Module 6: EtherChannel

Link Aggregation

A _____________ technology is needed that allows redundant links between devices that will not be blocked by STP.

EtherChannel

A link aggregation technology is needed that allows redundant links between devices that will not be blocked by STP. That technology is known as ?

EtherChannel

is a link aggregation technology that groups multiple physical Ethernet links together into one single logical link.

EtherChannel

It is used to provide fault-tolerance, load sharing, increased bandwidth, and redundancy between switches, routers, and servers.

EtherChannel technology

_________________ makes it possible to combine the number of physical links between the switches to increase the overall speed of switch-to-switch communication.

LAN switch-to-switch

EtherChannel technology was originally developed by Cisco as a ________________ technique of grouping several Fast Ethernet or Gigabit Ethernet ports into one logical channel.

port channel

When an EtherChannel is configured, the resulting virtual interface is called a ?

true

tru or false?

EtherChannel relies on existing switch ports. There is no need to upgrade the link to a faster and more expensive connection to have more bandwidth.

Load balancing

____________ takes place between links that are part of the same EtherChannel.

EtherChannel

____________ provides redundancy because the overall link is seen as one logical connection. Additionally, the loss of one physical link within the channel does not create a change in the topology.

true

tru or false?

Fast Ethernet and Gigabit Ethernet cannot be mixed within a single EtherChannel.

six EtherChannels

The Cisco Catalyst 2960 Layer 2 switch currently supports up to ?

• Port Aggregation Protocol (PAgP)

• Link Aggregation Control Protocol (LACP)

EtherChannels can be formed through negotiation using one of two protocols, These protocols allow ports with similar characteristics to form a channel through dynamic negotiation with adjoining switches

Port Aggregation Protocol (PAgP)

s a Cisco-proprietary protocol that aids in the automatic creation of EtherChannel links.

Port Aggregation Protocol (PAgP)

checks for configuration consistency and manages link additions and failures between two switches. It ensures that when an EtherChannel is created, all ports have the same type of configuration.

Port Aggregation Protocol (PAgP)

helps create the EtherChannel link by detecting the configuration of each side and ensuring that links are compatible so that the EtherChannel link can be enabled when needed.

• On

• PAgP desirable

• PAgP auto

The modes for PAgP as follows:

On

This mode forces the interface to channel without PAgP. Interfaces configured in the on mode do not exchange PAgP packets.

PAgP desirable

This PAgP mode places an interface in an active negotiating state in which the interface initiates negotiations with other interfaces by sending PAgP packets.

PAgP auto

This PAgP mode places an interface in a passive negotiating state in which the interface responds to the PAgP packets that it receives but does not initiate PAgP negotiation.

LACP

is part of an IEEE specification (802.3ad) that allows several physical ports to be bundled to form a single logical channel.

LACP

allows a switch to negotiate an automatic bundle by sending LACP packets to the other switch. It performs a function similar to PAgP with Cisco EtherChannel.

LACP

is an IEEE standard, it can be used to facilitate EtherChannels in multivendor environments. On Cisco devices, both protocols are supported.

LACP

helps create the EtherChannel link by detecting the configuration of each side and making sure that they are compatible so that the EtherChannel link can be enabled when needed.

• On

• LACP active

• LACP passive

The modes for LACP are as follows:

On

This mode forces the interface to channel without LACP. Interfaces configured in the on mode do not exchange LACP packets.

LACP active

This LACP mode places a port in an active negotiating state. In this state, the port initiates negotiations with other ports by sending LACP packets.

LACP passive

This LACP mode places a port in a passive negotiating state. In this state, the port responds to the LACP packets that it receives but does not initiate LACP packet negotiation.

EtherChannel support

All Ethernet interfaces must support EtherChannel with no requirement that interfaces be physically contiguous.

Speed and duplex

Configure all interfaces in an EtherChannel to operate at the same speed and in the same duplex mode.

VLAN match

All interfaces in the EtherChannel bundle must be assigned to the same VLAN or be configured as a trunk

Range of VLANs

An EtherChannel supports the same allowed range of VLANs on all the interfaces in a trunking EtherChannel. If the allowed range of VLANs is not the same, the interfaces do not form an EtherChannel, even when they are set to auto or desirable mode.

Step 1: interface range interface global configuration mode command.

Step 2: channel-group identifier mode active command

Step 3: e interface port-channel command

Configuring EtherChannel with LACP requires the following three steps:

show interfaces port-channel

This command displays the general status of the port channel interface.

show etherchannel summary

This command displays one line of information per port channel.

show etherchannel port-channel

This command information about a specific port channel interface.

show interfaces etherchannel

This command can provide information about the role of a physical member interface of the EtherChannel.