JN0-649 Enterprise Routing and Switching Professional (JNCIP-ENT) Question and Answers

Analyzing BGP Route Information:

The exhibit shows BGP route information for the prefix 203.0.113.0/24.

Both paths to this prefix are learned from the same BGP peer with IP address 192.168.10.36.

Understanding BGP Neighbors:

The presence of multiple paths for the same prefix does not necessarily indicate multiple neighbors.

In this case, the routes to 203.0.113.0/24 are both learned from a single neighbor (192.168.10.36), but via different interfaces (ae8.0 and ae7.0).

Conclusion:

The BGP routes in the exhibit indicate that the prefix is learned from one neighbor but via different interfaces.

References:

BGP route analysis

Understanding BGP multi-path and neighbor relationships

For Multiple Spanning Tree Protocol (MSTP) to operate correctly, all switches in the same region must have the same VLAN to instance mapping, revision level, and configuration name. These parameters ensure that all switches interpret the MSTP configuration consistently.

References:

MSTP Configuration Guide, Juniper Networks

Area-1 has no external connections. However, Area-1 has static route (172.16.31.0/24) that are not internal OSPF route. You can limit the external route advertisements to the area and advertise the static routes by designating the area an NSSA. In an NSSA, the ASBR (vMX1) generates NSSA external (Type 7) LSAs and floods them into the NSSA, where they are contained. Type-7 LSAs allow an NSSA to support the presence of ASBR and their corresponding external routing information. The ABR (vMX2) converts Type-7 LSAs into Type-5 External LSAs and leaks them to the other areas, but external routes from other areas are not advertised within the NSSA. An admin should check this and change it https://www.packetswitch.co.uk/configuring-junos-ospf-stub-and-nssa-areas/ https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/ref/statement/nssa-edit-protocols-ospf.html

B - because only one next hop in forwarding table C- becuse TTL=1 limiting bgp connection to be established only over loopbacks interface https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/topic-map/multihop-sessions.html Use the multihop statement to alter the default use of the neighbor 's physical address. In addition, you can also specify a time-to-live (TTL) value in the BGP packets to control how far they propagate. We use a TTL value of 1 to ensure that the session cannot be established across any other backdoor links in the network.

Understanding EVPN Route Types:

EVPN routes facilitate Layer 2 and Layer 3 connectivity across data centers.

Layer 2 and Layer 3 Connectivity:

For Layer 3 connectivity across data centers, where Layer 2 does not extend, IP prefixes need to be communicated.

Type 5 Routes:

Type 5 (IP Prefix Route):

Used to distribute IP prefixes between data centers.

Ensures that Layer 3 connectivity is established without extending Layer 2 domains.

References:

Juniper EVPN Type 5 Routes

Configuring EVPN for Data Center Interconnect

The leaf node is not configured for the family evpn NLRI (D):

The exhibit shows that there is an unsupported capability NP error for AFI 1, SAFI 70. This indicates that the leaf node is not configured to support the EVPN (Ethernet VPN) address family.

References:

The BGP configuration and troubleshooting details can be found in "Juniper Commands.pdf" and related EVPN configuration documents​​​​.

Understanding EVPN Route Types:

EVPN (Ethernet VPN) is used for providing Ethernet multipoint services over MPLS or VXLAN networks.

EVPN Route Types:

Type 1 (Ethernet Auto-Discovery Route): Used for auto-discovery of PEs and for detecting multi-homed devices.

Type 2 (MAC/IP Advertisement Route):

Carries endpoint MAC address information.

Carries endpoint IP address information.

Facilitates MAC learning and IP-to-MAC binding distribution.

Type 3 (Inclusive Multicast Route):

Carries replication information.

Used for forwarding multicast and broadcast traffic.

Type 5 (IP Prefix Route): Carries IP prefixes for inter-subnet connectivity, but not replication information.

Verification:

Type 2 routes are crucial for distributing MAC and IP information about endpoints.

Type 3 routes are used to manage multicast traffic effectively.

