The company has just completed an implementation that uses Cisco Express Forwarding (CEF) as a Layer 3 IP switching technology for optimized network performance and scalability. The following is the network infrastructure of the company. (Click the Exhibit(s) button.)You are creating the verification plan for this implementation. This includes verifying the routes known to the routers.Which component of the CEF switching technology contains routes to the 10.1.0.0/24 network along with the routes to the 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24 networks?
- Adjacency table
- Routing table
- Topology table
The forwarding information base (FIB) lookup table contains routes to 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24. CEF switching technology is an example of a topology-based switching mechanism that uses the FIB. The FIB contains the routing or forwarding information that the network prefix can reference. Thus, the FIB is the component that CEF based switching uses to store a route to 10.1.0.0/24 along with the routes to 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24. In the FIB, these specific entries would be ordered with the longest match followed by less specific subnets. When the switch receives a packet, it can easily examine the destination address and find the longest match entry in the FIB.
The adjacency table does not contain routes to 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24. The adjacency table is used by CEF to prepend Layer 2 addressing information. The adjacency table maintains Layer 2 next-hop addresses for all FIB entries. It stores the information for the nodes that are adjacent. Nodes in the network are said to be adjacent if they can reach each other with a single hop across a link layer.
The routing table does not contain routes to 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24. The router stores routing information, but CEF does not use the routing table for the purpose of making IP destination prefix-based switching decisions.
The topology table does not contain routes to 10.1.1.0/24, 10.1.2.0/24, or 10.1.3.0/24. The topology table is not a component of CEF switching technology. It is a component of EIGRP and stores the details of all the destinations along with the list of neighbors that advertise the destination. For each of these entries, the metrics of the neighbor advertising the destination are also stored.
Layer 2 Technologies
Configure and verify switch administration