Etherchannel configuration on LINUX

                                Creating Ether channel on LINUX
 
Creating an EtherChannel between a Red Hat Enterprise 5 server, and a Cisco Catalyst 3750 Switch. This is actually far simpler then it sounds, and can be completed in about ten minutes.

We’ll begin with configuring the IEEE 802.3ad Dynamic link aggregation (AKA EtherChannel) on the Red Hat Enterprise Linux server. Begin by logging in via SSH, Telnet or directly on the console itself. I do recommend having access to the console directly, so should anything go wrong and you lose network connectivity you’ll be able to easily change things back.

Once logged into the server, switch user to "root" if you’re not already logged in as root. Change directory to "/etc" and modify the "modprobe.conf" file using your favorite text editor such as "vi". I personally like using "nano". Add the lines in bold from the example "modprobe.conf" below to your file. Then save your changes and return to the bash prompt.

Sample /etc/modprobe.conf

alias scsi_hostadapter megaraid_sas
alias scsi_hostadapter1 usb-storage
alias eth0 bnx2
alias eth1 bnx2
alias bond0 bonding
options bond0 miimon=100 mode=4 lacp_rate=1

Next we need to create a network script for the "bond0" interface that we defined above in the "modprobe.conf" file. This will be used to configure the network properties for the virtual adapter. Once again, use your favorite text editor to create a new file called "ifcfg-bond0" in the "/etc/sysconfig/network-scripts" directory. In this file you will define the device name used above"bond0", IP address, gateway, network mask etc for the virtual adapter. Below is an example.

Sample /etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond0
BOOTPROTO=none
ONBOOT=yes
NETWORK=192.168.0.0
NETMASK=255.255.255.0
IPADDR=192.168.0.25
USERCTL=no
GATEWAY=192.168.0.1
TYPE=Ethernet
IPV6INIT=no
PEERDNS=yes

When you’re done configuring the properties of the virtual adapter, save your changes and exit the editor.

The next step is to modify the network script for each adapter that will be added to the EtherChannel. The adapters that we’ll be using in this server are eth0 and eth1. Please note your interfaces may be different, so check before continuing.

Start by modifying "ifcfg-" using your text editor, where is the interface name. In this case my file name is "ifcfg-eth0". Add the proper references to the virtual adapter created above "bond0" and remove any IP information such as IP address, gateway, netmask etc since that information will be handled by the virtual adapter. Below is an example of the "ifcfg-eth0" file. Note the bold items are required for the EtherChannel to function properly.

Sample /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
BOOTPROTO=none
HWADDR=00:11:22:33:44:55
ONBOOT=yes
MASTER=bond0
SLAVE=yes
TYPE=Ethernet
USERCTL=no
IPV6INIT=no
PEERDNS=yes

Repeat the steps above for each additional interface you add to the Etherchannel.

Sample /etc/sysconfig/network-scripts/ifcfg-eth1

DEVICE=eth1
HWADDR=66:77:88:99:aa:bb
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none
TYPE=Ethernet
USERCTL=no

Now that each physical adapter has been associated to the virtual adapter,