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Beginner

Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello Everyone...
I am just a beginner and I need your help to understand the following issue.
I used SVI over a set of Catalyst 3650 switches, and I want to use Etherchannel over these switches also. Because of that, I need to understand what happens if I use the combination of SVI and Etherchannel if it is possible.
With regards 

3 ACCEPTED SOLUTIONS

Accepted Solutions
Highlighted
Beginner

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello, Abdel-Nasser,

1) Etherchannel is a technology allowing you to use several physical links as a logical one from STP perspective. If it is omitted, only one link could be active, others would be blocked by STP on either of 2 sides.
2) SVI is a logical L3 interface allowing you to assign an IP address to the switch in a VLAN without dedicating a certain port for it.

In other words, those features are totally distinct and do not interfere with each other so you can safely implement both. I would also suggest using LACP for bundling as it rules out miscabling.

Hall of Fame Expert

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello Abdel,

you can use SVIs L3 interface Vlans and L2 etherchannels configured as L2 trunk or (less likely) L2 access port.

A L3 port-channel is instead a type of routed port where the IP address is assigned to the port-channel interface and all member links have no switchport no ip address.

A L3 port-channel cannot be used as L2 trunk.

If the L2 vlan that is associated to the SVI is permitted over the L2 trunk over the L2 etherchannel on both ends you are fine.

Example:

vlan 100 of interface vlan 100 is allowed / permitted on both ends of the L2 etherchannel it is okay to use it.

 

Hope to help

Giuseppe

 

Hall of Fame Expert

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello Abdel,

thanks for your kind remarks.

 

>> 1) SVI and EtherChannel can be used over trunk or access ports.

I mean that an SVI interface is compatible with an etherchannel configured either as a L2 trunk or a L2 access port.

 

>> 2)SVI ports can't be used as trunking ports, because of the no switchport command.

Yes, SVI are logical L3 interfaces associated to a single Vlan they can provide a default gateway to hosts in the L2 vlan broadcast domain.

A L2 trunk is a physical interface that can carry and receive traffic of multiple Vlans using 802.1Q header to discriminate frames as belonging to different L2 Vlans.

>> 3)Finally, there is no problem to use SVI and EtherChannel if the VLAN is permitted over the interface.
Yes, I mean SVIs and L2 trunk etherchannel can work together if the L2 Vlan is permitted over the port-channel interface (and on member links)

 

>> Another thing according to your comment about L3 port-channel  "all member links have no switchport no IP address". 
Why did you say "no IP address" although we use the L3 port as a routed port!?

 

When I say member link I am referrring to the physical links that are member of an L3 etherchannel.

This is the way to configure one:

int gi1/0/25

desc member link 1

no switchport

no ip address

channel-group 10 active

int gi1/0/26

desc member link 2

no switchport

no ip address

channel-group 10 active

!

At this point interface po10 is created and you configure the IP address only under the logical interface po10:

 

int po10

desc L3 port-channel

no switchport

ip address 10.10.10.1 255.255.255.0

no shut

!

 

Hope to help

Giuseppe

 

6 REPLIES 6
Highlighted
Beginner

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello, Abdel-Nasser,

1) Etherchannel is a technology allowing you to use several physical links as a logical one from STP perspective. If it is omitted, only one link could be active, others would be blocked by STP on either of 2 sides.
2) SVI is a logical L3 interface allowing you to assign an IP address to the switch in a VLAN without dedicating a certain port for it.

In other words, those features are totally distinct and do not interfere with each other so you can safely implement both. I would also suggest using LACP for bundling as it rules out miscabling.

Beginner

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Dear Iaroslav
Best thanks for your replay

Hall of Fame Expert

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello Abdel,

you can use SVIs L3 interface Vlans and L2 etherchannels configured as L2 trunk or (less likely) L2 access port.

A L3 port-channel is instead a type of routed port where the IP address is assigned to the port-channel interface and all member links have no switchport no ip address.

A L3 port-channel cannot be used as L2 trunk.

If the L2 vlan that is associated to the SVI is permitted over the L2 trunk over the L2 etherchannel on both ends you are fine.

Example:

vlan 100 of interface vlan 100 is allowed / permitted on both ends of the L2 etherchannel it is okay to use it.

 

Hope to help

Giuseppe

 

Beginner

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Dear Giuseppe Larosa  
First of all thanks for your replay. 
I have a piece of comments, please.
I understood from your comments that:
1) SVI and EtherChannel can be used over trunk or access ports.
2)SVI ports can't be used as trunking ports, because of the no switchport command.
3)Finally, there is no problem to use SVI and EtherChannel if the VLAN is permitted over the interface.

If there are misunderstandings and comments on my previous words please correct me.

Another thing according to your comment about L3 port-channel  "all member links have no switchport no IP address". 
Why did you say "no IP address" although we use the L3 port as a routed port!?

With regards 
Abdel-Nasser

Hall of Fame Expert

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Hello Abdel,

thanks for your kind remarks.

 

>> 1) SVI and EtherChannel can be used over trunk or access ports.

I mean that an SVI interface is compatible with an etherchannel configured either as a L2 trunk or a L2 access port.

 

>> 2)SVI ports can't be used as trunking ports, because of the no switchport command.

Yes, SVI are logical L3 interfaces associated to a single Vlan they can provide a default gateway to hosts in the L2 vlan broadcast domain.

A L2 trunk is a physical interface that can carry and receive traffic of multiple Vlans using 802.1Q header to discriminate frames as belonging to different L2 Vlans.

>> 3)Finally, there is no problem to use SVI and EtherChannel if the VLAN is permitted over the interface.
Yes, I mean SVIs and L2 trunk etherchannel can work together if the L2 Vlan is permitted over the port-channel interface (and on member links)

 

>> Another thing according to your comment about L3 port-channel  "all member links have no switchport no IP address". 
Why did you say "no IP address" although we use the L3 port as a routed port!?

 

When I say member link I am referrring to the physical links that are member of an L3 etherchannel.

This is the way to configure one:

int gi1/0/25

desc member link 1

no switchport

no ip address

channel-group 10 active

int gi1/0/26

desc member link 2

no switchport

no ip address

channel-group 10 active

!

At this point interface po10 is created and you configure the IP address only under the logical interface po10:

 

int po10

desc L3 port-channel

no switchport

ip address 10.10.10.1 255.255.255.0

no shut

!

 

Hope to help

Giuseppe

 

Beginner

Re: Etherchannel over SVI ports On Cisco Catalyst 3650 switches

Dear Giuseppe Larosa 
Thanks a lot for making it simple.
Thanks for your simplicity and precisely in explanation .

With Regards 
Abdel-Nasser

 
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