Connect Same Subnet From Two Different Distant Locations

[Collins773]

Hello,

I'm in need of some help. I'm trying to figure out how to connect a piece of equipment that acts like a host pc to connect to a distant end location device that also belongs to the same subnet. The equipment will go to a switch over a l3 link to a router than shot over through a satellite to another router where it will go across a l3 link to a switch and then to the device it needs to go too.

[Georg Pauwen]

Hello,

you could consider Local Area Mobility, a feature designed for cases like yours.There are a few requirements though, one of them being that you need a routing protocol that can send classless routes (since what you basically do is exchange host routes).

Cisco IOS Local-Area Mobility

http://www.cisco.com/en/US/products/ps9390/products_white_paper09186a00800a3ca5.shtml

[Joseph W. Doherty]

Georg, neat - I didn't know about this technology.

Collins, another possible solution would be to implement a L2 tunnel between locations.

[Collins773]

How would the L2 tunnel be implemented? I'm assuming at the switch level but does a 3750 switch have the ability to do so?

[Julio E. Moisa]

You could use EoMPLS for example, I dont think the l2vpn can be implemented on 3750 switches. 

Routers

int fa0/0
no shut

int fa0/0.10
encapsulation dot 10
xconnect <remote IP> <Virtual Circuit ID> encapsulation mpls. 

If you are not using mpls between the devices you could use L2TP encapsulation to use IP protocol instead..

pseudowire-class L2TP
encapsulation l2tpv3
ip local interface <source interface>

interface F0/0
no ip address
xconnect <remot IP> <vc id> encapsulation l2tpv3 pw-class L2TP

So no MPLS is required. 

Hope it is useful

:-)

[Joseph W. Doherty]

It's very likely a 3750 would not directly support any kind of L2 tunnel, well excluding the type of solution that Julio mentions.

You did describe the next device up from the switch was a router.  It may have some L2 tunnel capabilities.  (Capabilities depends much on the actual device and features licenses.)

You also mention it's a routed link between the switch and the router.  Okay, then you would need to trunk the switch side and subinterface the router side to get the host's L2 traffic to the router that would place it into a L2 tunnel.

[Collins773]

How reliable is LAM though?