I am familiar with trunk ports (switchport mode trunk) and access ports (switchport mode access), but what is the proper term for a port that does not have a switchport mode command? It wouldn't be a trunk port or a switchport so do you just call it a port?

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    It is an access port unless it negotiates a trunk with DTP, so it depends on what is plugged into it. – Ron Maupin Apr 1 '16 at 19:27

In the context of switch ports, any port that has no explicitly stated mode is using the default (access). In the context of non-switch ports, we don't call those "ports"; we call them "interfaces" -- short for routed interface.

(Yes, you'll find port and interface used interchangeably.)

  • Yes, I meant in the context of switch ports. Thank you for the clarification. – user5870571 Apr 1 '16 at 19:46
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    I have to disagree with the definition/distinction provided between port and interfaces. Even in Cisco Catalyst 1900, you configure interfaces, you show interfaces, etc. It is really only in the context of CatOS that interfaces were designated as ports. Rather than making this sound like a established industry distinction (which I haven't found basis for nor see referenced in your post), it is more a matter of vendor/developer/personal preference. – YLearn Apr 7 '16 at 22:42
  • Cisco (CLI) calls everything an interface; that's just configuration language. When people talk about the holes on a switch, they use the word port. When people talk about the various connectors on a router, they use the word interface. I've worked with this stuff for decades, with people all over the world, in various languages, and that's the way we talk. – Ricky Apr 8 '16 at 0:26
  • (ps: most documentation these days is generated by tech writers - not engineers or technicians, or anyone who actually uses the technology. That's why most vendor docs are of lower quality ("crap") today. Even once mighty Cisco's docs are a shadow of what they used to be.) – Ricky Apr 8 '16 at 0:36
  • I wonder if it is wise to mention that the default mode when one isn't set is vendor dependent. Cisco switches default to using DTP (dynamic auto), which might make the port an access port or might make the port a trunk port. Non-Cisco switches (who can't use Cisco proprietary DTP) typically default to access. – Eddie Apr 8 '16 at 16:29

You could call it either an interface or port.

You will sometimes hear people try to create distinct meanings for the two terms. For example that "port" is hardware (i.e. where you connect the cable) and "interface" is software. Or perhaps port is L2 and interface is L3/routed.

The reality is that to my knowledge, the terms "port" and "interface" really do not have a clear distinction industry wide. When and how they are used in my experience seems to depend largely on personal preference and background (i.e. which vendors/platforms you are familiar with, environments in which you have worked, etc).

Cisco of today generally seems to try to use the term "port" when referring to the "hardware entity" and "interface" when referring to a "logical entity" such as you will find in this example. However in the past they have used the two terms a bit differently, such as the use of port in CatOS. When it comes to calling something a "trunk port" or an "access port", you are really calling out the difference in the mode of operation.

There is only one context I can think of in which I know I have always seen a very consistent use of these two terms industry wide. When referring to a passive connection point (such as on the wall behind your desk or on a patch panel), always use port and never interface. However, to keep it confusing, passive connection points may also be referred to as a jack, socket, or outlet as well.

  • I find it interesting that people commonly refer to a socket as a jack. The original terms, jack and jill, referred to the gender (male and female) of the connectors. Based on that, a socket shouldn't be a jack. It's one of those things that was lost between generations. – Ron Maupin Apr 7 '16 at 23:40
  • @RonMaupin, totally agree. I personally seldom use the term jack, but I hear it commonly enough. I guess it could be argued that the "wall jack" for Ethernet is the male component, since the male/female distinction is generally made based on the metal conductors and with Ethernet it is the wall portion that inserts the conductors into the slits in the cable portion. – YLearn Apr 7 '16 at 23:44
  • Based on that, I suppose one could argue that all 8P8C connectors are jacks, since neither type has female metal conductors. I think I always refer to "wall sockets" or "outlets". It works equally well, with the proper distinction, for power, network, and phone, and just about everyone understands it, even the technically-challenged. – Ron Maupin Apr 8 '16 at 0:21
  • Or if you deal with regulatory docs (NEC), it's plug and receptacle. :-) Or DTE vs. DCE (which is actually how pins are arranged.) – Ricky Apr 8 '16 at 0:32

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