adding another core block

[bluesea2010]

Hi,

Hi ,

I would like to do the above-collapsed core architecture. Currently, I have building 1  only .

Since  there is no room for new access switches I am trying to put a another  core block (2) (building 2 ) 

What are the pros and cons?

Currently all the VLAN svis are   on   core block 1  , How can I do it on core block 2 

Thanks 

[marce1000]

 - What model(s) are those devices , what are your goals ? -> Redundancy  , load-balancing , both , or and elaborate....

 M.

[bluesea2010]

Hi @marce1000 

Presently I have the top block (building 1 ), I want to add more edge switches to the core . Unfortunately, I  cannot add modules to the existing core block. So adding another core block in building  2. 

Please see the diagram below 

[Joseph W. Doherty]

First, did you really mean for the upper right switch and lower left switch have dual links?  I would have expected one of those links would be between the upper left switch and the lower left switch.

Since you want to extend VLANs, we're looking at L2 interconnections?  If so, the way to extend VLANs (plural) is generally via using a Cisco trunk port.  However, if these switches are L3 capable, I generally advise not extending multiple VLANs beyond an edge switch and its uplink partner(s).  As L3 MLS is generally just as fast as L2 switching, the former avoids many potential L2 issues.

Do your switches support any kind of switch combining, e.g. stacking, VSS, vPC?

[bluesea2010]

Hi,

It supports  VSS,  I have corrected the  link , this will be ok ?   

Please advise 

[balaji.bandi]

VSS getting old and Cat 6K getting retired soon. but feasible ? suggest to have different domain.

maybe if you looking StackWise virtual yes, that can be done, but they need to a different domain

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-9/configuration_guide/ha/b_169_ha_9500_cg/configuring_cisco_stackwise_virtual.html

if you looking vPC, they you can deploy enhanced vPC

[paul driver]

Hello

If building 1  switch is VSS then you can add building two into the same VSS domain as such you would end up with two logical switches, which is viable.

[bluesea2010]

Hi @paul driver 

what if I create another VSS domain and add these building 2 switches in  another domain

And you said if I add in the same vss domain , it will be two  logical switches . If I add it in the same domain how come there will be two logical switch

Thanks

[balaji.bandi]

I would advise another domain, by the what is the purpose of another VSS in the network? what role ?

is the Access Layers connecting new Core Layer 2 ? or Layer 3 ?

You looking to extend Layer2 between VSS ?

if they are separate cores to handle different access switches, suggest having Layer3 between VSS to exchange routes.

[Leo Laohoo]

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@balaji.bandi wrote:

VSS getting old and Cat 6K getting retired soon. but feasible ? suggest to have different domain.

maybe if you looking StackWise virtual yes, that can be done, but they need to a different domain

---

StackWise Virtual is VSS and VSS is Stackwise Virtual.  

• VSS is coined for chassis that support "classic" IOS. 
• StackWise Virtual is marketing "buzz word" for IOS-XE.  

At the end of the day, other than the underlying OS, they are both the same.  

[balaji.bandi]

StackWise Virtual is VSS and VSS is Stackwise Virtual.  

yes,  we do all know that cisco shipping old wine in the new bottle here.

My suggestion was doing not to use the old Cat6K, rather i go with the new Cat 9K switch with StackWise virtual.

[bluesea2010]

hi @balaji.bandi 

is the Access Layers connecting new Core Layer 2 ? or Layer 3 ?

layer2

You looking to extend Layer2 between VSS ?

Yes 

[balaji.bandi]

Then my suggestion as below :  (Considering All Layer 3 SVI still on OLD Core, May be new ne you can create on new Core too, but those  vlan need to extend to old core)  - make sure you adjust stp priorities if required.

[paul driver]

Hello

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@bluesea2010 wrote:

And you said if I add in the same vss domain , it will be two  logical switches . If I add it in the same domain how come there will be two logical switch

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Apologies, wasnt thinking straight , menat to say "not" 

@balaji.bandi  thanks for highlighting