I know there are two platforms in any networking device separating the control packets from the traffic, which I call control plane and data plane. My question is, how does the control packets enter the router? Is it through the data plane or they enter the control plane directly? Since the interfaces are all part of the data plane, I am bit confused here.

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    The control and data planes are just imaginary concepts. See this answer for more information. – Ron Trunk Oct 23 '20 at 16:08
  • sure, but there should be a way for a switch/router to know if that's a control traffic or data traffic right? Is there an algorithm to identify this in the networking software? – Rakesh Nittur Oct 23 '20 at 16:19
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    Control traffic uses different protocols than IP, so it's quite easy to tell. Also, control traffic is usually addressed to the router itself. – Ron Trunk Oct 23 '20 at 16:23
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    Again, there's no "control plane" process or "forwarding plane" process. Those are just abstract concepts. – Ron Trunk Oct 23 '20 at 16:26