fdx

Indicates the interface is operating in full-duplex mode.

ARA type

ARP type on the interface.

ARP timeout

Number of hours, minutes, and seconds an ARP cache entry will stay in the cache.

No. of active members in this channel: 4

Number of Fast Ethernet interfaces that are currently active (not down) and part of the Fast EtherChannel group.

Member 0: FastEthernet1/0/0

Specific Fast Ethernet interface that is part of the Fast EtherChannel group.

Last input

Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.

output

Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.

output hang

Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.

last clearing

Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.

*** indicates the elapsed time is too large to be displayed.

0:00:00 indicates the counters were cleared more than 231ms (and less then 232ms) ago.

Queueing strategy

First-in, first-out queuing strategy (other queueing strategies you might see are priority-list, custom-list, and weighted fair).

Output queue, drops
input queue, drops

Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped because a queue was full.

5 minute input rate
5 minute output rate

Average number of bits and packets received or transmitted per second in the last 5 minutes.

packets input

Total number of error-free packets received by the system.

bytes (input)

Total number of bytes, including data and MAC encapsulation, in the error-free packets received by the system.

no buffer

Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.

broadcasts

Total number of broadcast or multicast packets received by the interface.

runts

Number of packets that are discarded because they are smaller than the medium's minimum packet size.

giants

Number of packets that are discarded because they exceed the medium's maximum packet size.

input errors

Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum might not balance with the other counts.

CRC

Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. On a serial link, CRCs usually indicate noise, gain hits or other transmission problems on the data link.

frame

Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.

overrun

Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.

ignored

Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be incremented.

abort

Illegal sequence of ones bit on the interface.

watchdog

Number of times watchdog receive timer expired. It happens when receiving a packet with length greater than 2048.

multicast

Number of multicast packets received.

input packets with dribble condition detected

Dribble bit error indicates that a frame is slightly too long. This frame error counter is incremented just for informational purposes; the router accepts the frame.

packets output

Total number of messages transmitted by the system.

bytes (output)

Total number of bytes, including data and MAC encapsulation, transmitted by the system.

underruns

Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle.

output errors

Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this might not balance with the sum of the enumerated output errors, as some datagrams can have more than one error, and others can have errors that do not fall into any of the specifically tabulated categories.

collisions

Number of messages retransmitted due to an Ethernet collision. This is usually the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). A packet that collides is counted only once in output packets.

interface resets

Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within a certain interval. If the system notices that the carrier detect line of an interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an unrecoverable interface processor error occurred, or when an interface is looped back or shut down.

babbles

The transmit jabber timer expired.

late collision

Number of late collisions. Late collision happens when a collision occurs after transmitting the preamble.

deferred

Deferred indicates that the chip had to defer while ready to transmit a frame because the carrier was asserted.

lost carrier

Number of times the carrier was lost during transmission.

no carrier

Number of times the carrier was not present during the transmission.

output buffer failures

Number of times that a packet was not output from the output hold queue because of a shortage of MEMD shared memory.

output buffers swapped out

Number of packets stored in main memory when the output queue is full; swapping buffers to main memory prevents packets from being dropped when output is congested. The number is high when traffic is bursty.

Related Commands Related Command

Command Description

interface port-channel

Specifies a Fast EtherChannel and enters interface configuration mode.

Glossary

Cisco Express Forwarding (CEF)—Layer 3 switching technology. CEF can also refer to central CEF mode, one of the two modes of CEF operation that enables a route processor to perform express forwarding.

Distributed CEF (dCEF)—One of two modes of CEF operation that enables line cards to perform the express forwarding between port adapters.

port-channel—Type of interface in Cisco IOS software used to group up to four Fast Ethernet interfaces.

Fast EtherChannel—Feature used to group together multiple full-duplex 802.3 Fast Ethernet to provide fault-tolerant, high-speed links between switches, routers, and servers.