ABRs (Area Border Routers), 8
Access layer, 39
Access lists as distribution lists
extended, 32–33
standard, 31–32
Acknowledgment, 10
Active
routes marked as, 19
routes staying, 102–104
Active routes, stuck in, 101–104
AD (administrative distance), 26
Addresses
broadcast, 7
multicast, 5
summarization, 37
Administrative distances, 82–84
Administrative tag, 26
ADs (administrative distances), 82–84
Aggregation, traffic, 38
Algorithm, Diffusing Update, 1
AS (autonomous system), 23
number, 25
ASBRs (Autonomous System Border
Routers), 8
Asymmetrical routing, 57–58
Autonomous systems, multiple, 48–49, 87–89
Backup strategies, dial, 74–76
Bandwidth, 4
Bandwidth consumption, limiting, 12–13
Bandwidth statements, frame relay and, 62–64
BGP (Border Gateway Protocol), 9
BRI (basic rate interface), 66
Broadcast address, 7
Broadcast queue, frame-relay, 72–74
BUS (broadcast and unknown server), 98
CDIR (classless interdomain routing), 25
CDP (Cisco Discovery Protocol), 49
CEF (Cisco Express Forwarding), 57
CIR (committed information rate), 63, 65
Cisco routers, redistribution on, 27
Cisco’s EIGRP (Enhanced Interior
Gateway Routing Protocol), 1
Classful, 7
Commands, network, 23–25
Communication, one-way, 96–97
Configuration, EIGRP, 23–35
distribution lists, 31–33
hello and hold timers, 33–34
logging neighbor status, 34
passive interface, 34–35
redistribution, 25–27
running EIGRP, 23–25
starting EIGRP, 23–25
stub neighbors, 35
summarization, 28–31
Converge, failure to, 107–108
Convergence time, 18
Count-to-infinity problem, 3, 18
Database, topology, 4
Default network, 59–62
Delay, 4
Design considerations, miscellaneous, 91–93
Design, network, 37–93
Dial backup strategies, 74–76
Dial issues, WAN and, 62–76
Dirty link, overburdened or, 100–101
Discontiguous subnets, 43
Distance vector protocols, 1–4
metrics, 4
updates, 2–4
Distribution layer, 38
extended access lists as, 32–33
standard access lists as, 31–32
Distribution. See also Redistribution
DLCI (data link connection identities), 64
DUAL (Diffusing Update Algorithm), 1, 13–17
EIGRP (Enhanced Interior Gateway
Routing Protocol)
basics of, 8–13
limiting bandwidth consumption, 12–13
neighbor relationships, 8–9
reliable multicast, 9–12
compared to other protocols, 6–8
configuration, 23–35
deciding where to use, 22
foundation: Diffusing Update
Algorithm (DUAL), 13–17
fundamentals, 1–22
multiple, 87–89
network design, 37–93
redistributing metrics into, 27
running, 23–25
starting, 23–25
uses incremental updates, 3
Events, diagnosing, 108
FD (feasible distance), 14
Feasible successor, queries with no, 20–21
Filtering, route, 45–47, 89–90
Floating static route, 46
Frame relay
and bandwidth statements, 62–64
broadcast queue, 72–74
point-to-point subinterfaces, 9
FS (feasible successor), 14, 17
HDLC (high-level data link control), 9
Hello
interval, 70
packet, 9
timers, 33–34
Horizon, split, 17–22
IDs
duplicate router, 104–106
process, 25
IGRP (Interior Gateway Routing Protocol), 1–3
in same autonomous system, 85–87
Incremental updates, 3
Information hiding, 39
Interfaces
changing metric components on, 50–52
multipoint, 64–67
passive, 34–35
See also Subinterfaces
Interval, hello, 70
IS-IS (Intermediate System to
Intermediate System), 5–6, 8
K values, changing, 53–54
LAN (local area network), 9
LANE (LAN emulation), 98
Link state protocols, 1–2, 5–6
Links
multipoint, 9
overburdened or dirty, 100–101
point-to-point, 9
Links and SIAs, low-speed NBMA, 69–71
Lists
extended access lists as distribution, 32–33
offset, 52–53
standard access lists as distribution, 31–32
Lists as distribution lists, standard access, 31–32
Load, 4
MAC (media access control), 9
Metric components, changing on interface, 50–52
MTU (maximum transmission unit), 15, 26
Multicast address, 5
Multicast-only between two routers, 99–100
Multicast, reliable, 9–12
Multipoint interfaces and subinterfaces, 64–67
Multipoint links, 9
Mutual redistribution
at multiple points between two networks, 81–82
at single point, 80–81
NBMA links and SIAs, low-speed, 69–71
NBMA (nonbroadcast multiaccess), 69
Neighbor relationships, 8–9
problems with, 95–101
Neighbor status, logging, 34
Neighbors, stub, 35
Network command, 23–25
Network design, 37–93
minimizing query range, 41–50
miscellaneous design considerations, 91–93
network topology, 37–40
path selection issues, 50–62
redistribution issues, 76–90
WAN and dial issues, 62–76
