The BGP attribute that you would use to forward all Internet traffic through the R1 device is the local preference1.

The local preference is an attribute that is used within an autonomous system (AS) and exchanged between iBGP routers1. It is used to select an exit point from the AS1. The path with the highest local preference is preferred1. By setting a higher local preference for the routes received from R1, you can make R1 the preferred exit point for all Internet traffic1.

The configuration shown in the exhibit is an example of a routing instance of type virtual-router. A routing instance is a collection of routing tables, interfaces, and routing protocol parameters that create a separate routing domain on a Juniper device1. A virtual-router routing instance allows administrators to divide a device into multiple independent virtual routers, each with its own routing table2.

The configuration also includes a rib-group statement, which is used to import routes from one routing table to another. A rib-group consists of an import-rib statement, which specifies the source routing table, and an export-rib statement, which specifies the destination routing table.

In this case, the rib-group name is inet-to-ispi, and the import-rib statement specifies inet.0 as the source routing table. The export-rib statement specifies ispi.inet.0 as the destination routing table. This means that the routes from inet.0 will be imported into ispi.inet.0.

Therefore, the correct answer is B. The inet.0 route table will be imported into the ispi.inet.0 route table.

References:

1: Routing Instances Overview 2: Virtual Routing Instances : [rib-group (Routing Options)]

A keepalive OAM probe is a mechanism that can be used to monitor the state of a GRE tunnel and detect any failures in the tunnel path. A keepalive OAM probe consists of sending periodic packets from one end of the tunnel to the other and expecting a reply. If no reply is received within a specified time, the tunnel is considered down and the line protocol of the tunnel interface is changed to down1.

To configure a keepalive OAM probe for a GRE tunnel, you need to specify two parameters: the keepalive-time and the hold-time. The keepalive-time is the interval between each keepalive packet sent by the local router. The hold-time is the maximum time that the local router waits for a reply from the remote router before declaring the tunnel down2.

According to the Juniper Networks documentation, the hold-time value must be two times the keepalive-time value for a GRE tunnel2. This is because the hold-time value must account for both the round-trip time of the keepalive packet and the processing time of the remote router. If the hold-time value is too small, it may cause false positives and unnecessary tunnel flaps.

In the exhibit, the configuration shows that the keepalive-time is set to 10 seconds and the hold-time is set to 15 seconds for the gr-1/1/10.1 interface. This means that the local router will send a keepalive packet every 10 seconds and will wait for 15 seconds for a reply from the remote router. However, this hold-time value is not two times the keepalive-time value, which violates the recommended configuration. This may cause traffic drops if the remote router takes longer than 15 seconds to reply.

Therefore, option D is correct, because the hold-time value must be two times the keepalive-time value for a GRE tunnel. Option A is incorrect, because BFD is not required for GRE tunnels; BFD is another protocol that can be used to monitor tunnels, but it is not compatible with GRE keepalives3. Option B is incorrect, because the “event link-adjacency-loss” option is not related to GRE tunnels; it is an option that can be used to trigger an action when a link goes down4. Option C is incorrect, because LLDP does not need to be removed from the gr-1/1/10.1 interface; LLDP is a protocol that can be used to discover neighboring devices and their capabilities, but it does not interfere with GRE tunnels5.

References:

1: Configuring Keepalive Time and Hold time for a GRE Tunnel Interface 2: keepalive | Junos OS | Juniper Networks 3: Configuring Bidirectional Forwarding Detection 4: event link-adjacency-loss | Junos OS | Juniper Networks 5: Understanding Link Layer Discovery Protocol

• A is correct because IBGP updates the next-hop attribute to ensure reachability within an AS. This is because the next-hop attribute is the IP address of the router that advertises the route to a BGP peer. If the next-hop attribute is not changed by IBGP, it would be the IP address of an external router, which may not be reachable by all routers within the AS. Therefore, IBGP updates the next-hop attribute to the IP address of the router that received the route from an EBGP peer1.
• B is correct because IBGP peers advertise routes received from EBGP peers to other IBGP peers. This is because BGP follows the rule of advertising only the best route to a destination, and EBGP routes have a higher preference than IBGP routes. Therefore, IBGP peers advertise routes learned from an EBGP peer to all BGP peers, including both EBGP and IBGP peers1.

