Configuring cisco switch Etherchannels - on , PAgP, LACP

Configuring Etherchannels

Objective; Configure an Etherchannel  between switch1 and switch 2.

What is an Ether channel?

1.      An EtherChannel allows you to bundle up to 8 Fast Ethernet or Gigabit Ethernet links into a single logical link.

2.      Single Spanning tree instance treats Port Channel as single interface

TYPES OF ETHERCHANNELS

1.      MANUAL configuration   - Turn Etherchannel on

2.      Automatic Configuration - Using PAgP or LACP

EtherChannel Modes
Mode	Description
on	Forces the interface into an EtherChannel without PAgP or LACP. 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.
Desirable (PAGP)	Places an interface into an active negotiating state, in which the interface starts negotiations with other interfaces by sending PAgP packets.
Auto (PAGP)	Places an interface into a passive negotiating state, in which the interface responds to PAgP packets it receives but does not start PAgP packet negotiation. This setting minimizes the transmission of PAgP packets.
Active (LACP)	Places an interface into an active negotiating state, in which the interface starts negotiations with other interfaces by sending LACP packets.
Passive (LACP)	Places an interface into a passive negotiating state, in which the interface responds to LACP packets that it receives, but does not start LACP packet negotiation. This setting minimizes the transmission of LACP packets.

The Port Aggregation Protocol (PAgP) and Link Aggregation Control Protocol (LACP) facilitate the automatic creation of EtherChannels by exchanging packets between Ethernet interfaces. PAgP is a Cisco-proprietary protocol that can be run only on Cisco switches and on those switches licensed by licensed vendors to support PAgP. LACP is defined in IEEE 802.3AD and allows Cisco switches to manage Ethernet channels between switches that conform to the 802.3AD protocol.

By using one of these protocols, a switch learns the identity of partners capable of supporting either PAgP or LACP and learns the capabilities of each interface. It then dynamically groups similarly configured interfaces into a single logical link (channel or aggregate port); these interfaces are grouped based on hardware, administrative, and port parameter constraints. For example, PAgP groups the interfaces with the same speed, duplex mode, native VLAN, VLAN range, and trunking status and type. After grouping the links into an EtherChannel, PAgP adds the group to the spanning tree as a single switch port.

SW1 Configuration	SW2 Configuration	Protocol	Trunk formed or not?
ON	ON	NONE	YES
ON	AUTO	NONE	NO
ON	Desirable	NONE	NO
ON	Passive	NONE	NO
ON	Active	NONE	NO
Desirable	Desirable	PAgP	YES
Desirable	AUTO	PAgP	YES
AUTO	AUTO	NONE	NO
ACTIVE	ACTIVE	LACP	YES
ACTIVE	PASSIVE	LACP	YES
PASSIVE	PASSIVE	NONE	NO

 ETHERCHANNEL ON -LAB Tasks;

1.      Configure FE0/13 and FE 0/14 on SW1 as channel group 1 mode on

2.      Configure FE0/13 and FE 0/14 on SW2 as channel group 1 mode on

Verification commands;

Ping R1 to R2 and R2 to R1

Show etherchannel summary

Show interface port-channel 1

show interface port-channel1 switchport

Show interfaces trunk

show spanning-tree vlan 100

Final Configurations

SW1:

interface FastEthernet0/13

channel-group 1 mode on

!

interface FastEthernet0/14

channel-group 1 mode on

!

interface Port-channel1

switchport mode dynamic desirable

SW2:

interface FastEthernet0/13

channel-group 1 mode on

!

interface FastEthernet0/14

channel-group 1 mode on

!

interface Port-channel1

switchport mode dynamic desirable

 ETHERCHANNEL PAGP-LAB

PAGP Final Configuration;

SW1:

interface FastEthernet0/13

channel-group 1 mode desirable

!

interface FastEthernet0/14

channel-group 1 mode desirable

!

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode trunk

SW2:

interface FastEthernet0/13

channel-group 1 mode auto

!

interface FastEthernet0/14

channel-group 1 mode auto

!

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode trunk

 ETHERCHANNEL LACP-LAB 

Final Configurations;

SW1:

interface FastEthernet0/13

channel-group 1 mode active

!

interface FastEthernet0/14

channel-group 1 mode active

!

interface Port-channel1

switchport mode dynamic desirable

SW2:

interface FastEthernet0/13

channel-group 1 mode passive

!

interface FastEthernet0/14

channel-group 1 mode passive

!

interface Port-channel1

switchport mode dynamic desirable