Load sharing or Failover for a router? Or should I have two LANs?

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I have a router that I think will do load sharing between two internet
connections. It's an ASUS RT-AC66U. The internet connections are:
1: Local WISP: Radio on roof feeds through a  Cat 5 ethernet cable to
the router's WAN connection. Speeds are slow, 3Mbps max. The WISP is
pretty reliable, if slow.
2. Hughesnet Gen 5: Dish on roof feeds through another cat 5 cable to
port 1 on the ASUS.Speed are usually good, up to 25 Mbps The satellite
service is less reliable, heavy rain (I'm in Houston area) causes loss
of signal.

The ASUS software recognizes that there is a connection to a WAN on
each port.

The software gives me the option of setting up as either failover or
load sharing. I'd prefer Load Sharing, because one or the other
sometimes gets very slow.

There's another complication.... the Hughesnet service is through
their router. The system "works" with a cat 5  from one of the
Hughesnet router LAN ports to the ASUS LAN port 1.... but both routers
are DHCP servers. So far I've seen no problems with this.... but I
haven't run both connected this way for very long.

AM I likely to have problems due to both apparently assigning DHCP
addresses? I could turn off DHCP serving on the ASUS, but then I think
the WISP wouldn't be able to serve any computers. I don't see any way
to turn off DHCP on the Hughesnet router.

Is one or the other mode (Failover or Load sharing) likely to be more
trouble free? Any advantage to either one?

My local network consists of three computers, a connection to a Dish
network recorder, a connection to a Roku, and occasional access by a
couple of tablets and cell phones. Ideally, I'd like to keep
everything on one LAN, but if this setup with the one router is likely
to have problems, is it possible to have two LANs, with some sort of
connections so that the computers in one LAN and communicate with
those in the other?

Re: Load sharing or Failover for a router? Or should I have two LANs?
On Sun, 30 Jul 2017 15:40:57 -0500, Charlie Hoffpauir

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"How to configure Dual WAN on AsusWRT routers"
<https://leonid.shevtsov.me/post/how-to-configure-dual-wan-on-asuswrt-routers/

"FAQ: [WAN] How to set up Dual WAN"
<https://www.asus.com/support/FAQ/1011719/

There are a few things broken in dual WAN using AsusWRT firmware, so I
switched to AsusWRT-Merlin. (I need SNMP to work):
<https://asuswrt.lostrealm.ca
Asuswrt-Merlin Changelog
========================
380.67 (16-July-2017)
 - FIXED: UPNP and SNMP issues in Dual WAN mode.
 - FIXED: NAT Loopback (merlin mode) in Dual WAN mode  
   wasn't supported.

I don't believer that Dual WAN was fixed in the recent 374.43
AsusWRT-Merlin LTS release but I'm not sure:
<https://www.snbforums.com/threads/fork-asuswrt-merlin-374-43-lts-releases-v26e3.18914/
Find the change log and see.  (I'm lazy tonite).

I can supply details if you insist but methinks you'll get better
answers in the Merlin forum:
<https://www.snbforums.com/forums/asuswrt-merlin.42/


--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Load sharing or Failover for a router? Or should I have two LANs?
On Sun, 30 Jul 2017 15:40:57 -0500, Charlie Hoffpauir

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Whether you use failover or load share, it will only work well if the
router can detect loss of a link and divert traffic.....
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The DHCP servers are in 2 different domains.

the Hughes "LAN" is treated as a WAN by the Asus, so it is just
working the same way as any other ISP connection with dynamic IP
addresses, even though the Hughes router is running that server

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On the home LAN you should only have the Asus serving DHCP - but that
sounds like the way it is working.

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The key is detecting when 1 link stops working and diverting sessions.

Load balancing for a home router has to normally use "per session"
balancing, because the 2 ports it sends traffic out will do address
translation to the ISP assigned address  
- so splitting the session traffic means the far end device sees that
as sessions from 2 different devices.

Load balancing in general only works well if either
- the 2 links have comparable performance and the router just assigns
sessions randomly to either  
- the router measures performance in some way (latency or bandwidth
maybe) and allocates sessions in proportion.

even if load balancing then works, you have a gotcha
- any 1 session may go either way, but will be limited to that WAN
link, so anything that needs performance better than the slower link
is 50% risk of failing depending on allocation

so failover may be better if 1 link is preferable when both are
working.

The drawback with failover is you dont use the lower performance link,
so there is some risk it will fail in a way you dont notice until you
need it.......
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The system just gets more complex with multiple devices and has more
potential states, although "human driven" changeover may be ok :)
- if you can get it to work with 1 router then I would stick with
that.
Stephen Hope stephen_hope@xyzworld.com
Replace xyz with ntl to reply

Re: Load sharing or Failover for a router? Or should I have two LANs?
On Sun, 30 Jul 2017 22:15:04 +0100, Stephen

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Thanks for your replies, you've explained a lot. I'll probably just
use one or the other, manually changing between the two depending on
traffic and weather.

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