300-410 Practice Exam 55 — 20 Questions

Question 1

A network engineer runs the following command to troubleshoot a BGP Troubleshooting issue:

R1# show bgp neighbors 10.1.1.2 received-routes
BGP table version is 14, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete

Network          Next Hop            Metric LocPrf Weight Path
*> 10.0.0.0/24      10.1.1.2                 0    100      0 65001 i
*> 192.168.1.0/24   10.1.1.2                 0    100      0 65001 i

Total number of prefixes 2

What does this output indicate?

Accepted Answer

R1 is receiving two routes from neighbor 10.1.1.2, both from AS 65001.. The show bgp neighbors received-routes command displays routes received from the neighbor 10.1.1.2. Both routes have next hop 10.1.1.2 and originate from AS 65001. The 'valid' and 'best' status indicates they are installed in the routing table.

Answer

R1 is sending two routes to neighbor 10.1.1.2.

Answer

R1 is receiving two routes, but one is filtered out by inbound policy.

Answer

R1 is receiving two routes, but the neighbor is not reachable.

Question 2

Which BGP message type is used to advertise, withdraw, and update routes?

Accepted Answer

UPDATE. BGP UPDATE messages carry path attributes and NLRI for route advertisements and withdrawals.

Answer

OPEN

Answer

NOTIFICATION

Answer

KEEPALIVE

Question 3

Drag and drop the steps to establish an eBGP session between two IOS routers into the correct order, from first to last.

Accepted Answer

Configure BGP router ID under router bgp. The correct order starts with configuring the BGP router ID, then the local AS and neighbor remote AS, followed by specifying the neighbor update source, enabling the neighbor, and finally verifying the session.

Question 4

Which TWO commands would a network engineer use to verify the operation of an Embedded Event Manager (EEM) applet that triggers on a syslog pattern? (Choose TWO.)

Accepted Answer

show event manager history events. The 'show event manager history events' command displays recent EEM events, including those triggered by syslog patterns, while 'show event manager policy active' lists currently registered and active EEM applets. The other options either show unrelated EEM data or require additional configuration to be useful.

Answer

show event manager detector syslog

Answer

show event manager environment

Answer

debug event manager action all

Question 5

A network engineer runs the following command to troubleshoot a BGP Troubleshooting issue:

R1# show ip bgp vpnv4 vrf CUSTOMER routes
BGP table version is 10, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete

Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 100:1 (default for vrf CUSTOMER)
*> 10.0.0.0/24      10.1.1.2                 0    100      0 65001 i
*> 192.168.1.0/24   10.1.1.2                 0    100      0 65001 i

Total number of prefixes 2

What does this output indicate?

Accepted Answer

The VRF CUSTOMER has two routes, both learned via BGP from AS 65001.. The show ip bgp vpnv4 vrf CUSTOMER routes command displays BGP VPNv4 routes for a specific VRF. The output shows two routes with route distinguisher 100:1, received from AS 65001. These are the routes available in the VRF CUSTOMER.

Answer

The VRF CUSTOMER is not receiving any routes because the RD is incorrect.

Answer

The VRF CUSTOMER has two routes, but they are not installed in the routing table.

Answer

The VRF CUSTOMER has two routes, but they are filtered by RT import policy.

Question 6

What is the default BGP hold timer value in Cisco IOS-XE?

Accepted Answer

180 seconds. The default BGP hold timer is 180 seconds, as per RFC 4271 and Cisco IOS-XE defaults.

Answer

90 seconds

Answer

120 seconds

Answer

240 seconds

Question 7

A network engineer runs the following command to troubleshoot a BGP Troubleshooting issue:

R1# show bgp ipv4 unicast summary
BGP router identifier 1.1.1.1, local AS number 65000
BGP table version is 15, main routing table version 15
2 network entries using 288 bytes of memory
2 path entries using 160 bytes of memory
2/2 BGP path/bestpath attribute entries using 296 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory
BGP using 800 total bytes of memory
BGP activity 6/0 prefixes, 6/0 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.1.1.2        4        65001      15      15       15    0    0 00:12:34        2
10.2.2.2        4        65002      10      12       15    0    0 00:08:21        0

What does this output indicate?

