Question : ip address , msn messenger

I have subscribed to a cable internet and I got 192.168** address, which sounds like my network is behind a router.I have asked the cable company to give an IP which is visible externally, but he says he can not give.Now the real problem is my MSN messenger or AOL messenger does not work under this situation , no voice , no picture, but chat is ok.However Yahoo messenger works both voice &video.
Is there a way under this scenario to make MSN/AOL working?Becasue Yahoo messenger does not give good voice quality compared to MSN/AOL?Also can somebody tell me what is difference between these messengers?

Answer : ip address , msn messenger

You can see if your ISP has the ability to enable UPnP. If they can then you should be able to install the latest version of MSN and do video and audio.

Otherwise you are out of luck. Your ISP has oversold its IP addresses and has implemented their own NAT to compensate for the shortcoming. Looks like you are stuck with Text.