350-401 Practice Test 25 — 15 Questions

Question 1

A network engineer runs the following command on Router R1:

R1# show ip pim neighbor
PIM Neighbor Table
Neighbor Address  Interface           Uptime    Expires   Mode
10.1.1.2          GigabitEthernet0/0  2w0d      00:01:25  DR
10.1.1.3          GigabitEthernet0/0  2w0d      00:01:20  B

Based on this output, what can be concluded?

Accepted Answer

PIM Bidir mode is configured on this interface.. The 'show ip pim neighbor' output shows two neighbors on the same interface. The 'Mode' column indicates the PIM neighbor role: 'DR' means Designated Router, 'B' means Bidir-capable. The presence of both DR and B on the same interface suggests that PIM Bidir mode is enabled, as Bidir uses a different DR election and the B flag indicates Bidir capability. The correct answer is that PIM Bidir is configured.

Answer

PIM sparse mode is operating on this interface.

Answer

PIM dense mode is in use on this interface.

Answer

PIM SSM is enabled on this interface.

Question 2

A network engineer issues the following command on Router R5:

R5# show ip pim interface
Interface          PIM  Nbrs  Hello  DR    DR
                        Count Intvl  Prior
GigabitEthernet0/0 on    2     30     1     10.1.1.1
GigabitEthernet0/1 on    1     30     1     10.2.2.2
Loopback0          on    0     30     1     10.3.3.3

Based on this output, what can be concluded?

Accepted Answer

The DR on GigabitEthernet0/0 is 10.1.1.1.. The 'show ip pim interface' output shows that GigabitEthernet0/0 has 2 PIM neighbors, a hello interval of 30 seconds, DR priority of 1, and the DR is 10.1.1.1. GigabitEthernet0/1 has 1 neighbor and its DR is 10.2.2.2. Loopback0 has no neighbors and its DR is the router's own IP. The correct answer is that the DR on GigabitEthernet0/0 is 10.1.1.1, which is not the local router (since the local router's IP is not shown, but it is likely different).

Answer

The DR on GigabitEthernet0/1 is the local router.

Answer

PIM is disabled on Loopback0.

Answer

The hello interval on GigabitEthernet0/0 is 60 seconds.

Question 3

A network engineer issues the following command on Router R9:

R9# show ip pim bsr-router
PIMv2 Bootstrap Router (BSR) information
This system is the Bootstrap Router (BSR)
BSR address: 10.0.0.11
Uptime: 1w2d, BSR priority: 0, Hash mask length: 30
Next bootstrap message in 00:00:45

Based on this output, what can be concluded?

Accepted Answer

This router is the elected BSR.. The 'show ip pim bsr-router' output shows that this router is the BSR with address 10.0.0.11, priority 0, and hash mask length 30. The next bootstrap message will be sent in 45 seconds. The hash mask length of 30 means that the group-to-RP mapping uses a 30-bit mask for hashing. The correct answer is that the BSR is elected and operational.

Answer

This router is a candidate BSR but not elected.

Answer

The BSR priority is 192.

Answer

The hash mask length is 32.

Question 4

A network engineer issues the following command on Router R2:

R2# show ip mroute 239.1.1.1
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry, E - Extranet,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group session,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.1.1.1), 00:03:45/00:02:15, RP 10.0.0.1, flags: S
  Incoming interface: GigabitEthernet0/0, RPF nbr 10.0.0.1
  Outgoing interface list:
    GigabitEthernet0/1, Forward/Sparse, 00:03:45/00:02:15

Based on this output, what can be concluded?

Accepted Answer

The RP for this group is 10.0.0.1.. The 'show ip mroute' output shows a (*,G) entry for group 239.1.1.1 with flags 'S' (Sparse mode) and an RP of 10.0.0.1. The incoming interface is GigabitEthernet0/0 with RPF neighbor 10.0.0.1, and the outgoing interface list includes GigabitEthernet0/1 in Forward state. This indicates that the multicast route is using PIM sparse mode and the RP is known. The correct answer is that PIM sparse mode is used with an RP at 10.0.0.1.

Answer

The group is using PIM dense mode.

Answer

The multicast traffic is being hardware switched.

Answer

The group is a Bidir group.

Question 5

A network engineer runs the following command on Router R6:

R6# show ip pim rp 239.3.3.3
RP 10.0.0.4

Info source: 10.0.0.4, via bootstrap, priority 192, holdtime 150, expires in 00:02:30

Based on this output, what can be concluded?

