How to configure netif_backup in AIX 4.3.3 @ Maintenance Level 08

Contents

Description of netif_backup?

The term refers to network interface backup mode. Adapters are plugged into different Ethernet switches, each of which is capable of getting to any other machine on the subnet/network. In the network interface backup mode, the channel only activates one adapter at a time.When a problem is detected, either with the direct connection, or through the inability to ping a machine, the channel deactivates the current adapter, and activates a backup adapter.

netif_backup was a feature of the IBM 10/100 PCI Ethernet adapter, which is the adapter used in this example. There are a couple of filesets you need to check before using netif_backup with your IBM 10/100 PCI adapters (23100020). First, make sure your device driver is at the very latest level. Run the following command to check the device driver level:

# lslpp -l devices.pci.23100020.*

  Fileset                      Level      State     Description
------------------------------------------------------------------------
Path: /usr/lib/objrepos
devices.pci.23100020.diag      4.3.3.50   APPLIED   IBM PCI 10/100 Mb 
                                                    Ethernet Adapter (23100020) 
Diagnostics
devices.pci.23100020.rte       4.3.3.51   APPLIED   IBM PCI 10/100 Ethernet
                                                    Adapter Software      

Note: The APAR for rte is IY18028

Related documentation

For more information related to this document see:
AIX 5L Differences Guide Version 5.1 Edition

The product documentation library is also available:
http://www.rs6000.ibm.com/resource/aix_resource/Pubs/index.html

How to configure netif_backup

The netif_backup feature is part of etherchannel configuration, although not a true etherchannel. It appears in the same smitty panels as etherchannel because only etherchannel or netif_backup may be on a set of adapters. This example assumes that we have two adapters we want to use in our netif_backup channel (ent0 and ent1). Follow these steps:

1. Enter the following command to display the Etherchannel menu:

   # smitty etherchannel 
   
                  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 , and then press the Enter key to display the next selection menu:

   +---------------------------------------------- + 
   ¦ Available Network Interfaces ¦ 
   ¦ Move cursor to desired item and press F7. 
   ¦ ONE OR MORE items can be selected. 
   ¦ Press Enter AFTER making all selections. ¦ 
   ¦ > ent0 
   ¦ > ent1 
   

3. Select the adapters you want to use in your netif_backup channel. The > symbol indicates a selected adapter when you highlight it, and then press the F7 key (or press Esc+7 if you are working in ASCII mode).
   
   
4. After selecting the adapters, press the Enter key to display the configuration menu.

           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                                   netif_backup + 
   
   Enable GIGABIT ETHERNET JUMBO frames   no           + 
   Internet Address to Ping              [10.10.10.1] 
   Number of Retries                     [10] # 
   Retry Timeout (sec)                   [30] # 

5. To use netif_backup, set the following in the Add an Etherchannel menu:
   
   
   • Mode:
     set this to netif_backup
   • Internet Address to Ping:
     The address will be pinged if the address field has a non-zero address and the mode is set to netif_backup. If the channel is unable to ping the address for the Number of Retries times in Retry Time-out invervals, the channel will switch adapters.
   • Number of Retries:
     The number of retries is the number of ping response failures before the channel switches adapters. The default is three times.
   • Retry Timeout:
     The retry timeout is the interval in seconds between the times when the channel will send out a ping packet and poll the adapter's Link Status. The default is one second intervals.

   This example specifies that the adapter will ping the indicated IP address 10 times every 30 seconds. At 300 seconds the card would fail over to the second adapter.
   
   

6. Press Enter to display the command status:

   COMMAND STATUS 
   Command: OK stdout: yes stderr: no
   

   Before command completion, additional instructions may appear below.

   ent3 Available 
   

   This example indicates that a new virtual device, ent3, has been created. This device will have an en3 interface associated with it. This interface is configured by means of the IP and subnet mask.
   
   

7. Enter the following command to configure this ethernet interface:

   #smitty chinet 
   

8. From the following menu, select the en3 interface to configure:

   Change / Show a Standard Ethernet Interface 
   
   Type or select values in entry fields. 
   Press Enter AFTER making all desired changes. 
                                                [Entry Fields] 
   Network Interface Name                        en3 
   INTERNET ADDRESS (dotted decimal)            [10.10.10.100] 
   Network MASK (hexadecimal or dotted decimal) [255.255.255.0] 
   Current STATE                                 down          + 
   Use Address Resolution Protocol (ARP)?        yes           + 
   BROADCAST ADDRESS (dotted decimal)           [] 
   

9. Press the Enter key to execute the change.
   
   
10. Lastly, bring the interface to an up state by running the following command:

    #chdev -l en3 -a state=up 
    

The interface comes to the up state and the adapters are now set up in a netif_backup channel. Should one adapter card disconnect, fail, have cabling issues or other problems the other adapter in the channel will take its place.

[ Doc Ref: 99737720410112     Publish Date: Nov. 15, 2001]