Can Port Channel members going to different switch? Why?

[getaway51]

In this case, the port-channel members are connected to 2 different distribution switch dissw01 and dissw02.

I thought port-channel members from one switch suppose to connect to same one switch. 

What happen when port-channel from one switch going to 2 different switches? Is this for redundancy and load-sharing purpose? The port status is trnk-bndl, sounds like showing it config is port-channel & bundling?

accsw01# sh port-channel summary
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
b - BFD Session Wait
S - Switched R - Routed
U - Up (port-channel)
p - Up in delay-lacp mode (member)
M - Not in use. Min-links not met
--------------------------------------------------------------------------------
Group Port- Type Protocol Member Ports
Channel
--------------------------------------------------------------------------------
1 Po1(SU) Eth LACP Eth1/3(D) Eth1/4(P)

[Jon Marshall]

It depends. 

If the two switches are seen as separate switches then no you cannot have the same port channel spread across both switches, that is not supported. 

However if the two switches are seen as a single virtual switch by the rest of the network eg. stacked switches, 6500 using VSS, Nexus using vPC then yes you can spread the interfaces across both switch members. 

Jon

[balaji.bandi]

In your case both the port-channels treat as seperate, there is load-share happends here.

[getaway51]

I can see tht the members frm the same port-channel, each currently going to different switch.

How can i check whether the two different switches are stacked? any command?

From the comments, can i say the port-channel doesn't work if the switches were not stacked (i.e. they are different switches)? 

[Jon Marshall]

What switches are they going to ? 

Jon

[balaji.bandi]

yes if they are not stacked it will not work the way you want to implement.

How can i check whether the two different switches are stacked? any command?

BB - show switch  - (but again @Jon Marshall  as commneted what switches they are ?)

[getaway51]

The access switch port-channel 1 has 2 members with each member connected to a Cisco distribution switch.

Port 1/3-Switch A port 1/7

Port 1/4 -Switch B port 1/7

Can i conclude tht the best argument would be these 2 switches are stacked together? Otherwise port-channel doesn't works?

[Jon Marshall]

What are the distribution switches ?

Jon

[balaji.bandi]

ask you again, you are not providing the information what we request.

please re-read all the question asked and answer the inputs so best  suggestion can be provided  please.

[getaway51]

The distribution and access switches are all cisco. Is this the info required? 

[Deepak Kumar]

Hi,

We are happy to know that your network is fully Cisco. We are a big fan of Cisco. 

Basically, are an argument is going on the EtherChannel (port channel) "Can we connect two different Switch in Single EtherChannel?" and here, as usual, my Ans is no, you can't expect Both switches are not a member of Stack/VPC/VSS in the Cisco domain. 

How to identify that those switches are in the Stack or not? 

May I ask you one question? How are you managing to those switches? Are you using a single Management IP for both switches? If your answer will yes then those switches are the Stack.  

You can login in the switch and run a command: "Show Switch" 

Regards,

Deepak Kumar

[getaway51]

Hi,

Thanks for yr info. Here i m trying to find whether the adjacent switches are under a single vpc domain.

The reason was the port-channel destination for switch A is going to B & C. So i guess B & C is vpc together, otherwise how can port channel going to different switches that weren't part of vpc.Hence i nd to find the cmd & output to support this.

[Deepak Kumar]

Hi,

Great, I hope you are near to find the solution. Here is a command for check the VPC details "show vpc brief"

Run on both switches and match all parameters as Domain ID, Ports etc.

[balaji.bandi]

in that case go in to B & C (lets confirm what model, if they are not nexus, no vpc, i could be VSS) - until we have below information there is no way we can think of what is your setup.

post both the switch 

show version

show vpc

[Scott Hodgdon]

Notice from your original output that you have one port-channel member UP (Eth 1/4) and one port-channel member DOWN (Eth 1/3):

accsw01# sh port-channel summary
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
b - BFD Session Wait
S - Switched R - Routed
U - Up (port-channel)
p - Up in delay-lacp mode (member)
M - Not in use. Min-links not met
--------------------------------------------------------------------------------
Group Port- Type Protocol Member Ports
Channel
--------------------------------------------------------------------------------
1 Po1(SU) Eth LACP Eth1/3(D) Eth1/4(P)

This means that while you were able to create a port-channel, you only have one active member (Eth 1/4 in this case). On the surface, this would indicate that these two port-channel members are connected to two separate switches that are not in a stack or running Virtual Switching System (VSS), StackWise Virtual (SWV) or Virtual Port Channel (vPC). A port-channel cannot connect to two separate physical switches unless those switches are in a stack or are running VSS, SWV or vPC. VSS, SWV and vPC are separate features that allow two physical switches to be combined into one logical device.