EtherChannel* Configuration and Features for AIX v4.3 and v5.1

Contents

This document describes procedures for configuring and unconfiguring an Etherchannel for AIX machines running AIX v4.3 or v5.1. The document also includes procedures for listing an etherchannel and changing an etherchannel configuration.

Etherchannel introduction

Hardware

The ethernet adapters inside, which are members of the etherchannel, can be any supported ethernet adapter. The ethernet adapters must be connected to a switch which supports Etherchannel.

Configuration

In AIX 4.3.3, a single etherchannel can combine either two or four ethernet adapters in the channel.

You can configure multiple etherchannels on a single system. Be aware that each etherchannel constitutes an additional ethernet interface. The no option, ifsize (default 8), needs to be increased to include not only the ethernet interfaces for each adapter, but also any Etherchannels that are configured. See the no command documentation in regards to modifying ifsize.

The adapters in an etherchannel need to be configured to the same speed (10 or 100 Mbps) and mode (half or full duplex).

Configuring Etherchannel

Etherchannel is configured through SMIT. The following setup demonstrates how etherchannel is configured:

• The etherchannel contains two ethernet adapters, ent0 and ent1.
• No etherchannel alternate address is specified.
• There are 5 ethernet adapters to choose from.

Follow these steps to configure (and add) an etherchannel:

1. Run the following command

     # smitty etherchannel

This command displays the SMIT Etherchannel panel as follows:

       Etherchannel

Move cursor to desired item and press Enter.

  List All Etherchannels
  Add An Etherchannel
  Change / Show Characteristics of an Etherchannel
  Remove An Etherchannel



2. Select Add An Etherchannel to display the following panel:

            Available Network Adapters

     Move cursor to desired item and press F7.
                 ONE OR MORE items can be selected. 
     Press Enter AFTER making all selections. 

     ent0
     ent1
     ent2
     ent3
     ent4

     F1=Help          F2=Refresh          F3=Cancel
     F7=Select        F8=Image            F10=Exit
     Enter=Do         /=Find              n=Find Next

NOTE: The "Available Network Adapters" displays all of the ethernet adapters. Selecting an ethernet adapter that is already being used (i.e. has an interface defined) results in an error similar to the following:

Method error (/usr/lib/methods/cfgech):
0514-001 System error: Method error (/usr/lib/methods/chgent):
0514-062 Cannot perform the requested function because the specified
device is busy.

3. Select one more more of the listed adapters to display the following panel:

           Add an Etherchannel

 Type or select values in entry fields.
 Press Enter AFTER making all desired changes.

  [Entry Fields]
  Etherchannel Adapters                    ent0 ent1      +
  Enable ALTERNATE ETHERCHANNEL address    no             +
  ALTERNATE ETHERCHANNEL address           []             +
  Mode standard +
  Enable GIGABIT ETHERNET JUMBO frames     no             +
  Internet Address to Ping                 []
  Number of Retries                        []             #
  Retry Timeout (sec)                      []             #

 F1=Help        F2=Refresh       F3=Cancel      F4=List
 F5=Reset       F6=Command       F10=Edit       F8=Image
 F9=Shell       F10=Exit         Enter=Do

4. Press the Enter key. Command output similar to the following is displayed:

COMMAND STATUS

Command: OK stdout: yes stderr: no

Before command completion, additional instructions may appear below.

ent5 Available

NOTE: Since an alternate address was not specified, the config method for the etherchannel changed the alternate address of ent1 to the hardware address of ent0. If an alternate address was specified, both ent0 and ent1 would have that alternate address.

5. Finally, add an interface, en5 for standard ethernet or et5 for IEEE 802.3, through the normal means. The easiest way is to use the "Minimum Configuration & Startup" TCP/IP smit menu.

Listing Etherchannels

1. Run the following command

     # smitty etherchannel

This command displays the SMIT Etherchannel panel as follows:

          Etherchannel

Move cursor to desired item and press Enter.

