MikroTik RouterOS is designed to be easy to operate in various aspects of network configuration. Therefore creating limitation for individual IP or natting internal clients to a public address or Hotspot configuration can be done without the knowledge about how the packets are processed in the router - you just go to corresponding menu and create necessary configuration.
However more complicated tasks, such as traffic prioritization, routing policies, where it is necessary to utilize more than one RouterOS facility, requires knowledge: How these facilities work together? What happens when and why?
To address these questions we created a packet flow diagram.
As it was impossible to get everything in one diagram, Packet flow diagram for Mikrotik RouterOS v3.x was created in 2 parts:
- Bridging or Layer-2 (MAC) where Routing part is simplified to one "Layer-3" box
- Routing or Layer-3 (IP) where Bridging part is simplified to one "Bridging" box
The packet flow diagram is also available as a PDF.
Changes in RouterOS v6
The following changes have been made to the Packet Flow in RouterOS v6, see red cirdled elements in the image:
MPLS Packet Flow
Each and every facilities in this section corresponds with one particular menu in RouterOS. Users are able to access those menu and configure these facilities directly
Automated processes and decisions
- bridge goes through the MAC address table in order to find a match to destination MAC address of packet. When match is found - packet will be send out via corresponding bridge port. In case of no match - multiple copies of packet will be created and packet will be sent out via all bridge ports
- router goes through the route n order to find a match to destination IP address of packet. When match is found - packet will be send out via corresponding port or to the router itself . In case of no match - packet will be discarded.
Bridging with use-ip-firewall=yes