JNCIA System Architecture 2

Question 1

What is the Routing Engine (RE) responsible for in Junos architecture?

Accepted Answer

Running routing protocols, managing configuration, and maintaining the routing table

Answer

The Routing Engine runs the Junos OS kernel, executes routing protocols (OSPF, BGP), maintains the routing and MPLS tables, and handles management plane functions.

Question 2

What does the Packet Forwarding Engine (PFE) do in Junos?

Accepted Answer

Forwards transit packets at line rate using the forwarding table programmed by the Routing Engine

Answer

The PFE is the data plane component that performs high-speed packet forwarding using Application-Specific Integrated Circuits (ASICs), using the FIB programmed by the Routing Engine.

Question 3

In a dual-RE Junos chassis, what is the function of the backup Routing Engine?

Accepted Answer

Maintains a synchronized copy of the routing state and can take over as master if the primary RE fails

Answer

The backup RE stays synchronized with the primary RE via GRES and NSR, allowing near-instantaneous RE failover without disrupting protocol adjacencies or active sessions.

Question 4

What Junos process is responsible for managing routing protocols?

Accepted Answer

rpd (Routing Protocol Daemon)

Answer

The Routing Protocol Daemon (rpd) is the primary process managing all routing protocols including OSPF, IS-IS, BGP, RIP, LDP, RSVP, and PIM in Junos OS.

Question 5

What is the significance of the 'inet.0' routing table in Junos?

Accepted Answer

It is the main IPv4 unicast routing table used for unicast forwarding decisions

Answer

inet.0 is the default IPv4 unicast routing table in Junos. All IPv4 unicast routing protocols (OSPF, BGP, static, connected) install routes here for forwarding decisions.

JNCIA - Juniper Networks Certified Internet Associate Practice Test

JNCIA - Juniper Networks Certified Internet Associate Practice Test

JNCIA System Architecture 2