Port Aggregation & Load BalancingBy: Joe B., Nabeel O.Miguel & Mufaddal J.

ObjectivesSwitch ConfigurationPort AggregatioonPort ChannelsFast EtherchannelsLoad Balancing

EtherchannelsThe EtherChannel provides full-duplex bandwidth up to 800Mbps (Fast EtherChannel) or 2Gbps (Gigabit EtherChannel) between your switch and another switch or host.Each EtherChannel can consist of up to eight compatibly configured Ethernet interfaces. All interfaces in each EtherChannel must be the same speed, and all must be configured as Layer2 interfaces.

Port ChannelsEtherChannel consists of individual Fast Ethernet or Gigabit Ethernet links bundled into a single logical link

EtherChannel ModesAuto Places an interface into a passive negotiating state, in which the interface responds to PAgP packets it receives but does not initiate PAgP packet negotiation. This setting minimizes the transmission of PAgP packets.Desirable Places an interface into an active negotiating state, in which the interface initiates negotiations with other interfaces by sending PAgP packets.On Forces the interface to channel without PAgP. With the on mode, a usable EtherChannel exists only when an interface group in the on mode is connected to another interface group in the on mode.

Switch ConfigurationSwitch#config tSwitch(config)#int fa 0/7Switch(config-if)#channel-group 1 mode desirableCreating a port-channel interface Port-channel 1Switch(config-if)#exitSwitch(config)#int fa 0/8Switch(config-if)#channel-group 1 mode desirableSwitch(config-if)#exitSwitch(config)#int fa 0/9Switch(config-if)#channel-group 1 mode desirableSwitch(config-if)#exit

Switch ConfigurationSwitch#sh runBuilding configuration...Current configuration : 1531 bytes!version 12.1no service single-slot-reload-enableno service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption! hostname Switch!!ip subnet-zero!spanning-tree extend system-id!!interface Port-channel1 no ip address!interface FastEthernet0/2 no ip address! interface FastEthernet0/7 no ip address channel-group 1 mode desirable!interface FastEthernet0/8 no ip address channel-group 1 mode desirable!interface FastEthernet0/9 no ip address channel-group 1 mode desirable!interface FastEthernet0/10 no ip address!......................................!interface FastEthernet0/24 no ip address!

Switch Config. (Cont.)interface Vlan1 no ip address no ip route-cache shutdown!ip http server!!line con 0line vty 5 15!End

Switch#config tSwitch(config)#port-channel load-balance dst-macSwitch(config)#endSwitch#show etherchannel l

Destination MAC address

Channel-GroupEach EtherChannel has a logical port-channel interface numbered from 1 to 6.

Load Distribution and Forwarding Methods

Default EtherChannel Configuration Channel groups None assigned.PAgP mode No default. PAgP learn method Aggregate-port learning on all interfaces. PAgP priority 128 on all interfaces. (Changing this value on Catalyst2950 switches has no effect.)Load balancing Load distribution on the switch is based on the source-MAC address of the incoming packet.

Configuring EtherChannels Configure Layer2 EtherChannels by configuring the Ethernet interfaces with the channel-group interface configuration command, which creates the port-channel logical interface. Note:Layer2 interfaces must be connected and functioning for IOS to create port-channel interfaces

Configuring EtherChannels Step1:configure terminalStep2interface interface-id1) Enter global configuration mode 2) Enter interface configuration mode, and specify a physical interface to configure.Valid interfaces include physical interfaces.Up to eight interfaces of the same type and speed can be configured for the same group.

Configuring EtherChannelsStep3:channel-group channel-group-number mode {auto [non-silent] | desirable [non-silent] | on}Step4:end3) Assign the interface to a channel group, and specify the PAgP mode. The default mode is auto silent.For channel-group-number, the range is 1 to 6. Each EtherChannel can have up to eight compatibly configured Ethernet interfaces.4) Return to privileged EXEC mode

Configuring EtherChannelsStep5:show running-configStep6:copy running-config startup-configTo remove an interface from the EtherChannel group, use the no channel-group interface configuration command 5) Verify your entries.6) (Optional) Save your entries in the configuration file.

Configuring EtherChannel Load Balancing This section describes how to configure EtherChannel load balancing by using source-based or destination-based forwarding methods Beginning in privileged EXEC mode to configure EtherChannel load balancing

Configuring EtherChannel Load BalancingStep1:configure terminalStep2:port-channel load-balance {dst-mac | -mac}Step3:endStep4:show etherchannel load-balanceStep5:copy running-config startup-configTo return EtherChannel load balancing to the default configuration, use the no port-channel load-balance global configuration command.

1) Enter global configuration mode.2) Configure an EtherChannel load-balancing method.The default is -mac.3) Return to privileged EXEC mode 4) Verify your entries 5) (Optional) Save your entries in the configuration file.

Commands for Displaying EtherChannel and PAgP Status show etherchannel [channel-group-number] {brief | detail | load-balance | port | port-channel | summary}show pagp {channel-group-number} {counters | internal | neighbor}Displays EtherChannel information in a brief, detailed, and one-line summary form. Also displays the load-balance or frame-distribution scheme, port, and port-channel information.Displays PAgP information such as traffic information, the internal PAgP configuration, and neighbor information

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