SOLVED: What do the different types of interfaces mean ?

RouterOS Beginner Basics
1

Dear Forum,

the default config of my RB configures different types of interfaces, and I would like to understand what they mean. Could not find much information in the manual.

The interface list gives me

#     NAME                                TYPE         MTU L2MTU  MAX-L2MTU
 0  R  ether1-gateway                      ether       1500  1598       4074
 1   S ether2                              ether       1500  1598       4074
 2   S ether3                              ether       1500  1598       4074
 3   S ether4                              ether       1500  1598       4074
 4  RS ether5                              ether       1500  1598       4074
 5  RS ether6-master-local                 ether       1500  1598       2028
 6   S ether7-slave-local                  ether       1500  1598       2028
 7   S ether8-slave-local                  ether       1500  1598       2028
 8   S ether9-slave-local                  ether       1500  1598       2028
 9   S ether10-slave-local                 ether       1500  1598       2028
10  R  bridge-local                        bridge      1500  1598

and the bridge looks like this:

#    INTERFACE              BRIDGE              PRIORITY  PATH-COST    HORIZON
 0 I  ether2                 bridge-local            0x80         10       none
 1 I  ether3                 bridge-local            0x80         10       none
 2 I  ether4                 bridge-local            0x80         10       none
 3    ether5                 bridge-local            0x80         10       none
 4    ether6-master-local    bridge-local            0x80         10       none

ether1-gateway is my WAN gateway.
bridge-local is a virtual interface, that combines ether2..ether6.
The bridge creates a broadcast-domain, so all broadcasts are forwarded to all links of the bridge.
Traffic with individual destination is only forwarded to the link where that destination is expected (correct?). :question:
But what does the slave “S” mean, and what is specific to ether6-master-local and ether7..10-slave-local ? :question:

And how/when should I use the different types in my network ? :question:

Thanks a lot for any help.

Walt

2
  1. They’re all ethernet interfaces, so they are the same type.
  2. You can name an interface whatever you want, the names ‘mean’ nothing.
  3. Slave, under the default name, means it has master-port set and is part of a switchgroup.

http://wiki.mikrotik.com/wiki/Manual:Default_Configurations

3

Dear lordkappa (et al),

thanks for your reply and the reference.
Let me clarify the questions:

Interfaces ether1..5 have their “Switch”-attribute set to switch1, ether6..10 have it set to switch2. This corresponds to the two switch chips of the router. Is the following correct?:

  • the association between interfaces and switches[1|2] if fixed and cannot be modified
  • without further configuration, no switching takes place, all ports are equal and routed through the RB CPU
  • switching between two or more ports can be enabled by setting the same master port. In my configuration, ether7..10 have the same master port, so packets between these ports are switched, bypassing the CPU, rather than routed (via the RB CPU).
  • the master port and the switched ports must connect to the same switch chip.

So after reading “Interface-Case Studies-Switch Chip Features”, this is my current understanding of port switching, I hope it is correct (please comment!). But what does it mean that “Interfaces for which the ‘master’ port is specified become inactive”? In my config, ether6 is the master of ether7..10 and the hosts connected to it can communicate just like any other.

Now what about bridging? Accroding to the manual, “the bridge feature allows the interconnection of hosts connected to separate LANs (…) as if they were attached to a single LAN”. Refering to my configuration, is the following correct?:

  • ether6..10 are configured as a port switched group, because ether6 is master of the others. So these ports appear as one single LAN.
  • all other interfaces represent individual LANs. The “bridge-local” specifies a bridge that brings these different LANs together, plus ether6 as the master the switching group.

Summarising this, and ignoring additional features (like rule definition) for the moment, port switching is a good (fast) method when ports connected to the same switch chip shall form a LAN. The bridge is the solution if ports that are not connected to the same switch chip shall appear as a singel LAN.

Is this correct?

Walt

4

Correct, the exact association is visible in the block diagram listed on routerboard.com: Example http://i.mt.lv/routerboard/files/Block-RB2011.pdf

Essentially, yes. The diagram above shows some of the internal bottlenecks in the hardware links.

Exactamundo.

Interfaces with Master-port set cannot have IP addresses applied to them and cannot be configured manually. You, in essence, lose control of them but the master port itself can be configured.

Basically, yes. http://wiki.mikrotik.com/wiki/Manual:Switch_Chip_Features#Port_Switching explains in more detail how master-ports behave.

5

@lordkappa: thanks a lot for the detailed reply. :smiley:
Walt