Danielhertzberg's Blog

This is a write up of how to connect a cisco switch in this case a 2950 to Etherchannel LACP with a Fedora server. I have 14 Ethernet interfaces total. Since I finished up with my VCP lab(fail) and I have two extra interfaces why not etherchannel them together. I am using interface Fa0/3 and Fa0/4 on my 2950 and on my server eth0 and eth14.

With Linux distros like Fedorea,Centos this will work. Other Linux distros the etc interface files are collected in a /etc/interfaces. Fedora puts a config file for each interface. I WOULD HIGHLY SUGGEST not following this remotely, as anyone who has delt with Etherchannel things never go right the first try.

Step one is adding a bond0 interface, in fedora when you vi into a network interface that is not create it will then create the bond0 interface.

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

here is what my bond0 configuration looks like.

DEVICE=bond0

BONDING_OPTS=”mode=4 miimon=500 lacp-rate=1″ #mode=4 is LACP(802.3ad)

BOOTPROTO=none

ONBOOT=yes

USERCTL=no

PEERDNS=no

IPV6INIT=no

NM_CONTROLLED=no

TYPE=Ethernet

NETMASK=255.255.255.0

IPADDR=192.168.1.125

GATEWAY=192.168.1.1

DNS1=8.8.8.8

There are plenty of different aggregation methods, mode 4 is for LACP. There are some others which include backup interfaces and a round robin feature.

Next step is go under each of the interfaces and tell them they have a master which is bond0 and they are slaves to bond0. This is similar to saying they have a layer 2 connection over both interfaces. Bond0 is the layer3 in this case.

vi /etc/sysconfig/network-scripts/ifconfig-eth0

DEVICE=”eth0″

BOOTPROTO=none

MASTER=bond0

SLAVE=yes

NM_CONTROLLED=”yes”

ONBOOT=”yes”

TYPE=Ethernet

DEFROUTE=yes

IPV4_FAILURE_FATAL=yes

IPV6INIT=no

NAME=”System eth0″

#UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03

#IPADDR0=192.168.1.125

#PREFIX0=24

#GATEWAY0=192.168.1.1

#DNS1=8.8.8.8

#HWADDR=00:30:67:AA:37:23

Notice I have commented out the old configuration I had where this was my managment interface. Also notice in line 3 master is bond0 and line 4 slave is yes.

vi /etc/sysconfig/network-scripts/ifconfig-eth14

TYPE=Ethernet

BOOTPROTO=none

MASTER=bond0

SLAVE=yes

DEFROUTE=yes

IPV4_FAILURE_FATAL=no

IPV6INIT=no

NAME=”Auto eth14″

UUID=7399bea9-a957-4ec7-be5b-03b280e7fdd3

ONBOOT=yes

#HWADDR=00:1B:21:B0:74:56

#IPADDR0=155.1.146.100

PREFIX0=24

At this point the configuration is about 75% done on the Server. Next we move to the Cisco Device.

conf t

int range fa0/3 – 4

channel-protocol lacp

channel-group 1 mode active

At this point this will form a Port-channel interface.

AggSwitch#sh ip int po1

Port-channel1 is up, line protocol is up

Chances are it will not be up.

Configuration is done on the Cisco Device.

Moving back to to the server. This is where someone would lose managment remotely, we are going to attempt to bring up the bond.

ifup bond0

if this does not work I would restart /etc/network restart. Or reboot after you should see the following.

[burnyd@dynamips ~]# ifconfig bond0

bond0 Link encap:Ethernet HWaddr 00:30:67:AA:37:23

inet6 addr: fe80::230:67ff:feaa:3723/64 Scope:Link

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

RX packets:8169 errors:0 dropped:0 overruns:0 frame:0

TX packets:804 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:947585 (925.3 KiB) TX bytes:140837 (137.5 KiB)