Juniper JN0-363 Service Provider Routing and Switching, Specialist (JNCIS-SP) Exam Practice Test

the Database Description (DD) packets serve two main purposes:

1. determinining which router is in charge of the database synchronization

2. tansferring the LSA headers between the two systems

The Database Description (DBD) OSPF packet is used during the adjacency formation process to describe the contents of the topological database between routers. The routers exchange DBD packets to determine the master and slave relationship, which dictates the router in charge of the database synchronization.References:

• OSPF Design Guide, Juniper Networks Documentation
• OSPF Database Description Packets, Juniper Networks Documentation

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.

When you want to advertise an interface in OSPF but not form an OSPF adjacency over that interface (for example, towards an ISP), you can configure the interface as passive. This will advertise the network on the interface in OSPF without sending OSPF hello packets or forming OSPF neighbor relationships on that interface.

References

• Juniper Networks Technical Documentation on OSPF
• OSPF Configuration Guide - Juniper Networks

Filter-based forwarding in Junos requires the creation of a routing policy to specify the match conditions and actions and the application of a match filter to classify traffic to use the policy.References:

• Filter-Based Forwarding Overview, Juniper Networks Documentation
• Example: Configuring Filter-Based Forwarding, Juniper Networks Documentation

In BGP (Border Gateway Protocol), the Update message is used to advertise new routes to a peer or to withdraw previously advertised routes. If there's a change in the routing information or if a new route needs to be advertised, BGP uses an Update message. This message is crucial for maintaining the most current and accurate routing information among BGP peers.

The other message types serve different purposes:

Keepalive: This message type is used to maintain the connection between BGP peers and ensure that the link is still active. Keepalive messages are periodically sent between peers when there is no other BGP activity to maintain the session.

Notification: This message is used to indicate errors or other significant events to a BGP peer. If a BGP error condition is detected, a Notification message is sent and the BGP session is typically closed.

Refresh: This is not a standard BGP message type. However, in the context of BGP, Route Refresh is a capability (not a message type) that allows a BGP router to request a full or partial re-advertisement of routes from a peer. This helps in re-synchronizing routing tables without tearing down the BGP session.

The BGP Update message is used to advertise routable destinations and includes route advertisements, route withdrawals, and path attribute modifications. Update messages are used to re-advertise routes that have already been acknowledged.References:

• BGP Operations and Message Types Overview, Juniper Networks Documentation
• BGP Update Message, Juniper Networks Documentation

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.

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 segment routing, SIDs (Segment Identifiers) are used to identify different types of segments that can be traversed. A node SID represents an instruction to route a packet to a particular node, and an adjacency SID represents an instruction to route a packet over a specific link or adjacency between two nodes.

References

• Juniper Networks Technical Documentation on Segment Routing

To enable MPLS on a physical interface in Junos, the family mpls statement must be added to the interface configuration. Additionally, the interface itself must be specifiedunder the protocols mpls section of the configuration.References:

• MPLS Configuration Guide, Juniper Networks Documentation
• Configuring MPLS, Juniper Networks Documentation

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

Given the RSVP Signaled Service Provider MPLS Core network shown in the exhibit, only a single Label Switched Path (LSP) is required to support all four networks because MPLS can use label stacking to multiplex multiple LSPs over a single physical path. Therefore, one LSP can be established through the MPLS core, and all networks can use this LSP with different label stacks.References:

• MPLS Fundamentals, Juniper Networks Documentation
• RSVP-TE Signaling, Juniper Networks Documentation

IS-IS is a link-state routing protocol that uses a Shortest Path First (SPF) algorithm to create a topology map of the network. It floods link-state advertisements (LSAs) to all nodes within the network area to ensure each node has a consistent view of the network topology.

References

• Juniper Networks Technical Documentation on IS-IS
• Understanding IS-IS - Juniper Networks

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

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 community attribute in BGP is an optional transitive attribute. It is not mandatory for BGP operations, but when it is present, it should be passed unchanged to other BGP peers unless explicitly modified by a routing policy. The community attribute is used to group destinations in a certain way, often to apply routing policies to those destinations collectively.

References:

• Juniper Networks documentation on BGP communities: BGP Communities Overview

The policy statement shown in the exhibit has a term that specifiesload-balance per-packet, which indicates that per-packet load balancing is being used. This means that the routing device will distribute packets out multiple paths on a per-packet basis, rather than on a per-flow (per-destination or per-source-destination pair) basis.

References:

• Juniper Networks documentation on Load Balancing: Load Balancing Overview

For IS-IS to form adjacencies, the 'family iso' statement must be configured on the interface. This is required because IS-IS operates over the connectionless network service (CLNS) and not over IP. Without the 'family iso' configuration, IS-IS cannot form adjacencies over the interface.

References:

• Juniper Networks documentation on IS-IS: IS-IS User Guide for Routing Devices

When establishing an EBGP session, it's necessary to specify both the local AS number and the local address that the session will use. The local address is required for establishing the TCP connection for BGP. The local AS must be specified to identify the autonomous system of the router.References:

• Configuring BGP, Juniper TechLibrary
• BGP Peers and BGP Sessions, Juniper TechLibrary

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.

In the given exhibit, interfacege-0/0/0is configured to accept VLANs 101-120 andge-0/0/1is configured with flexible VLAN tagging, which means it can tag traffic with any VLAN ID specified. However, only VLAN 200 is explicitly mentioned forge-0/0/1.A. Traffic tagged with VLAN 101 will pass throughge-0/0/0and will egress onge-0/0/1with the same VLAN tag, because the VLAN ID is within the allowed range on both interfaces.B. VLAN 100 is not specified in the allowed VLAN range forge-0/0/0(which is 101-120),nor is it specified underge-0/0/1. Therefore, it will be dropped.References:

• Understanding VLAN Tagging, Juniper TechLibrary
• Configuring VLANs for EX Series Switches, Juniper TechLibrary

In the exhibit, the interface is configured with thenative-vlan-id 20parameter. This means that any untagged frames arriving on this interface will be associated with VLAN 20. The native VLAN serves as the default VLAN for untagged frames on a trunk port.

References:

• Juniper Networks documentation on VLANs: Configuring VLANs

The exhibit shows the output of the commandshow spanning-tree bridge, which provides information about the spanning tree status of the switch. From the output, we can see that the switch has a bridge ID different from the root ID, which implies that this switch is not the root bridge. The "Topology change initiator" field shows ge-0/0/14, which indicates that the last topology change occurred on this interface, and this is also the interface used to reach the root bridge.

References:

• Juniper Networks documentation on Spanning Tree Protocol: Understanding Spanning Tree Protocols

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 exhibit shows theshow vrrp summaryoutput from two routers, with both routers listing the state of their VRRP group asmaster. VRRP allows for multiple routers to share a virtual IP address and a virtual MAC address, but usually, only one router is the master at any given time while others are in backup state. However, in some configurations, VRRP can operate in an active/active mode where multiple routers handle traffic simultaneously for load sharing. Since both routers show the state asmasterand there is no evidence of misconfiguration in the virtual IP addresses or priority, it indicates that VRRP is likely functioning in an active/active setup.

References:

• Juniper documentation on VRRP: Junos OS VRRP Overview

Theshow system switchovercommand is used to display the status of the Graceful Routing Engine Switchover (GRES) feature. This command is available when nonstop routing (NSR) is enabled, which works in conjunction with GRES to maintain uninterrupted routing in case of a Routing Engine switchover.

References:

• Juniper Networks documentation on CLI Commands: show system switchover