The output shown in the exhibit is the result of the command “show ip bgp neighbor 10.36.1.4 received-routes”, which displays all received routes (both accepted and rejected) from the specified neighbor.

Option A is correct, because the routes displayed have traversed one or more autonomous systems. This can be seen from the AS_PATH attribute, which shows the sequence of AS numbers that the route has passed through. For example, the route 10.0.0.0/8 has an AS_PATH of 65001 65002, which means that it has traversed AS 65001 and AS 65002 before reaching the local router.

Option B is correct, because the output shows routes that were received prior to the application of any BGP import policies. This can be seen from the fact that some routes have a status code of “r”, which means that they are rejected by an import policy. The“received-routes” keyword shows the routes coming from a given neighbor before the inbound policy has been applied. To see the routes after the inbound policy has been applied, the “routes” keyword should be used instead.

Option C is incorrect, because the output does not show routes that are active and rejected by an import policy. The status code of “r” means that the route is rejected by an import policy, but it does not mean that it is active. The status code of “>” means that the route is active and selected as the best path. None of the routes in the output have both “>” and “r” status codes.

Option D is incorrect, because the routes displayed are not being learned from an IBGP peer. An IBGP peer is a BGP neighbor that belongs to the same AS as the local router. The output shows that the neighbor 10.36.1.4 has a remote AS of 65001, which is different from the local AS of 65002. Therefore, the neighbor is an EBGP peer, not an IBGP peer.

• The exhibit shows the output of the command show ospf neighbor, which displays information about the OSPF neighbors on a router1.
• The output shows that the OSPF neighbor with the address 172.26.1.1 and the interface ge-0/0/3.0 is in the Exstart state1.
• The Exstart state is the fourth state in the OSPF neighbor formation process, after Down, Init, and 2-Way states2. In this state, the OSPF neighbors establish a master-slave relationship and exchange database description (DBD) packets, which contain summaries of their link-state databases2.
• The most common reason for OSPF neighbors to be stuck in the Exstart state is an MTU mismatch between the interfaces3. MTU stands for maximum transmission unit, which is the largest size of a packet that can be transmitted on a network segment4. If the MTU values of two OSPF neighbors are different, theymay not be able to exchange DBD packets successfully, as some packets may be dropped or fragmented due to their size exceeding the MTU limit3.
• To solve this problem, you need to ensure that the MTU values of both OSPF neighbors are the same or compatible. You can use the command show interfaces to display the MTU value of an interface5. You can also use the command ping with the do-not-fragment option to test the MTU size between two routers. You can change the MTU value of an interface by using the command set interfaces interface-name mtu mtu-value in configuration mode5.

Option A is correct. Creating multiple areas in OSPF can help to reduce the convergence time . This is because changes in one area do not affect other areas, so fewer routers need to run the SPF algorithm in response to a change.

Option D is correct. Creating multiple areas in OSPF can help to reduce Link State Advertisement (LSA) flooding across the network. This is because LSAs are not flooded out of their area of origin.

• The output shown in the exhibit is a brief display of the Ethernet switching table, which shows the learned Layer 2 MAC addresses for each VLAN and interface1.
• The command show ethernet-switching table displays the Ethernet switching table with brief information, such as the destination MAC address, the VLAN name, the forwarding state, and the interface name1.
• The command show route forwarding-table displays the routing table information for each protocol family, such as inet, inet6, mpls, iso, and so on2. It does not show the Ethernet switching table or the MAC addresses.
• The command show ethernet-switching table extensive displays the Ethernet switching table with extensive information, such as the destination MAC address, the VLAN name, the forwarding state, the interface name, the VLAN index, and the tag type1. It shows more details than the brief output shown in the exhibit.
• The command show route forwarding-table family ethernet-switching displays the routing table information for the ethernet-switching protocol family, whichshows the destination MAC address, the next-hop MAC address, and the interface name3. It does not show the VLAN name or the forwarding state.

