Layer 2 Network Extension trough VPN

[Patrick Werner]

Hi Community.

We like to extend our Layer 2 Network to another branch office. We like to use VPN.

The network in "branch office 1" is 172.16.4.0/22 and the network in the other "branch office 2" has the same network 172.16.4.0/22.

Broadcast and Multicast should be forwarded to the other branch office and vice versa.

How do we accomplish this ?

Best regards patrick

[Gurpreet Puri · Accepted solution]

Dear Patrick,

You can achieve this through GRE Tunnel.

For details, how to create, please visit below mentioned link:

https://supportforums.cisco.com/document/13576/how-configure-gre-tunnel

Regards,

Gurpreet Singh

[Patrick Werner]

Hi Gurpreet.

I've read the docu in that link. But that docu assumes that on the other side is another network.

But i want to have the same Network/Subnet on both side.

Patrick

[Gurpreet Puri]

Hi Patrick,

The link was just an example.

You can achieve this by GRE tunnel for same subnet as well.

and if you want the encryption, you can use IPSec also.

Regards,

Gurpreet Singh

(Please rate helpful post)

[Patrick Werner]

Have you a config example for that? And do you know which devices supports GRE Tunneling?

[Gurpreet Puri]

Hi Patrick,

Configuration can be modified as per the shared link.

and

Many devices supports GRE Tunnel like 3850, 6500 etc. You can visit the datasheet of the different routers and check whether they supports IPSec VPN Tunneling or not. If they do, the that model supports GRE.

Cheers :)

Regards,

Gurpreet Singh

(Please rate helpful posts)

[Patrick Werner]

Hi Gurpreet.

Just to clarify.

If PC1 with the address 192.168.1.10 in branch office 1 likes to communicate with the PC2 with the address 192.168.1.20 in branch office 2. The IP packet will never be sent to the Router because both are in the same subnet.

So how do that work?

Best Regards Patrick

[Patrick Werner]

Hi Guys.

Have someone time to explain my upper question, please.

Additional question why do i need route commands if both PC belongs to the same subnet. I'm a bit confused.

Thanks and best regards Patrick

[SANTHOSHKUMAR SARAVANAN · Accepted solution]

Hi ,

 You need to check with your service provider for layer 2 VPN .

Layer 2 VPN (VPLS)
Layer 2 MPLS VPNs, or VPLS (virtual private LAN service), offers a “switch in the cloud” style VPLS service. VPLS provides the ability to span VLANs between sites. L2 VPNs are typically used to route voice, video, and AMI traffic between substation and data center locations.

Or 

Share me your Device Details (Router/Switch) , Let me check whether it support Xconnect 

HTH

Sandy

[Patrick Werner]

Hi Sandy.

We do presales for that project, so if you know which Cisco devices support that. Then we will buy one.

Patrick