ccna 2 certification exam

ccna 2 certification exam.Mayberry can establish the mapping relationship shown in Example 14-6 in two ways. One uses a static configuration mapping, and the other uses a dynamic method called reverse ARP. The following two subparagraphs explain the details of each option.(1) Reverse ARPReverse ARP dynamically creates a mapping between a Layer 3 address (such as an IP address) and a Layer 2 address (DLCI). The end result of Reverse ARP is the same as IPARP on the LAN: the router establishes a mapping relationship between an adjacent Layer 3 address and the corresponding Layer 2 address. However, the reverse ARP process operates differently from ARP on the LAN. After the VC is enabled, each router announces its network layer address by sending a reverse ARP message on this VC. This process is shown in Figure 14-4.As shown in Figure 14-4, reverse ARP announces its Layer 3 address as soon as the LMI sends out the signal that the PVC is up. The reverse14.2 Foundational Content 295296 Chapter 14 Implementing Frame Relay ARP starts by being informed of the DLCI data link layer address (via an LMI message) and then announces the use of that VC's Layer 3 address. Reverse ARP is enabled under default conditions.l-ARPI Am 199.1.1.1 (IP) -l-ARP I Am 199.1.1.2 (IP)V------------------------------------------------------------------------------------------ Figure 14-4 Reverse ARP ProcessIn Example 14-6, Mayberry shows two different entries in the output of the show frame-relay map command. Maybeny uses reverse ARP to learn that DLCI 52 maps to the next hop IP address 199.1.1.2, and DLCI 53 maps to the next hop IP address 199.1.1.3. Interestingly, Mayberry learns this information from the reverse ARP received by MountPilot and Raleigh, respectively.