I have 2 WANs:
- Fiber internet (25 mbps down / 25 mbps up)
- Cable internet (500 mbps down/ 20 mbps up)
Generally, I want most traffic to be using the Cable, since I run servers on the Fiber internet and I don’t want to saturate it.
However, I was doing a big upload today via SFTP, and I noticed my web browsing slowing to a crawl. It looks like by saturating the Cable modem upload, I was causing trouble on the download.
Right now I’m using the Least Used for the Default Outbound Policy, but I realized this is probably not what I want, since it watches the download bandwidth, apparently ignoring the upload.
I want a rule which says “Prefer the cable modem connection, but if it gets slow, then use the Fiber connection instead”.
Here are the rules I can choose from:
Weighted Balance - Traffic will be proportionally distributed among available WAN connections according to the specified load distribution weight.
Persistence - Traffic coming from the same machine will be persistently routed through the same WAN connection.
Enforced - Traffic will be routed through the specified connection regardless of the connection’s health status.
Priority - Traffic will be routed through the healthy connection that has the highest priority.
Overflow - Traffic will be routed through the healthy WAN connection that has the highest priority and is not in full load. When this connection gets saturated, new sessions will be routed to the next healthy WAN connection that is not in full load.
Least Used - Traffic will be routed through the healthy WAN connection that is selected in the field Connection and has the most available downlink bandwidth.
Lowest Latency - Latency checking packets will be periodically sent to all selected healthy connections. Latency will then be determined by the response time of the second and third hops. New traffic will then be routed to a healthy connection with the lowest average latency during that detection period.
Fastest Response Time - Traffic will be duplicated and sent to all selected healthy connections. The connection with the earliest response will be used to send all further traffic from the session for the fastest possible response time. If there are any slower responses received from other connection afterwards, they will be discarded. As a result, this algorithm selects the most responsive connection on a per session basis.
Lowest Latency might sound good, but since the fiber almost always has better latency (under 10ms) than Cable (20-40ms) it would use the fiber by default almost always.
Overflow might work, but it depends how “is not in full load” is defined - is this upload bandwidth or download?
Edit to add: it looks like it’s download: “When this connection gets saturated (95% of defined download bandwidth), new sessions will be routed to the next healthy WAN connection that is not in full load.” (source)
Ideas?
