How to Configuring Layer 2 Etherchannel

Configuring Layer 2 Etherchannel networkingguruji1.com/2020/01/configuring-layer-2-etherchannel.html

My Dear Friend in today’s article, I will tell you “Configuring Layer 2 Ether channel” If you any problem after reading this article, you can see the video below. Please don't forget to Like, Share, Comment & Subscribe to our Networking Guruji Channel for more video.

Previous post: - What is a Virtual Local Area Network (VLAN)…. Click Here

“What is Ether Channel” Ether channel makes two physical links into one logical link and STP (Spanning tree protocol to run on the logical link, not on the physical link) will run on the logical link.

1/9

Ether channel is a technology that allows you to aggregate multiple physical links of the same capabilities into a single logical one. In this way, you can increase the bandwidth.

Normally when you have multiple links connecting between switches STP blocks redundant port, with Ether channel the links are aggregated and not blocked by STP.

The technique for aggregating bandwidth of Physical links together. Also known as‌ 1.

Port Channels 2.

Channeling 3.

Link Aggregation (LAG) 4.

NIC Teaming Ether Channel Physical vs. Logical View

2/9

Why we configure Ether Channel?

1.

2.

It increases the bandwidth of the link Provide redundancy at link level

Ether Channel Provides aggregated bandwidth as per the following: 1 Fast Ethernet up to 800Mbp 2. Gigabit Ethernet up to 8Gbps 3. 10 Gigabit Ethernet up to 80Gbps “Cisco CCNA – EtherChannel” Ether Channel Can be configured in 2 different ways – 1. Manual configuration 2. Using Negotiation Protocol There are two Ether Channel negotiation protocol.

1. PAgP - Port Aggregation Protocol 2. LACP - Link Aggregation Control Protocol - PAgP is Cisco proprietary EtherChannel negotiation protocol 3/9

- LACP is an open standard EtherChannel negotiation protocol.

“Layer 2 Etherchannel” For an EtherChannel to from all member’s interface must agree on the same configuration, and both of the channels must agree on the same negotiation protocol. In the bellow show EtherChannel summary output the protocol field is null or nothing, which means that no negotiation was used. This comes from one mode of the channel-group command. This output also shows that the port-channel is in the (SU) state, which means L2 switch port is up, and the member’s ports are in the (P) state, which is in the port-channel.

Layer 2 Etherchannel Configuring Configure on SW-2, all inter-switch links between SW-2 and SW-4 on Dynamic Auto state.

Configure on SW-4, all inter-switch link between SW-2 and SW-4 on Dynamic Desirable sate.

Configure layer 2 Etherchannel on all inter-switch link (fa0/1 fa0/3) between SW-2 and SW-4.

Use port-channel number 24 on both the switches.

These links should not use dynamic Etherchannel negotiation.

Note: - only new link add between SW-2 fa0/3 and Sw-4 port fa0/5

4/9

Configuring Layer 2 Etherchannel SW-2 SW-2(config)#interface fatstethernet 0/1 SW-2(config-if)#switchport mode dynamic auto SW-2(config)#interface fastethernet fa0/3 SW-2(config-if)#switchport mode dynamic auto SW-4 SW-4(config)#interface fatstethernet 0/1 SW-4(config-if)#switchport mode dynamic desirable SW-4(config)#interface fastethernet fa0/3 SW-4(config-if)#switchport mode dynamic desirable SW-2 SW-2(config)#interface fatstethernet 0/1 5/9

SW-2(config-if)#channel-group 24 mode on SW-2(config)#interface fastethernet fa0/3 SW-2(config-if)#channel-group 24 mode on SW-4 SW-4(config)#interface fatstethernet 0/1 SW-4(config-if)#channel-group 24 mode on SW-4(config)#interface fastethernet fa0/3 SW-4(config-if)#channel-group 24 mode on

Sw-2# show EtherChannel summary Flags: D-Down

p-bundled in port-channel

I – stand-alone S – suspended H – Hot-standby (LACP only) 6/9

R – Layer 3

S – Layer2

U – in use

f – failed to allocate aggregator

M – not in use, minimum links not met U – unsuitable for bundling W – waiting to be aggregated D – default port Number of channel-groups in use: 1 Number of aggregators: 1 Group 24

Port-channel po24

protocol -

ports fa0/1(P) fa0/3(P)

SW-4#show EtherChannel summary Flags: D-Down

p-bundled in port-channel

I – stand-alone S – suspended H – Hot-standby (LACP only) R – Layer 3

S – Layer2

U – in use

f – failed to allocate aggregator

M – not in use, minimum links not met U – unsuitable for bundling W – waiting to be aggregated D – default port Number of channel-groups in use: 1 Number of aggregators: 1 Group 24

Port-channel po24 (SU)

protocol -

ports fa0/1(P) fa0/5(P)

“Cisco CCNA – EtherChannel” Since SW-3’s member interfaces were in dynamic desirable mode, newly created the port-channel interface copy this attribute and start negotiating with other ends of the switch, which is SW-2 and SW2’s member interfaces (physical interfaces) were configured in Dynamic auto mode, created port-channel interface copy this 7/9

attribute and respond to the negotiation, as result port-channel interface has become a trunk.

SW-4#show interface trunk Port Po24

Mode desirable

Encapsulation n-isl

Status trunking

Native VLAN 1

Port Po24

VLAN allowed on trunk 1-1005

Port Po24

Vlans allowed and active in management domain 1,10,20,30

Port Po24

VLAN in spanning tree forwarding state and not pruned 1,10,20,30

SW-2#show interface trunk Port Po24

Mode auto

Encapsulation n-isl

Status trunking

Native VLAN 1 8/9

Port Po24

VLAN allowed on trunk 1-1005

Port Po24

VLANs allowed and active in management domain 1,10,20,30

Port Po24

VLAN in spanning tree forwarding state and not pruned 1,10,20,30

Upcoming Layer 2 Etherchannel tutorial..... step by step......

This is a full article “Configuring Layer 2 Etherchannel� Thank you so much.

9/9