Question 1mediummultiple choice
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Complete 300-410 Bidirectional Forwarding Detection (BFD) question bank — all 0 questions with answers and detailed explanations.
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 1500(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 1500(0) Rx Count: 120, Tx Count: 150
Based on this output, which statement is correct?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Down 0(0) Gi0/0
Session state is DOWN OurAddr: 10.1.1.1 Handle: 1 Local Diag: 1, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 0(0) Rx Count: 0, Tx Count: 50
Based on this output, what is the most likely cause of the BFD session being down?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 3000(0) Rx Count: 150, Tx Count: 150 Echo function: Active
Based on this output, which statement is correct?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 500000, Received Multiplier: 3 Holddown (hits): 1500(0) Rx Count: 200, Tx Count: 200
Based on this output, what is the holddown timer value in milliseconds and why?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 3000(0) Rx Count: 100, Tx Count: 100
Based on this output, what is the BFD session's negotiated transmit interval?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 3000(0) Rx Count: 100, Tx Count: 100
Based on this output, what is the BFD session's negotiated receive interval?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 3000(0) Rx Count: 100, Tx Count: 100
Based on this output, what is the BFD session's detection time?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 3000(0) Rx Count: 100, Tx Count: 100
Based on this output, what is the BFD session's local discriminator?
A network engineer runs the following command on Router R1:
R1# show bfd neighbors detail
IPv4 Sessions NeighborAddr LD/RD Int State Holdown(mult) Intf
10.1.1.2 1/3 Gi0/0 Up 3000(3) Gi0/0
Session state is UP and not using echo function. OurAddr: 10.1.1.1 Handle: 1 Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 3000(0) Rx Count: 100, Tx Count: 100
Based on this output, what is the BFD session's remote discriminator?
Consider the following partial configuration on a router:
interface GigabitEthernet0/1 ip address 10.1.1.1 255.255.255.252
bfd interval 100 min_rx 100 multiplier 3 !
router ospf 1 network 10.1.1.0 0.0.0.3 area 0
!
What is the effect of this configuration?
Examine the following configuration:
interface GigabitEthernet0/0 ip address 192.168.1.1 255.255.255.0
bfd interval 50 min_rx 50 multiplier 5 !
router eigrp TEST network 192.168.1.0
bfd interface GigabitEthernet0/0 !
Which statement is true about BFD operation on this interface?
A network engineer has configured BFD for OSPF as shown:
interface GigabitEthernet0/0
bfd interval 300 min_rx 300 multiplier 3 !
router ospf 1
bfd all-interfaces !
However, BFD sessions are not coming up. What is the most likely missing configuration?
Consider the following BGP configuration with BFD:
router bgp 65000 neighbor 10.1.1.2 remote-as 65001 neighbor 10.1.1.2 fall-over bfd
!
interface GigabitEthernet0/0 ip address 10.1.1.1 255.255.255.252
bfd interval 200 min_rx 200 multiplier 4 !
What is the effect of the 'neighbor fall-over bfd' command?
Examine the partial BFD configuration on a router:
interface GigabitEthernet0/0
bfd interval 100 min_rx 100 multiplier 3 !
interface GigabitEthernet0/1
bfd interval 200 min_rx 200 multiplier 3 !
router ospf 1
bfd all-interfaces !
The router has OSPF neighbors on both interfaces. Which statement is true?
A router has the following BFD configuration for a static route:
ip route 10.0.0.0 255.255.255.0 192.168.1.2
bfd map 192.168.1.2 10.0.0.0 255.255.255.0
interface GigabitEthernet0/0 ip address 192.168.1.1 255.255.255.0
bfd interval 100 min_rx 100 multiplier 3 !
What is the purpose of the 'bfd map' command in this context?
A network engineer runs the following command to troubleshoot a BFD issue:
R1# debug bfd event *Mar 1 00:12:34.567: BFD: [R1-to-R2] state DOWN -> UP (async) *Mar 1 00:12:34.568: BFD: [R1-to-R2] echo mode enabled, min-echo-rx-interval 50 ms *Mar 1 00:12:34.569: BFD: [R1-to-R2] starting echo timer, interval 50 ms *Mar 1 00:12:34.570: BFD: [R1-to-R2] sending async packet, state UP, interval 300 ms
What does this output indicate?
