Ccna2-Chapter8

Front 1

Level 1 routes

Back 1

- used to speed up the lookup process when locating routes.
-Level 1 route is a route with subnet mask equal or less than the classful mask of the network address.

Front 2

commands for routing

Back 2

debug ip routing
show ip route

Front 3

functions of level 1 route

Back 3

-default route (static route with address 0.0.0.0/0)
-supernet route - network addressw with a mask less than the classful mask
-network route - subnet mask is equal that of the classful mask. Network route can also be a parent route

Front 4

Ultimate route

Back 4

route that includes
next hop IP address
and/or exit interface

Front 5

example of a level 1 network route

Back 5

-directly connected network b/c it has a subnet mask same as the classful mask and it has an exit interface

Front 6

parent route

Back 6

-does not contain next hop IP or exit information. It is usually added when the child is added.
-Parent route is just to indicate that there is a child route.

Front 7

Child route/level 2 route

Back 7

-a route that is a subnet of a classful network address.
-They are also considered ultimate routes

Front 8

variably subnetted parent route

Back 8

when there are two or more child routes with different subnet masks belonging to the same classful network.

Front 9

router lookup process

Back 9

-first look at level 1 routes including nework routes, supernet route fore the best match.
-if a best match is a level1 ultimate route, it's used.
-if the best match is a parent route:
-looks at child routes of that parent
-if no match, go to:
-check if the route is using classful or classless routing
-if classful -drop the packet
-if classless - continue searching level 1 supernet routes.
-if there is a lesser match, use that.
- if no match is found, drop the packet.

Front 10

what is a best matched route

Back 10

- the destination IP and the route should have a minimum of left most bits that match.
-the route IP should have atleast the number of matching bits indicated by the subnet mask.

Front 11

example of best matched route

Back 11

dest IP 172.16.0.10
-routes: 172.16.0.0/12, 172.16.0.0/18 and 172.16.0.0/26. Twenty six bits from 172.22.0.0 matches the dest and thus the match is 172.16.0.0/26

Front 12

classfull and classless behavior

Back 12

is different than classful and classless routing protocols. They determine how the routing table is searched after being populated.

Front 13

how are they independent

Back 13

-a routing table can be populated with a classless routing protocol such as RIPv2 and a classful routing behaviour b/c the no ip classless is configured.

Front 14

configure classful and classless behavior

Back 14

ip classless -default
no ip classless (classful)
8.3.3.2