Final answer:
To summarize the LANs attached to routers 2-A and 3-A, find the smallest network range covering all the LANs' addresses; this involves determining the common high-order bits and creating a summary static route, which simplifies and improves routing efficiency upstream.
Step-by-step explanation:
In the context of network design and routing, the question pertains to the process of creating a summary static route to represent multiple local area networks (LANs). To advertise the LANs attached to routers 2-A and 3-A with a single address, you'll want to find the smallest network range that includes all of the addresses in those LANs. You would typically start by listing all the involved network addresses and then finding the largest common subnet that can include all these addresses.
For example, if one LAN is on 192.168.1.0/24 and another on 192.168.2.0/24, your summary address would be 192.168.0.0/22, which covers both networks. The process involves finding the common high-order bits in the network addresses and counting the number of bits that are common to all the LAN network addresses. You continue to mask off bits until you've found the summary that fits all. Note that without the exact network addresses, we cannot provide a specific summary address.
Lastly, the resulting summary route will be configured in your router to effectively reduce the number of routes that must be handled upstream, leading to more efficient routing and reduced table sizes.