HI,
I have an issue with mikrotik Rb-750 gigabyte, 5.11 v router board BGP configuration. My router using my both ISP connection for download and upload bandwidth while i monitor in interface but i want to use my 1st connection as primary cnnection and secondary mean 2nd isp connection as backup connection how can i prioritize my primary connection for upload/download traffic in my router and keep my 2nd ISP connection as backup.
Greetings,
The cleanest way to accomplish this is using BGP Local Pref.
You can set local pref using a routing filter on the way in from each ISP. (make your preferred connection have a local pref of 80, and your backup connection have a local pref of 70). I’m assuming you’re only receiving a handful of routes, or a default route and not a full feed if you’re using a RB750.
But that only gets you halfway there (prioritizing your outbound traffic).
In order to prevent inbound traffic from using your backup connection while your primary is up…your backup ISP needs to support BGP communities. Specifically, one that will let you lower the local pref on their side below their upstreams. You set the BGP community on the outbound filter facing your backup connection. For example, Level 3 would have you use the 3356:70 community to set the Local Pref to 70 on their side. (which will essentially stop advertising your route unless they see your prefix disappear from your primary connection).
~Matthew
Communities are certainly preferred to influence inbound traffic, but you can also use prepending if communities are not available