A user of a home telephone picks up her phone and makes a telephone call to a friend’s home telephone in another part of town. Which of the following is likely to be true about this call? A. It uses a single pair of wires on the local loop at each end of the call 2. Which of the following are services that telcos have offered as WAN services over the years? A. Switched analog circuits B. Dedicated digital circuits 3. This chapter claims that IP routers work well as devices that connect to many different types of interfaces, including LANs and WANS.
Which of the following answers list the reasons why routers do well in this role? A. Routers have much faster CPUs and can do the hard work to translate the incoming datalink header into the outgoing data-link format D. Routers discard old data-link headers and insert new data-link headers as part of their logic, which treats each Interfaces lower-layer detallds as Independent from each other 4. An enterprise network has many routers that connect to both a LAN as well as the WAN. Which of the following statements best describe how routers typically use and think about their WAN connections?
B. As a transport service to deliver IP packets to the next Ip router 5. An enterprise builds a WAN design on paper. The main site, where all the servers sit, is shown in the center ofa network diagram. The WAN has a leased line from that site to every remote site, with the remote sites drawn around the edges of the drawing In a big circle. None of the remote sites have a leased line directly between them. Which of the following terms is most typically used to describe this WAN topology? D. Hub-and-spoke 6. A U. S. based company wants to order a leased line between two sites, with the eased line using the traditional T-carrier DSO, DSI, and DS3 types of lines. Which of the following answers describes the speed and distances for the leased line? A. No faster than 43,736 Mbps (T3) D. No literal distance Ilmltatlon 7. A telco customer has purchased a Tl leased line between two sites. The customer has already bought a router for one site, with a serial interface card with a built-in CSU/DSU. Which of the following answers lists other physical parts that the customer will need for that sites installation of the Tl leased line?
B. A serial cable 8. A telco customer has a Tl leased line between two sites, called sites A and B. he telco has several switches between sites A and B that use T3 trunks. These switches use the T3 trunks along with time-division multiplexing (TDM) to create the leased line from site A to B. which of the following answers is true about how TDM works in this design? C. The switches map the Tl customer lines to one of 28 different frequencies in the T3 trunks 9. A telco network has TDM switches in the CO, ready to support Tl leased lines to customer sites.
Two such switches have a single T3 trunk connecting the two switches, set aside to support T Is that run Just between those two co swltcnes. nlcn 0T tne Tollowlng answers Dest aescrlDes tne numDer 0T customer T Is the telco can support with these switches and the trunk? C. 28 10. A customer ordered a full Tl leased line between two sites. The telco implemented that leased line in its network using the T-carrier technology discussed in this chapter, with DSI, DS2, and DS3 lines plus switches that use time-division multiplexing (TDM) logic.
Into which of the following general WAN categories does this service fit? B. Packet switching 1 1 . A telco customer orders a leased line between sites A and B, with requested speed of 1. 024 Mbps. The customer plans to use an external CSU/DSU at each site. The telco uses only T-carrier technology and none of the more modern options like SONET, ATM, MPLS, or Metro Ethernet. Which of the following answers is true about the speeds used on this link? B. The physical line between the telco CO and site B uses a line speed of 1. 2544 Mbps 12.
A telco customer orders a leased line between sites A and B, with requested speed of 512 Kbps. The customer plans to use an external CSU/DSU at each site. The telco uses only T-carrier technology and none of the more modern options like SONET, ATM, MPLS, or Metro Ethernet. Which of the following answers is true about the speeds used between the router and the CSU/ DSU? A. THe CSU/DSU controls the router’s sending and receiving speeds using clocking 13. Which of the following answers are true about DSI framing and channels? A. Each frame has 193 bits C.
The frame groups 8 bits together for each of 24 channels, plus overhead 14. Which of the following data-link protocols was created to be used on leased lines, with support for multiple Layer 3 protocols by including a Type field that identifies the type of packet inside the data-link frame? C. PPP 15. Which fields that exist in both the HDLC and PPP headers have such relatively small use in point-to-point leased lines today, to the point that the PPP standards actually allows the nodes to simply not bother to include these fields when sending PPP frames?
B. Address C. Control 16. Think about the differences in a circuit switching the T-carrier system (ignoring analog circuit switching) versus packet switching. Which of the following answers are true about packet switching, but not about circuit switching? B. The telco switch can queue the data waiting on the congested outgoing to trunk to become available D. The switches look at the bits to find an address, and use that address to make a choice where to send the bits 17.
In a Frame Relay network, which of the following terms refers to the customer router that connects to the Frame Relay network? D. Access link 18. Which of the following answers is not true about a Frame Relay network? B. Defined by the telco ahead of time, when the customers orders the service 19. A new Frame Relay customer is considering two competing Frame Relay design for his WAN. One design uses a full-mesh topology of PVCs between the 20 routers. The second design uses a partial mesh that looks like a hub-and-spoke design.
Assuming that all other technical details not mentioned in this question are the same when comparing the two designs, which of these answers are true about the partial-mesh design but not true about the full-mesh design? A. Not all routers can send a Frame Relay frame alrectly to eacnotner B Frame Relay Trames, wlll De Torwaraea Dy tne network Dasea on the DLCI field in the Frame Relay 20. Which two of the following WAN services make good use of protocols that enterprise have used for many years, with those protocols being expanded and enhanced to create new types of WAN services?