Distribution & Core layer switch configuration

[9898nishit]

Hi,

I have 6500,4500 & 3500 switches. I want to configure 6500 as core, 4500 as distribution & 3500 as access layer switch for the campus lan.

As best pracitce where should i configure intervlan routing on core 6500 or on distribution 4500. I am clear on role of access layer switch on which will act as layer 2 only and i will map vlans to respective ports. But i am not clear on role of distribution layer switch and core layer switch. Should i create only vlans in distribution layer switch and create interface vlan for intervlan routing on core switch.

Best Regards,

Nishith

[Amit Singh]

Hi Nishith,

In my opinion configure the inter-vlan routing, STP domains and other services at distribution layer which 4500 and run l3 protocol between 4500 and 6500 so that you terminate your L2 domain at 4500. This would make sure that your unwanted L2 traffic doesnot travel to core and takes the unnecessary traffic processing out of the core layer.

Core layer is used for high-speed traffic switching. As a best pratice, You should not extend your layer-2 domains beyound distribution layer. Typically core layers servers as a L3 backbone to your entire campus and different distribution layers. You can run a L3 protocol like EIGRP/OSPF between core and distribution layer for faster covergence across the backbone.

Distribution Layer: Typically terminates your L2 domains including VLANs and STP domains. Configure the Vlans locally to each distribution layer and have them talk to backbone and other distribution buildings in your campus at l3. Configure STP root bridges, policy routing, Inter-vlan routing, QOS policies, Security ACL's at distribution layer so that traffic is filtered locally at this layer and you dont oversubscribe the core for these servies.

Hope this Helps,

-amit singh

[9898nishit]

Hi Amit,

Most of the doubt on role of distribution & core layer switch is clear. Thank you very much.

I have some quries as mentioned below.

1. If vlans are spread across the campus then where should i configure those vlans ? I need to configure those VLANs database & intervlan routing for those VLANs in each distribution switches ? I have five 4500 as distribution switches. Out of 20 vlans 10 vlans user are spread across campus.

2. If we configure all VLANs, STP domains in distribution switch then role of core switch is only to do routing ?

Thanks & Regards,

Nishith

[Marwan ALshawi]

i think amit has given here the best practice for your question

but i have question for you

do you have redundant link from your access switch to the distribution i switch ?

if yes, then you may need to think about HSRP in your design or if your access switch L3 capable you may run routed access layer design model

good luck