| Question: | Which of the following IP Addresses is a Class C Private network address?
A. 11000000.10101010.00010001.00001001
B. 10100000.10101000.00010001.00001001
C. 11000000.11101000.00010001.00001001
D. 11000000.10101000.00010001.00001001
E. 11000000.10101001.00010001.00001001
|
| Answer: | D. 11000000.10101000.00010001.00001001
|
| Explanation: | RFC1918 specifies the allocation of IP Addresses for Private Internets.
Class A 10.0.0.0 - 10.255.255.255 (10/8 prefix)
Class B 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
Class C 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
or in binary (only the first 2 otctets are represented)
Class A 0000 1010.0000 0000
Class B 1010 1100.0001 0000
Class C 1100 0000.1010 1000
|
|
| Question: | In OSPF the DRs use which IP Address to exchange link-state information?
A. 224.0.0.5
B. 224.0.0.6
C. 224.0.0.9
D. 224.0.0.10
|
| Answer: | A. 224.0.0.5
|
| Explanation: | OSPF uses 224.0.0.5 (all OSPF routers) to exchange link-state information and listens to 224.0.0.6 (all OSPF designated routers) to receive multicast updates from DRothers.
More reserverd multicast addresses can be found here: http://www.iana.org/assignments/multicast-addresses |
|
| Question: | We want to advertise only a default route via EIGRP. How do we achieve this?
A. R1(config)#interface serial0 R1(config-if)#ip summary-address eigrp 1000 0.0.0.0 0.0.0.0
B. R1(config)#router EIGRP 1000 R1(config-router)#neighbor 172.16.1.25 default-originate always
C. R1(config)#router EIGRP 1000 R1(config-router)#ip summary-address eigrp 1000 0.0.0.0 0.0.0.0
D. R1(config)#ip summary-address eigrp 1000 0.0.0.0 0.0.0.0
|
| Answer: | A. R1(config)#interface serial0 R1(config-if)#ip summary-address eigrp 1000 0.0.0.0 0.0.0.0
|
| Explanation: | To advertise just a default route and suppress all other routing updates we use the ip summary-address eigrp as_number 0.0.0.0 0.0.0.0 command in interface configuration mode. Replacing 0.0.0.0 0.0.0.0 with a summary address and network mask will advertise that summary route. We also need to disable the automatic summarization with the no auto-summary router configuration command. |
|
| Question: | EIGRP uses the following tables?
A. Route/Forwarding table
B. Cost table
C. Topology table
D. Link-state table
E. Neighbor table
F. EIGRP table
|
| Answer: | A. Route/Forwarding table
C. Topology table
E. Neighbor table
|
| Explanation: | The neighbor table contains every formed adjacency. The topology table is where all the learned routes are kept. The route/forwarding table contains the lowest composite metric routes. |
|
| Question: | When using autoconfiguration with IPv6 what are the minimum requirements?
A. R1(config)#ipv6 unicast-routing R1(config)#interface type R1(config-if)#ipv6 enable
B. R1(config-if)#ipv6 unicast-routing
C. R1(config)#ipv6 unicast-routing R1(config-router)#ipv6 enable
D. R1(config)#ipv6 unicast-routing
|
| Answer: | A. R1(config)#ipv6 unicast-routing R1(config)#interface type R1(config-if)#ipv6 enable
|
| Explanation: | When a node initializes it generates a link-local address for that interface. The link-local address is the interface?s identifier concatenated with the well-known link-local prefix FE80:: The rightmost zeros of the link-local prefix are replaced with the interface ID.
Example, link-local prefix FE80:0:0:0:0:0:0:0 and interface ID 200:CFF:FE0A.2C51 form link-local address FE80:0:0:0:200:CFF:FE0A.2C51 The node then initiates the duplicate address detection progress and if no duplicate address exists then the node assigns the generated local-link address to the interface. |
|
| Question: | We want to redistribute our RIP routes into OSPF. What is the correct configuration to achieve this?
A. R1(config)#router rip R1(config-router)#redistribute ospf
B. R1(config)#redistribute rip ospf
C. R1(config)#router ospf 100 R1(config-router)#redistribute rip subnets
D. R1(config)#router ospf R1(config-router)#redistribute rip subnets
|
| Answer: | C. R1(config)#router ospf 100 R1(config-router)#redistribute rip subnets
|
| Explanation: | The redistribute command allows to inject routes from one routing protocol into another. The subnets keyword is needed to redistribute subnetted routes otherwise only non-subnetted routes are redistributed. |
|
| Question: | What happens when a Designated Router fails in an OSPF network?
