Juniper Updated JN0-649 Exam Questions and Answers by noa

To troubleshoot why ISP peers are not receiving any routes in a multihomed BGP setup, the following steps are essential:

Verify Active BGP Routes: Ensure that the BGP routes are active in the routing table. Only active routes can be advertised to BGP peers.

shell

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show route protocol bgp

Verify Export Policies: Check the export policies configured on your router. The export policies determine which routes are advertised to BGP peers. If these policies are incorrectly configured or missing, routes will not be advertised.

shell

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show configuration policy-options policy-statement

show configuration protocols bgp group export

References:

Useful Juniper Commands.txt

Tech Ops Managed Router Juniper Install Guide

When MVRP is enabled, the protocol manages VLAN registration dynamically. In forbidden mode, VLANs are neither registered nor declared on the interface, meaning it prevents VLANs from being learned or propagated.

References:

Juniper Networks Configuration Guide on MVRP

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 BGP Communities:

BGP communities are used to tag routes with certain attributes to control their distribution and processing.

The no-export community ensures that the routes tagged with this community are not advertised to any BGP peers outside the local AS (Autonomous System).

Applying the no-export Community:

To ensure that all routes in the 10.0.0.0/8 address range are not advertised outside the AS, the no-export community should be assigned to these routes. This prevents the routes from being propagated beyond the local AS boundary.

References:

Juniper BGP Communities

Configuring BGP Community Attributes