Earlier cisco defined their campus network design as the three layers Access Layer, Distribution Layer and Core Layer and they implemented them as L3 vlans throughthe Distribution blocks and the L2 vlan would extend to the Core layer and the Core layer would be trunked redundantly to the distribution layer, The core layer would perform only switching operations and no routing, filtering and security features will be implemented. PVST is to be implemented with Port fast/Uplink fast/Backbone fast as per the requirements in the campus.
As, The New model High Availability Model is there which say's that there would be routing between the core and distribution layers and can extend it to the access layer, the vlans would be terminated on the distribution blocks or the access blocks and rest all the links will be routed without the use of any FHRP, Here i am unable to understand that how multiple vlans data will be moving between the core layers if we chose the switchport option and we move it on trunk then in core we have to use the SVI but how we can use SVI without extending vlans and the other option is that we will use this port as routed portand if we make it a routed port then how multiple vlan data will move on that.
Please throw some light on this so that i can have a better overview.
In the current HA-CND, it is recommended that you do not extend VLANs past the distribution layer. Or in the case of a complete layer 3 Campus, the Access layer. Utilizing Layer 3 in the Distribution and Core speeds convergence. You can still have a FHRP running on the Distribution Layer 3 switches. The key is to make sure the Primary HSRP switch and STP primary root switch are on the same Distribution Layer switch if you plan on load balancing the VLAN traffic across the uplinks.
Check out the new CCNP Switch FLG and OCG for a very nice explanation.
Hope this helps.
You might also want to have a look at the "Campus Network for High Availability Design Guide" document if you have not seen it.
Thanks Brain, i am going through FLG but it seems confusing some times,
Do you have any document that has an example of HA-CAN, kindly share a link.
Borderless Campus 1.0 Design Guide might be a better document, don't overlook that the introduction of new products or new product features can also lead to new best practices.