Extending a VLAN over WAN

[usman_noor27]

Good day to all of you!

I am currently working on a project which requires extending a VLAN over WAN. Please allow me to elaborate:

The equipment I currently possess are:

2 CISCO 1720 Series Routers (1 Serial & 1 10/100 Ethernet per router)

2 Paradyne DSL Modems (1 Serial & 1 RJ-11 per modem)

The two sites are about about 1 KM apart.

Trunking between the two sites is not possible since:

- Maximum available length of CAT 5, 5e and 6 are 100m.

- Laying a Fiber Optic cable of any kind is not possible since the terrain is extremely rough and would not allow it. Also, there is no existing infrastructure to allow re-using of old Fiber Optic Cables.

- Using a Microwave Transmitter & Receiver did not work. Atmosphere is too humid and too dusty to allow it. A minor success was achieved but only limited to small ICMP packet exchange. Data transfer failed immediately.

Giving the circumstances, I tried to connect both the sites using the format below:

Cisco 1720 === DSL Modem ===================================== DSL Modem === Cisco 1720

But I am facing serious problems in accomplishing the mentioned scenario.

I am well aware which routing protocols are used to achieve trunking and inter-VLAN routing. Also, I am also aware that this question might not have an answer because a router would BY DEFAULT not forward any packet to the WAN whose destination address is currently connected to its LAN. It would either drop the packet or just won't pay any attention to it.

Really looking forward to a good solution for this problem.

Thank You all in advance for all the help and efforts!

[paul driver]

Hello
Something like this could meet your requirements
http://www.cisco.com/en/US/docs/ios/12_2/12_2z/release/notes/rn1700zn.html

Res
paul

Please rate any posts that may have been helpful

Sent from Cisco Technical Support iPad App

[usman_noor27]

Dear pdriver,

Thank you for the prompt reply. I would check and report back whatever outcome comes forth.

==========================================================================

BTW, I would like to put it out to all if anyone has any idea whether an ETHERNET -> DSL and a DSL -> ETHERNET converter exists...

So instead of using a router to do the trunking, we can use the TRUNK PORT of the switch, modulate it to DSL and then unmodulate it on the other side back to ethernet. I hope I was clear... If not, please reply to this message and I would try harder to explain the scenario.

Let me make it clear that the device what I am asking for is NOT THE ADSL ROUTERS commonly found in the market since it works in one way, not the other way.

Do also let me know if there is a way to make the traditional ADSL routers to work as I want in the scenario.

All suggestions are welcome.

Thank You.

[Neeraj Arora]

Hi Usman,

as you mentioned earlier, using routers you would not be able to extend vlan across L3 interfaces. Moreover you've already quoted the possible solutions of extending the LAN which is not feasible in your case.

so I would suggest that you use two separate Subnets at both sites and use these 1720 routers for connectivity. But do keep in mind that these are quite old routers and would not be able to handle huge amounts of data per second.

Rest if I remember correctly, OC3 or Sonet devices were used to extend vlans across large distances but that would be a very costly affair

[usman_noor27]

Dear Neeraj,

Thank you for the very helpful suggestion. And probably the only good and reasonable suggestion.

I shall keep you posted for any progress regarding this topic.

And if I succeed, I will make sure that I post all the configuration of the routers and how I did it.

Thank you for your help again!

Regards,

Usman M. Nooruddin