LTE Failover within LAN of Balance 380

Hello, looking for some guidance from a more seasoned admin on this (my employer does not currently employ a network engineer so modifying our existing implementation is always an adventure).

What I’ve got:
-Balance 380 load-balancing two WAN connections each coming from a separate modem -->
-LAN of Balance 380 is distributed via ethernet and WiFI Radios.

My Problem:
-Need to keep the clients downstream of the SM (or any other break point) online in the event the SM loses connectivity with its AP

My Ideal Solution:
Implement a MAX BR1 ENT with LTE SIM card installed that will leverage the Balance 380’s LAN as its primary WAN when available, and the LTE SIM card when the Primary WAN is lost (i.e. when the wifi connection breaks)

What is the best way to accomplish this? Is it possible to do this on the same subnet so that the client static IP Addresses won’t have to be modified?

Hi Garth - welcome to the forum!
Whats a SM? Is that a wifi to ethernet bridge / adapter?
How many clients are on the remote wireless link? What bandwidth do you have and need there over that link?

1 Like

Hi Martin, thank you for the warm welcome and of course for reaching out!

I apologize for leaving out some of those clarifying details, all valid questions.

By SM I mean Subscriber Module, and yes that’s a Wifi Radio that receives its WiFI link from the configured Access Point and converts it back to ethernet. We use this method to distribute the LAN of the Balance 380 across an outdoor environment to a number of network segments. Each network segment has a subset of clients utilizing the LAN of the Balance 380 for production.

The main goal would be to provide some LTE failover for when the WiFi link is lost and the clients lose connection to the Balance 380 LAN. Each segment is made up of about 10-15 clients, and bandwidth should be fine with standard LTE SIM as we really only needs to be about 20mbps down and maybe 10mbps up being that this failover connection would just be to minimize downtown when environmental elements are impacting the WiFi bridge due to things like storms, construction blocking the WiFi line of sight, or hardware failure.

Hopefully that sheds some more light on things, let me know if you have other questions.

For what it’s worth - My first attempt at mapping this out was as follows:

Balance 380 configured as 192.168.92.1/23
Primary WAN coming from Modem of ISP.

For Segment A – Max BR1 for with LTE failover configured as 192.168.92.3
MAX BR1 Priority 1 set as Primary WAN connecting to Balance 380 LAN at Static IP 192.168.92.3
MAX BR1 Priority 2 set as LTE
Clients on Segment A configured with Static IPs with default gateway as 192.168.92.3

For Segment B – Max BR1 with LTE failover configured as 192.168.92.4
MAX BR1 Priority 1 set as Primary WAN connecting to Balance 380 LAN at Static IP 192.168.92.4
MAX BR1 Priority 2 set as LTE
Clients on Segment B configured with Static IPs with default gateway as 192.168.92.4

When doing this, I would not be able to ping all three routers (Balance 380, Max BR1 for Seg A, and Max BR1 for Seg B) at the same time and I’m not well-versed enough to know why.

Thanks - that’s helpful. Last couple of questions.
The network segments, can they be properly segmented and use their own subnets - ie are they just using the LAN of the Balance for internet access? Do they need to be able to route traffic to each other?

Do you need packet level seamless failover between LTE and wifi or can you lose all active sessions and start them again when the wifi / SM fails?

ie, Is this a bunch of home users streaming netflix and iplayer and you are their Wireless ISP, or are the network segments nuclear cooling rod control stations and you’re the nuclear physicist in charge of production. You get what i mean, will the segment devices / users cope with a brief 1-2sec max outage or do we need hot failover that is transparent to the end user/device?

1 Like

Well, ideally I would be able to implement a configuration that doesn’t require a new subnet for each segment as there are more than 20 segments and it feels like a waste to use that many subnets. I do know how to do this with a new subnet for each segment, as we have used that solution in the past but the larger we get, the more subnets we are burning through. That said, I was hoping there was a way to do this all on the same subnet, but that’s why I am here as I don’t know if that is doable.

Technically the segments don’t need to route to one another, no. As far as the failover goes, no it doesn’t need to be seamless. A 1-2 second outage is absolutely acceptable.

That is the whole point of subnets though - to sub divide or segment a network. If you used a a /27 subnet mask that would give you 30 host IPs a subnet and 2048 subnets in a 172.16.x.x class B network.

Anyways. If you can cope with the failover as you suggest then I would suggest a BR1 Enterprise in Drop in mode.

For the devices connected to its LAN all they see is the LAN IP of the Balance and they are on the same network as it when connected via wifi. When that wifi link fails, the BR1 will route traffic out to the internet via cellular.

If you wanted seamless failover I’d use Layer 2 Speedfusion but then you have a bandwidth limit of 60Mbps (speedfusion with encryption - 100Mbps if unencrypted) on the BR1 ent, and the B305 has a limit of 150Mbps total over Speedfusion (which is also need a licnese for).

2 Likes

You are a wizard, plain and simple. I may have other questions in the near future but you’ve given me plenty to chew on. Truly grateful.

Last question would be, where did you create that lovely graphic?Just using power point or?

1 Like

No worries. Shout if you need any help - its what I do. Where are you geographically?

I make network diagrams in gliffy.com and import the peplink product icon packs.

2 Likes

Based in Minneapolis but deploy equipment all around the US.

1 Like

Thank you again for all the help with this Martin. I’ve staged the Drop-In Mode solution in our lab and things appear to be functioning as desired. I only have one question/concern: While my Balance 380 and BR1 ENT in Drop-In Mode both have “Established” PepVPN status on the device Web UI, my Host 1350 shows a “Route Conflict” for the Balance 380 remote profile. I assume this is due to the fact that both devices are configured on the same subnet? (I have the Balance 380 set as 192.168.x.1 and the BR1 ENT set as 192.168.x.2)

Does it matter that there is a route conflict if I can access both devices, or is this just the expected behavior when leveraging Drop-In mode within the LAN of another Pep device?