So my home router is connected to the Internet and can afford traffic onto the Internet even though
it doesn't know all the rats in the Internet.
Internet routing tables are growing all the time.
So there are more than 500000 rants on the Internet and a small Rodda wouldn't be able to handle that
number of Roths in its routing table.
Now it's possible to telnet to life BGP routers on the Internet.
So in this example I'm going to telnet to ROFFT hyphen server IP dot AT&T dot net.
I'm told that I can log in with this username which gives me a read only access to the router and I'm
in a top show route summary as you can see here there are eight point five million odd routes in the
writing table with 560 seven thousand destinations.
BGP summary will show me the BGP writing table BGP is the writing protocol used on the Internet.
So total Pardes 8.5 million active is 560 7000.
As you can imagine a small Rodda he's not going to be able to handle this number of routes in his writing
table.
Here you can see examples of Roths in the BGP writing table on this router and how long those routes
have been in the writing table.
Small rods aren't going to handle that number of rats.
So you would typically use a default route pointing your rodded to a gateway of last resort.
So a default route is a special type of static route pointing your device or router to a gateway of
last resort.
This is similar to the concept of a default gateway on a PC or a device such as an iPhone or iPad when
the router doesn't know where to send the traffic.
It simply sends it to the gateway of last resort.
In other words it will send it to this IP address as configured with the static default route Another
advantage of static Grotz is that you as the administrator determine explicitly where traffic flows.
So rather than a writing protocol making the decision for you you decide and have control over where
traffic goes or where packets are routed.
But on the flip side the burden of Management and keeping things up to date also fall on your shoulders.
So you have to administer the running table.
Keep it up to date.
Make sure that Roths are not pointing to non-existent devices where networks go down.
You would have to update the writing table and that's simply not scalable in large typologies.
So hence dynamic routing protocols such as OSPF or GAAP are used to dynamically add or remove routes
from a writing table.
BGP is mentioned is the writing protocol used on the internet for very large scale implementations.
The major advantage of dynamic routing protocols is that there is the dynamic automatic adjustment of
the writing table based on topology changes in your network.
So rather than you having to manually adjust to a topology change the routing protocols update insert
or remove rots from the writing table based on changing conditions in the network.
As soon as you enable a routing protocol such as OSPF or GOP the routers will form a neighbor or peer
relationships with each other and exchange rates with one another.
The rodders will thus automatically learn about the networks available in the typology rotas exchange
information about Grotz using different methods.
But as an example OSPF uses a link state updates to advertise information about routes that are available
in the network topology.
This puts overhead on the network because additional traffic is sent and received by rotas as they communicate
with one another.
However as the network grows there is an exponential increase in the amount of work that would be required
if static routes were used and thus because of the advantage that dynamic routing protocols put less
overhead and workload on administrators to maintain routing tables.
They are used in most networks today especially large networks with the largest being the Internet which
runs on BGP or border gateway protocol.
And once again dynamic routing protocols can adjust to changes in the topology automatically and without
administrative intervention.