ministrative distance (see AD) allowing MTU path discovery administrator tag, 144 packets, 333 advertisement requests, 46 allowing outbound traceroute and age of a route, 97 ping, 332 aged out information in route cache, 187 application points for ACLs, 324 AIS (alarm indication signal), 279 most-used lines at beginning, 327 alarms naming ACLs, 326 DS3, channelized DS3, 297 top-down processing, 326 T1, 276-279 Turbo ACLs, 331 blue alarm (AIS), 279 using groups in PIX ACLs, 328-331 red alarm, 277 wildcard masks, 323 yellow alarm (RAI), 278, 285 function of each entry, 172 "Algorhyme", 67 GRE and, 161 alpha-geek syndrome, 542 IP address space allocation and, 492 AMI (Alternate Mark Inversion) in multilayer switches, 334-337 encoding, 270 configuring port ACLs, 334 DS3 links, 292 configuring router ACLs, 335 analog and digital, 254 configuring VLAN maps, 336 ARAP (AppleTalk Remote Access PIX firewall, using object groups for Protocol), 357 complex lists, 372-375 area border router (ABR), OSPF, 121 reflexive access lists, 338-342 ARP (Address Resolution Protocol), 12 configuring, 340-342 changes to ARP table, route cache active mode (LACP and PAgP), 60 and, 187 active PIX firewall, 378 use in Ethernet networks for MAC failure of address to IP address mapping, 302 switching roles with standby PIX, 382 ASBR (autonomous system border router), forcing standby PIX to become, 383 OSPF, 121 saving configuration changes to ASE (autonomous system external) standby, 389 LSAs, 122 active routers, 164 ASN (autonomous system number), 104 replacement by standby router, 166 EIGRP configuration, 117 ACTS (Automated Computer Time prefixed onto autonomous system path in Service), 511 BGP, 127 AD (administrative distance), 108 redistribution of IGRP routes from, 135 EIGRP and OSPF, redistributed ATM (Asynchronous Transfer Mode) routes, 142 networks, 3 internal VS. external routes, 105 atomic clocks, 507 listed in example routing table entry, 97 authentication, 343-360 redistributed routes, 136 AAA (Authentication, Authorization, and ro