LAN switching - Core - Aggregation - Access - design help needed

[amarula115]

I need to add multiple new stacks of 2960-X to the existing network. However, two existing 4500-X Core switches (in VSS) have no ports available to connect these stacks.

I have another set of 4500-X which I want to connect to the Core as an aggregation switches (Layer 2 only) and use them to aggregate new stacks of 2960-x. 4500-X seems to me as an overkill to implement as just an aggregation Layer 2 but in the future I will be able to switch them to real Distribution switches by enabling Layer 3 on them and use EIGRP or OSPF for routing redistribution to Core switches. I am attaching diagram presenting 3 scenarios which I "invented" as the possible ways to connect aggregation switches to core switches. Which one of these 3 scenarions would be most recommended. Other suggestions welcomed.  I am presently restricted by limited maintenance window to implement real Distribution (L3) at this time.

Any help appreciated

[Seb Rupik · Accepted solution]

Scenario 3 all the way. Why have uplink ports blocking, when they could be forwarding??

Scenarios 1 & 2 would truly be a waste of one of the 4500-x switches.

cheers,

Seb.

[amarula115]

Thanks a lot for your comments. Appreciated

[Deepak Kumar]

Hi, 

The diagram 3 is fine. It is also advised that in the multi-chassis EtherChannel add one link in cross switches mean: Coresw1 to Distribution layer sw2 and vise versa.   

It is recommended in the Cisco documents and practically also that make sure that Distribution layer sends only route summary to the core layer. 

Regards,

Deepak Kumar

[amarula115]

Thanks a lot for your comments