I think I have a misconfiguration. I'm trying to explain to myself how that could be true, yet, I'm still able to to telnet into a misconfigured router (BGP, PPP)

Here's a link to a crudely drawn topology (with shortened subnets) that will be helpful to look over before reading the rest of my post: https://imgur.com/a/isrKF

tl;dr: I can telnet from 16.1 to 100.2. I'm trying to explain why this is possible, if this misconfiguration or accidental cable swap actually exists. And I'm almost 100% certain it exists.

Does this make any sense to you guys? I left work troubled with this problem because so much didn't make sense when I was working on it. I might be trying to fit a square peg into a round hole, but after thinking about this for hours, I'm almost certain that the misconfiguration depicted in my topology is the current layout of the network. And I'm trying to explain to myself why I am able to telnet into R1 if this misconfiguration exists.

I have shortened and sanitized the IPs (to 2 octets) in the topology I provided to make it easier to look at. There are 3 "subnets", 100.0/8, 200.0/8 and 16.0/8.

The 16.1 host can telnet into 100.2 host when clearly there is a misconfiguration.

I discovered this when I tried to bounce the 200.1 port thinking I was safe from disconnecting my telnet session. When I bounced it, I lost my telnet session. That's when (i think) I realized that the 200.1 port was actually the edge port, despite fully expecting 100.2 to be the edge IP. Luckily I had a tech onsite to power cycle the router and reload the startup config. Thinking I made a mistake and losing remote access, I did not pursue that any further. (until I left work and thought about it more_

But after thinking about all of the other troubleshooting I did, I have come to the conclusion that either the port configuration is ass backwards inside the router, or the LAN/WAN cables got swapped somehow. Now I just need to explain to myself how, if that is the case, that I am able to telnet into the device. (see topology for my explanation and tell me if it makes sense to you)

BTW, I did extensive troubleshooting with tech onsite. I was in R1 and unable to ping tech's laptop connected directly to interface 0/1. I had the tech statically configure his laptop to the 200.0 network, as it would normally supposed to be configured in this scenario. Looking back, I wish I would have had him configure his laptop to the 100.0 network.

tl;dr: I can telnet from 16.1 to 100.2. I'm trying to explain why this is possible, if this misconfiguration or accidental cable swap actually exists. And I'm almost 100% certain it exists.