Accepted Answer

The RP was learned via BSR.. The 'show ip pim rp' command shows the RP for group 239.3.3.3 is 10.0.0.4, learned via bootstrap (BSR). The priority is 192, holdtime 150 seconds, and it expires in 2 minutes 30 seconds. This indicates that BSR is the mechanism used to learn the RP. The correct answer is that the RP was learned via BSR.

Answer

The RP was learned via Auto-RP.

Answer

The RP was statically configured.

Answer

The RP is 10.0.0.5.

Question 6

A network engineer executes the following command on Router R3:

R3# show ip igmp groups 239.2.2.2
IGMP Connected Group Membership
Group Address    Interface                Uptime    Expires   Last Reporter
239.2.2.2        GigabitEthernet0/0       1d04h     00:02:10  192.168.1.100

Based on this output, what can be concluded?

Accepted Answer

A host at 192.168.1.100 has joined group 239.2.2.2.. The 'show ip igmp groups' output shows that group 239.2.2.2 is present on interface GigabitEthernet0/0, with the last reporter being 192.168.1.100. The uptime is 1 day and 4 hours, and the expiry timer is about 2 minutes. This indicates that there is at least one IGMP host on that subnet interested in the group. The correct answer is that a host at 192.168.1.100 has sent an IGMP report for this group.

Answer

The multicast group is being sourced from 192.168.1.100.

Answer

The router is the RP for this group.

Answer

The group is using IGMP version 3.

Question 7

A network engineer issues the following command on Router R7:

R7# show ip pim tunnel
Tunnel1:
  Type: PIM Encap
  Source: 10.0.0.7, Destination: 10.0.0.8
  Status: up

Based on this output, what can be concluded?

Accepted Answer

This tunnel is used for PIM register encapsulation to the RP.. The 'show ip pim tunnel' output shows a PIM encapsulation tunnel (Tunnel1) with source 10.0.0.7 and destination 10.0.0.8, and the status is up. This type of tunnel is used for PIM register encapsulation when a source sends to an RP. The correct answer is that this tunnel is used for sending register messages to the RP.

Answer

This tunnel is used for MDT data group forwarding.

Answer

This tunnel is used for BSR messages.

Answer

This tunnel is used for Auto-RP announcements.

Question 8

Examine the following configuration on a Cisco IOS-XE router:

ip multicast-routing distributed
!
interface GigabitEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 ip pim sparse-dense-mode
 ip igmp version 2
!

Which statement about this configuration is true?

Accepted Answer

Multicast routing is enabled with distributed switching, and the interface will use sparse-mode if an RP is known for the group, otherwise dense-mode.. The 'ip multicast-routing distributed' command enables multicast routing with support for distributed switching (CEF). The interface is configured with PIM sparse-dense-mode, which allows the interface to operate in dense-mode if no RP is known for the group, or in sparse-mode if an RP is known. IGMPv2 is used for group membership.

Answer

The interface will operate in dense-mode for all multicast groups because no RP is configured.

Answer

The router will only support IGMPv2, and IGMPv3 queries will be ignored.

Answer

The configuration is invalid because 'ip multicast-routing distributed' is not a valid command.

Question 9

Given the following configuration on a Cisco IOS-XE router:

ip multicast-routing
!
interface GigabitEthernet0/0
 ip address 10.1.1.1 255.255.255.0
 ip pim sparse-mode
 ip igmp version 2
!
router ospf 1
 network 10.1.1.0 0.0.0.255 area 0
!

What is missing from this configuration to support Source-Specific Multicast (SSM) for group range 232.0.0.0/8?

Accepted Answer

The interface must be configured with 'ip igmp version 3' to support SSM.. SSM requires IGMPv3 to allow hosts to specify sources. The configuration uses IGMPv2, which does not support source filtering. Additionally, PIM sparse-mode is used, but SSM typically uses PIM SSM (which is essentially PIM sparse-mode with the SSM range). The missing piece is IGMPv3; the SSM range is automatically enabled for 232.0.0.0/8 when IGMPv3 is configured.

Answer

The router must be configured with 'ip pim ssm' command to enable SSM.

Answer

An RP must be configured for the 232.0.0.0/8 range.

Answer

The interface must be configured with 'ip pim dense-mode' for SSM to work.