A. The Backup Designated Router takes over the role of Designated Router but seizes to have this role when the original Designated Router comes back online and a new Backup Designated Router is elected
B. An election is held between all the Backup Designated Routers and the Backup Designated Router with the highest priority becomes the Designated Router
C. The Backup Designated Router takes over the role of Designated Router even if the Designated Router comes back online and a new Backup Designated Router is elected
D. An election is held between all the Backup Designated Routers and the Backup Designated Router with the lowest priority becomes the Designated Router
|
| Answer: | C. The Backup Designated Router takes over the role of Designated Router even if the Designated Router comes back online and a new Backup Designated Router is elected
|
| Explanation: | A significant problem with the Designated Router (DR) scheme is that if the DR fails, a new DR must be elected. New adjacencies must be established, and all routers on the network must synchronize their databases with the new DR (part of the adjacency-building process). While all this is happening, the network is unavailable for transit packets.
To prevent this problem, a Backup Designated Router (BDR) is elected in addition to the DR. All routers form adjacencies not only with the DR but also with the BDR. The DR and BDR also become adjacent with each other. If the DR fails, the BDR becomes the new DR. Because the other routers on the network are already adjacent with the BDR, network unavailability is minimized.
When an OSPF router becomes active and discovers its neighbours, it checks for an active DR and BDR. If a DR and BDR exist, the router accepts them. If there is no BDR, an election is held in which the router with the highest priority becomes the BDR. If more than one router has the same priority, the one with the numerically highest Router ID wins. If there is no active DR, the BDR is promoted to DR and a new election is held for the BDR.
It should be noted that the priority can influence an election, but will not override an active DR or BDR. That is, if a router with a higher priority becomes active after a DR and BDR have been elected, the new router will not replace either of them. So the first two DR-eligible routers to initialize on a multi-access network will become the DR and BDR. |
|
| Question: | What type of LSAs are not flooded into a totally stubby area?
A. LSA type 2
B. LSA type 1
C. LSA type 5
D. LSA type 4
|
| Answer: | C. LSA type 5
D. LSA type 4
|
| Explanation: | Because totally stubby areas use a default route to all destinations (external to the AS and area) the ABR will block LSA type 4 and 5 but also all summary LSAs with the exception of a single type 3 LSA to advertise the default route. |
|
| Question: | What type of LSA are used to advertise routes that have been redistributed into OSPF?
A. LSA type 5
B. LSA type 1
C. LSA type 3
D. LSA type 7
|
| Answer: | A. LSA type 5
|
| Explanation: | LSA type 5 or Autonomous System External LSAs are used to advertise routes that have been redistributed into OSPF. They are flooded throughout the entire system except for stub, totally stub and not-so-stubby areas. |
|
| Question: | How can we influence the DR and BDR election?
A. R1(config)#interface ethernet0 R1(config-if)#ip ospf priority 220
B. R1(config)#interface ethernet0 R1(config-if)#ip priority 220
C. R1(config)#interface ethernet0 R1(config-if)#ip ospf priority 0
D. R1(config)#router ospf 10 R1(config-router)#priority 220
|
| Answer: | A. R1(config)#interface ethernet0 R1(config-if)#ip ospf priority 220
|
| Explanation: | The ip ospf priority command will set a value to the interface that will be used when the DR and BDR is elected. The highest priority will win the election, in case of a tie the highest RID will win. |
|
| Question: | What command do we use to view the state of adjacencies formed with other routers in OSPF?
A. Show ip ospf database summary
B. Show ip ospf detail
C. Show ip ospf database
D. Show ip ospf neighbor
|
| Answer: | D. Show ip ospf neighbor
|
| Explanation: | The show ip ospf neighbor command shows the operational status of all OSPF neighbors (adjacencies). |
|
| Question: | A route external to the OSPF AS that does not take the cost to the ASBR into account is entered in the routing table with the following code?
A. O E2
B. O E1
C. O
D. O IA
|
| Answer: | A. O E2
|
| Explanation: | Type 2 external paths (E2) are routes external to the OPSF AS and do no take the cost into account of the path to the ASBR. |
|
| Question: | We want to inject a summary route, from other OSPF areas, into the backbone area 0 from an ABR. What command do we use?
A. area x range network networkmask
B. summary-address network networkmask
C. area network networkmask
D. summary-route network networkmask
|
| Answer: | A. area x range network networkmask
|
| Explanation: | To inject a summary route of other OSPF areas via the ABR into the backbone we use the area area_id range network_address network_mask router configuration command on the ABR. |
|
| Question: | A network LSA originates from which router?
