I read an interesting article on master ports: http://www.manitonetworks.com/mikrotik/2016/5/22/master-port-configuration
There is also the possibility to bind ports together using bridging.
What are the pro’s and cons for both solutions?
Do bridges benefit from all ports in a bridge being on the same switch chip?
–jeroen
Bridge is software switching, master port is hardware switching. Use master ports to switch multiple physical interfaces where you want full wire speed. Use bridges to connect those master ports together, possibly with wlan ports as well.
With hardware switching alone there is no way to place a wired Ethernet segment on the same broadcast domain as a wireless segment, or interconnect different switch chips. For that, you need to use software switching (bridge functionality).
In a WISP situation, I usually do not bother with master/slave ports because it is rare, given the limitations of wireless PtMP radio equipment, that you will ever be in a situation where you are switching gigabit traffic; in such situations, where you are usually switching <100Mbps, hardware switching introduces additional complexity of configuration while decreasing CPU load only minimally.
The difference is much greater when dealing with traffic nearing gigabit speeds; any switching at this rate that you can remove from the router CPU and offload to the switch CPU makes it worth setting up master/slave, even though it makes the configuration a little more complicated.
Just to add to above: when creating a typical LAN setup with multiple ethernet ports and a wireless interface, I usually set the ethernet ports to a master port (thus utilising the switch chip for anything wired), add the master port to the bridge together with the WLAN interface (thus creating a single broadcast domain).
Another difference is that the hardware switching is pretty vanilla on most platforms, regarding the features available to you.
Other than vlan tagging and port mirroring (e.g. for wireshark captures), most platforms can’t do any other typical switch features such as (R)STP, PAGP, etc.
Bridging allows you to throw the full feature set of ROS at it - you can enable the IP Firewalls feature on the bridge and use the IP-layer filtering/mangling rules.
Bridge filters also have their own capabilities at layer 2 (MAC address NAT, blocking/allowing certain types of packets, etc)
Basically, I tend to use HW switching for multiple ethernet interfaces all being grouped together, and use bridging if multiple interface types (tunnels, wlans, etc) need to be on the same broadcast domain. One thing I do that’s not the optimal solution is that I tend to use the bridging / vlan sub-interfaces even on configurations where the hw-switching’s vlan support would work. Something about it is just unintuitive to me and I never bothered to learn it well enough to hang my hat on it. (so to speak)
Thanks for all the answers.
What’s PtMP and WISP?
PtMP refers to Point-to-Multipoint, WISP refers to Wireless Internet Service Provider.
Thanks again.
–jeroen