"URL" is the alphanumeric address, like
www.yoyoyo.com/yo/123.htm, which translates into a specific IP of the server or the router in question, by going through a domain name server (?). Or, actually, in the example above, the URL would translate to an IP for
www.yoyoyo.com through likely a domain name server of your ISP's, which would send the request to yoyoyo.com's server, which would further internally route it to the /yo/123.htm webpage.
i think
try running the ping command for a domain name and it will resolve it to it's IP.