Serial DTE/DCE connection between routers in real life

[TomCom01]

Hi, I'm currently studying for the ICND1 CCENT exam. I'm reading Wendell Odom's official cert guide. In Chapter 3, he wrote that a serial connection with a DTE and a DCE cable can be used for a lab. However, is there an application in real life, too? I know that in real life a CSU/DSU sets the clock rate, hence it is the DCE, isn't it? Nevertheless, is there any use for a serial connection with a DTE/DCE cable in real life, too or is it just for lab?

Thanks for support!

[Georg Pauwen]

Hello,

I guess you are right, the serial DCE/DTE cable is used in labs, in order to configure two routers back to back, and in order to simulate a WAN connection. I have never seen it in a real, live network, it wouldn't work well anyway since you are limited by the length of the cable (3meters max as far as I remember).

That said, serial connections (if you exclude the high speed HSSI links which support speeds up to 52MB) themselves have become rare, since they only support speeds of 4MB max.

[TomCom01]

Thanks, I think I understand this now. However, external CSU/DSUs are connected via a serial cable to the router in real environments, aren't they? So, support this link just 4MB, too?

[Georg Pauwen]

Hello,

a very long time, let's say 15 years  ago, a T1 (1,5MB) was considered an ultra high speed connection. Nowadays you get 100MB to your home for 30 dollars a month. I haven't seen a serial connection in a real, live environment for ages. The technology is completely outdated, similar to frame relay. 4 to 6MB was max indeed...