Doubt in a Network Diagram

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Hello,
Let me attach a picture here.

To implement the following network, the router should have 4 NICs inside it right?? @wes-bryan
Thanks.

In this diagram you will need at least two NICS each with two IP addresses

For example:

NIC 1
192.168.0.1/25
192.168.0.129/26

NIC 2
192.168.0.193/27
192.168.0.225/27

@wes-bryan So would you have a virtual bridge attached to each NIC configured for the second network?

A single interface can be connected to multiple networks, as well as using sub-interfaces which allow you to treat a single physical interface into multiple virtual interfaces. The steps to perform are beyond the scope of the Network+ exam. Bridging is a layer 2 technology, routing is a layer 3 technology. For the specifics on configuring the routers interface, check out our Cisco section of the library.

@wes-bryan Hello Sir,
Okay, I get that configuring multiple IPs on a single NIC is beyond the scope of Network + exam but is there any limit for how many Network IP Addresses that we can assign to a single NIC? Like 2, 3, or more because you said multiple which was sort of general.

@Atharva-Bet said in Doubt in a Network Diagram:

@wes-bryan Hello Sir,
Okay, I get that configuring multiple IPs on a single NIC is beyond the scope of Network + exam but is there any limit for how many Network IP Addresses that we can assign to a single NIC? Like 2, 3, or more because you said multiple which was sort of general.

The limitation behind the use of sub interfaces is limited by the bandwidth on the interface (min. 100 Mbps) and 16-bits. So theoretically, you could have up to 65,535 possible sub interfaces but this is not practical.

@Ronnie-Wong Hii Sir,
Thanks for replying. But I have some more doubts now.
Should I remember the theoretical number of possible sub interfaces to be 65,535 for any type of NIC? Also, how did you derive that number which is 65,535? Also, did you mean that we need to have a minimum speed of 100 Mbps to configure sub-interfaces? And what are those 16 bits?

Also, then referring to my original post in this thread where I have posted the image of the network diagram, all of those 4 subnets could be configured using 1 NIC also right? Then why did @wes-bryan Sir said that we will minimum need 2 NICs? Was there a reason behind it? The top limit is 65,535 right??

Thanks.

Here is information from Cisco on the specifics; https://www.cisco.com/c/en/us/td/docs/routers/access/800M/software/800MSCG/routconf.html

@Ronnie-Wong @wes-bryan,
Also, Is it mandatory to have 'x' VLANs if we have 'x' switches under a router?

@Atharva-Bet said in Doubt in a Network Diagram:

@Ronnie-Wong Hii Sir,
Thanks for replying. But I have some more doubts now.
Should I remember the theoretical number of possible sub interfaces to be 65,535 for any type of NIC? Also, how did you derive that number which is 65,535? Also, did you mean that we need to have a minimum speed of 100 Mbps to configure sub-interfaces? And what are those 16 bits?

the interface configuration for sub-interfaces happens on software. It is not based on a hardware limitation. So any type of NIC will do, usually this is implemented on routers, as in Wes's example.. Because it is done in software, the limitation on devices that would allow you to do sub interfaces was probably programmed in 32 bit. So the interface configuration takes some bits, and there was an arbitrary decision to make the number of possible subterfaces 16 bits = 65,536 (corrected, I forgot that you can assign 0 as a sub interface).
There is a practical limitation of how much data you can send down the interface. When you create sub-interfaces you will hit that limitation faster because there is additional overhead. There were routers that had 10 Mbps interfaces, though you can create subinterfaces on them. They will operate poorer.

Also, then referring to my original post in this thread where I have posted the image of the network diagram, all of those 4 subnets could be configured using 1 NIC also right? Then why did @wes-bryan Sir said that we will minimum need 2 NICs? Was there a reason behind it? The top limit is 65,535 right??

Yes and no. Though you can use sub interfaces there is fact that it is still a single port physically. This means it only plugs into a one device. This means you must understand more but it will not help you on the network + level. To find out more, you may want to think about taking a look into our Cisco CCNA show as well. This will help introduce you to some of these concepts.

I'm assuming that Wes was directly referring to his example in the show.

Thanks.