Subtitles of the Movie

There is another form of encapsulation, which is called HDLC, which stands for High Level Data Link Control. And there have actually been a couple of different HDLC's, there was the original HDLC, which was a CISCO proprietary protocol, and was adopted as an ISO standard. But the high level data link control encapsulation would only support one protocol within it. There is an enhanced HDLC, which supports multi-protocol point-to-point connections. And so typically these days when we say HDLC, and when we talk about the fact that the default encapsulation type between two CISCO devices using synchronous serial point-to-point links is HDLC, we are really talking about the enhanced HDLC. So, it's just important to understand that HDLC is a proprietary protocol. We don't need to set interfaces out of the box to HDLC; if they are serial interfaces that are point-to-point to another location, they will be HDLC. Now, if they have been set to Frame or if they have been set to PPP and then we want to match them up for the other side, then we would use the encapsulation command, and set them back to HDLC. So there could be a test question about the fact that do you need to set the default, in other words, is the default setting HDLC, and yes it is. But it is possible then to change an interface which is set to a different encapsulation type back to HDLC. So it stands for high-level data link controls, the default encapsulation type between two CISCO devices used with synchronous serial data links. And the enhanced version supports multi-protocol point-to-point connections between CISCO devices. If we are using other than CISCO devices, we are not going to be using the HDLC protocol. We are going to be using PPP or some other protocol. So, it's important to understand Wide Area Network Protocols, and the way that networks communicate with each other is by sending packets back and forth to each other. Well, that whole process is called routing. So, in our next chapter, we will discuss routing. That's next. So, in our next chapter, we will discuss routing. That's next.