PPP Frame Relay and Static Mapping

altjx

Okay, I think I could be misunderstanding something but would like someone's opinion.

I originally chose A for my answer, but the answer was AE. Why would the frame-relay interface-dlci static mapping command need to be used when moving from a physical interface to a point-to-point subinterface? The text states that point-to-point subinterfaces do not need to use DLCI static mapping.

advanex1

I've always been taught that on any point-to-point subinterfaces that it needs a frame-relay interface-dlci command to tell the router that the specific DLCI goes there. It can learn the mapping via inverse arp or with the way that point-to-point links work, it basically assumes if it's not for me, then it must be for you and sends it out. Basically the frame-relay interface-dlci assigns the pvc to that link.

Here's some text from cisco press,

"On point-to-point subinterfaces, the destination is identified and configured with the frame-relay interface-dlci command beginning in interface configuration mode. When configured on a point-to-point subinterface, the command associates the selected point-to-point subinterface with a DLCI. The command also allows users to select the type of Frame Relay encapsulation to be used on the specific VC"

"On point-to-point subinterfaces, you do not need to use the frame-relay map command to perform static address mapping, because it is always assumed that the end point of the point-to-point connection automatically resides on the same subnet as the start point. It is also not required to enable or disable Inverse ARP, because there is only a single remote destination on a point-to-point PVC and discovery is not necessary."

I think you may have gotten the two mixed up. Like I said, I've always understood the frame-relay interface-dlci to be the command you run on point-to-point subinterfaces. Feel free to correct me if I'm wrong.

altjx

advanex1 wrote: »

I've always been taught that on any point-to-point subinterfaces that it needs a frame-relay interface-dlci command to tell the router that the specific DLCI goes there. It can learn the mapping via inverse arp or with the way that point-to-point links work, it basically assumes if it's not for me, then it must be for you and sends it out. Basically the frame-relay interface-dlci assigns the pvc to that link.

Here's some text from cisco press,

"On point-to-point subinterfaces, the destination is identified and configured with the frame-relay interface-dlci command beginning in interface configuration mode. When configured on a point-to-point subinterface, the command associates the selected point-to-point subinterface with a DLCI. The command also allows users to select the type of Frame Relay encapsulation to be used on the specific VC"

"On point-to-point subinterfaces, you do not need to use the frame-relay map command to perform static address mapping, because it is always assumed that the end point of the point-to-point connection automatically resides on the same subnet as the start point. It is also not required to enable or disable Inverse ARP, because there is only a single remote destination on a point-to-point PVC and discovery is not necessary."

I think you may have gotten the two mixed up. Like I said, I've always understood the frame-relay interface-dlci to be the command you run on point-to-point subinterfaces. Feel free to correct me if I'm wrong.

Thanks for the input. Are those from two different sources? I thought the frame-relay map and the frame-relay interface-dlci performed pretty much the same functions? What exactly is the difference?