JN0-363 Practice Exam Questions with Answers Service Provider Routing and Switching, Specialist (JNCIS-SP) Certification

static route with a next-hop of next-table pointing to the appropriate routing table which contains more accurate information rib-groups to mirror routing information from one route-table to another. However, in many cases, in order to make this work, interface-routes also need to be mirrored. RIB Group policy can be used to constrain the routing information instance-import and instance-export statements configured within the individual routing-instances to leak routes from one table to another. Again, policy can be used here to constrain the routing information. This method is more straightforward than the rib-group method A final approach is to use physical interfaces or logical-tunnels to stitch routing-instances and use a routing protocol or static routes across this connection between the two routing-instances.

To share routes between two routing instances on a Junos device, you can configure an instance import policy in one or both instances to import routes from the other instance. Alternatively, a RIB (Routing Information Base) group can be used to share routes between instances.References:

• Routing Instances Overview, Juniper Networks Documentation
• RIB Groups Configuration Guide, Juniper Networks Documentation

Junos devices learn about MAC addresses by examining the source MAC address of frames received on an interface and then storing these MAC addresses in the MAC address table (also known as the forwarding database) along with the interface on which the traffic was received.References:

• Understanding Learning and Forwarding, Juniper TechLibrary
• MAC Address Table Processing, Juniper TechLibrary

In MPLS (Multiprotocol Label Switching) networks, routers use label switching to forward packets. The first router at the edge of the MPLS network (R1) will perform a lookup in the mpls.0 table to determine the label to attach to the packet as it enters the MPLS network. This label informs the next routers in the MPLS network (like R2) on how to forward the packet. Internal MPLS routers, like R2, also perform lookups in their mpls.0 table to determine how to switch the packet toward its destination (label swapping). The inet.3 table is used for resolving next-hop information for labeled routes, but it's the mpls.0 table that is used for label switching decisions.

References:

• Juniper Networks documentation on MPLS: MPLS Applications User Guide for Routing Devices

To prevent a router from participating in the OSPF designated router (DR) and backup designated router (BDR) election process, you set the OSPF priority to 0 on the interfaces of that router. This tells OSPF that the router on those interfaces is not to be considered for election as either DR or BDR, effectively making them DRother routers. The exhibit indicates that this is the desired configuration, and therefore the correct command to issue on the Juniper device would be to set the priority to 0 on the relevant interfaces.

According to the exhibit, the primary LSP is configured with a strict path via R2 to R4. Since the configuration shows valid next-hops and there is no indication of any issues, the primary LSP will be signaled and its state will be up. The secondary LSP with any-path is also configured and will be signaled as a backup; therefore, its state will be up as well, ready to take over if the primary fails.References:

• MPLS LSP Configuration, Juniper Networks Documentation
• Configuring Primary and Secondary LSPs, Juniper Networks Documentation

To create connections between routing instances on the same Junos device and route between them, you can use logical tunnel interfaces, which are virtual interfaces that can be used to route traffic between instances without the need for physical connectivity. Additionally, loopback interfaces, which represent the device itself, can be used to route traffic between routing instances as they are always up and can be reached within the device.

References

• Juniper Networks Technical Documentation on Routing Instances
• Juniper Networks Technical Documentation on Logical Tunnel Interfaces

The adjacency SID in segment routing is advertised by one router to inform another about the label that should be used to forward traffic to it over a particular link. In this scenario, Router B would advertise an adjacency SID to Router A, which would be usedby Router A to forward traffic to Router B. Based on the exhibit, the adjacency SID that Router B advertises to Router A would be 12.

References:

• Juniper Networks documentation on Segment Routing: Segment Routing Overview

In the OSPF routing table output, prefixes are marked with different route types. An external prefix injected into OSPF is marked as 'Ext' (External) followed by a number that indicates whether it's an E1 or E2 route. The prefix 172.18.1.0/24 is marked as Ext2, which indicates that it is an external route that has been redistributed into OSPF from another routing protocol or static configuration.

References

• Juniper Networks Technical Documentation on OSPF

The Segment Routing Global Block (SRGB) defines a range of MPLS labels reserved for segment routing. With an SRGB starting label of 10,000 and an index range of 500, the first usable label is indeed 10,001 because label 10,000 is typically reserved and not usedfor forwarding. The last usable label would be 10,499 because the range includes 500 labels starting from 10,001.

