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So my home router is connected to the Internet and can afford traffic onto the Internet even though

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it doesn't know all the rats in the Internet.

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Internet routing tables are growing all the time.

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So there are more than 500000 rants on the Internet and a small Rodda wouldn't be able to handle that

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number of Roths in its routing table.

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Now it's possible to telnet to life BGP routers on the Internet.

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So in this example I'm going to telnet to ROFFT hyphen server IP dot AT&T dot net.

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I'm told that I can log in with this username which gives me a read only access to the router and I'm

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in a top show route summary as you can see here there are eight point five million odd routes in the

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writing table with 560 seven thousand destinations.

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BGP summary will show me the BGP writing table BGP is the writing protocol used on the Internet.

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So total Pardes 8.5 million active is 560 7000.

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As you can imagine a small Rodda he's not going to be able to handle this number of routes in his writing

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table.

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Here you can see examples of Roths in the BGP writing table on this router and how long those routes

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have been in the writing table.

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Small rods aren't going to handle that number of rats.

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So you would typically use a default route pointing your rodded to a gateway of last resort.

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So a default route is a special type of static route pointing your device or router to a gateway of

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last resort.

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This is similar to the concept of a default gateway on a PC or a device such as an iPhone or iPad when

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the router doesn't know where to send the traffic.

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It simply sends it to the gateway of last resort.

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In other words it will send it to this IP address as configured with the static default route Another

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advantage of static Grotz is that you as the administrator determine explicitly where traffic flows.

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So rather than a writing protocol making the decision for you you decide and have control over where

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traffic goes or where packets are routed.

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But on the flip side the burden of Management and keeping things up to date also fall on your shoulders.

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So you have to administer the running table.

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Keep it up to date.

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Make sure that Roths are not pointing to non-existent devices where networks go down.

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You would have to update the writing table and that's simply not scalable in large typologies.

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So hence dynamic routing protocols such as OSPF or GAAP are used to dynamically add or remove routes

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from a writing table.

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BGP is mentioned is the writing protocol used on the internet for very large scale implementations.

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The major advantage of dynamic routing protocols is that there is the dynamic automatic adjustment of

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the writing table based on topology changes in your network.

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So rather than you having to manually adjust to a topology change the routing protocols update insert

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or remove rots from the writing table based on changing conditions in the network.

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As soon as you enable a routing protocol such as OSPF or GOP the routers will form a neighbor or peer

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relationships with each other and exchange rates with one another.

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The rodders will thus automatically learn about the networks available in the typology rotas exchange

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information about Grotz using different methods.

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But as an example OSPF uses a link state updates to advertise information about routes that are available

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in the network topology.

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This puts overhead on the network because additional traffic is sent and received by rotas as they communicate

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with one another.

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However as the network grows there is an exponential increase in the amount of work that would be required

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if static routes were used and thus because of the advantage that dynamic routing protocols put less

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overhead and workload on administrators to maintain routing tables.

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They are used in most networks today especially large networks with the largest being the Internet which

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runs on BGP or border gateway protocol.

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And once again dynamic routing protocols can adjust to changes in the topology automatically and without

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administrative intervention.