I am currently studying for my CCNA exam and I am stuck at the concept of DLCIs in a network using frame relay encapsulation. This may be because I am a non native english speaker and misinterpret the material I have got.
This is the text in question:
VCs provide a bidirectional communication path from one device to another. VCs are identified by DLCIs, as shown in Figure 2. DLCI values typically are assigned by the Frame Relay service provider. Frame Relay DLCIs have local significance, which means that the values themselves are not unique in the Frame Relay WAN. A DLCI identifies a VC to the equipment at an endpoint. A DLCI has no significance beyond the single link. Two devices connected by a VC may use a different DLCI value to refer to the same connection.
Locally significant DLCIs have become the primary method of addressing, because the same address can be used in several different locations while still referring to different connections. Local addressing prevents a customer from running out of DLCIs as the network grows.
Which has a picture for reference:
The VC (virtual circuit) spans from the Sending node (DLCI 102) to the receiving node (DLCI 201). It then states that DLCIs have 'local significance', and are not unique in the Frame Relay WAN.
My question is: Since a DLCI is local, what device is meant by 'endpoint'?
- Does a DLCI(102) define a link from
- Does a DLCI(102) define the link from
Receiving Node(SN -> A -> B -> C-> D -> Receiving Node) ?
In the end it boils down to: Is the single link mentioned in the text, the single physical line between the router and the switch or the line between the 2 ultimate endpoints?