A network engineer runs the following command to verify BFD operation:
R1# show bfd neighbors detail
IPv4 Sessions NeighAddr LD/RD RH/RS State Int
10.1.1.2 1/2 Up Up Gi0/0
Session state is UP and not using echo function. Session type: single-hop Local Diag: 0, Demand mode: 0, Poll bit: 0 MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3 Received MinRxInt: 1000000, Received Multiplier: 3 Holddown (hits): 0 (0), Hello (hits): 1000/5 Rx Count: 1000, Rx Interval (ms) min/max/avg: 900/1100/1000 Tx Count: 1000, Tx Interval (ms) min/max/avg: 900/1100/1000
What does this output indicate?
A network engineer runs the following command to troubleshoot BFD with OSPF:
R1# show ip ospf interface gigabitethernet 0/0
GigabitEthernet0/0 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0 Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1 Backup Designated router (ID) 2.2.2.2, Interface address 10.1.1.2 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:03 Supports Link-local Signaling (LLS) Cisco NSF helper support enabled IETF NSF helper support enabled Index 1/1/1, flood queue length 0 Next 0x0(0)/0x0(0)/0x0(0) Last flood scan length is 1, maximum is 25 Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 2.2.2.2 (Backup Designated Router) Suppress hello for 0 neighbor(s) BFD enabled, BFD interval 100 msec, BFD multiplier 3
What does this output indicate?
A network engineer runs the following command to verify BFD with EIGRP:
R1# show ip eigrp 100 topology 10.2.2.0/24
EIGRP-IPv4 Topology Entry for AS(100)/ID(10.2.2.0/24) State: Passive, Query origin flag: 1, 1 Successor(s), FD is 131072 Descriptor Blocks:
10.1.1.2 (GigabitEthernet0/0), from 10.1.1.2, Send flag: 0x0
Composite metric: (131072/130816), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 100 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 Originating router is 2.2.2.2 BFD enabled, BFD state: UP
What does this output indicate?
A network engineer runs the following command to troubleshoot BFD with BGP:
R1# show bgp ipv4 unicast 10.3.3.0/24
BGP routing table entry for 10.3.3.0/24, version 2 Paths: (1 available, best #1, table default) Advertised to update-groups: 1 Refresh Epoch 1 Local
10.1.1.2 from 10.1.1.2 (2.2.2.2)
Origin IGP, metric 0, localpref 100, valid, external, best rx pathid: 0, tx pathid: 0x0 BFD enabled, BFD state: UP
What does this output indicate?
A network engineer runs the following command to verify BFD session details:
R1# show bfd neighbors detail | include (NeighAddr|LD/RD|State|Int|MinTxInt|Multiplier)
NeighAddr LD/RD RH/RS State Int
10.4.4.2 100/200 Up Up Gi0/1
MinTxInt: 500000, MinRxInt: 500000, Multiplier: 5
What does this output indicate?
A network engineer runs the following command to troubleshoot BFD session flapping:
R1# debug bfd packet *Mar 1 00:15:23.456: BFD: [R1-to-R3] received async packet from 10.5.5.2, state UP, diag 0 *Mar 1 00:15:23.457: BFD: [R1-to-R3] sending async packet, state UP *Mar 1 00:15:23.458: BFD: [R1-to-R3] received echo packet from 10.5.5.2, state UP *Mar 1 00:15:23.459: BFD: [R1-to-R3] echo packet lost, no echo received for 300 ms *Mar 1 00:15:23.460: BFD: [R1-to-R3] state UP -> DOWN (echo failure)
What does this output indicate?
A network engineer runs the following command to verify BFD with MPLS LDP:
R1# show mpls ldp neighbor 10.6.6.2 detail
Peer LDP Ident: 10.6.6.2:0, Local LDP Ident: 10.6.6.1:0 TCP connection: 10.6.6.2.646 - 10.6.6.1.53456 State: Oper; Msgs sent/rcvd: 100/100; Downstream Up time: 00:10:00 LDP discovery sources: GigabitEthernet0/2, hello interval: 5 s, hello hold: 15 s Addresses bound to peer LDP ident:
10.6.6.2 10.7.7.2
BFD enabled, BFD state: UP
What does this output indicate?
A network engineer runs the following command to troubleshoot BFD with static routes:
R1# show ip route 10.8.8.0/24
Routing entry for 10.8.8.0/24 Known via "static", distance 1, metric 0 Routing Descriptor Blocks:
* 10.9.9.2, via GigabitEthernet0/3
Route metric is 0, traffic share count is 1 BFD enabled, BFD state: UP
What does this output indicate?