Pass the Juniper JNCIP-ENT JN0-649 Questions and answers with ValidTests

https://www.juniper.net/documentation/us/en/software/junos/routing-policy/bgp/topics/example/bgp-advertise-peer-as.html

LLDP-MED (Link Layer Discovery Protocol-Media Endpoint Discovery) is an extension of LLDP (Link Layer Discovery Protocol) that provides additional functionalities specifically for voice over IP (VoIP) devices, including automatic negotiation of power requirements. This protocol is essential for automatically negotiating power with IP phones when they are connected to EX Series switches.

Steps:

Enable LLDP-MED:

set protocols lldp-med

Configure LLDP-MED on the interfaces:

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode access

set interfaces ge-0/0/0 unit 0 family ethernet-switching interface-mode access

set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members default

set interfaces ge-0/0/0 unit 0 family ethernet-switching storm-control default

Commit the configuration:

References:

Useful Juniper Commands.txt

Tech Ops Managed Router Juniper Install Guide

IS-IS (Intermediate System to Intermediate System) is a link-state routing protocol used to move information efficiently within a computer network. Here is the detailed explanation about the statements:

Option A: IS-IS uses areas and an autonomous system.

This statement is correct. IS-IS organizes the network into a single autonomous system (AS), which can be divided into smaller groups called areas. Routing between areas is organized hierarchically. Each IS-IS network is treated as an autonomous system, and within that AS, multiple areas can be defined for efficient routing.

Option B: Level 1/2 routers automatically inject a default route to the nearest Level 1 router.

This statement is incorrect. Level 1/2 routers do not automatically inject default routes. Instead, they set the ATTACHED bit in their Level 1 link-state PDU when they can reach other areas, prompting Level 1 routers to use them as default gateways.

Option C: Level 2 routers must share the same area address.

This statement is incorrect. Level 2 routers operate across multiple areas and do not need to share the same area address. They are responsible for inter-area routing and thus work across different areas.

Option D: Level 1 routers route traffic between autonomous systems.

This statement is incorrect. Level 1 routers route traffic within a single area and forward inter-area traffic to Level 2 routers, which handle inter-area routing.

ConclusionGiven the above explanations, the correct statement about IS-IS is:

A. IS-IS uses areas and an autonomous system.

This is based on the hierarchical structure of IS-IS routing where the network is divided into areas within a single autonomous system.

For further details, you can refer to the Juniper IS-IS Overview.

Understanding the Problem:

The issue involves voice packets being dropped in a newly implemented VoIP network.

Voice packets are marked correctly for the expedited forwarding (EF) queue, indicating that classification is working as intended.

Dropped packets suggest that there may be insufficient resources allocated to handle the traffic in the EF queue.

Key Concepts:

Classifiers: These are used to mark packets so that they can be placed into the appropriate forwarding class. This step is already correctly implemented as indicated by the problem statement.

Rewrite Rules: These ensure that packets retain their markings as they transit the network, but this is not the issue here as packets are already marked correctly.

Policers: These control the rate of traffic to ensure it does not exceed specified limits, but policing is not required here as the issue is with packet drops due to insufficient resources.

Schedulers: These allocate resources (bandwidth, priority) to different queues to ensure that high-priority traffic (like VoIP) is transmitted with minimal delay and packet loss.

Solution: Configuring a Scheduler:

To prevent the EF queue from being starved of resources and to ensure voice packets are not dropped, you need to configure a scheduler. This scheduler will allocate appropriate bandwidth and priority to the EF queue.

Configuring Scheduler on Juniper Devices:

Here is a sample configuration to allocate bandwidth to the expedited forwarding queue:

set class-of-service schedulers voip-scheduler transmit-rate percent 20

set class-of-service schedulers voip-scheduler priority strict-high

set class-of-service forwarding-classes queue 1 expedited-forwarding

set class-of-service forwarding-classes queue 1 scheduler voip-scheduler

In this configuration:

The voip-scheduler is set to allocate 20% of the bandwidth and is given strict-high priority to ensure voice packets are transmitted with the highest priority.

