stackwise-virtual Configuration

[vivarock12]

Hello People,

I have a question about the stackwise-virtual configuration.

Should i use 2 links for the virtual Link? and should they be in a port channel? or not?

The question is because we want to have 2 links for the Virtual link and 1 the dual-active-detection link and we wanted to know if the config is via portchannel or is just:

interface TenGigabitEthernet1/0/1
 stackwise-virtual link 1

!

interface TenGigabitEthernet1/0/2
 stackwise-virtual link 2
and etc.  for each new link.

[brselzer]

Hello,

You do not need to put them into a port-channel. The stackwise virtual protocol will figure out which links are enabled and load balance between them automatically. You can use as many links as you think you need. The more links you have, the more redundancy you have. I believe 2-4 is recommended. Here is a config guide:

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-6/configuration_guide/b_166_ha_9500/b_166_ha_9500_chapter_01.pdf

You can enable dual-active detection using PAgP but that wouldn't be for a port-channel between the two members of stackwise virtual. This dual-active detection utilizes a downstream switch to detect if the other neighbor is active. 

Hope that helps!

[vivarock12]

Thanks for the reply Bradley Selzer so the confif would look like this if i use 2 cables for the Virtual link of each link:

!

interface TenGigabitEthernet1/1/1
 stackwise-virtual link 1

!

interface TenGigabitEthernet1/1/2
 stackwise-virtual link 2

!

[brselzer]

Hello,

Actually, I believe you use the same number for both, like this:

interface TenGigabitEthernet1/1/1
 stackwise-virtual link 1

!

interface TenGigabitEthernet1/1/2
 stackwise-virtual link 1

The same way you would say "channel-group 1 mode on" for both if you were putting them in the same port-channel. I don't think the stack will come up if you try to use different numbers. 

Hope that helps!

[vivarock12]

I´ll try the config today thanks for the help.

[Adnan Khan]

Hi,

I have configured the SVL with same Link number 1 and I can see both interfaces in neighbor as SVL.

Question1: In configuration guide there is no Switch 1 or 2 selection. When i reboot switc number elected automatically. Is there any way to control that perticular switch will become Active Switch of virtual domain.

Question2: in documentation, port-channel 128  is reserved for SVL and it should generate automatically. but I assigned two SVL with same number and no Port-Channel created. any idea?

[brselzer]

Hello,

1) You can use the same command to configure priority that you would a normal stack. "Switch [switch number] priority [priority number]"

2) Port-channel 128 will not be visible or something you can edit. It is internal to the switch. You will not be able to see it with show ip int br or show etherchannel sum. 

Hope that helps!

[Adnan Khan]

Thanks Brselzer, so before configuring stackwise virtual We can set switch priority separately than configure switches for stackwise virtual after that?

If I configure Interfaces as below it will be the part of PO128 automatically?

interface range te1/3/0/1-2

 stackwise-virtual link 1

[brselzer]

Hello,

That is correct. Just remember, you won't see Po128. 

Hope that helps!

[Adnan Khan]

Thanks Brselzer got it.

[xUnder]

Good day!

Shouldn't the link number match with the domain id?

[Adnan Khan]

No it is not required. Domain number can be x and link number can b y.