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C9600 | StackWise Virtual Link

zekebashi
Level 4
Level 4

Hello,

 

Can you use two SVL links or only one to form a StackWise logical switch? I understand that the requirement is to configure a single SVI (formed as an EtherChannel interface comprising of up to 1-8 physical member ports); however, I was wondering if I could configure two SVIs to provide higher resiliency.

 

Also, when configuring two switches in StackWise Virtual Link configuration, do I need to configure a P2P L3 link between them?

 

Thanks in advance for your input.

 

Best, ~zK

1 Accepted Solution

Accepted Solutions

I completed building the SVL domain. It turns out that the system only allows a single SVL link. I tried to create a secondary SVL link but the command was rejected. So, the way it works is that when creating SV domain, you will need to decide whether you want to include 1 or more 10Gbps or 40Gbps ports as member ports. Then the system will transparently create the SVL port-channel.

 

HTH.

 

Best, ~zK

View solution in original post

8 Replies 8

Reza Sharifi
Hall of Fame
Hall of Fame

Hi,

For SVL, all you need is 2 10 or 40gig interfaces and no need for any PTP L3 config: see sample:

On Switch 1:
Device>enable
Device#configure terminal
Device(config)#interface FortyGigabitEthernet1/0/5
Device(config-if)#stackwise-virtual link 1
WARNING: All the extraneous configurations will be removed for FortyGigabitEthernet1/1/1 on reboot
INFO: Upon reboot, the config will be part of running config but not part of start up config.
Device(config-if)#end
Device#write memory
Device#reload
On Switch 2:
Device>enable
Device#configure terminal
Device(config)#interface FortyGigabitEthernet1/0/5
Device(config-if)#stackwise-virtual link 1
WARNING: All the extraneous configurations will be removed for FortyGigabitEthernet1/1/1 on reboot
INFO: Upon reboot, the config will be part of running config but not part of start up config.
Device(config-if)#end
Device#write memory
Device#reload  

Link

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9600/software/release/16-12/configuration_guide/ha/b_1612_ha_9600_cg/configuring_cisco_stackwise_virtual.html

HTH 

Thanks for the quick response, Reza!

 

So, a single SVL with either 1, 2, up to 8 member ports in a EtherChannel. The ports can be either 10Gbps or 40Gbps, correct?

 

 

Thanks in advance, ~zK

Sure, so looking at the documentations, there is no need for any Portchannel anymore like the way it was for VSS. So, I would just use a couple of 10 or 40Gig ports. Remember as long as all your access switches are connected to both chassis, there is really no need for a whole a lot of bandwidth for SVL.

HTH

Interesting. I am using this doc: https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-9000/nb-06-cat-9k-stack-wp-cte-en.pdf

 

Review Pg 9; under the StackWise Virtual link Redundancy; third paragraph. 

 

I'd certainly prefer to use two individual SVI links over a single port-channel (2 or even 8 member ports). Thoughts?

 

Also, just curious, since FHRP(HSRP) solution is not used in this type of design, would traffic be forwarded to the the active SVL switch or since data traffic is distributed traffic would be forwarded to either switch depending on the hash result of the port-channel in the downstream device (let's say an access-layer switch is uplinked to the SVL pair via a port-channel)!!!

 

~zK

 

 

That is correct. Both chassis will forward data depending on the hash result and since there is no more HSRP, VRRP, etc.. So, both chassis are active unlike when you run HSRP or VRRP where only the active chassis forwards traffic. 

I'd certainly prefer to use two individual SVI links over a single port-channel (2 or even 8 member ports). Thoughts?

I see the note on page 8 but the config guide I posted earlier only talks about individual interfaces. I don't have a 9600 to test with but not sure if it is possible to configure a Portchannel just like the way it is with VSS. Either way, I would use a couple single ports.

HTH

Excellent!!! 

 

I have brand new C9600 pair. I will test by configuring both individual SVLs and Port-Channel and post the results. 

 

 

I really appreciate you valuable input, as always!! 

 

 

Best, ~zK 

Glad to help!

That would be great if you could update us.

Reza

I completed building the SVL domain. It turns out that the system only allows a single SVL link. I tried to create a secondary SVL link but the command was rejected. So, the way it works is that when creating SV domain, you will need to decide whether you want to include 1 or more 10Gbps or 40Gbps ports as member ports. Then the system will transparently create the SVL port-channel.

 

HTH.

 

Best, ~zK

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