Which statement is correct about the IS-IS ISO NET address?
Correct Answer:B
✑ An ISO NET address is a type of network address used by the IS-IS routing
protocol. It identifies a point of connection to the network, such as a router interface, and is also called a Network Service Access Point (NSAP)1.
✑ An ISO NET address consists of three parts: an area ID, a system ID, and a selector2. The area ID identifies the IS-IS area to which the device belongs. The system ID uniquely identifies the device within the area. The selector identifies a specific service or function on the device, such as routing or management2.
✑ An ISO NET address must be unique for each device in the network, because it is used by IS-IS to establish adjacencies, exchange routing information, and compute shortest paths2. If two devices have the same ISO NET address, they will not be able to communicate with each other or with other devices in the network. Therefore, it is important to assign different ISO NET addresses to each device in the network.
Which two BGP attributes must be supported by all BGP implementations and must be included in every update? (Choose two.)
Correct Answer:AC
BGP attributes are properties that BGP uses for route advertisement, path selection, and loop prevention1. There are four categories of BGP attributes123:
✑ Well-known mandatory: Must be recognized by all BGP routers, present in all BGP updates, and passed on to other BGP routers123.
✑ Well-known discretionary: Supported by all BGP implementations, and are optionally included in BGP updates1.
✑ Optional transitive: May not be supported by all implementations of BGP1.
✑ Optional non-transitive: May not be supported by all implementations of BGP1. The well-known mandatory attributes must be supported by all BGP implementations and must be included in every update123. These include the AS path and next hop attributes23. Therefore, options A and C are correct.
Exhibit
Which command displays the output shown in the exhibit?
Correct Answer:B
✑ 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 interface1.
✑ 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 name1.
✑ The command show route forwarding-table displays the routing table information for each protocol family, such as inet, inet6, mpls, iso, and so on2. 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 type1. 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, whichshows the destination MAC address, the next-hop MAC address, and the interface name3. It does not show the VLAN name or the forwarding state.
What is a purpose of using a spanning tree protocol?
Correct Answer:B
✑ A broadcast storm is a network condition where a large number of broadcast packets are sent and received by multiple devices, causing congestion and performance degradation1. A broadcast storm can occur when there are loops in the network topology, meaning that there are multiple paths between two devices2.
✑ A spanning tree protocol is a network protocol that prevents loops from being formed when switches or bridges are interconnected via multiple paths. It does this by creating a logical tree structure that spans all the devices in the network, and disabling or blocking the links that are not part of the tree, leaving a single active path between any two devices3.
✑ By eliminating loops, a spanning tree protocol also eliminates broadcast storms, as broadcast packets will not be forwarded endlessly along the looped paths. Instead, broadcast packets will be sent only along the tree structure, reaching each device once and avoiding congestion3.
Which two statements about redundant trunk groups on EX Series switches are correct? (Choose two.)
Correct Answer:BD
Redundant Trunk Groups (RTGs) on EX Series switches provide a simple solution for network recovery when a trunk port on a switch goes down1. They are configured on the access switch and contain two links: a primary or active link, and a secondary link1. Therefore, option B is correct because if the active link fails, the secondary link automatically starts forwarding data traffic without waiting for normal spanning-tree protocol convergence1.
Option D is also correct. In a typical enterprise network composed of distribution and access layers, RTGs are used where one Access switch is connected to two different uplink switches2. This implies that RTGs must be connected to the same aggregation switch2.