1 identifying static and dynamic routes static route uses a route that a network administrator...
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Identifying Static and Dynamic Routes
•Static RouteUses a route that a network administrator enters into the router manually
•Dynamic RouteUses a route that a network routing protocol adjusts automatically for topology or traffic changes
Default Route Example
• Routing protocols are used between routers to determine paths and maintain routing tables.
• Once the path is determined a router can route a routed protocol.
NetworkProtocol
DestinationNetwork
ConnectedRIP
IGRP
10.120.2.0172.16.2.0172.17.3.0
Exit Interface
E0S0S1
Routed Protocol: IPRouting protocol: RIP, IGRP
172.17.3.0
172.16.1.010.120.2.0
E0S0
Interior or Exterior Routing Protocols
Autonomous System 100 Autonomous System 200
IGPs: RIP, IGRP EGPs: BGP
– An autonomous system is a collection of networks under a common administrative domain– IGPs operate within an autonomous system– EGPs connect different autonomous systems
Split Horizon
AA BB CC
10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0
E0 S0 S0 S1 S0 E0 XXXXXX
Routing TableRouting Table
10.3.0.0 S0
S0
S0
S0
11
2210.1.0.0
10.2.0.0
10.4.0.0
0
0
Routing TableRouting Table
10.1.0.0 E0
S0
S0
S0
11
2210.4.0.0
10.3.0.0
10.2.0.0
0
0
Routing TableRouting Table
10.2.0.0 S0
S1
S1
E1
11
2210.1.0.0
10.4.0.0
10.3.0.0
0
0
• It is never useful to send information about a route back in the direction from which the original packet came
Poison Reverse
AA BB CC
10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0
E0 S0 S0 S1 S0 E0 XX
Routing TableRouting Table
10.3.0.0 S0
S0
S0
S0
11
2210.1.0.0
10.2.0.0
10.4.0.0
0
Infinity
Routing TableRouting Table
10.1.0.0E0
S0
S0
S0
11
2210.4.0.0
10.3.0.0
10.2.0.0
0
0
Routing TableRouting Table
10.2.0.0S0
S1
S1
E1
11
2210.1.0.0
10.4.0.0
10.3.0.0
0
0
• Routers set the distance to infinity if the destination is routed on that link
Hold-Down Timers
• Router keeps an entry for the network down state, allowing time for other routers to recompute for this topology change
Network 10.4.0.0 is downthen back up
then back down
Update afterhold-down Time
Update afterhold-down Time
Network 10.4.0.0is unreachable
Network 10.4.0.0is unreachable
AA BB CC
10.1.0.0 10.2.0.0 10.3.0.0 10.4.0.0
E0 S0 S0 S1 S0 E0 XXUpdate after
hold-down TimeUpdate after
hold-down Time
Triggered Updates
• Nodes send messages as soon as they notice a change in their routing table
AA BB CC
10.2.0.0 10.3.0.0 10.4.0.0
E0 S0 S0 S1 S0 E0 XX
Network 10.4.0.0is unreachable
Network 10.4.0.0is unreachable
Network 10.4.0.0is unreachable
Network 10.4.0.0is unreachable
Network 10.4.0.0is unreachable
Network 10.4.0.0is unreachable
10.1.0.0
Hybrid Routing
• Share attributes of both distance-vector and link-state routing
Choose arouting path based on distance vectors
Converge rapidly using change-based
updates
Choose arouting path based on distance vectors
Converge rapidly using change-based
updates
Balanced Hybrid RoutingBalanced Hybrid Routing
Dynamic Routing Configuration
– Defines an IP routing protocol
Router(config)#router protocol [keyword]
• Mandatory configuration command for each
IP routing process
• Identifies the physically connected network that routing updates are forwarded to
Router(config-router)#network network-number
RIP Configuration
Router(config)#router rip
Router(config-router)#network network-number
• Selects participating attached networks• The network number must be a major classful
network number
Displaying the IP Routing Table
