Understanding Fiber Links between 2 Catalyst 3650 Switches

[crazywavau]

Hello everyone, 

thanks for at least reading this post. I am having trouble understanding linking 2 switches using a fiber connection we already have installed.

I was going to use An etherchannel to connect 2 Fiber connections. Then a port-channel to allocate the appropriate ports on the switch to the fiber connection. I am not sure if this is the correct way to achieve this. Basically all I need is a L2 bi directional connection from one to the other switch. One of the problems I am having is, the fiber ports seem to be listed as gigabyte ports when viewing running config. I was hoping someone would be able to let me know if I am planning to do this correctly, also if it is do I include the gigabyte port in the int range command somehow?

Thank you in advance. 

[Reza Sharifi · Accepted solution]

Hi,

You can simply add each fiber port to a Portchannel.  Here is an example:

in the case the interface number is gigabit 0/24 and 0/24 and the portchannel id is 10

config t

interface  gigabitEthernet0/24

swtchport

switchport mode trunk

channel-group 10 mode passive

interface  gigabitEthernet0/25

swtchport

switchport mode trunk

channel-group 10 mode passive

interface portchannel 10

no sh

Make the same config on the other switch but have it configured as active see below:

interface  gigabitEthernet0/25

swtchport

switchport mode trunk

channel-group 10 mode active

interface portchannel 10

HTH

[crazywavau]

Thank you Reza,

Tested as functional this morning!! I also have to say thank you to Joseph for the heads up on the hashing. Load balancing is working perfectly so we are good to go. 

Thanks again everyone

[Reza Sharifi]

Glad to help.

If you want to know the type of hasting load balancing on the 3650 series, here is the command and the output:

c3650-xx-xx#  sh etherchannel load-balance
EtherChannel Load-Balancing Configuration:
        src-mac

EtherChannel Load-Balancing Addresses Used Per-Protocol:
Non-IP: Source MAC address
  IPv4: Source MAC address
  IPv6: Source MAC address

HTH

[Joseph W. Doherty]

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Posting

BTW, I'm not familiar with a 3650's default Etherchannel hashing, but you might need to adjust to obtain optimal load balancing for your traffic.

[Ganesh Hariharan]

Hello,

You can add fiber port on port-channel without any issue.

example is given by Reza's Post... You can either have L2 ether channel or L3 based on your requirement.

Below is another sample configuration for L2 port channel with all plans allowed

switch# configure terminal
switch (config)# interface ethernet 1/4
switch(config-if)# switch port
switch(config-if)# switch port mode trunk
switch(config-if)# channel-group 5 mode on
switch (config)# interface ethernet 1/5
switch(config-if)# switch port
switch(config-if)# switch port mode trunk
switch(config-if)# channel-group 5 mode on

Hope it Helps..

-GI

[casanavep]

ports within a port channel "have to be of the same capability"; so, you may (will likely) get an error if you are adding gigabit ports to an active channel-grouping with fast Ethernet ports already in it.  All ports need to be gigabit or fast Ethernet, and be of the same capabilities (i.e. port are on different chassis blades with different buffer capabilities would not be able to be grouped, even if they are both gigabit).