  List All Etherchannels
  Add An Etherchannel
  Change / Show Characteristics of an Etherchannel
  Remove An Etherchannel



2. Select List All Etherchannels to display output similar to the following:

   COMMAND STATUS

 Command: OK stdout: yes stderr: no

 Before command completion, additional instructions may appear below.

 ent5 Available Etherchannel

Changing the alternate address

1. Run the following command:

     # smitty etherchannel

This command displays the SMIT Etherchannel panel as follows:

                 Etherchannel

Move cursor to desired item and press Enter.

  List All Etherchannels
  Add An Etherchannel
  Change / Show Characteristics of an Etherchannel
  Remove An Etherchannel



2. Select Change / Characteristics of an Etherchannel to display the Available Etherchannels panel on the screen:

                  Available Etherchannels

   Move cursor to desired item and Enter.

   ent5


     F1=Help          F2=Refresh          F3=Cancel
     F7=Select        F8=Image            F10=Exit
     Enter=Do         /=Find              n=Find Next

3. Select the etherchannel (in our example ent5), and then press Enter to display the Change / Show Characteristics of an Etherchannel panel.
4. To change the etherchannel alternate address to 1234deadbeef (for example), enter field values as shown on the following example panel:

           Change / Show the Characteristics of an Etherchannel

Type or select values in entry fields.
Press Enter AFTER making all desired changes.
                                          [Entry Fields]
Etherchannel                               ent5             +
Enable ALTERNATE ETHERCHANNEL address      yes              +
ALTERNATE ETHERCHANNEL address             [0x1234deadbeef] +

5. Press Enter to see results of the command similar to the following:

   COMMAND STATUS

  Command: OK stdout: yes stderr: no

  Before command completion, additional instructions may appear below.

  ent5 changed

NOTE: To add or delete an ethernet adapter from the etherchannel, you must first use the Remove an Etherchannel smit menu option to remove the etherchannel. Then, add the etherchannel again with the Add An Etherchannel smit menu option, making the desired changes in the configuration.

Unconfiguring the Etherchannel

Follow these steps to unconfigure (that is, remove) an etherchannel:

1. Run the following command to display the SMIT etherchannel panel:

     # smitty etherchannel

2. From the menu options, select Remove an Etherchannel, and then press Enter.
3. On the Etherchannel panel, select the desired etherchannel (in this example, ent5), and then press Enter. Command output similar to the following is displayed:

   COMMAND STATUS

  Command: OK stdout: yes stderr: no

  Before command completion, additional instructions may appear below.

  ent5 deleted

  ent0 changed
  ent1 changed

Troubleshooting

The entstat command reports the aggregate statistics of all the adapters in an etherchannel. To print the statistics of each adapter, run the entstat command with the -d flag.

Restrictions

Modes

Standard

In this mode the channel will hash on the destination IP address and use this value to choose which adapter it will send the packet out on. This mode will guarantee packets are sent out over the channel in the order they were sent, but may not make full use of the bandwidth.

Round Robin

In this mode the channel will rotate through the adapters, giving each adapter one packet before repeating. In this mode packets may be sent out in a slightly different order than they were given to the channel, but the channel will make the best use of its bandwidth.

Network Interface Backup

In this mode, the channel will only activate one adapter at a time. The intention is that the adapters are plugged into different ethernet switches, each of which is capable of getting to any other machine on the subnet/network. When a problem is detected, either with the direct connection, or through inability to ping a machine, the channel will deactivate the current adapter, and activate a backup adapter.

The channel will poll the adapter for Link Status in "Retry Timeout" intervals. If the Link Status is not up (either due to a cable being unplugged, switch down, or device driver problem) , the channel will switch to another adapter.

This mode is the only one that makes use of the "Internet Address to Ping", "Number of Retries", and "Retry Timeout" fields.

Internet address to ping

Number of retries

Retry timeout

*Etherchannel is a registered trademark of Cisco Systems, Inc.

[ Doc Ref: 100324727618234     Publish Date: Nov. 06, 2001]