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

Step 1: Identify the problem.

Devices do not support VPN NLRI, and you must prevent these devices from receiving BGP VPN routes.

Step 2: Analyze the possible solutions.

Option A: Configure an import policy on the remote peer to reject the routes when they are received.

This approach would require configuration on the remote peer, which might not always be practical or possible.

Option B: Configure an export policy on the local BGP peer to reject the VPN routes being sent to the remote peer.

This ensures the local BGP peer does not send the VPN routes to the remote peer, directly addressing the problem.

Option C: Configure a route reflector for the VPN NLRI.

This does not solve the issue of preventing the advertisement of VPN routes to non-supporting peers.

Option D: Configure the apply-vpn-export feature on the local BGP peer.

This feature ensures that the VPN export policies are applied, preventing the advertisement of VPN routes to peers that do not support VPN NLRI.

Step 3: Verify the configurations.

Option B and Option D directly address the requirement without needing configurations on the remote peer.

References:

Juniper BGP configuration guide on export policies​​​​​​.

Commands for applying export policies:

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set policy-options policy-statement term from protocol bgp-vpn

set policy-options policy-statement term then reject

set protocols bgp group export

set protocols bgp apply-vpn-export

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

From the provided IS-IS adjacency outputs:

R1 is configured to participate in both Level 1 and Level 2 (A): This is indicated by the adjacency states for both Level 1 and Level 2 on the R1 interfaces.

R2 is configured to participate in Level 2 only (D): This is shown by the adjacency state for Level 2 only on the R2 interfaces.

References:

The IS-IS adjacency outputs indicate the state and levels of participation for each router.

Configuration and command references from "Example configs for VMRCAXP01W.txt" and other documents provide context for understanding IS-IS states and levels​​​​​​.

For devices like printers that do not support 802.1X authentication, you can configure static MAC bypass. This allows traffic from devices with specific MAC addresses to bypass 802.1X authentication and gain network access directly.

References:

From the Juniper documentation, you can implement static MAC bypass for devices that do not support 802.1X by configuring their MAC addresses to be statically permitted on the network.

Useful Juniper Commands.txt

Tech Ops Managed Router Juniper Install Guide

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# Example configuration for static MAC bypass

set protocols dot1x authenticator interface ge-0/0/1.0 mac-radius static-mac 00:11:22:33:44:55

commit

These configurations and explanations should address the questions accurately based on the provided information and referenced documents.

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

Understanding 802.1X Authentication:

802.1X is a network access control protocol that restricts access until the device or user is authenticated.

Guest VLAN Configuration:

When hosts fail authentication, they need to be placed in a separate VLAN to provide limited network access.

server-reject-vlan Command:

This command configures a VLAN for unauthenticated devices.

Ensures that devices that fail authentication are placed in a designated guest VLAN.

Configuration Example:

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set protocols dot1x authenticator interface ge-0/0/1.0 server-reject-vlan guest-vlan

References:

Juniper 802.1X Authentication Configuration Guide

Juniper Guest VLAN Configuration

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

In OSPF, the ExStart state indicates that the routers are attempting to establish a relationship and exchange information about their MTU settings. If the MTU settings do not match between the two routers on the link, it can prevent the adjacency from progressing past the ExStart state.

References:

From the image provided, you can see that the OSPF adjacency on the interface ge-0/0/2.0 is stuck in the ExStart state.

This state often suggests that there is a mismatch in the MTU settings between the routers on that interface.

To resolve this, ensure that both interfaces have the same MTU setting. You can check and set the MTU on Juniper routers using the following commands:

# Check current MTU settings

show interfaces ge-0/0/2

# Set MTU to a specific value (e.g., 1500)

set interfaces ge-0/0/2 mtu 1500

# Commit the configuration

commit

Dynamic VLAN assignment using 802.1X authentication relies on vendor-specific attributes (VSAs) to assign VLANs dynamically based on the authentication results. The modes that support using VSAs for dynamic VLAN assignment are:

Single-Secure Supplicant Mode: This mode supports a single secure client on a port and can use VSAs to dynamically assign VLANs based on the authentication result.

Multiple Supplicant Mode: This mode supports multiple clients on a single port, each with its own authentication session, and can use VSAs to dynamically assign VLANs.

