triggered updates, 418, 422
triggered updates (loops), 372
Trivial File Transfer Protocol, See TFTP
troubleshooting
loops, 418
routes when there are multiple routes to the
trunks
status, displaying, 188
verifying configuration, 191193
VLAN pruning, 196
tunnel destination command, 413
tunnel interfaces, 409
tunnel mode command, 413
tunnel source command, 413
tunneling, 409
configuration, 412413
encapsulation protocol, 410
justification for, 411
operation of, 410411
passenger protocol, 410
transport protocol, 410
VPNs, 411412
UAAs (Universally Administered Addresses), See
DNS, 224
functions of, 224226
headers, 225
multiplexing, 224
NFS, 224
versus TCP, 224226, 317
unicast MAC addresses, 138
Universally Administered Addresses (UAAs), See
User Datagram Protocol, See UDP
user EXEC mode (IOS CLI), 2930, 34, 56
V.35 WAN interface standard, 599
variance command, 374, 395, 419
VCs (virtual circuits), 97, 530, 599
Frame Relay status, displaying, 697
See also DLCIs, SVCs, PVCs
virtual private networks, See VPNs
vlan command, 188
VLAN Membership Policy Server (VMPS), 171
VLAN tagging, 175
VLAN Trunking Protocol, See VTP
vlan-membership command, 188
VLANs (virtual LANs)
configuration
on a single switch, 188190
on multiple switches, 190193
defining, 188
efficiency of, 172
function of, 171173
implementing
in multiple switches, 174175
membership, displaying, 188
naming, 188
network changes, facilitating, 173
numbering, 188
parameters, verifying, 190
pruning, 196
enabling, 198