An aggregate route is a route that summarizes multiple more specific routes into a single route advertisement. For example, an aggregate route to 10.0.0.0/8 can represent many routes to 10.x.x.x/24 subnets. An aggregate route has several purposes, such as:

To decrease the number of route advertisements: By consolidating multiple routes into one, an aggregate route reduces the size of the routing table and the amount of routing updates that need to be exchanged between routers. This can improve the scalability and efficiency of the network12.

To hide internal routes from external peers: By advertising only the aggregate route and not the more specific routes, an aggregate route can provide a level of abstraction and security for the internal network topology. This can prevent external peers from knowing the details of the internal routes and avoid potential attacks or misconfigurations13.

The other options are not correct because:

C. To allow external peers to see internal routes: This is the opposite of what an aggregate route does. An aggregate route hides the internal routes from external peers, not exposes them13.

D. To increase the number of route advertisements: This is also the opposite of what an aggregate route does. An aggregate route decreases the number of route advertisements, not increases them12.

MAC limiting protects against flooding of the Ethernet switching table (also known as the MAC forwarding table or Layer 2 forwarding table). This feature is enabled on interfaces (ports). MAC limiting sets a limit on the number of MAC addresses that can be learned on a single Layer 2 access port. The MAC limit value in the EX-series switch’s default configuration is five MAC addresses. You can configure the MAC limit on an interface, on an interface in a VLAN, or on all interfaces. You can also specify the action to be taken when the MAC limit is exceeded, such as dropping packets, logging messages, or shutting down the interface. Additionally, you can configure specific “allowed” MAC addresses for the access port. Any MAC address that is not in the list of configured addresses is not learned. Allowed MAC binds MAC addresses to a VLAN so that the address does not get registered outside the VLAN. References:

[EX] How to control MAC address access through Junos OS for EX Series switches1

Configuring MAC Limiting2

Understanding MAC Limiting and MAC Move Limiting3

The output shown in the exhibit is a brief display of the Ethernet switching table, which shows the learned Layer 2 MAC addresses for each VLAN and interface 1 .

The command  show ethernet-switching table  displays the Ethernet switching table with brief information, such as the destination MAC address, the VLAN name, the forwarding state, and the interface name 1 .

The command  show route forwarding-table  displays the routing table information for each protocol family, such as inet, inet6, mpls, iso, and so on 2 . It does not show the Ethernet switching table or the MAC addresses.

The command  show ethernet-switching table extensive  displays the Ethernet switching table with extensive information, such as the destination MAC address, the VLAN name, the forwarding state, the interface name, the VLAN index, and the tag type 1 . It shows more details than the brief output shown in the exhibit.

The command  show route forwarding-table family ethernet-switching  displays the routing table information for the ethernet-switching protocol family, which shows the destination MAC address, the next-hop MAC address, and the interface name 3 . It does not show the VLAN name or the forwarding state.