MLS Procedures

MLS Procedures
We discussed the three required components of MLS. It is important to understand how they work
together to enable layer 3 switching. Let’s look at a sample network topology that supports MLS.
Figure 18.2 shows a simple architecture of a router and a switch with two connected hosts
on the switch. Again, the hosts have different VLAN assignments, requiring the router’s intervention
to route packets. Notice that the figure depicts the main interface with two subinterfaces:
FE0/0.2 and FE0/0.3. As it stands, the current topology requires that all packets sent from
the client on VLAN 3 to the client on VLAN 2 be routed by the external router. If there are a
large number of packets, this creates a lot of unnecessary work.