References:

Juniper EVPN Configuration Guide

Understanding EVPN Route Types

When video packets are being dropped, and the network is configured to use the expedited-forwarding forwarding class, it typically indicates that the scheduler assigned to this class does not have sufficient bandwidth to handle the traffic. Adjusting the scheduler to allocate more bandwidth to the expedited-forwarding class will ensure that video packets are transmitted without being dropped.

Steps:

Identify the scheduler map: First, identify the scheduler map that is applied to the interfaces. This can be done using the following command:

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show configuration class-of-service scheduler-maps

Adjust the scheduler: Modify the scheduler for the expedited-forwarding forwarding class to support a higher transmit rate. You can edit the scheduler configuration to increase the bandwidth allocated.

Example:

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set class-of-service schedulers expedited-forwarding transmit-rate percent 30

Apply the configuration: Apply the modified scheduler to the interfaces using the following commands:

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set class-of-service interfaces ge-0/0/0 scheduler-map

set class-of-service interfaces ge-0/0/1 scheduler-map

commit

References:

Useful Juniper Commands.txt

Tech Ops Managed Router Juniper Install Guide

The correct sequence for BGP active route selection when BGP multipath or multihop are not configured is as follows:

Higher local preference: Routes with a higher local preference are preferred.

Shortest AS path: Routes with the shortest AS path are preferred.

Lower origin code: Routes with lower origin code (IGP < EGP < Incomplete) are preferred.

Lowest router ID: Routes with the lowest router ID are preferred.

Lowest peer address: Routes with the lowest peer address are preferred.

References:

Standard BGP route selection criteria as outlined in network routing protocols.

Documentation from "Useful Juniper Commands.txt" and "Juniper Commands.pdf" which include detailed BGP operational commands and preferences​​​​.

Reviewing POE Interface Information:

The exhibit shows the output of show poe interface and show poe controller commands.

The show poe interface command provides information about the PoE (Power over Ethernet) status on each interface.

Maximum Wattage Allocation:

The show poe controller output indicates that the maximum power available is 100 watts:

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Controller Maximum Power consumption Guard Management Status Lldp

index power band

0 100.00W 22.40W 10W Class AT_MODE Disabled

Thus, statement A is correct.

Power Consumption and Interface Priority:

The interface ge-0/0/11 has a high priority with a max power of 25.4W and current consumption of 11.4W:

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ge-0/0/11 Enabled ON 25.4W(L) High 11.4W 4

Given its high priority, ge-0/0/11 will continue to receive power even if the total power consumption exceeds 90 watts, as high-priority interfaces are less likely to be powered off when resources are low.

POE Status on Interfaces:

The ge-0/0/0 interface is shown as Enabled OFF, indicating PoE is not currently enabled.

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ge-0/0/0 Enabled OFF 15.4W Low 0.0W not-applicable

PoE+ Support:

The ge-0/0/10 interface has a power class of 4, which indicates support for PoE+.

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ge-0/0/10 Enabled ON 25.4W(L) Low 11.0W 4

References:

Exhibit output for show poe interface

Understanding PoE and PoE+ classes and priorities

"Secondary interfaces are supported for LAN interfaces (the primary interface can be a LAN interface, but any secondary interfaces are treated as point-to-point unnumbered links over the LAN). In this scenario, you must ensure that there are only two routing devices on the LAN or that there are only two routing devices on the LAN that have secondary interfaces configured for a specific OSPF area." [https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/topic-map/configuring-ospf-areas.html#id-example-configuring-multiarea-adjacency-for-ospf]

To ensure proper functioning within an MST (Multiple Spanning Tree) region, the following parameters must match across all switches:

Revision number:

The revision number identifies the version of the MST configuration. All switches within the same MST region must have the same revision number to ensure consistency.

MSTI-to-VLAN mapping:

The MSTI (Multiple Spanning Tree Instance) to VLAN mapping must be identical on all switches. This mapping ensures that each VLAN is assigned to the correct spanning tree instance.

Configuration name:

The configuration name (or region name) must be the same across all switches. This name uniquely identifies the MST region and must be consistent to ensure switches recognize they are part of the same region.

References:

The MSTP configuration requirements are detailed in Juniper network configuration guides and standards documents on MSTP​​​​.