Accepted Answer

Neighbor 10.2.2.2 is not sending any routes, possibly due to filtering or no routes to advertise.. The show bgp summary output shows BGP neighbor states and prefix counts. Neighbor 10.1.1.2 is up and has sent 2 prefixes. Neighbor 10.2.2.2 is up but has sent 0 prefixes, indicating a possible issue with route advertisement or filtering.

Answer

Both neighbors are fully operational and exchanging routes.

Answer

Neighbor 10.1.1.2 is not sending any routes.

Answer

The BGP session with 10.2.2.2 is down.

Question 8

What is the default BGP administrative distance for routes learned from an external peer (eBGP) in Cisco IOS-XE?

Accepted Answer

20. Cisco IOS-XE assigns eBGP routes an administrative distance of 20 by default.

Answer

200

Answer

110

Answer

120

Question 9

An engineer is troubleshooting BGP convergence issues. Which THREE commands can be used to verify BGP path selection and best path criteria? (Choose THREE.)

Accepted Answer

show ip bgp . BGP path selection can be verified using 'show ip bgp ' to see the best path and all paths, 'show ip bgp neighbors routes' to see received routes, and 'show ip bgp' to see the BGP table summary. 'show ip route bgp' shows only the RIB, not the BGP decision process. 'show ip bgp community' filters by community but does not show path selection details.

Answer

show ip route bgp

Answer

show ip bgp community <community>

Question 10

A network engineer runs the following command to troubleshoot a BGP Troubleshooting issue:

R1# show bgp ipv4 unicast 192.168.1.0/24
BGP routing table entry for 192.168.1.0/24, version 12
Paths: (1 available, best #1, table default)
  Advertised to update-groups:
     1          
  Refresh Epoch 1
  65001, (received & used)
    10.1.1.2 from 10.1.1.2 (10.1.1.2)
      Origin IGP, metric 0, localpref 100, valid, external, best
      Community: 100:200

What does this output indicate?

Accepted Answer

The prefix 192.168.1.0/24 has a community attribute of 100:200, which may affect routing decisions.. The show bgp output for a specific prefix shows one path with community 100:200 attached. The community is a BGP community value that can be used for route tagging and policy enforcement. The path is valid and best.

Answer

The prefix 192.168.1.0/24 is not installed in the routing table.

Answer

The prefix 192.168.1.0/24 is being filtered due to the community value.

Answer

The community 100:200 indicates the prefix is from a confederation.

Question 11

Which BGP attribute is used as the first tie-breaker in the route selection process when comparing routes from different peers?

Accepted Answer

WEIGHT. BGP selects the route with the highest WEIGHT (Cisco proprietary) first, then LOCAL_PREF.

Answer

LOCAL_PREF

Answer

AS_PATH length

Answer

MED

Question 12

Which TWO statements about Embedded Event Manager (EEM) applet configuration are true? (Choose TWO.)

Accepted Answer

An EEM applet can be configured with multiple event statements using the 'event' command with the 'or' operator.. EEM applets can use multiple event statements combined with a Boolean operator, and the 'action' command supports Cisco IOS CLI commands via the 'cli' keyword. The other statements are false: applets do not require a Tcl script, multiple actions are allowed, and the 'event none' option is valid for manual triggering.

Answer

An EEM applet must include a Tcl script to perform any actions.

Answer

An EEM applet can only have a single action command.

Answer

The 'event none' configuration is not allowed in an EEM applet.

Question 13

A network engineer runs the following command to troubleshoot a BGP Troubleshooting issue:

R1# show bgp ipv4 unicast 192.168.1.0/24
BGP routing table entry for 192.168.1.0/24, version 12
Paths: (2 available, best #2, table default)
  Advertised to update-groups:
     1          
  Refresh Epoch 1
  65001
    10.1.1.2 from 10.1.1.2 (10.1.1.2)
      Origin IGP, metric 0, localpref 100, valid, external
  Refresh Epoch 2
  65002
    10.2.2.2 from 10.2.2.2 (10.2.2.2)
      Origin IGP, metric 0, localpref 100, valid, external, best

What does this output indicate?

