I have two sites, both with 80/20 FTTC broadband connections that terminate at the standard white box BT modem. The connections both have fixed IP. I’d like to connect these up to each other and form a VPN between them so I can route traffic between the networks at either end. I am considering using Cisco 1921 routers with EHWIC-VA-DSL-A cards at either end to accomplish this. I am also planning at some point to add an E-band wireless connection between the sites that would present at either end as an RJ-45 connected to one of the GB interfaces on the 1921. I’d then like to use the E-band as the primary connection and route over the FTTC VPN as a backup. I am wondering if anyone has any hints and tips for me to give me some confidence in this solution - even if just to sanity check my plans.

  • The E-band is 60 to 90 GHz, and it will not travel very far, nor will it penetrate walls. The frequency is too high. Wireless networking in this range is considered good for conference rooms because it is generally confined to the one room. – Ron Maupin Jul 9 '20 at 12:12
  • Thanks Ron. I currently have the e-band solution in place serving another premises. I am using ALFOplus80 radio units which span about a quarter mile at 1Gbps with LOS. – Steve Gould Jul 9 '20 at 17:25
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can post and accept your own answer. – Ron Maupin Dec 17 '20 at 19:27

The easiest way to accomplish your plan is to:

  1. Create a VPN connection over the FTTC connections.
  2. Create a second VPN connection over the E-band connections.
  3. Set up your internal routes through both VPN tunnels. Use a lower metric (=higher priority) on the desired VPN link.

That way, the lower metric causes the routes over E-band VPN to be used normally. If the link fails, the routes become inactive and the higher-metric routes via FTTC kick in.

If you use dynamic routes (e.g. with OSPF), make sure your VPN interface metrics are set according to the desired routing preferences.

  • Thanks for the answer Zac. Do you think I would need a VPN over the e-band? - it is essentially a private connection anyway. Would you say that my spec in terms of router and WIC will do the job? – Steve Gould Jul 9 '20 at 17:27
  • Of course, if the link is "private" enough you don't need a VPN overlay. Can't say much to the hardware, you haven't specified your performance requirements. – Zac67 Jul 9 '20 at 18:08

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