JNCIA Routing Protocols

Question 1

What type of routing protocol is OSPF?

Accepted Answer

Link-State Interior Gateway Protocol

Answer

OSPF (Open Shortest Path First) is a link-state IGP that builds a complete topology map of the network using LSAs and calculates the shortest path using Dijkstra's SPF algorithm.

Question 2

In Junos, what command enables OSPF on an interface?

Accepted Answer

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

Answer

In Junos, OSPF interfaces are configured by adding them to an OSPF area under the protocols hierarchy: 'set protocols ospf area [area-id] interface [interface]'.

Question 3

What is the function of the OSPF Designated Router (DR) on a broadcast network?

Accepted Answer

To reduce the number of OSPF adjacencies by acting as a central point for LSA flooding on the broadcast segment

Answer

On multi-access broadcast segments (Ethernet), OSPF elects a DR and BDR to minimize the number of full adjacencies. All routers form Full adjacencies only with the DR and BDR, reducing LSA flooding.

Question 4

What is the BGP attribute 'LOCAL_PREF' used for?

Accepted Answer

To influence outbound routing decisions within an AS by preferring routes with higher LOCAL_PREF values

Answer

LOCAL_PREF is a BGP well-known discretionary attribute shared among iBGP peers within the same AS. Higher LOCAL_PREF values are preferred, influencing which exit point is used for outbound traffic.

Question 5

Which Junos command shows all routes redistributed from OSPF into the local routing table?

Accepted Answer

show route protocol ospf

Answer

'show route protocol ospf' in Junos operational mode filters the routing table to show only routes learned via OSPF, which includes redistributed routes if they are installed in the RIB.

JNCIA - Juniper Networks Certified Internet Associate Practice Test

JNCIA - Juniper Networks Certified Internet Associate Practice Test

JNCIA Routing Protocols