core switch and sub switch gateway

[moongeegee1]

I have a Layer 3 core switch(backbone) 10.18.16.0/24, and the core switch needs to connect to multiple Layer 2 sub switches.

The Layer 2  sub switches will connect to multiple workstations. The sub switches network will be 172.20.10.0/24, 172.20.40/24 and so on.

 I use core switch IP 10.18.16.11 to connect to sub switch 172.20.10.0/24. Which gateway IP  should I use for 172.20.10.0/24 ? Should I use 172.20.10.1 or 10.18.16.11 ?

Thank you for your help in advance.

[Reza Sharifi · Accepted solution]

I am not sure what you mean by "sup switches", but usually you need a management IP/vlan segment, so you can use it to access the devices.  So if your management segment is 172.20.10.0/24 you assign an SVI to every layer-2 switch and give it an IP in this range and the gateway for all the SVIs should be on the core (172.20.10.1/24

example:

access switch-1 172.20.10.11/24

access switch-2 172.20.10.12/24

access switch-3 172.20.10.13/24

and so on

The default gateway for all your layer-2 switches should be the SVI on the core (172.20.10.1/24)

HTH

[moongeegee1]

I am sorry that I did not use the correct term to describe it. Please see attached my network diagram.

I have read doc and searched on the Internet, but am still not sure what I should use for the gateway.

Please help. Thank you.

[Reza Sharifi]

Yes, use 172.20.10.1 as the gateway for all layer-2 switches.  As I said before, you also need to create a an SVI on the core with IP address 172.20.10.1

on your layer-2 switches you need this command:

ip default-gateway 172.20.10.1

HTH