Question : IP Configuration settings for T1 line on my Router

I have a new T1 line from Speakeasy installed and ready to go, but I don't know how to setup my TP-LINK TL-R480T+ router for the T1 I line. I'm having trouble interpreting the IP configuration details that speakeasy gave to me. I'm not sure if it's "safe" to post specific details about my IP configuration, so I'm censoring out those details, but will provide them if necessary/

Here's what speakeasy told me to use:

Your WAN IP is: aa.aa.aa.aaa
Your WAN Subnet Mask is: 255.255.255.0
Your LAN IP is: bb.b.bbb.b
Your LAN Subnet Mask is: 255.255.255.240
The broadcast address for your /28 block is bb.b.bbb.31.
Your last usable IP address will be the IP before the Broadcast address.


But on my router, I only have the ability to enter settings for:
IP address:
Subnet mask:
Default Gateway:


And I'm not sure which settings to use. I'm especially confused as to the difference between WAN ip and LAN ip -- I'm assuming WAN ip is what "the rest of the internet" sees as my IP address, so then what's the point of the LAN ip for my internal network? I'm already using DHCP so maybe the LAN ips are unnecessary for my network... if someone could please explain that I'd appreciate it.

Basically what I need right now is correct router settings (for the above fields), and if somebody's feeling especially generous with their time, a clarification on what the difference between WAN / LAN ips are and an example of usage.

Thanks!

Answer : IP Configuration settings for T1 line on my Router

>1. T1 is already connected to CPE, getting green lights and all that.
Perfect

>2. WAN: so this is NOT what I should be putting into my router. got it.
Correct, this would be the addressing scheme for the P2P T1 from you to the ISP

>3. LAN: I have no idea what magic you used to guess .17 as my speakeasy-supplied lan octet, but you're correct.
you stated "The broadcast address for your /28 block is 72.1.bbb.31."
and you provided the subnet mask of 255.255.255.240, which is 16 addresses in that block (16-31).
We know that we can not use 16 or 31, so the next available would be .17

>4. I don't know what a "bridge connection" is -- the T1 line goes straight into the speakeasy-provided T1 router (Speakeasy instructed me to just plug the T1 into P0, no config required), then from ETH0 into my TP-Link router. So maybe .18 is the IP I need to be using on my TP-Link Router's WAN page.

Possibly, not sure why they gave you .17 and not the IP for the default gateway

5. That leaves out gateway -- do I not need to input a Gateway address on my Tp-link router?

Yes you would need a gateway, I would talk to speakeasy to get clarification on that, but it appears that they might have used .17 on their side of the CPE router and you would use .18 and your default gateway would more than likely be .17

Billy