Question 10

Given the following partial configuration on a Cisco IOS-XE router:

ip pim rp-address 10.0.0.1 10
access-list 10 permit 224.0.0.0 0.255.255.255
!
interface GigabitEthernet0/0
 ip pim sparse-mode
!

What is the effect of this configuration?

Accepted Answer

The router will use 10.0.0.1 as the RP for all multicast groups from 224.0.0.0 to 224.255.255.255, and the interface will operate in sparse-mode.. This configures a static RP at 10.0.0.1 for multicast groups matching access-list 10, which permits all groups in the 224.0.0.0/8 range. The interface is in PIM sparse-mode. However, the RP address must be reachable via unicast routing. The configuration is valid but note that 224.0.0.0/8 includes reserved link-local addresses (224.0.0.0/24) which are not typically used with PIM.

Answer

The router will ignore the static RP because the ACL includes the reserved link-local range (224.0.0.0/24).

Answer

The interface must also be configured with 'ip pim dense-mode' for the RP to work.

Answer

The RP address 10.0.0.1 must be configured on a loopback interface on the same router.

Question 11

What is the default IGMP version on a Cisco IOS interface when IP multicast routing is enabled?

Accepted Answer

IGMPv2. The default IGMP version on Cisco IOS interfaces is version 2, which is widely supported and provides basic membership reporting and querying.

Answer

IGMPv1

Answer

IGMPv3

Answer

IGMPv2 is default only if PIM is enabled; otherwise, no IGMP.

Question 12

Consider the following configuration on a Cisco IOS-XE router:

ip multicast-routing
!
interface GigabitEthernet0/0
 ip address 10.0.0.1 255.255.255.0
 ip pim sparse-mode
 ip igmp static-group 239.1.1.1
!

What is the effect of the 'ip igmp static-group 239.1.1.1' command?

Accepted Answer

The router will include this interface in the outgoing interface list for group 239.1.1.1, even without any IGMP hosts.. The 'ip igmp static-group' command statically adds the interface to the multicast group 239.1.1.1, meaning the router will treat the interface as if a host has joined that group. This can be used for testing or to ensure multicast traffic is forwarded to that interface even without an active IGMP member.

Answer

The router will send IGMP membership reports for group 239.1.1.1 out of this interface.

Answer

The router will drop all multicast traffic for group 239.1.1.1 on this interface.

Answer

The router will create a static multicast route for 239.1.1.1 via this interface.

Question 13

Which PIM mode requires a rendezvous point (RP) to function?

Accepted Answer

PIM Sparse-Mode. PIM sparse-mode (SM) requires an RP to act as a meeting point for receivers and sources. Dense-mode uses flood-and-prune without an RP, and bidirectional PIM also uses an RP but with a different mechanism.

Answer

PIM Dense-Mode

Answer

PIM Sparse-Dense-Mode

Answer

PIM Bidirectional

Question 14

Drag and drop the steps of RPF check verification for multicast forwarding into the correct order, from first to last.

Accepted Answer

Examine source IP address of multicast packet. The RPF check ensures that incoming multicast packets arrive on the correct interface toward the source. First, the router examines the source IP address. Then it consults the unicast routing table to find the best route. It identifies the outgoing interface for that route. It compares that interface with the arrival interface of the multicast packet. If they match, the packet is forwarded; otherwise, it is dropped.

Question 15

Examine the following configuration snippet:

ip pim send-rp-announce Loopback0 scope 10 group-list 10
ip pim send-rp-discovery scope 10
access-list 10 permit 239.0.0.0 0.255.255.255
!
interface Loopback0
 ip address 192.168.0.1 255.255.255.255
 ip pim sparse-mode
!

What is the purpose of this configuration?

Accepted Answer

The router will act as both a candidate RP for groups 239.0.0.0/8 and a mapping agent for Auto-RP within a scope of 10 hops.. This configures the router as an Auto-RP mapping agent and candidate RP. The 'send-rp-announce' command advertises this router as a candidate RP for groups matching ACL 10 (239.0.0.0/8) with a TTL scope of 10. The 'send-rp-discovery' command makes the router act as a mapping agent, listening for RP announcements and sending RP-discovery messages. The loopback interface is used as the RP address.

Answer

The router will only act as a mapping agent and will not advertise itself as an RP.

Answer

The router will use the IP address of GigabitEthernet0/0 as the RP address.

Answer

The router will only accept RP announcements from other routers within 10 hops.