JN0-105 Exam Dumps - Junos - Associate (JNCIA-Junos) 2024 Exam

In the OSI model, the Data Link Layer is responsible for node-to-node delivery of data. It frames the packets received from the Network Layer and prepares them for physical transmission. The Protocol Data Unit (PDU) for the Data Link Layer is called a "frame." Frames encapsulate the network layer packets, adding a header and a trailer that include the hardware addresses of the source and destination, among other things, facilitating the data link layer services like frame synchronization, flow control, and error checking.

In Junos OS routing policy evaluation, "next policy" (A) and "next term" (C) are common actions that affect the flow of policy evaluation. "Next policy" directs the evaluation to the next policy in the sequence, whereas "next term" moves the evaluation to the next term within the current policy, allowing for granular control over routing decisions.

Operating an Interior Gateway Protocol (IGP) within an Autonomous System (AS) provides several benefits, including determining the optimal paths for data transmission (B), reacting quickly to network changes (D), and learning all about the subnets and best paths within the network (E). IGPs are designed to manage routing within a single AS efficiently, adapting to changes and ensuring data is routed through the best available paths.

Routing policies in Junos OS are crucial for controlling route advertisements and path selection. The correct answers are B and C. An import routing policy for BGP determines which received prefix advertisements are placed in the routing information base (RIB), and policy terms are evaluated from top to bottom, with action taken on the first match found. This sequential evaluation allows for precise control over routing decisions.

Implementing Class of Service (CoS) in a network provides numerous benefits, particularly in managing traffic based on its importance, source, or type. CoS enables network administrators to manage traffic congestion by applying various queuing techniques and policies to ensure that critical services remain unaffected during high congestion periods. Additionally, CoS allows for the prioritization of latency-sensitive traffic such as voice and video, ensuring that these services maintain quality despite varying network conditions.