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

Considering the bandwidth reservations shown, the only path from R4 to R6 that has sufficient available bandwidth for a new LSP with 400 Mbps reservation is via R1, R2, and R5. This is because the R4-R5 direct link and the R4-R1-R2-R3-R6 path do not have enough unreserved bandwidth to accommodate an additional 400 Mbps LSP.

References:

• Juniper Networks documentation on RSVP: RSVP-TE Overview

The diagram you provided shows two routers, Router A and Router B, with MPLS labels between them. In the context of segment routing with MPLS, each router advertises a set of SIDs (Segment Identifiers). These SIDs can be node SIDs, which are associatedwith the router itself, or adjacency SIDs, which are associated with the links between routers.

Given the information from the exhibit:

• Router A has a Router ID of 10.1.1.1 and is associated with the MPLS label 11.
• Router B has a Router ID of 10.1.1.2 and is associated with the MPLS label 12.

The adjacency SID in segment routing is used to identify a specific adjacency between two routers. In this case, the question is asking for the adjacency SID that Router B advertises to Router A. This would be the label that Router B tells Router A to use to send packets directly to Router B over their shared adjacency.

So, the adjacency SID that Router B advertises would be associated with the link that Router A would use to send traffic to Router B, which is labeled with the number 12 in the exhibit.

Therefore, the answer to the question is:

D. 12

This is the label that packets would carry when being sent from Router A to Router B to identify the specific adjacency between the two routers in the context of segment routing.

To test connectivity to a server from within a specific routing instance, you use thepingcommand along with therouting-instanceoption to specify the routing instance from which you are pinging. This is necessary because the routing table associated withvr3is separate from the main routing table, and you must explicitly tell the device to use thevr3routing table to reach the server.

References:

• Juniper Networks documentation on Routing Instances: Routing Instances Overview

Upon a link failure in an RSVP-signaled LSP, the router upstream of the failure (R2) sends a PathTear message upstream to the ingress router (R1), and the router downstream of the failure (R3) sends a ResvTear message downstream to the egress router (R4). These messages signal the failure and initiate tear down of the LSP state in the respective directions.References:

• RSVP-TE Overview, Juniper Networks Documentation
• Understanding RSVP Signal Failures, Juniper Networks Documentation

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

The IPv6 header includes a new field that is not found in the IPv4 header, called the flow label. The flow label in IPv6 is used to identify packets that require special handling by routers for quality of service (QoS) or other reasons, allowing these packets to be handled efficiently as they move through the network.

References

• Juniper Networks Technical Documentation on IPv6
• IPv6 Header Fields - Juniper Networks

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

The AS path is a BGP attribute that lists the autonomous systems (AS) that routing information has passed through to get to a destination. It is used to detect and prevent routing loops by checking if the router's own AS number is in the path.

References:

• Juniper Networks documentation on BGP: BGP Attributes and Policy

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.

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

To ensure that MPLS traffic-engineered routes are used without affecting IGP routes in the route tables, the mpls-forwarding traffic engineering setting should be used. This setting allows MPLS to influence forwarding without changing the IGP route selection.References:

• MPLS Traffic Engineering, Juniper Networks Documentation
• Traffic Engineering and LSP Optimization, 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

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

Local preference is a BGP attribute that dictates which path is preferred when multiple paths to the same destination are available. A higher local preference is preferred over a lower one. Since ISP A (AS 65501) is advertising a local preference of 100 and ISP B (AS 65502) is advertising a local preference of 200 to AS 65512, traffic from devices in AS 65512 will prefer the path via ISP B for all networks that ISP B advertises. However, since ISP A advertises the 172.20.21.0/24 network and ISP B does not, traffic for 172.20.21.0/24 will go through ISP A. For the 172.20.0.0/24 network, which both ISPs advertise, devices in AS 65512 will prefer the path via ISP B due to the higher local preference.

References:

• Juniper Networks documentation on BGP attributes: BGP Attributes and Policy

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

The FE80::/10 prefix is reserved for IPv6 link-local addresses. These addresses are auto-configured on all IPv6-enabled interfaces and can be used for communication within the local link (subnet) only.

References

• Juniper Networks Technical Documentation on IPv6 Addressing

The router identifier is used by BGP and OSPF to identify the routing device from which a packet originated. The router identifier usually is the IP address of the local routing device. If you do not configure a router identifier, the IP address of the first interface to come online is used. This is usually the loopback interface. Otherwise, the first hardware interface with an IP address is used

In OSPF, if a router ID is not manually configured, Junos OS will automatically select the router ID based on the highest IP address of any of the router’s loopback interfaces. If no loopback interface exists, the highest IP address of any active interface will be used. Therefore, answer C is correct.

References:

• Juniper Networks documentation on OSPF: OSPF Overview

To verify the status of the tunnel from R1, you would issue a ping from the source address that is assigned to R1's end of the tunnel. In the exhibit, we can see that the tunnel interface (gre-0/0/0.0) has the IP address 198.51.100.1 on R1. Therefore, to test the tunnel's status, you should ping the IP address at the other end of the tunnel (which is likely the address on User B's interface or another interface on R2) from R1's tunnel source address.

References:

• Juniper Networks documentation on GRE: GRE Interface Configuration

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