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061dd548 QY |
1 | ******** |
2 | Glossary | |
3 | ******** | |
4 | ||
62333307 QY |
5 | .. glossary:: |
6 | ||
7 | distance-vector | |
8 | A distance-vector routing protocol in data networks determines the best | |
9 | route for data packets based on distance. Distance-vector routing | |
10 | protocols measure the distance by the number of routers a packet has to | |
11 | pass. Some distance-vector protocols also take into account network | |
12 | latency and other factors that influence traffic on a given route. To | |
13 | determine the best route across a network, routers on which a | |
14 | distance-vector protocol is implemented exchange information with one | |
15 | another, usually routing tables plus hop counts for destination networks | |
16 | and possibly other traffic information. Distance-vector routing protocols | |
17 | also require that a router informs its neighbours of network topology | |
18 | changes periodically. [distance-vector-rp]_ | |
19 | ||
20 | link-state | |
21 | Link-state algorithms (also known as shortest path first algorithms) | |
22 | flood routing information to all nodes in the internetwork. Each router, | |
23 | however, sends only the portion of the routing table that describes the | |
24 | state of its own links. In link-state algorithms, each router builds a | |
25 | picture of the entire network in its routing tables. Distance vector | |
26 | algorithms (also known as Bellman-Ford algorithms) call for each router | |
27 | to send all or some portion of its routing table, but only to its | |
28 | neighbors. In essence, link-state algorithms send small updates | |
29 | everywhere, while distance vector algorithms send larger updates only to | |
30 | neighboring routers. Distance vector algorithms know only about their | |
31 | neighbors. [link-state-rp]_ | |
32 | ||
33 | Bellman-Ford | |
34 | The Bellman–Ford algorithm is an algorithm that computes shortest paths | |
35 | from a single source vertex to all of the other vertices in a weighted | |
36 | digraph. [bellman-ford]_ | |
37 | ||
38 | ||
39 | .. [distance-vector-rp] https://en.wikipedia.org/wiki/Distance-vector_routing_protocol | |
40 | .. [link-state-rp] https://en.wikipedia.org/wiki/Link-state_routing_protocol | |
41 | .. [bellman-ford] https://en.wikipedia.org/wiki/Bellman-Ford_algorithm |