References:

• Juniper Networks documentation on Segment Routing: Segment Routing Overview

In a service provider MPLS network, P routers are interior routers that are used to transit MPLS-labeled packets between edge routers but do not attach or remove MPLS labels themselves. These routers are also referred to as transit routers. They are neither ingress nor egress routers (which are typically labeled as PE routers).

References:

• Juniper Networks documentation on MPLS: MPLS Fundamentals

By default, the router that originally sourced the route into BGP places its peer address into the attribute field. The next-hop value is then typically changed when the route is transmitted across external gGP (EBGP) links. Internal BGP (IBGP) peers do not alter the next-hop value between themselves.

B. By default, the next-hop value is changed when a route is passed from an EBGP peer to another EBGP peer.C. By default, the next-hop value is retained when a route is advertised across IBGP links.References:

• BGP Next Hop Attribute, Juniper TechLibrary
• Understanding BGP Next-Hop Selection, Juniper TechLibrary

The "ultimate-hop-popping" term refers to the action taken by the penultimate router in an LSP to remove the MPLS label before delivering the packet to the ultimate router,which is not desired here. Configuring the "explicit-null" statement causes the penultimate router to replace the top label with a label that has a value of 0, which instructs the ultimate router to perform a label lookup and preserve the label switching for the entire LSP.

References:

• Juniper Networks documentation on MPLS: MPLS Applications User Guide for Routing Devices

A route being hidden in BGP usually indicates a configuration that prevents it from being used, such as a next-hop that is not reachable.B. Configuring a routing policy on R1 that sets the next-hop to the address used for IBGP peering ensures reachability of the next-hop within the local AS.D. Applying the correct routing policy as an export policy to the IBGP group on R1 will share the route with the IBGP peers, in this case, R2 and R3.References:

• Understanding BGP Path Selection, Juniper TechLibrary
• BGP Policies and Route Selection, Juniper TechLibrary

When deploying Link Aggregation Groups (LAGs), it is necessary for all ports in the LAG to operate at the same speed to ensure consistent performance and avoid issues with load balancing. Multi-Chassis LAG (MC-LAG) allows for the use of member links that span multiple physical devices, offering redundancy and higher bandwidth by combining the links from two separate devices into a single logical LAG.

References

• Juniper Networks Technical Documentation on Link Aggregation Groups
• Juniper Networks Technical Documentation on MC-LAG

Segment routing labels can be distributed by link-state routing protocols such as IS-IS and OSPF, which have been extended to support segment routing capabilities.References:

• Segment Routing Overview, Juniper Networks Documentation
• Understanding Segment Routing with OSPF, Juniper Networks Documentation
• Understanding Segment Routing with IS-IS, Juniper Networks Documentation

R2 can not forward IBGP learned routes to another IBGP neighbor correct

R3 will learn about Route X from R2 only. R1 is in a separate AS and Route X is advertised to R2 through eBGP. R2 will then advertise the route to R3 using iBGP. R3 cannot learn routes directly from another AS without having a direct eBGP session with that AS.References:

• BGP Route Propagation and Selection, Juniper Networks Documentation
• Understanding iBGP and eBGP Route Distribution, Juniper Networks Documentation

IPv6 link-local addresses are automatically generated for each interface and have a prefix of fe80::/10. The interface's MAC address is typically used as part of the process to create the Interface Identifier (IID) in the link-local address, following the EUI-64 format.

References

• Juniper Networks Technical Documentation on IPv6
• IPv6 Interface Addresses - Juniper Networks

An Integrated Routing and Bridging (IRB) interface is used to provide Layer 3 routing services to hosts within a bridge domain. The IRB acts as a default gateway for hosts in that domain, enabling communication with other networks.

References

• Juniper Networks Technical Documentation on IRB Interfaces

In OSPF, a totally stubby area does not permit type 3 summary LSAs (inter-area routes) or type 5 external LSAs (routes from outside the OSPF domain) to be flooded into the area. The area border router (ABR) will only send a default route as a type 3 LSA into the totally stubby area.

References:

• Juniper Networks documentation on OSPF Areas: Understanding OSPF Areas

A router’s priority for becoming the designated router is indicated by an arbitrary number from 0 through 127, which you configure on the IS-IS interface. The router with the highest priority becomes the designated router for the area (Level 1, Level 2, or both), also configured on the IS-IS interface. If routers in the network have the same priority, then the router with the highest MAC address is elected as the designated router. By default, routers have a priority value of 64.

https://www.juniper.net/documentation/us/en/software/junos/is-is/topics/concept/routing-protocol-is-is-security-designated-router-understanding.html