The EF queue (queue 1) is associated with the voip-scheduler.

Verification:

Ensure the scheduler is applied and active on the interfaces handling the VoIP traffic.

Monitor the interface statistics to ensure that packet drops are minimized and voice quality issues are resolved.

References:

Juniper Networks Documentation on Class of Service

Configuring Schedulers

Multitenancy with Routing Instances:

In a multitenant network, different tenants are isolated using routing instances.

Each routing instance can have its own routing table and policies.

BGP and Load Balancing:

BGP (Border Gateway Protocol) is often used for interconnecting different autonomous systems or for internal routing.

Load balancing in BGP can be achieved using the multipath feature, which allows the installation of multiple paths to the same destination in the routing table.

Additionally, configuring per-packet load balancing ensures that traffic is distributed across multiple paths more granularly.

Configuring Multipath in BGP:

Hierarchy Considerations: The multipath option must be configured at appropriate hierarchies to ensure it applies to the correct scope (either globally or within a specific routing instance).

Detailed Configuration:

Statement C: Configure a load-balance per-packet policy and apply it at the [edit routing-options forwarding-table] hierarchy.

Correct: Configuring a load-balance per-packet policy ensures that packets are distributed evenly across multiple paths. This is crucial for achieving effective load balancing.

Configuration Example:

shell

Copy code

set routing-options forwarding-table export load-balance-per-packet

Policy Definition Example:

shell

Copy code

set policy-options policy-statement load-balance-per-packet term 1 then load-balance per-packet

Statement D: Configure the multipath option at the [edit routing-instances routing-options] hierarchy.

Correct: Configuring multipath within a routing instance ensures that the load balancing feature is applied specifically to that instance, which is crucial in a multitenant environment.

Configuration Example:

shell

Copy code

set routing-instances routing-options multipath

References:

Useful Juniper Commands

Juniper Routing Instances and Multipath Configuration

These configurations ensure that load balancing is achieved within each routing instance, leveraging both per-packet load balancing and the multipath feature in Junos OS for BGP. By configuring at the forwarding-table and routing-instance levels, you ensure the load balancing behavior is correctly applied to achieve the desired network performance and redundancy.

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:

plaintext

Copy code

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:

plaintext

Copy code

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.

plaintext

Copy code

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+.

plaintext

Copy code

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

To ensure that each host is placed on a separate VLAN when using an unmanaged switch between the hosts and the EX Series switch:

Configure an input firewall filter on interface ge-0/0/3 to match the source MAC or IP address of the hosts to assign the VLANs:

By configuring an input firewall filter, you can match the source MAC or IP address of incoming traffic and assign the appropriate VLAN based on these criteria.

This method ensures that even though the switch between hosts and EX Series is unmanaged, VLAN assignments are still properly enforced at the EX Series switch.

Configuration Example:

set firewall family ethernet-switching filter VLAN-assignment term VLAN100 from source-mac-address xx:xx:xx:xx:xx:xx

set firewall family ethernet-switching filter VLAN-assignment term VLAN100 then vlan-assignment vlan 100

set firewall family ethernet-switching filter VLAN-assignment term VLAN200 from source-mac-address yy:yy:yy:yy:yy:yy

set firewall family ethernet-switching filter VLAN-assignment term VLAN200 then vlan-assignment vlan 200

set firewall family ethernet-switching filter VLAN-assignment term VLAN300 from source-mac-address zz:zz:zz:zz:zz:zz

set firewall family ethernet-switching filter VLAN-assignment term VLAN300 then vlan-assignment vlan 300

set interfaces ge-0/0/3 unit 0 family ethernet-switching filter input VLAN-assignment

References:

The command references from "Useful Juniper Commands.txt" and network configuration guides provide details on firewall filters and VLAN assignments​​.