Network statement and routes, 27
Network topology, 37–40
hierarchy, 38–39
redundancy, 39–40
Networks
default, 59–62
multiple, 82
mutual redistribution at multiple points
between two, 81–82
simplifying, 107
See also Subnets
Numbers, AS (autonomous system), 25
ODR (on-demand routing), 49, 69
Offset lists, 52–53
One-way communication between two
routers, 96–97
One-way redistribution, 80
OSPF (Open Shortest Path First), 5–6
Packet, hello, 9
Passive
entries marked as, 19
interfaces, 34–35
Path selection issues, 50–62
asymmetrical routing, 57–58
changing K values, 53–54
changing metric components on
interface, 50–52
default routing strategy, 58–62
offset lists, 52–53
variance, 55–57
Paths, transit, 39
Point-to-point links, 9
Point-to-point subinterfaces, 64
frame relay, 9
Process ID, 25
Protocols
distance vector, 1–4
EIGRP compared to other protocols, 6–8
multiple routing, 49–50
PVC (permanent virtual circuit), 64–65
Quality of service, 39
Queries, 8
ending of, 21–22
with no feasible successor, 20–21
split horizon and, 17–22
Query ranges, minimizing, 41–50
multiple autonomous systems, 48–49
multiple routing protocols, 49–50
route filtering, 45–47
stub routers, 47–48
summarization, 42–45
Query scopes, 41
Queues, frame-relay broadcast, 72–74
RD (reported distance), 14
Redistributed routes, source of, 84–90
IGRP in same autonomous system, 85–87
multiple EIGRP autonomous systems, 87–89
route filtering, 89–90
Redistribution, 25–27
caveats, 27
on Cisco routers, 27
externals and internals, 26–27
forms of, 80–82
administrative distances, 82–84
mutual redistribution at multiple
points between two networks, 81–82
mutual redistribution at single point, 80–81
mutual redistribution between multiple
networks at multiple points, 82
one-way redistribution, 80
source of redistributed routes, 84–90
issues, 76–90
forms of redistribution, 80–82
general issues, 77–80
mutual, 82
one-way, 80
Redistribution at single point, mutual, 80–81
Relationships
neighbor, 8–9
problems with neighbor, 95–101
Remotes, dual-homed, 47, 67–69
RIP (Routing Information Protocol), 1, 3
Route filtering, 42, 45–47, 89–90
Route summarization, 42
Router IDs, duplicate, 104–106
Routers
isolating misbehaving, 107–108
multicast-only between two, 99–100
one-way communication between two, 96–97
redistribution on Cisco, 27
stub, 47–48
unicast-only between two, 97–98
Routes
active, 19
floating static, 46
going active, 101–102
network statement and, 27
source of redistributed, 84–90
staying active, 102–104
stuck in active, 101–104
Routing, asymmetrical, 57–58
Routing protocols, multiple, 49–50
Routing strategy, default, 58–62
default network, 59–60
default network or default route, 61–62
default route, 60–61
RTO (retransmission timeout), 10–11
Running EIGRP, 23–25
Scope, query, 41
Service, quality of, 39
SIA (Stuck in Active), 21, 101–102, 104
SIAs, low-speed NBMA links and, 69–71
SMDS (switched multimegabit data service), 63–64, 66, 70
Split horizon
NBMA (non broadcast multiaccess)and, 72
and queries, 17–22
SRTT (smooth round-trip time), 10–11
Starting EIGRP, 23–25
Stub neighbors, 35
Stub routers, 47–48
frame relay point-to-point, 9
multipoint interfaces and, 64–67
point-to-point, 64
Subnets, discontiguous, 43
Successor, 14
address, 37
configuring, 28–31
autosummarization, 28–29
manual summarization, 29–31
route, 42
Tag, administrative, 26
Time, convergence, 18
Timers
hello, 33–34
Topology, 7
database, 4
network, 37–40
Traffic aggregation, 38
Transit paths, 39
Troubleshooting, 95–108
duplicate router IDs, 104–106
failure to converge, 107–108
diagnosing events, 108
isolating misbehaving routers, 107–108
simplifying networks, 107
one-way communication between two
routers, 96–97
multicast-only between two routers, 99–100
overburdened or dirty-link, 100–101
unicast-only between two routers, 97–98
problems with neighbor relationships, 95–101
stuck in active routes, 101–104
Unicast-only between two routers, 97–98
Updates, incremental, 3
Variance, 55–57
VLANs, 39
VLSM (variable-length subnet masks), 77
WAN (wide area network), 38
and dial issues, 62–76
dial backup strategies, 74–76
dual-homed remotes, 67–69
frame relay and bandwidth statements, 62–64
frame-relay broadcast queue, 72–74
low-speed NBMA links and SIAs, 69–71
multipoint interfaces and subinterfaces, 64–67
NBMA (non broadcast multiaccess)
and split horizon, 72
point-to-point subinterfaces, 64
links, 62