cisco ccna in 60 days

cisco ccna in 60 days.DLCI is only confusing if you look at it from a device and network segment perspective. For example, when Router A wants to send data to Router B, it encapsulates the data in a Frame Relay frame and adds DLCI address 200 to the frame header. switch 1 receives the frame, looks at the DLCI address and inbound interface, and compares it to the DLCI exchange table. If it finds a matching entry, the switch gets the DLCI number of the next segment from it, uses it to replace the original DLCI in the frame header, and forwards the frame to the next device. In this example, the DLCI number remains the same, at 200. switch 2 receives the frame from switch 1, performs the same process, and realizes that it needs to forward the frame to router B; to do so, it must change the DLCI number in the frame header to 201. o When router B receives the frame, it also looks at the DLCI address in the frame header. After seeing that the DLCI address is 201, Router B knows that the frame originated at Router AoAt first glance, this process is confusing. To make it easier to understand, take a look at it from the router's perspective.. Router A is going to Router B with DLCI 200o. Router B is going to Router A using DLCI 201o. When Router C is going to Router A, use DLCI 201oWhen an operator creates a PVC between two sites, it assigns DLCI numbers that you must use to travel from one site to the other. Some DLCI numbers are reserved for management and control. such as DLCI numbers 0 and 1023 for LMI. the reserved DLCIs are 0.15 as well as 1008.1023,DLCI number 16.1007 for data connections.Exam Essentials DLCI is only locally meaningful: the router uses the local DLCI number in the Frame Relay frame header to indicate to which destination peer the frame should be forwarded. The carrier switch is responsible for mapping the DLCI number of the VC between the DTE and the DCE.Network Interconnection and Service InterconnectionAs stated earlier in this chapter, Frame Relay is implemented between Frame Relay DTEs and Frame Relay DCEs. There is no provision for how frames are carried in the Frame Relay operator network, but in most cases, ATM is used at Layer 2o Like Frame Relay, ATM uses VCs, but uses notChapter 25 Frame Relay 687