Index E

D

D Channel, 481

data communications equipment (DCE), 480-481

Data Country Code (DCC), 480

data direct VCC connection, 480

data encapsulation

defined, 480

in OSI model, 11-12, 11

Data Exchange Interface (DXI), 483

data frames, 480

Data Link and Medium Access Control (DLMAC) group, 47

Data-Link Connection Identifier (DLCI), 482

data link control layer, 480

Data Link layer, 12, 480

Data Service Units (DSUs), 483

Data Set Ready (DSR) circuit, 483

data terminal equipment (DTE), 483

data terminal ready (DTR) circuit, 483

databases in layer 2 switching, 137

Datagram Delivery Protocol (DDP), 481

datagrams, 480

DCC (Data Country Code), 480

DCE (data communications equipment), 480-481

DDP (Datagram Delivery Protocol), 481

DDR (dial-on-demand routing), 481

DE bit, 481

DE (Discard Eligibility) field, 481

debugging, 257, 421-422

default gateways, 218-219

default priority for root bridges, 143

default rendezvous points, 324

default routes, 481

defense in depth concept, 29

delays

in best efforts networks, 356-357

with BPDUs, 144, 163

defined, 481

in process switching, 266

in voice transmissions, 352-353

delivery management for multicasts, 306

Reverse Path Forwarding for, 306-307

routing protocols for. See routing protocols

Time to Live for, 307-308, 307

Demand-Base Switching, 420

Demand Priority Access Method (DPAM), 50

demarc points, 481

demodulation, 481

demultiplexing, 481

denial-of-service (DoS) attacks, 481

dense-mode option, 320

description command, 67

designated bridges, 481

designated ports

defined, 482

in spanning tree operation, 142, 145

designated roots, 152

Designated Routers (DRs)

defined, 482

in OSPF, 310

desirable option

in PAgP, 186

for trunk ports, 104

destination addresses, 482

Destination-IP flow masks, 259

Destination Service Access Points (DSAPs), 483

deterministic paths, 9

dia parameter, 168

dial backup, 482

dial-on-demand routing (DDR), 481

differentiated services, 482

Differentiated Services Code Points (DSCPs), 360

DiffServ (Differentiated Services) model, 359-361, 359-360

Digital Equipment Corporation, Intel, and Xerox (DIX) consortium, 47

Digital Subscriber Line (DSL), 483

Dijkstra algorithm, 148digital waveforms, 482

directed broadcasts, 482

disabled state in spanning tree operation, 146

disabling

MLS, 250-252

spanning tree, 150

Discard Eligibility (DE) field, 481

discard eligible packets

in best efforts networks, 358

defined, 482

discovery in MLSP, 245-247, 246

discovery mode, defined, 482

DISL (Dynamic ISL), 103

distance limitations

in 10BaseT networks, 49

in campus networks, 5

in FastEthernet, 52

Distance Vector Multicast Routing Protocol (DVMRP), 317

defined, 483

for multicast delivery, 308, 309

distance-vector routing algorithm, 482

distribute lists, 482

Distributed Forwarding Cards, 420

distribution layer

defined, 482

full-duplex Ethernet in, 51

in hierarchical model, 19

switches for, 21

distribution trees, 302-305, 304-306

DIX (Digital Equipment Corporation, Intel, and Xerox) consortium, 47

DLCI (Data-Link Connection Identifier), 482

DLMAC (Data Link and Medium Access Control) group, 47

DNS (Domain Name System), 482

domains in VTP, 107

assigning, 253-254

configuring, 114, 117, 118

passwords for, 114

DoS (denial-of-service) attacks, 481

DPAM (Demand Priority Access Method), 50

DRs (Designated Routers)

defined, 482

in OSPF, 310

DS field, 360

DSAPs (Destination Service Access Points), 483

DSCPs (Differentiated Services Code Points), 360

DSL (Digital Subscriber Line), 483

DSR (Data Set Ready) circuit, 483

DSUs (Data Service Units), 483

DTE (data terminal equipment), 483

DTP (Dynamic Trunking Protocol), 103

DTR (data terminal ready) circuit, 483

DUAL (Diffusing Update Algorithm), 483

dual cores, 25, 26

duplex command, 69, 458

duplex configuration, 68-69

DVMRP (Distance Vector Multicast Routing Protocol), 317

defined, 483

for multicast delivery, 308, 309

DXI (Data Exchange Interface), 483

dynamic entries, 483

Dynamic ISL (DISL), 103

dynamic routing, 483

Dynamic Trunking Protocol (DTP), 103

dynamic VLANs

assigning switch ports to, 94

defined, 483