Command the router considers routes to that network

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command, the router considers routes to that network for installation as the gateway of last resort on the router. 21 ip route 172.16.5.2 255.255.255.0 s0/0 Router(config)#ip route {destination network}{mask}{next hop address} e.g ip route 172.16.5.2 255.255.255.0 172.16.12.8 R1#show ip route Codes: C - connected, S - static, 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, i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area, * - candidate default, U - per-user static route, o ODR, P - periodic downloaded static route Gateway of last resort is not set R D O E2 80.1.1.0/24 [120/1] via 10.1.1.2, 00:00:04, Ethernet0/0.1 80.0.0.0/8 [90/281600] via 10.1.1.2, 00:02:02, Ethernet0/0.1 80.1.0.0/16 [110/20] via 10.1.1.2, 00:00:14, Ethernet0/0.1 R1(config)#ip default-network 198.10.1.0
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Cisco CCENT Cram Guide v3.0 © Paul Browning 2017 If you want the router to use a route if the routing protocol fails you can install a floating static route and add an AD to the end which is higher than that of the routing protocol. The below default route will forward packets to unknown IPv6 destinations via Serial0/1 using the Link-Local address of the next-hop router as the IPv6 next-hop address. For broadcast interfaces (such as Ethernet) you need to add an exit interface. Distance Vector Distance Vector protocols understand the direction and distance to any given network connections. Algorithms calculate the cost to reach the connection and pass this information to every neighbor router. Examples are RIP and IGRP. Problems with distance vector protocols include routing loops and counting to infinity. To overcome these problems the following can be implemented: Defining a maximum number of hops, 15 for RIP and 255 for IGRP Split Horizon if the router learns a route on an interface does not advertise it out of the same interface. Hold Down Timers ignores new routing updates until a determined time has passed. Triggered Updates instead of routing updates being sent at the default intervals; a triggered update is sent every time to indicate a change in the routing table. Link State These have a picture of the entire network from link state advertisements (LSA) and link state packets (LSP). Once these have all been passed only changes to the network are sent out reducing network traffic. Link state protocols do require a lot of CPU time and bandwidth when LSAs are flooded out. Examples are OSPF and ISIS. Routers use administrative distances to determine how believable the route learned is depending upon the protocol it learns the router from. 22 R1(config)#ipv6 route ::/0 Serial0/1 FE80::3333 Router(config)#ip route 192.168.1.0 255.255.255.0 172.16.5.3 115 Source Default Distance Directly Connected Interface 0 Static hop to next router 1 EIGRP Summary 5 External BGP 20 EIGRP (Internal) 90 OSPF 110 IS-IS 115
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Cisco CCENT Cram Guide v3.0 © Paul Browning 2017 RIP 120 Exterior Gateway Protocol (EGP) 140 External EIGRP 170 Internal BGP 200 Unknown 255
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  • Winter '17
  • James Smith
  • Computer Science, IP address, Paul Browning, Cram Guide v3, CCENT Cram Guide, Cisco CCENT Cram

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