I have 2 linux boxes running centos 6.5 each with 2 interfaces bonded together, linked to a Cisco 2960-S switch with lacp configured ports.
The configuration on the switch
port-channel load-balance src-dst-mac
!
interface Port-channel1
switchport access vlan 100
switchport mode access
!
interface Port-channel2
switchport access vlan 100
switchport mode access
!
interface FastEthernet0
no ip address
!
interface GigabitEthernet0/1
switchport access vlan 100
switchport mode access
speed 1000
duplex full
spanning-tree portfast
channel-protocol lacp
channel-group 1 mode active
!
interface GigabitEthernet0/2
switchport access vlan 100
switchport mode access
speed 1000
duplex full
spanning-tree portfast
channel-protocol lacp
channel-group 1 mode active
!
interface GigabitEthernet0/3
switchport access vlan 100
switchport mode access
speed 1000
duplex full
spanning-tree portfast
channel-protocol lacp
channel-group 2 mode active
!
interface GigabitEthernet0/4
switchport access vlan 100
switchport mode access
speed 1000
duplex full
spanning-tree portfast
channel-protocol lacp
channel-group 2 mode active
!
and on the both linux sides I've loaded the kernel bonding module with the configuration
alias bond0 bonding
options bond0 miimon=100 mode=4 lacp_rate=1
Now the problem is that I transfer many files from one server to another monitoring the traffic graphs showing that the speed doesn't exceed the 1Gb/s speed for the bonding interface bond0.
is there any problem with the configuration ? shouldn't the speed be doubled to 2Gb/s ?
Best Answer
LACP will not split packets across multiple interfaces for a single stream/thread. For example a single TCP stream will always send/receive packets on the same NIC.
See the following post for reference:
Link aggregation (LACP/802.3ad) max throughput
Hope this helps.