Default gateway of SVI subnet

[mahesh18]

Hi Everyone,

Need to understand  the  concept below.

Say we have Switch 1 which has SVI  Vlan say 10 it has IP 192.168.1.1

Users connect to the Subnet of Vlan 10 which is 192.168.1.x

Is this ok to have default gateway for this vlan 10  on say Router 7201 even though this router has no vlan 10 ?

Is this design ok?

Regards

Mahesh

[Vignesh Rajendran Praveen · Accepted solution]

Hi Mahesh,

You need to create a sub-interface on the physical interface of the 7200 router where the switch 1 connects to. And then use the enacpsulation dot1Q 10 representing vlan 10 on the sub-interface. Then assign an IP address in the 192.168.1.0/24 subnet and use this IP as the G/W IP for the Vlan 10 on the LAN side.

On Cisco 7200

interface gi 0/0.10

encapsulation dot1q 10

ip address 192.168.1.11 255.255.255.0

Now the IP 192.168.1.11 can be used as the G/W IP for the vlan 10 on the LAN side.

Hope this helps.

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Thanks & Regards,

Vignesh R P

[John Blakley · Accepted solution]

Mahesh,

If the switch is L2, you'll need to create a subinterface on the router like Vignesh stated. If it's a L3 switch, you won't have to do that if routing is enabled on the switch, but you will need vlan 10 created on the switch. Then all of your users will use the SVI as their gateway. If you have a L3 switch, the router doesn't need to know about vlan 10 itself, but will need to know how to route to that subnet.

HTH,
John

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[mahesh18]

Hi John,

Thanks for more and clear explanation.

Yes the switch is Layer 3.

Router is learning  the route via routing.

Regards

MAhesh

[NirmalDesai6643]

You need to configure a sub interface on router and ensure that the configured sub-interface is tagging vlan 10. 

Interface GigabitEthernet 0/0.10

Encapsulation dot1q

IP address 192.168.1.x with mask

Ensure that Gigbabitethernet 0/0 is not shutdown. You do not need to assign IP address to Gi-0/0

Hope this helps.