Distance vector routing is used when the network is simple and has no hierarchical design. Examples of distance vector routing protocols are RIP and IGRP.
Which two technologies can be used in distance vector routing protocols to prevent routing loops?
Which two technologies can be used in distance vector routing protocols to prevent routing loops?
Which two technologies can be used in distance vector routing protocols to prevent routing loops?
Distance-vector algorithms refer to routing protocols - protocols used by routers to inform each other about available routes. In distance-vector algorithms, such as RIP or EIGRP, the routers inform each other about their routing tables, and each router adds a metric (or distance) to the route - however, the routers don't know about the topology of the network (unlike the link-state protocols, such as OSPF).
In a distance vector routing protocol, such as RIP or EIGRP, each router sends its routing table to neighboring routers. The routers don't know the topology, i.e., how other routers are interconnected. In a link state routing protocol, such as OSPF or IS-IS, routers first exchange information about connections within the network (or an area of the network), and build a topology table. Then each router uses Dijkstra's algorithm to calculate the best route to each destination.
The availability of networks, and the metric (or "cost" or "distance") to reach them, according to the system used by the routing protocol to calculate this "metric".The availability of networks, and the metric (or "cost" or "distance") to reach them, according to the system used by the routing protocol to calculate this "metric".The availability of networks, and the metric (or "cost" or "distance") to reach them, according to the system used by the routing protocol to calculate this "metric".The availability of networks, and the metric (or "cost" or "distance") to reach them, according to the system used by the routing protocol to calculate this "metric".
That would be a distance-vector routing protocol. Examples (taught at Cisco Academies) include RIP, IGRP (obsolete in the new version of the curriculum), and EIGRP - but those are only for IP, and there are also distance-routing protocols for other networking protocols, for example, RIP for IPX.
Cisco uses DUAL FSM (EIGRP) to make sure that on a global level a route is recalculated when the possibility exists that it might cause a routing loop. In essence, this attempts to prevent routing loops. Other algorithms used in path calculation are the Bellman-Ford (shortest path) and Ford-Fulkerson (maximum flow).
Enhanced Interior Gateway Protocol It is a Cisco proprietary protocol. It uses bandwidth and delay by default to calculate the best path. It can also use load and delay, but these are usually not used. It is a distance vector routing protocol. It keeps a topology map, but it is only similar to the topology map of link state routing protocols.
administrative distance and metrics
Interior Gateway Routing Protocol (IGRP) IGRP is a distance-vector interior gateway protocol (IGP). Distance-vector routing protocols call for each router to send all or a portion of its routing table in a routing-update message at regular intervals (every 90 seconds) to each of its neighboring routers. As routing information proliferates through the network, routers can calculate distances to all nodes within the internetwork. IGRP uses a combination (vector) of metrics. Internetwork delay, bandwidth, reliability, and load are all factored into the routing decision. Network administrators can set the weighting factors for each of these metrics. IGRP uses either the administrator-set or the default weightings to automatically calculate optimal routes.Routing Information Protocol (RIP) The Routing Information Protocol (RIP) is a distance-vector protocol that uses hop count as its metric. RIP is widely used for routing traffic in the global Internet and is an interior gateway protocol (IGP), which means that it performs routing within a single autonomous system. RIP only uses hop count to determine the best route to a remote network, RIP has a maximum hop count of 15, 16 is deemed unreachable. RIP works well in small internetworks, but is inefficient for large networks. RIP is susceptible to all the problems normally associated with distance vector routing protocols. It is slow to converge and forces routers to learn network information only from neighbors. RIP version 1 uses classful routing (all devices in the network must use the same subnet mask because RIP version 1 doesn't send updates with subnet information). RIP version 2 uses classless routing and does send subnet mask information with route updates. RIP networks need the same hop count to load balance multiple links.
router