A. DR
B. BDR
C. ABR
D. ASBR
|
| Answer: | A. DR
|
| Explanation: | Network LSAs (type 2) originate from the DR on every multi-access network and list all attached routers including it self. |
|
| Question: | Which of the following are well-known mandatory attributes?
A. Atomic_Aggregate
B. Multi_Exit_Disc
C. Local_Pref
D. Aggregator
E. Next_hop
F. AS_path
|
| Answer: | E. Next_hop
F. AS_path
|
| Explanation: | The 3 well-known mandatory attributes are:
- Origin
- AS_Path
- Next_Hop
|
|
| Question: | We want to configure EIGRP on R1 but E1 is not allowed to participate in the EIGRP process. How do we achieve this?
A. R1(config)#router eigrp 10 R1(config-router)#network 10.1.1.1 0.0.0.0 as 10 R1(config-router)#network 192.168.1.0
B. R1(config)#router eigrp 10 R1(config-router)#network 10.1.1.1 0.0.0.0 R1(config-router)#network 192.168.1.0
C. R1(config)#router eigrp 10 R1(config-router)#network 10.1.1.1 R1(config-router)#network 192.168.1.0
D. R1(config)#router eigrp 10 R1(config-router)#network 10.1.1.1 R1(config-router)#network 192.168.1.0 R1(config)#interface ethernet 1 R1(config-if)#ip eigrp passive
|
| Answer: | B. R1(config)#router eigrp 10 R1(config-router)#network 10.1.1.1 0.0.0.0 R1(config-router)#network 192.168.1.0
|
| Explanation: | Since the release of IOS 12.01(T) the network statement was given the ability to use wildcard masks like OSPF. Prior to that IOS release the router (IOS) would correct the address to the major classful network number, in this case 10.0.0.0 which would include ethernet 1. In earlier releases this would be achieved with the passive-interface router configuration command. |
|
| Question: | What is the configuration for R1 in the network shown in the exhibit? AS123 has internal BGP and R1 is peering with R4. [Click exhibit]
A. R1(config)#router bgp 123 R1(config-router)#neighbor 192.158.1.3 R1(config-router)#neighbor 192.168.1.7 R1(config-router)#neighbor 192.168.1.11
B. R1(config)#router bgp 123 R1(config-router)#neighbor 192.158.1.3 R1(config-router)#neighbor 192.168.1.7 R1(config-router)#neighbor 192.168.1.11 remote-as 456
C. R1(config)#router bgp 123 R1(config-router)#neighbor 192.158.1.3 remote-as 123 R1(config-router)#neighbor 192.168.1.7 remote-as 123 R1(config-router)#neighbor 192.168.1.11
D. R1(config)#router bgp 123 R1(config-router)#neighbor 192.168.1.3 remote-as 123 R1(config-router)#neighbor 192.168.1.7 remote-as 123 R1(config-router)#neighbor 192.168.1.11 remote-as 456
|
| Answer: | D. R1(config)#router bgp 123 R1(config-router)#neighbor 192.168.1.3 remote-as 123 R1(config-router)#neighbor 192.168.1.7 remote-as 123 R1(config-router)#neighbor 192.168.1.11 remote-as 456
|
| Explanation: | To configure BGP on a router follow the following steps:
Step1: Enable the BGP process and specify the local AS number with the router bgp command.
Step2: Use the neighbor remote-as command to specify a neighbor and its AS number |
|
| Question: | Which of the following statements are true about route reflectors?
A. If a route is received from a client, advertise the route to the other clients and non clients
B. If a route is received from an eBGP peer advertise the route to all clients but not to the non clients
C. if a route is received from a non client advertise the route to all the clients
D. If a route is received from a non client, drop the route
|
| Answer: | A. If a route is received from a client, advertise the route to the other clients and non clients
C. if a route is received from a non client advertise the route to all the clients
|
| Explanation: | Route reflectors use the following rules:
- if the route is received from a non client peer then advertise that route to all the clients
- if the route is received from a client peer then advertise the route to all non clients and client peers
- if the route is received from an external BGP peer advertise the route to all the client and non client peers
|
|
| Question: | Which of the following statements are true about BGP?
