I have understood that router is a networking device, used to connect multiple subnets. And it does the job of routing the packets from one subnet to another subnet. As depicted in the below topology-

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One more thing we can infer is that each port of the router connected to a different subnet.

With this above understanding i am unable to convince myself how does all the devices in the below diagram/topology to exist in the same subnet!?

enter image description here

When i ping PC0 (with IP address from PC1 (with IP addres, it succeeds!!

The config page of both the routers also looks different.

Router0 (1941) looks like-

enter image description here

WirelessRouter0 (WRT800N) looks like-

enter image description here

Can someone please help me in getting clarity - How multiple devices connected to the same router to be in the same subnet?

In the first case, i need to configure each interface of the router. Where as in the second case, i didn't have to

  • Your wireless router (which is off-topic here) is really a router, a wireless bridge, and a network switch. The LAN ports and the wireless connections are all in the same broadcast domain, connected to one "port" (the lan port) of the router.
    – Ron Trunk
    Mar 21 '18 at 11:19
  • @RonTrunk Why would it be off-topic, the question is about networking only, right? Furthermore, as you have hinted little bit on what i am actually looking for, could you confirm me, in the figure 2, in this case - The router WirelessRouter0 (WRT800N) is acting as a switch, with 3 ports (one to the printer, one to PC0 and one to the real Ethernet switch)? And there will be only 1 interface to connect to internet unlike in the figure where it had 2. Please correct me, if I am wrong.
    – Darshan L
    Mar 21 '18 at 11:47
  • Consumer-grade equipment, such as the WRT8000, is explicitly off topic here. You can ask questions about it on Super User.
    – Ron Trunk
    Mar 21 '18 at 12:08

Many routers have an integrated switch (with a few ports) or ports that can be configured as one or more switching groups.

SOHO routers very often have a single switch group that can't be separated. Think of it as a switch connected to a router port in a single case.

When you connect devices to ports in the same switching group they belong to the same L2 segment and (usually) to the same L3 subnet. Different switching groups or separate (true) router ports mean separate L2 segments and accordingly, separate L3 subnets.

Communication across separate L3 subnets requires routing - you can either use the router in your diagram or add another one that's connected to both subnets.

  • Can you please make the last paragraph more clearer? I'm confused with your statements - "the router you stated with" and "another one that's connected to both subnets". Which router are you referring to in each of your statement?
    – Darshan L
    Mar 21 '18 at 12:59
  • One more thing, do we have a seperate terms in networking to refer to such devices where router has integrated switch within?
    – Darshan L
    Mar 21 '18 at 13:14
  • @DarshanL, for your first comment, you could do the routing on the device you provided in your example or you could add a second router to do it (either option contingent on having the capability of being configured to do so). For your second comment, barring actual routers with switchports like the Cisco 7600, I generally call them “gateway devices.” They may technically be routers because they do route, generally they can’t be configured to do more than route the “WAN port” to the “LAN port(s).” They don’t have the features or necessarily behave like a router used by network professionals.
    – YLearn
    Mar 21 '18 at 15:54
  • 1
    I've made the last sentence a bit clearer. No, I don't think there's a term for the combination - there's "brouter" but that's something different. I call it "router with switched ports".
    – Zac67
    Mar 21 '18 at 17:51

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