Which two statements are correct about rules for EBGP and IBGP? (Choose two.)
Correct Answer: A,C
EBGP (External BGP)andIBGP (Internal BGP)operate with different rules due to the nature of their relationships. Step-by-Step Breakdown: * TTL Differences: * EBGP: By default, EBGP peers have a TTL of 1, meaning they must be directly connected, or the TTL needs to be manually increased for multihop EBGP. * IBGP: IBGP peers within the same AS have a TTL of 255, as they are expected to communicate over multiple hops within the AS. * Preference for EBGP Routes: * Routes learned viaEBGPare typically preferred over IBGP routes. This is because EBGP routes are considered more reliable since they originate outside the AS, while IBGP routes are internal. Juniper Reference: * BGP Configuration: The different handling of TTL and route preferences between EBGP and IBGP ensures proper route selection and security within Junos-based networks.
Question 22
Which statement is correct about aggregate routes?
Correct Answer: D
An aggregate route is a summarized route that is created by combining multiple specific routes into a single, broader route. In Junos OS, when an aggregate route is configured, its default next hop is set toreject. Step-by-Step Explanation: * Aggregate Route:Aggregate routes are used to reduce the size of routing tables by representing a collection of more specific routes with a single summary route. They help improve routing efficiency and scalability, especially in large networks. * Default Next Hop Behavior: * When you configure an aggregate route in Junos OS, it has arejectnext hop by default. * Therejectnext hop means that if a packet matches the aggregate route but there is no more specific route in the routing table for that destination, the packet will be discarded, and an ICMP "destination unreachable" message is sent to the source. * This behavior helps to prevent routing loops and ensures that traffic isn't forwarded to destinations for which there is no valid route. * Modifying Next Hop:If needed, the next hop behavior of an aggregate route can be changed todiscard (which silently drops the packet) or to another specific next hop. However, by default, the next hop is set toreject. Juniper Reference: * Junos Command: set routing-options aggregate route <route> reject to configure an aggregate route with a reject next hop. * Verification: Use show route to verify the presence and behavior of aggregate routes.
Question 23
What is the primary purpose of an IRB Layer 3 interface?
Correct Answer: C
The primary purpose of anIRB (Integrated Routing and Bridging)interface is to enableinter-VLAN routing in a Layer 3 environment. An IRB interface in Junos combines the functionality of both Layer 2 bridging (switching) and Layer 3 routing, allowing devices in different VLANs to communicate with each other. Step-by-Step Breakdown: * VLANs and Layer 2 Switching:Devices within the same VLAN can communicate directly through Layer 2 switching. However, communication between devices in different VLANs requires Layer 3 routing. * IRB Interface for Inter-VLAN Routing:The IRB interface provides a Layer 3 gateway for each VLAN, enabling routing between VLANs. Without an IRB interface, devices in different VLANs would not be able to communicate. * Configuration:In Juniper devices, the IRB interface is configured by assigning Layer 3 IP addresses to it. These IP addresses serve as the default gateway for devices in different VLANs. Example configuration: set interfaces irb unit 0 family inet address 192.168.1.1/24 set vlans vlan-10 l3-interface irb.0 This allows VLAN 10 to use the IRB interface for routing. Juniper Reference: * IRB Use Case: Inter-VLAN routing is essential in data centers where multiple VLANs are deployed, and Juniper's EX and QFX series switches support IRB configurations for this purpose.
Question 24
Which of the following are true regarding port modes in a VLAN setup? (Choose two)
Correct Answer: C,D
Question 25
Referring to the exhibit, which two statements are true? (Choose two.)
