The document discusses several routing protocols, including RIP, IGRP, OSPF, IS-IS, and EIGRP. RIP uses hop count as its metric and has a maximum of 15 hops. IGRP is a proprietary distance vector protocol from Cisco that uses bandwidth and delay as its metric. OSPF is an open standard link state protocol that uses the SPF algorithm to calculate the best routes and converges quickly. EIGRP is a hybrid routing protocol from Cisco that has characteristics of both distance vector and link state protocols.

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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