Index_D

D

D channel, 234, 537

data communication equipment (DCE), 537

Frame Relay and, 238

Data Country Code (DCC), 537

data direct VCC, 536

data encapsulation, 36–37, 37, 542

at Data Link layer, 33–34

Data Exchange Interface (DXI), 540

data frames, 7

802.3 Ethernet, 30

elements of, 30–31

Ethernet II, 30

data-link connection identifier (DLCI), 238, 239, 539

data link control layer, 537

Data Link layer (OSI), 29–34, 537

Logical Link Control sublayer, 31–32, 32

MAC sublayer, 32–33

WAN protocols, 33–34

data service units (DSUs), 11, 540

data set ready (DSR), 540

data terminal equipment (DTE), 540

Frame Relay and, 238

data terminal ready (DTR), 540

databases

MAC, forward/filter table, 75, 75–77

for NLSP, 377

in OSPF, 357

route, in EIGRP, 334

synchronization, 363

topology, 322

in EIGRP, 334

Datagram Delivery Protocol (DDP), 537

datagrams, 23, 536

DCC (Data Country Code), 537

DCE (data communication equipment), 537

Frame Relay and, 238

DDP (Datagram Delivery Protocol), 537

DDR (Dial-On-Demand Routing), 205,236, 537

in case study, 509

DE (Discard Eligible) bit for Frame Relay, 242

de-encapsulation of data, 37, 37

dedicated leased lines, 220, 220

default route, 537

delay, 538

in voice transmission, 494–495

demarc, 538

demilitarized zone (DMZ), 480–481, 539

demodulation, 538

demultiplexing, 538

denial of service, 538

denial of service (DoS) attacks, 484

real world scenarios, 484–485

design

methodology, 160–162

in PDIOO methodology, 156

pilot or prototype project, 462–465

design document

exam essentials, 466, 466–467

preparation, 458–462

appendixes, 461–462

design requirements, 460

design solution, 460–461

executive summary, 459–460

summary, 461

designated bridge, 538

designated port, for Spanning-TreeProtocol, 85

designated router, 538

in link-state routing, 323

in OSPF, 357, 359, 362–363

destination address in data frame, 30, 538

destination service access points (DSAPs),31, 539

DHCP (Dynamic Host Configuration Protocol), 412, 538

Dial-On-Demand Routing (DDR), 236, 537

in case study, 509

dialer-group command, 237

dialer-list command, 237

Diffusing Update Algorithm (DUAL), 540

Digital Network Architecture Session Control Protocol (DNA SCP), 21

digital subscriber line (DSL), 243–244, 538

Dijkstra’s algorithm, 323, 367

discontiguous addressing, 278, 539

discovery mode, 539

distance ospf command, 368

Distance Vector Multicast Routing Protocol (DVMRP), 540

distance-vector protocols, 539

routing algorithm vs. link-state routing, 324, 367

scalability limitations, 315–316

update intervals for, 318

distribute-list command, 342

distributed denial of service, 484–485, 539

distributed switching, for WANs, 227

Distribution layer, 539

distribution layer, in hierarchical network, 195–196

DLCI (data-link connection identifier), 238, 239, 539

DMZ (demilitarized zone), 480–481, 539

DNA SCP (Digital Network Architecture Session Control Protocol), 21

DNS (Domain Name System), 539

DOD (Department of Defense) model, 120–121

exam essentials, 142–143

Host-to-Host layer protocols, 124–127

Internet layer protocols, 127–129

Network Access layer protocols, 129–131

vs. OSI model, 121

Process/Application layer protocols,122–124

Domain Name System (DNS), 539

DoS (denial of service) attacks, 484

real world scenarios, 484–485

downtime, 539

information gathering about, 164

DSAP (Destination Service Access Point), 539

DSCP, 539

DSL (digital subscriber line), 243–244, 538

DSR (data set ready), 540

DSU (data service unit), 540

DTE (data terminal equipment), 540

Frame Relay and, 238

DTR (data terminal ready), 540

DUAL (Diffusing Update Algorithm), 540

dual attachment stations in FDDI, 41

dual homing, 41

dual-stack migration strategy, 296

dumb terminals, 3

DVMRP (Distance Vector Multicast Routing Protocol), 540

DXI (Data Exchange Interface), 540

dynamic addressing, 540

Dynamic Host Configuration Protocol (DHCP), 412, 538

dynamic routing, 540

dynamic VLANs, 96