Accepted Answer

The path from AS 65002 is best due to a tie-breaking rule, such as lower neighbor router ID.. The output shows two paths with equal local preference and metric. The best path is from AS 65002, likely due to a tie-breaking rule such as lower router ID or older route. The path from AS 65001 is valid but not best.

Answer

Both paths are equally preferred, and BGP load-balances traffic.

Answer

The path from AS 65002 is best because it has a higher local preference.

Answer

The path from AS 65001 is best because it was received first.

Question 14

What is the default behavior of BGP synchronization in Cisco IOS-XE?

Accepted Answer

Disabled by default. BGP synchronization is disabled by default in IOS-XE; routes can be advertised without being in the IGP.

Answer

Enabled by default

Answer

Enabled only for iBGP

Answer

Disabled only for eBGP

Question 15

Which THREE symptoms indicate that an Embedded Event Manager (EEM) applet configured to send a syslog message upon interface down has failed to execute? (Choose THREE.)

Accepted Answer

No custom syslog message appears on the console or in the log buffer when the interface goes down.. If the applet fails, no custom syslog is generated, the 'show event manager history events' will not show the trigger, and the 'show event manager policy active' may show the policy but with a non-zero failure count. The other options either describe normal behavior or unrelated issues.

Answer

The interface goes down and the router generates a default syslog message like '%LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down'.

Answer

The 'show event manager environment' output shows the variable '_event_type' as 'none'.

Question 16

Which BGP message type is sent when a fatal error is detected, causing the BGP session to close?

Accepted Answer

NOTIFICATION. NOTIFICATION messages are sent to report errors and terminate the BGP session.

Answer

OPEN

Answer

UPDATE

Answer

KEEPALIVE

Question 17

Which TWO configuration steps are required to enable an Embedded Event Manager (EEM) applet that sends an SNMP trap when a specific OID is polled? (Choose TWO.)

Accepted Answer

Configure 'event snmp oid 1.3.6.1.4.1.9.9.117.1.1.2.1.1 get-type exact' within the applet.. To trigger an EEM applet on an SNMP OID poll, you must configure the 'event snmp oid' command and ensure SNMP is enabled globally. The other options are either unnecessary (like configuring a community for the applet itself) or incorrect (like using 'event syslog' or 'event cli').

Answer

Configure 'event syslog pattern "SNMP"' to capture the SNMP poll.

Answer

Configure an SNMP community string with read-write access inside the applet using 'action snmp-community'.

Answer

Configure 'event cli command "snmpwalk" sync yes' to trigger on SNMP walks.

Question 18

Drag and drop the steps to troubleshoot BGP adjacency or connectivity failures into the correct order, from first to last.

Accepted Answer

Ping neighbor IP from source interface. First, check interface IP connectivity with ping; then verify BGP neighbor reachability and TCP port 179; next inspect BGP configuration for AS number mismatches; then examine BGP timers and update-source; finally use debug ip bgp to see session state transitions.

Question 19

Which TWO commands can be used to troubleshoot an Embedded Event Manager (EEM) applet that is not triggering as expected? (Choose TWO.)

Accepted Answer

debug event manager action all. The 'debug event manager action all' command provides detailed logs of EEM actions, while 'show event manager detector all' shows the status of all EEM detectors (including whether they are registered). The other options are either not valid or not useful for troubleshooting trigger issues.

Answer

show event manager policy registered

Answer

show event manager environment all

Answer

debug event manager all

Question 20

An engineer is troubleshooting a BGP route advertisement issue. Which TWO commands can be used to verify whether a prefix is being advertised to a specific BGP neighbor? (Choose TWO.)

Accepted Answer

show ip bgp . To verify BGP advertisement to a neighbor, 'show ip bgp neighbors advertised-routes' shows all routes advertised to that neighbor. 'show ip bgp ' includes an entry for each neighbor the route is advertised to. 'show ip bgp neighbors routes' shows routes received from the neighbor, not advertised. 'debug ip bgp updates' is a debug command, not a verification command. 'show ip bgp summary' shows neighbor states and counts, not specific prefix advertisement.

Answer

show ip bgp neighbors <neighbor> routes

Answer

debug ip bgp updates

Answer

show ip bgp summary