So, guys, now going forward and continuing from the previous lecture video.
Now in this topology, I have twisted the matrix of these links slightly from the previous diagram such
that from the source router s, the destination router B is reachable via two equal cost multiple paths.
The first path is this one which has the cost of seven.
And the second path is this one which has the cost of seven again.
Right?
So now let us try to understand that.
How does the routing table entry, which has looks like.
So you can see that in this topology the source router has when receives a traffic which is destined
for the router, B it distributes the traffic on the two outgoing links.
That is this link and this link, right?
So you can see that it does so because its routing table entry dictates it to do so.
The loopback address of the router.
B is 192.168 .0.2 and it says that whenever router needs to forward the traffic which is destined to
this IP address, then the traffic needs to be forwarded out of the two interfaces that is Ethernet
one and Ethernet two towards their respective gateways two, two, two two and 1111.
Right.
So this particular routing table entry in the routing table of Node S is enabled.
Why?
It is enabled because it has two gateways.
This is the first next hop and this is the second next hop, right.
So such type of routing table entries in the routing table of a router are ICMP entries.
Needless to say, if there are more number of links in the topology, then possibly there could be more
number of paths to reach the destination router B from the router s.
In that case, there would be more number of next hops tied to this particular routing table entry.
So I hope now you understand that how router forwards the traffic out of multiple interfaces in case
when it has routing table entry with next hops?