Connecting two MB300E switches into one VLAN Tagging Switch then to the Radio
One of our colleagues is suggesting to connect two separate MB300E network switches into one VLAN tagging switch then to the Microwave Radio Master I/O Ethernet port.
He is saying that by doing this he will keep both Md thing M300E separated & redundant to each other? is that a good thing (why) if that is a bad thing (why)?
He is maily doing this because he has no enough Ethetrnet ports in the Radio master i/o module.Taking into consideration that we have a TDM multiplexer and all we need to do is to get two intwrface cards put them in the mux and have all the through an E1 port, the interface port for this cards is ethernet.
For absolute & true redundancy, each network must have its own dedicated hardware. No components must be shared, e.g MUX, radio and antennas. This is a very costsome solution.
By multiplexing the traffic with a MUX, VLAN, etc the networks will not be totally isolated. E.g. loss of power, failure in radio, frequency jam may block all communication on both primary and secondary network simulataneously.
This is of course a calculated risk.
We know of several instances where redundant MB300 is sent over a singular radio link.
One very important thing to remember; to be able to let two MB300E networks to be multiplexed, e.g. via a VLAN or MUX, one network must have an odd number and the other must be given an even number, e.g. 11 and 12 is GOOD while 11 and 13 is NOT good.
If both primary and secondary network carry odd or even numbers, the MAC-addresses will NOT become unique and the unpacking multiplexer unit may not be able to differentiate if the packet was sent on the primary or secondary bus.