S0/0/0 vs S0/0 vs S0

[Larissa H]

Hello All

I am studying for the CCNA just to give you an idea of my current knowledge level.

What I know:

S0/0/0 = Serial: Module Slot 0 / Interface Card Slot 0 / Port 0

What I am confused on:

When you see S0 or S0/0 - which slots are removable and which take priority? What does S0 and S0/0 translate to?

AND

Are serial interfaces used only on routers?

[Richard Burts]

Your questions are reasonable "beginner" questions. And we were all beginners at some point. I hope this community will be helpful as you increase your understanding of networking.

I have learned to be careful about answers that present absolutes. So I am not going to say that the only devices that support serial interfaces are routers. I will say that I am not familiar with any device supporting serial interfaces that is not a router.

As for your question "What does S0 and S0/0 translate to?" there are multiple ways to identify interfaces and they frequently reflect the age and complexity of the architecture of the device. In many of the earlier (and more simple architecture) devices you might have interfaces Ethernet 0 and Ethernet 1 and Serial 0 and Serial1. You only need to identify interface type and an order identifier (order frequently based on which was closer to the power supply. As architectures got more complex you might need to identify a slot and an order identifier such as Serial0/0 and Serial0/1.

[Larissa H]

Hey, Richard

Thanks for the prompt reply!

Just to clarify..

If I see "S0/0" (the zeros representing any numerical value), do I assume there isn't a port, interface card slot, or a module slot? 

And if I see "S0" do I assume there is only a port, interface card slot, or a module slot? I believe this would be simply the module slot of the serial label.

Thanks!