• A is correct because you can deploy only stateless firewall filters on an EX Series switch. A stateless firewall filter is a filter that evaluates each packet individually based on the header information, such as source and destination addresses, protocol, and port numbers1. A stateless firewall filter does not keep track of the state or context of a packet flow, such as the sequence number, flags, or sessioninformation1. EX Series switches support only stateless firewall filters, which are also called access control lists (ACLs) or packet filters2.
• C is correct because you can apply firewall filters to both Layer 2 and Layer 3 traffic on an EX Series switch. Layer 2 traffic is traffic that is switched within a VLAN or a bridge domain, while Layer 3 traffic is traffic that is routed between VLANs or networks3. EX Series switches support three types of firewall filters: port (Layer 2) firewall filters, VLAN firewall filters, and router (Layer 3) firewall filters4. You can apply these filters to different interfaces and directions to control the traffic entering or exiting the switch.

A RIB group is a configuration that allows a routing protocol to install routes into multiple routing tables in Junos OS. A RIB group consists of an import-rib statement,which specifies the source routing table, and an export-rib statement, which specifies the destination routing table or group. A RIB group can also include an import-policy statement, which specifies one or more policies to control which routes are imported into the destination routing table or group1.

An import policy is a policy statement that defines the criteria for accepting or rejecting routes from the source routing table. An import policy can also modify the attributes of the imported routes, such as preference, metric, or community. An import policy can be applied to a RIB group by using the import-policy statement under the [edit routing-options rib-groups] hierarchy level1.

Therefore, option A is correct, because an import policy is applied to the RIB group to control which routes are installed in the destination routing table or group. Option B is incorrect, because all routes in the source routing table are imported into the destination routing table or group, unless filtered by an import policy. Option C is incorrect, because a firewall filter is not used to install routes in the RIB groups; a firewall filter is used to filter packets based on various criteria. Option D is incorrect, because an export policy is not applied to the RIB group; an export policy is applied to a routing protocol to control which routes are advertised to other devices.

References:

1: rib-groups | Junos OS | Juniper Networks

To isolate management traffic in a non-default routing-instance on Junos-based devices, you can use the set system management-instance and set routing-instances mgmt_junos commands12.

• set system management-instance: This command associates the management interface (usually named fxp0 or em0 for Junos OS, or re0:mgmt-* or re1:mgmt-* for Junos OS Evolved) with the non-default virtual routing and forwarding (VRF) instance1. After you configure the non-default management VRF instance, management traffic no longer has to share a routing table with other control traffic or protocol traffic1.
• set routing-instances mgmt_junos: This command creates a new routing instance named mgmt_junos. The name of the dedicated management VRF instance is reserved and hardcoded as mgmt_junos; you cannot configure any other routing instance by the name mgmt_junos1.

Therefore, options C and D are correct. Options A and B are not correct because they attempt to assign an interface to the mgmt_junos routing instance, which is not necessary for isolating management traffic1.

A. On R1, enable Level 1 on the ge-0/0/1 interface. In IS-IS, both levels (Level 1 and Level 2) are enabled by default when you enable IS-IS on an interface1. Level 1 systems route within an area2. If the destination is outside an area, Level 1 systems route toward a Level 2 system2. Therefore, enabling Level 1 on the ge-0/0/1 interface on R1 would allow packets to reach from R1 to R3.

D. On R3 enable Level 1 on the ge-0/0/4 interface Similarly, enabling Level 1 on the ge-0/0/4 interface on R3 would allow packets to reach from R1 to R3.

These explanations are based on the IS-IS configuration documents and learning resources available at Juniper Networks1 and Cisco34.

BFD is a protocol that can be used to quickly detect failures in the forwarding path between two adjacent routers or switches. BFD can be integrated with various routing protocols and link aggregation protocols to provide faster convergence and fault recovery.

According to the Juniper Networks documentation, the following protocols support BFD on Junos OS devices1:

• BGP: BFD can be used to monitor the connectivity between BGP peers and trigger a session reset if a failure is detected. BFD can be configured for both internal and external BGP sessions, as well as for IPv4 and IPv6 address families2.
• OSPF: BFD can be used to monitor the connectivity between OSPF neighbors and trigger a state change if a failure is detected. BFD can be configured for both OSPFv2 and OSPFv3 protocols, as well as for point-to-point and broadcast network types3.
• LACP: BFD can be used to monitor the connectivity between LACP members and trigger a link state change if a failure is detected. BFD can be configured for both active and passive LACP modes, as well as for static and dynamic LAGs4.

