JNCIP-ENT IP Multicast Practice Test 2 — 15 Questions

Question 1

Which operational command is used to verify the operational status and peer state of MSDP sessions on a Junos device?

Accepted Answer

show msdp summary. The 'show msdp summary' command provides an overview of MSDP peers, state, and connection status.

Answer

show igmp summary

Answer

show pim summary

Answer

show multicast summary

Question 2

An administrator wants to configure Candidate-RP (C-RP) advertisements using the Bootstrap Router (BSR) mechanism in PIM sparse-mode. Which hierarchy level in Junos is used to configure the local router as a Candidate-RP?

Accepted Answer

[edit protocols pim candidate-rp]. Candidate RPs in Junos are configured under protocols pim candidate-rp.

Answer

[edit protocols pim bsr]

Answer

[edit routing-options candidate-rp]

Answer

[edit protocols igmp candidate-rp]

Question 3

Which protocol version introduces explicit source inclusion and exclusion lists (TO_EX, TO_IN, IS_IN, IS_EX) in membership reports?

Accepted Answer

IGMPv3. IGMPv2 supports basic group membership, whereas IGMPv3 introduces source-filtering capabilities allowing hosts to specify include or exclude source lists.

Answer

IGMPv2

Answer

IGMPv4

Answer

IGMPv1

Question 4

During multicast troubleshooting, an engineer notices that a router is not accepting MSDP Source-Active messages from a specific peer. Where should an export policy be applied to control which SA messages are sent or accepted via MSDP?

Accepted Answer

set protocols msdp peer

import . MSDP policies in Junos are applied directly under the specific MSDP peer configuration or globally under protocols msdp export/import.

Answer

set routing-options msdp-policy <policy-name>

Answer

set protocols pim msdp-import <policy-name>

Answer

set protocols bgp group msdp export <policy-name>

Question 5

An administrator wants to configure an MSDP peer relationship on a Junos device and ensure that the MD5 password authentication is applied to the TCP session. Where is the MD5 authentication key configured for an MSDP peer?

Accepted Answer

set protocols msdp peer

authentication-key . MSDP authentication keys are configured under the specific MSDP peer statement using the authentication-key option.

Answer

set system authentication-key <key>

Answer

set protocols pim peer

authentication-key

Answer

set routing-options msdp authentication-key <key>

Question 6

Which IPv4 address is assigned as the all-systems multicast group address, used by routers to query all hosts on a local subnet?

Accepted Answer

224.0.0.1. 224.0.0.1 is the all-hosts (all-systems) multicast group address.

Answer

224.0.0.22

Answer

224.0.0.13

Answer

224.0.0.2

Question 7

An enterprise design uses PIM sparse-mode with a BSR. An engineer notices that the router has successfully elected a BSR, but no Candidate-RP messages are being processed. Which operational command should the engineer use to verify the BSR candidate information and elected BSR address on the router?

Accepted Answer

show pim bsr statistics. The 'show pim bsr local' or 'show pim bsr' commands display information regarding the BSR state, elected BSR, and received bootstrap messages.

Answer

show igmp bsr

Answer

show msdp bsr-state

Answer

show multicast bsr

Question 8

An engineer wants to configure a Junos router to act as a Bootstrap Router (BSR) for PIM sparse-mode. Which configuration hierarchy is used to enable the BSR function?

Accepted Answer

[edit protocols pim bsr]. BSR functionality on Junos is configured under protocols pim bsr.

Answer

[edit protocols msdp bsr]

Answer

[edit routing-options bsr]

Answer

[edit protocols pim candidate-rp]

Question 9

An enterprise network uses multiple routing instances with PIM sparse-mode. An engineer needs to configure Inter-AS multicast routing using MSDP. Which component is required to establish MSDP peering across different autonomous systems where BGP is also running?

Accepted Answer

Matching MSDP peer loopback addresses and TCP session establishment with MBGP routing. MSDP peers can be configured between BGP speakers in different ASs. The MSDP peer address often matches the BGP router ID or loopback, and MBGP supplies the RPF route for the source.

Answer

A shared PIM dense-mode tunnel between the AS border routers

Answer

IGMPv2 proxy configuration on the border routers

Answer

Static multicast routes for all 224.0.0.0/4 destinations

Question 10

An engineer needs to verify the Rendezvous Point (RP) currently learned via the Bootstrap Router (BSR) mechanism on a Junos device. Which operational command should be used?

Accepted Answer

show pim rps. The 'show pim rps' command displays all active RPs known to the router, including whether they were learned via static configuration, Auto-RP, or BSR.

Answer

show igmp rp

Answer

show msdp rp-list

Answer

show multicast rp-table

Question 11

An administrator troubleshooting an IGMP snooping issue on an EX Series switch notices that multicast traffic is flooding all ports in a VLAN. Which Junos command verifies the IGMP snooping status and active querier on a specific VLAN?

Accepted Answer

show igmp-snooping membership vlan vlan-name. On Juniper EX Series switches, IGMP snooping operational state and querier details per VLAN are displayed using 'show igmp-snooping membership' or 'show igmp-snooping statistics'.

Answer

show protocols igmp snooping vlan

Answer

show ethernet-switching igmp-snooping

Answer

show bridge igmp-snooping querier

Question 12

An engineer is configuring PIM sparse-mode in an enterprise network. Which TWO characteristics are true regarding PIM sparse-mode operation? (Choose two)

Accepted Answer

It uses explicit join messages (*,G or S,G) sent towards the RP or source.. PIM sparse-mode assumes that multicast traffic is not wanted across all segments by default, requiring explicit join messages. It relies heavily on a Rendezvous Point (RP) to connect sources and receivers initially.

Answer

It requires every interface to run IGMPv3 exclusively.

Answer

It floods multicast traffic across all router interfaces by default until pruned.

Answer

It does not require any unicast routing protocol for RPF checks.

Question 13

An administrator is troubleshooting an MSDP deployment between two autonomous systems. Which THREE factors can cause an MSDP peer session to fail to establish? (Choose three)

Accepted Answer

TCP port 639 being blocked by a firewall between the peers. MSDP runs over TCP port 639. Session establishment requires correct peer IP configuration, functional TCP connectivity, and matching authentication keys if configured.

Answer

An incorrect IGMPv2 timer setting on the receiver VLAN

Answer

An invalid PIM dense-mode setting on the core interface

Question 14

Which TWO statements are correct regarding IGMP version 2 (IGMPv2) features compared to IGMPv1? (Choose two)

Accepted Answer

IGMPv2 includes a querier election mechanism among multiple routers on a subnet.. IGMPv2 introduced explicit leave messages (Leave Group) and a designated querier election mechanism, unlike IGMPv1 which relied on timeout expiration.

Answer

IGMPv2 relies entirely on group membership timeout for leaving groups.

Answer

IGMPv2 supports source-specific filtering lists (include/exclude).

Answer

IGMPv2 requires PIM sparse-mode to be enabled on all participating hosts.

Question 15

Which TWO statements describe the function and operation of a PIM Bootstrap Router (BSR)? (Choose two)

Accepted Answer

The BSR collects Candidate-RP messages and periodically distributes the RP-set to all PIM routers.. The BSR collects Candidate-RP advertisements and distributes the RP-set to all routers in the domain via bootstrap messages.

Answer

The BSR acts as the data encapsulation point for multicast sources.

Answer

The BSR forwards multicast data packets directly to receivers.

Answer

The BSR is required to establish MSDP sessions between autonomous systems.