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Cisco CCNA / CCNP Certification: How And Why To make An Etherchannel
CCNA and CCNP candidates are well-versed in Spanning-Tree Protocol, and one of many terrific issues about STP is always that it works perfectly with little or no additional configuration. You can find one particular scenario exactly where STP works versus us simply a little bit even though it prevents switching loops, and that is the situation where by two switches have many Bodily connections.
You'd feel that In case you have two different physical connections involving two switches, 2 times just as much knowledge may very well be sent from a person swap into the other than if there was just one link. STP doesn’t let this by default, having said that in an effort to avoid switching loops from forming, on the list of paths will likely be blocked.
SW1 and SW2 are related through two independent Bodily connections, on ports fast0/11 and fast 0/twelve. As we can easily see right here on SW1, only port 0/eleven is really forwarding traffic. STP has put another port into blocking manner (BLK).
SW1#show spanning vlan 10
(some output removed for clarity)
Interface Job Sts Charge Prio.Nbr Sort
Fa0/eleven Root FWD 19 128.11 P2p
Fa0/12 Altn BLK 19 128.twelve P2p
Although STP is helping us by protecting against switching loops, STP is additionally hurting us by blocking us from employing a perfectly valid route amongst SW1 and SW2. We could virtually double the bandwidth offered between The 2 switches if we could use that path that may be now being blocked.
The secret to using the at this time blocked route is configuring an Etherchannel. An Etherchannel is just a reasonable bundling of two – 8 Actual physical connections among two Cisco switches.
Configuring an Etherchannel is actually quite easy. Make use of the command “channel-group one method on” on just about every port you ought to be positioned in to the Etherchannel. Of course, this must be performed on each switches when you configure an Etherchannel on a single change and don’t achieve this on the right ports on another swap, the road protocol will go down and keep there.
The fantastic thing about an Etherchannel is the fact STP sees the Etherchannel as one link. If any from the physical connections In the Etherchannel go down, STP will not see this, and STP will never recalculate. When traffic move among the two switches will clearly be slowed, the delay in transmission because of an STP recalculation is prevented. An Etherchannel also will allow us to work with many physical connections at a single time.
Here’s the way to place these ports into an Etherchannel:
SW1#conf t
Enter configuration commands, 1 per line. Stop with CNTL/Z.
SW1(config)#interface speedy 0/11
SW1(config-if)#channel-team one method on
Making a port-channel interface Port-channel one
SW1(config-if)#interface fast 0/twelve
SW2#conf t
SW2(config)#int speedy 0/eleven
SW2(config-if)#channel-team 1 method on
SW2(config-if)#int rapid 0/12
The command “present interface trunk” and “present spanning-tree vlan 10” are going to be accustomed to validate the Etherchannel configuration.
SW2#clearly show interface trunk (some output eradicated for clarity)
Port Manner Encapsulation Position Native vlan
Po1 attractive 802.1q trunking 1
SW2#exhibit spanning vlan ten (some output taken off for clarity)
Po1 Desg FWD 12 128.65 P2p
In advance of configuring the Etherchannel, we observed personal ports in this article. Now we see “Po1”, which stands for the interface “port-channel1”. This can be the reasonable interface established when an Etherchannel is constructed. We are now using both equally Actual physical paths concerning the two switches at a single time!
That’s one big benefit in action Enable’s see An additional. Ordinarily, if The only open up route involving two trunking switches https://socialhattori.com/ goes down, There's a big hold off though another legitimate route is opened – close to a moment in certain predicaments. We are going to now shut down port 0/11 on SW2 and see the effect on the etherchannel.
SW2(config-if)#shutdown
3w0d: %Url-five-Improved: Interface FastEthernet0/eleven, altered
state to administratively down
SW2#present spanning vlan ten
VLAN0010
Spanning tree enabled protocol ieee
Po1 Desg FWD 19 128.sixty five P2p
SW2#demonstrate interface trunk
Port Mode Encapsulation Standing Indigenous vlan
Po1 appealing 802.1q trunking one
The Etherchannel did not go down! STP sees the Etherchannel as only one hyperlink thus, so far as STP is concerned, very little occurred.
Setting up an Etherchannel and understanding how it could reward your network is An important ability for CCNA and CCNP accomplishment, and it is available in incredibly handy on The task likewise. Be sure to are relaxed with creating just one right before taking Cisco’s examinations!