In the lecture for this week, we discussed the history of the PSTN. In this week’s iLab, let’s examine the PSTN in a bit more detail, because it will not be going away anytime soon despite the increasing use of cellular telephones and VoIP. Keep in mind that at some point, cellular calls and VoIP traffic cross this same old PSTN. Data traffic from large organizations must continue to use landlines, because wireless connections do not have the capacity or the reliability for this.
As the lecture points out, in 1984, the Bell system was broken up into parts. Today, many of these pieces have been reassembled into larger organizations. In its present form, AT&T provides service to about one half of the United States.
In this iLab, you will examine the landline-based data services AT&T can provide to a large business today.
To do this, go to the AT&T website at www.att.com. Websites change over time, but the AT&T website will have a listing for these services somewhere on the home page. Right now, from the AT&T home page, select the menu item that says Business. Under it, select the menu item that says Enterprise Business. On this page, look for Network Services.
The Network Service page will show all of the services that AT&T can provide to a large business to connect their sites to each other, to other organizations, and to their customers. Thinking back to the basic networking courses you have taken, read these service descriptions, and then answer these questions.
1. What is a VPN as you understand it (before reading AT&T’s description)? (5 points)
2. What is a VPN as AT&T describes it? (5 points)
3. What is the difference between a MPLS and an IPSec VPN as AT&T explains it? (5 points)
4. What is metro Ethernet? (5 points)
5. What are SONET ring services? (5 points)
6. Does AT&T offer frame relay? (5 points)
7. Does AT&T offer T-carrier service, also called private line? (5 points)
8. AT&T offers DWDM as a service. What is DWDM? (5 points)