L2TP, 578
multiprotocol backbone, 310
SDLC into DLSw+, 479
single-protocol IP backbone, 310
STUN (Serial Tunneling), 336, 482
transport protocols, 483, 485
versus XOT, 338
two-tier model, 20, 26
two-way alternation operation (SLS), 458
two-way simultaneous operation (SLS), 458
two-way trusts, 276
two-wire leased lines, 391
two-wire local loop, NT1, 394
Type 1 LSAs, 221
Type 2 LSAs, 221
Type 3 LSAs, 221
Type 4 LSAs, 221
Type 5 LSAs, 222
Type 7 LSAs, 222, 229
UAAs (universally administered addresses), assigning,
U-frames (SDLC), 459
UNIs (user-to-network interfaces), 122
units of measurement, voice traffic, 622
Unspecified Bit Rate (UBR), 119
updates
SAPs, 268
UPSs (uninterruptible power supplies), implementing,
Variable Bit Rate (VBR), 119
variable-length subnet masking.
VBR (variable bit rate), 119, 605
VCI (Virtual Channel Identifier), 117
VeriSign, Inc, 576
VIP (Versatile Interface Processor) cards
OIR, 366
virtual nodes, 493
virtual routes, 446
VLANs, 91
enterprise server placement, 51
network infrastructure, 52
traffic patterns, 50
resiliency, 53
scalability, 55
security, 54-55
total cost of ownership, 54
deploying, 93, 95
VoATM
delay, 606
routing, 606
signaling, 605-606
signaling, 607
analog signaling, 598-599
dial plans, 601-602
CoS groups, 603