Comprehensive Detailed Step-by-Step Explanation with All Juniper Security References
Understanding Advanced Policy-Based Routing (APBR):
APBR: Allows routing decisions based on application-level information and policies.
Objective: Direct specific application traffic through different paths based on policies.
Routing Instances in Junos OS:
Forwarding Instance:
Used for features like filter-based forwarding (FBF) and APBR.
Provides a separate forwarding table but shares the global routing table.
Supports APBR.
Virtual Router:
Provides a separate routing table and forwarding table.
Used for logical separation of routing domains.
Does not support APBR directly.
Virtual Switch:
Operates at Layer 2.
Used for VLAN separation and Layer 2 switching.
Not applicable to routing or APBR.
Non-Forwarding Instance:
Used for management purposes.
Does not forward transit traffic.
Not suitable for APBR.
[Reference:, Juniper Networks Documentation:, "To configure advanced policy-based routing, you must create a forwarding-type routing instance.", Source: Configuring Advanced Policy-Based Routing, Why Other Options Are Incorrect:, Option B: virtual switch, Incorrect., Virtual switch instances are for Layer 2 switching and VLAN separation., They do not support routing or APBR., Option C: virtual router, Incorrect., Virtual router instances are used for isolating routing tables., While they support routing, they are not designed for APBR., Option D: non-forwarding, Incorrect., Non-forwarding instances do not handle transit traffic., They are used for management routing tables and cannot be used for APBR., Conclusion:, Correct Answer: A. forwarding, Rationale:, A forwarding routing instance is the appropriate type to support advanced policy-based routing., ]
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