Other protocols that support BFD on Junos OS devices are:

• IS-IS: BFD can be used to monitor the connectivity between IS-IS neighbors and trigger a state change if a failure is detected. BFD can be configured for both level 1 and level 2 IS-IS adjacencies, as well as for point-to-point and broadcast network types.
• RIP: BFD can be used to monitor the connectivity between RIP neighbors and trigger a route update if a failure is detected. BFD can be configured for both RIP version 1 and version 2 protocols, as well as for IPv4 and IPv6 address families.
• VRRP: BFD can be used to monitor the connectivity between VRRP routers and trigger a priority change if a failure is detected. BFD can be configured for both VRRP version 2 and version 3 protocols, as well as for IPv4 and IPv6 address families.

The protocols that do not support BFD on Junos OS devices are:

• RSTP: RSTP is a spanning tree protocol that provides loop prevention and rapid convergence in layer 2 networks. RSTP does not use BFD to detect link failures, but relies on its own hello mechanism that sends BPDU packets every 2 seconds by default.
• FTP: FTP is an application layer protocol that is used to transfer files between hosts over a TCP connection. FTP does not use BFD to detect connection failures, but relies on TCP’s own retransmission and timeout mechanisms.

References:

1: [Configuring Bidirectional Forwarding Detection] 2: [Configuring Bidirectional Forwarding Detection for BGP] 3: [Configuring Bidirectional Forwarding Detection for OSPF] 4: [Configuring Bidirectional Forwarding Detection for Link Aggregation Control Protocol] : [Configuring Bidirectional Forwarding Detection for IS-IS] : [Configuring Bidirectional Forwarding Detection for RIP] : [Configuring Bidirectional Forwarding Detection for VRRP] : [Understanding Rapid Spanning Tree Protocol] : [Understanding FTP]

• Option B is correct. Flooding is a mechanism used in Layer 2 bridging where the switch sends incoming packets to all its ports except for the port where the packet originated1. This is done when the switch doesn’t know the destination MAC address or when the packet is a broadcast or multicast1.
• Option C is correct. Learning is another mechanism used in Layer 2 bridging where the switch learns the source MAC addresses of incoming packets and associates them with the port on which they were received23. This information is stored in a MAC address table, also known as a bridge table23.
• Option A is incorrect. Blocking is a state in Spanning Tree Protocol (STP) used to prevent loops in a network2. It’s not a mechanism used in building and maintaining a Layer 2 bridge table2.
• Option D is incorrect. Listening is also a state in Spanning Tree Protocol (STP) where the switch listens for BPDUs to make sure no loops occur in the network before transitioning to the learning state2. It’s not a mechanism used in building and maintaining a Layer 2 bridge table2.

In BGP, routing policies are used to control the flow of routing information between BGP peers1.

Option C suggests that import policies are applied after the RIB-In table. This is correct because import policies in BGP are applied to routes that are received from a BGP peer, before they are installed in the local BGP Routing Information Base (RIB-In)1. The RIB-In is a database that stores all the routes that are received from all peers1.

Option D suggests that export policies are applied after the RIB-Local table. This is correct because export policies in BGP are applied to routes that are being advertised to a BGP peer, after they have been selected from the local BGP Routing Information Base (RIB-Local)1. The RIB-Local is a database that stores all the routes that the local router is using1.

Therefore, options C and D are correct.

Option A suggests that the MTU is not at least 1492 bytes. This is correct because IS-IS requires a minimum MTU of 1492 bytes to establish adjacencies1. If the MTU is less than this, IS-IS adjacencies will not be established1.

Option D suggests that the lo0 interface is not included as an IS-IS interface. This is also correct because the loopback interface (lo0) is typically used as the router ID in IS-IS1. If the loopback interface is not included in IS-IS, it could prevent IS-IS adjacencies from being established1.

Therefore, options A and D are correct.