References:

The Juniper documentation and configuration guides discuss the capabilities of these modes in supporting dynamic VLAN assignment through VSAs. Specific configuration examples and guidelines can be found in the documents:

Useful Juniper Commands.txt

Tech Ops Managed Router Juniper Install Guide

# Example of enabling single-secure supplicant mode

set protocols dot1x authenticator interface ge-0/0/1.0 supplicant multiple

# Example of enabling multiple supplicant mode

set protocols dot1x authenticator interface ge-0/0/1.0 supplicant multiple

Understanding the Configuration:

The provided configuration and output snippets show how traffic is classified and assigned to different forwarding classes based on the IP precedence values.

The inet-precedence classifier maps specific IP precedence values to forwarding classes with associated loss priorities.

Review of Classifiers:

IP Precedence Value 100:

The IP precedence value 100 in binary is represented as 100 (binary for 4).

Matching with Classifiers:

According to the configuration shown in the exhibit:

classifiers {

inet-precedence cos;

}

The classifier cos maps the following:

forwarding-class expedited-forwarding;

loss-priority low code-points 100;

Conclusion:

The IP precedence value 100 matches the expedited-forwarding forwarding class with low loss-priority as per the configuration.

Enabling LLDP-MED:

LLDP-MED (Link Layer Discovery Protocol - Media Endpoint Discovery) is an extension of LLDP specifically for VoIP devices.

It allows network devices to advertise and receive configuration information, such as VLAN IDs, from the network switch.

Voice VLAN Feature:

The voice VLAN feature on switches is designed to simplify the deployment of VoIP by automatically placing voice traffic on a designated VLAN.

Configuring the appropriate access interfaces and VLAN ID for voice traffic ensures that voice packets are prioritized and properly segmented from other types of traffic.

Configuration Steps:

Enable LLDP-MED on the appropriate access interfaces:

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set protocols lldp-med interface ge-0/0/0

Enable the voice VLAN feature and specify the VLAN ID:

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set ethernet-switching-options voip interface ge-0/0/0 vlan voice

set ethernet-switching-options voip interface ge-0/0/0 forwarding-class assured-forwarding

References:

Juniper documentation on LLDP-MED

Juniper EX Series switch configuration guide for voice VLAN

A modified deficit round-robin (MDRR) scheduler is defined by the following three variables:

Priority (A):

Priority determines the importance of the queue, influencing the order in which packets are serviced. Higher priority queues are serviced before lower priority queues.

Transmit rate (C):

The transmit rate controls the amount of bandwidth allocated to each queue. It determines how quickly packets from a queue can be transmitted.

Buffer size (E):

Buffer size defines the amount of memory allocated to each queue for storing packets before they are transmitted. Larger buffer sizes can accommodate more packets but may introduce more latency.

References:

Detailed information on MDRR and its variables can be found in Juniper's QoS configuration guides and related networking documents​​​​.

When troubleshooting an EVPN-VXLAN IP fabric loop, the following steps are crucial:

Issue the show route table bgp.evpn.0 command on Leaf2 and verify that Type 4 routes are present: Type 4 routes indicate EVPN Ethernet Segment routes, which are essential for detecting and mitigating loops.

Issue the show route table bgp.evpn.0 command on Leaf2 and verify that Type 3 routes are present: Type 3 routes (Inclusive Multicast Ethernet Tag routes) ensure that multicast and broadcast traffic is properly handled, helping identify and troubleshoot loop issues.

References:

The commands for verifying BGP EVPN routes are standard in troubleshooting EVPN-VXLAN fabrics.

Documentation from "Useful Juniper Commands.txt" and "Juniper Commands.pdf" which provide command references for verifying EVPN route types​​​​.

Understanding IEEE 802.3af Standard:

IEEE 802.3af, also known as PoE (Power over Ethernet), specifies the standard for delivering power over Ethernet cables.

This standard allows devices like IP phones to receive power along with data over the same cable.

Maximum Power Allocation:

According to the IEEE 802.3af standard, the maximum power that can be delivered to a powered device is 15.4 watts.

This power is delivered over Category 5 (Cat 5) cables or higher.

EX Series Switches Compliance:

Juniper EX Series switches with PoE support adhere to the IEEE 802.3af standard.

Thus, each PoE port on these switches can allocate up to 15.4 watts to connected devices.

References:

IEEE 802.3af standard specifications

Juniper EX Series switch documentation