1. Routing Protocols
Chapters 8-9
Networking Essentials – Eric Vanderburg © 2005

2. RIP
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Version 1
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15 max hop count
Broadcasts routing updates (30 secs)
Distance vector
Classfull
Hop count metric
Version 2
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255 max hop count
Multicasts routing updates
Classless (supports VLSM)
Supports authentication (MD5)

3. RIP commands
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Router rip
Network network address
 Version 2 (optional)
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Debug ip rip
 Passive-interface serial0 – does not
send out RIP updates from this interface
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4. IGRP
Distance vector
 Metric uses bandwidth & delay
 Bandwidth is based on the lowest speed
link in the route.
 Broadcasts route every 90 secs
 Classfull
 Cisco proprietary
 Grouped into AS
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5. IGRP commands
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Router igrp as#
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Network network number
Debug ip igrp transactions – shows updates
Debug ip igrp events – shows all igrp packets
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6. Distance Vector
Route Poisoning – send infinite metric
 Split Horizon – do not send out updates
from interfaces in which we received
those updates
 Poison reverse (Cisco only) – send
infinite metric to all devices
 Hold down timer – does not update
routes for an infinite metric route for a
certain amount of time
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7. OSPF (Open Shortest Path First)
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Link state
Keeps a topology database
Best route is calculated using the SPF
algorithm
Converges in about 10 secs
Classless
Uses hello messages to determine if a link is
down
Sends LSA’s (Link State Advertisements)
when a link changes
Grouped into AS (areas)

8. OSPF commands
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Router ospf processID
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Network ipaddress mask area areaID
Ip ospf cost cost – cost for an interface
Bandwidth bandwidth – for interface
Ip ospf hello # - hello interval
Show ip ospf neighbor – shows those with
whom you share updates
Debug ip ospf events – show ospf packets
Debug ip ospf hello – show hello messages

9. Integrated IS-IS
(Intermediate System to Intermediate System)
Link state
 Created by ISO
 Supports multiple layer 3 protocols (ISIS did not)
 Advertises CLNP (Connectionless
Network Protocol) routes as well as IP
routes.
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10. Link State
Sends updates when link state changes
 Everyone keeps a database of the entire
AS
 Shorter convergence time
 More processing required
 Unicast updates are sent to a DR
(Designated Router) & BDR (Backup
Designated Router) to save bandwidth.
 DR multicasts to the rest of the AS
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11. EIGRP (Enhanced Interior
Gateway Routing Protocol)
Hybrid protocol (balanced hybrid)
 DUAL (Diffusing Update Algorithm)
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uses less processing than SPF
 Calculates alternate routes as well
(successor / feasible successors) – can
switch immediately
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Converges in 3 seconds
 Cisco proprietary
 Classless
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12. EIGRP (Enhanced Interior
Gateway Routing Protocol)
Sends partial updates
 Supports authentication
 Same metric as IGRP * 256
 Compatible with IGRP
 Grouped into AS
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13. EIGRP commands
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Router EIGRP AS#
Network network number mask
 Maximum-paths # - number of routes to
same network stored in routing table
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Show ip eigrp neighbors – show those
you share updates with
 Show ip route eigrp – show only eigrp
routes
 Show ip eigrp topology – show
successors and feasible sucecssors
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