RouterA#sh ip routeCodes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default U - per-user static route, o - ODR T - traffic engineered route
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 1 subnetsC 172.16.1.0 is directly connected, Ethernet0 10.0.0.0/24 is subnetted, 2 subnetsR 10.2.2.0 [120/1] via 10.1.1.2, 00:00:07, Serial2C 10.1.1.0 is directly connected, Serial2R 192.168.1.0/24 [120/2] via 10.1.1.2, 00:00:07, Serial2
172.16.1.1
S2E0 S3
192.168.1.110.1.1.1 10.2.2.210.1.1.2
S2 S3
10.2.2.3
172.16.1.0 A B C192.168.1.0
E0
debug ip rip Command
172.16.1.1
S2E0 S3
192.168.1.110.1.1.1 10.2.2.210.1.1.2
S2 S3
10.2.2.3
172.16.1.0 A B C192.168.1.0
E0
RouterA#debug ip ripRIP protocol debugging is onRouterA#00:06:24: RIP: received v1 update from 10.1.1.2 on Serial200:06:24: 10.2.2.0 in 1 hops00:06:24: 192.168.1.0 in 2 hops00:06:33: RIP: sending v1 update to 255.255.255.255 via Ethernet0 (172.16.1.1)00:06:34: network 10.0.0.0, metric 100:06:34: network 192.168.1.0, metric 300:06:34: RIP: sending v1 update to 255.255.255.255 via Serial2 (10.1.1.1)00:06:34: network 172.16.0.0, metric 1
IGRP Composite Metric19.2 kbps19.2 kbps
Source
Destination
– Bandwidth– Delay– Reliability– Loading– MTU
Configuring a Serial Line
• Enter global
configuration mode
• Specify interface
• Set DCE clock rate
(optional)
• Set bandwidth (optional)
Router(config-if)#clock rate 56000Router(config-if)#
Router(config)#interface serial 1Router(config-if)#
Router#configure termRouter(config)#
Router(config-if)#bandwidth 56Router(config-if)#exitRouter(config)#exitRouter#
Configuring IGRP
Router(config-router)#network network-number
• Selects participating attached networks
Router(config)#router igrp autonomous-system
• Defines IGRP as the IP routing protocol
Router(config-router)#traffic-share { balanced | min }
• Control how load-balanced traffic is distributed
Router(config-router)#variance multiplier
• Control IGRP load balancing
debug ip igrp transaction Command
172.16.1.1
S2E0 S3
192.168.1.110.1.1.1 10.2.2.210.1.1.2
S2 S3
10.2.2.3
172.16.1.0 A B C192.168.1.0
E0
RouterA#debug ip igrp transactionsIGRP protocol debugging is onRouterA#00:21:06: IGRP: sending update to 255.255.255.255 via Ethernet0 (172.16.1.1)00:21:06: network 10.0.0.0, metric=8895600:21:06: network 192.168.1.0, metric=9105600:21:07: IGRP: sending update to 255.255.255.255 via Serial2 (10.1.1.1)00:21:07: network 172.16.0.0, metric=110000:21:16: IGRP: received update from 10.1.1.2 on Serial200:21:16: subnet 10.2.2.0, metric 90956 (neighbor 88956)00:21:16: network 192.168.1.0, metric 91056 (neighbor 89056)
debug ip igrp events Command
RouterA#debug ip igrp eventsIGRP event debugging is onRouterA#00:23:44: IGRP: sending update to 255.255.255.255 via Ethernet0 (172.16.1.1)00:23:44: IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.00:23:44: IGRP: Total routes in update: 200:23:44: IGRP: sending update to 255.255.255.255 via Serial2 (10.1.1.1)00:23:45: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.00:23:45: IGRP: Total routes in update: 100:23:48: IGRP: received update from 10.1.1.2 on Serial200:23:48: IGRP: Update contains 1 interior, 1 system, and 0 exterior routes.00:23:48: IGRP: Total routes in update: 2
172.16.1.1
S2E0 S3
192.168.1.110.1.1.1 10.2.2.210.1.1.2
S2 S3
10.2.2.3
172.16.1.0 A B C192.168.1.0
E0
ip classless Command
–With ip classless Default–With no ip classless Drop
Router(config)#ip classless
S0
Default route
172.16.0.0E0
10.1.0.0
NetworkProtocol
DestinationNetwork
CC
RIP
10.1.0.0 10.2.0.0172.16.0.0 via0.0.0.0
Exit Interface
E0S0S0E0
10.2.0.0
To get to 10.7.1.1: