In my working environment that I managed for almost 2 years running network that had multiple subnet on it .The subnet are and The question is the subnet was run without logically separated with VLAN or physically separated with LAN, but it run well and how it possible?

Because as I know in order those 2 subnet to work it must on the same subnet mask and in this case it would be using netmask /17 or the network must be separated either with a LAN or VLAN?

The main switch HP ProCurve 2530-48G which is connected with router SonicWall TZ105 and it is connected with only 1 port on the router (X0). The switch was managed by me and the router was managed by our HQ in Japan.

Here is the diagram of our network:

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  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Aug 7, 2017 at 19:12

1 Answer 1


It may be seen, today, as a poor design, but it's a perfectly valid configuration. The nodes in one subnet are mostly unaware of those in the other subnet. (yes, they can see each others broadcast traffic, but it isn't a problem.) This is no different from running other layer-3 protocols within the same broadcast domain.

  • Sorry look like I am not mentioned that the two subnet can connected each other. How it possible, It just make me confused.
    – dchochan
    Commented Apr 1, 2016 at 3:42
  • A router on both subnets. Or by "interface" routes telling the hosts the other network is on the wire.
    – Ricky
    Commented Apr 1, 2016 at 4:33
  • Yes a router on both subnet, the main switch connected with one of router NIC (X0 in this case) and the other switch connected with the main switch. The switch not run a VLAN nor the network separated physically using different switch that connected to different port on the route.
    – dchochan
    Commented Apr 1, 2016 at 4:55

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