In this section, we are going to learn about etherchannel. 2
What is etherchannel? We will learn about this using an example case. 3
Let’s add 2 switch, we will use 2960. 4
And then connecting this 2 switch using 2 cable. 5
If we see here, one of the interface is orange, 6
this is means that this interface is blocked by spanning tree. 7
Spanning tree is protocol that used to prevent looping in the network. 8
This protocol is active by default, so we don’t need to worry about spanning tree. 9
Here we can see that the interface blocked by spanning tree is fa0/2 in the switch 0, 10
let’s just remove the name of the interface so we can see the topology clearly. Go to preference, 11
and then uncheck always show port label. 12
Okay now we can see the topology clearly. Here we can see that the blocked port is in switch 0. 13
Let’s add 1 more cable, 14
here we can see that two cable or two interface blocked by spanning tree. 15
So remember that spanning tree will only allow 1 cable active between switches, 16
if there is 3 cable between switches like this, spanning-tree will block 2 cable, 17
and if there is 4 cable, so spanning-tree will block 3 cable, and others. 18
The case is, let’s say we need high bandwidth between switches, 19
let’s say the bandwidth of interface is only 100 mega, but we need 300 mega. 20
If we see here, we already connecting this 2 switches using 3 cable, 21
but 2 cable is blocked by spanning tree, so here we just have 100 mega. 22
but here actually we have 4 cable between switches, let’s remove 1 cable. Okay so here we 23
have 3 cable like this, and 2 cable is blocked by spanning tree, so we only have 100 mega bandwidth. 24
If we want 300 mega, we can use 25
etherchannel. If we configure an etherchannel in this 2 switch, all three cable will active, 26
because etherchannel will combine this 3 physical cable become 1 logical cable. 27
With etherchannel, switch will consider this 3 physical cable as only 1 logical cable, 28
so spanning tree will not block any cable, because there is only 1 logical cable. 29
And there is no cable blocked by spanning tree, 30
so now the bandwidth is 100 multiple by 3, which is 300 mega. 31
Okay that is the concept of etherchannel, 32
I think enough for this video, in the next video, we are going to learn 33
how to configure etherchannel. 34
Thankyou for watching and see you on the next video.