A. BGP is a link-state protocol
B. BGP does not support VLSM
C. Is a distance vector protocol.
D. BGP uses TCP port 179
E. BGP is described in RFC 1771
|
| Answer: | D. BGP uses TCP port 179
E. BGP is described in RFC 1771
|
| Explanation: | BGP is described in RFC 1771 (http://www.ietf.org/rfc/1771rfc.txt) and uses TCP port 179 as its transport protocol. |
|
| Question: | Which of the following fields belong to the OPEN message in BGP?
A. Path attributes
B. Network Layer Reachability Information
C. Hello time
D. Version
E. Autonomous system number
|
| Answer: | D. Version
E. Autonomous system number
|
| Explanation: | The BGP OPEN message contains the following fields:
- BGP version number
- Autonomous system number
- Hold time
- BGP identifier
- Optional parameters
|
|
| Question: | In which order are the following six decisions evaluated during the BGP decision process?
A. First,Second,Third,Fouth,Fifth,Sixth
B. Next Hop Availability,Highest Administrative Weight,Highest Local Prefernece,Shortest AS Path,Lowest MED,External over Internal BGP
|
| Answer: | B. Next Hop Availability,Highest Administrative Weight,Highest Local Prefernece,Shortest AS Path,Lowest MED,External over Internal BGP
|
| Explanation: | The BGP decision process follows the following steps:
- if the next hop is unavailable ignore the route
- prefer the path with the highest administrative weight (Cisco proprietary)
- if the weights are equal prefer the route with the highest local preference
- if the local preferences are equal prefer the route with the shortest AS_Path
- if the AS_Paths are equal prefer the route with the lowest origin type
- if the origin type is the same prefer the route with the lowest MED
- if the MED is equal prefer external BGP routes over internal BGP routes
- if everything is still equal prefer the route with the shortest path to the BGP Next_Hop, i.e. the route with the lowest IGP metric to the next-hop router
- the last step is prefer the route advertised by the router with the lowest RID |
|
| Question: | How can we influence the metric of OSPF?
A. R1(config)#interface serial0 R1(config-if)#bandwidth 256
B. R1(config)#interface serial0 R1(config-if)#bandwidth 256k
C. R1(config)#interface serial0 R1(config-if)#ip ospf cost 10
D. R1(config)#router ospf 10 R1(config-router)#cost 10
E. R1(config)#router ospf 10 R1(config-router)#ip cost 10
|
| Answer: | A. R1(config)#interface serial0 R1(config-if)#bandwidth 256
C. R1(config)#interface serial0 R1(config-if)#ip ospf cost 10
|
| Explanation: | OSPF uses cost as a metric which is derived from the formula 10^8/bandwidth. Changing the bandwidth statement of an interface running OSPF will influence the metric. We can also use the ip ospf cost value interface configuration command to influence the cost. |
|
| Question: | How can we change the default cost calculation of OSPF?
A. R1(config-router)#ospf reference-bandwidth 1000
B. R1(config-if)#ospf reference-bandwidth 1000
C. R1(config)#ospf reference-bandwidth 1000
D. R1(config-router)#ospf auto-cost reference-bandwidth 1000
E. R1(config)#ospf auto-cost reference-bandwidth 1000
F. R1(config)#ospf auto-cost reference-bandwidth 1000
|
| Answer: | D. R1(config-router)#ospf auto-cost reference-bandwidth 1000
|
| Explanation: | Using the ospf auto-cost reference-bandwidth value router configuration command we can control how OSPF calculates default metrics for the interface. The value range is 1 to 4294967, the default is 100. |
|
| Question: | When configuring BGP we want to use loopback0 as the interface to establish the peering sessions. How can we achieve this?
A. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 update-source loopback0
B. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 update-peer loopback0
C. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 update-interface loopback0
D. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 peer loopback0
|
| Answer: | A. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 update-source loopback0
|
| Explanation: | The update-source command used in combination with the neighbor command lets us choose the interface we will use as a source IP address for the peering session with that neighbor. |
|
| Question: | In the network [click exhibit] only R3 needs to receive a default route from R1. What do we configure on R1?
A. router bgp 123 no synchronization network 192.168.1.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 456 neighbor 10.1.1.4 remote-as 789 no auto-summary
B. router bgp 123 no synchronization network 192.168.1.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 456 neighbor 10.1.1.2 default-route neighbor 10.1.1.4 remote-as 789 no auto-summary
C. router bgp 123 no synchronization network 192.168.1.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 456 neighbor 10.1.1.4 remote-as 789 neighbor 10.1.1.2 default-originate no auto-summary
D. router bgp 123 no synchronization network 0.0.0.0 network 192.168.1.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 456 neighbor 10.1.1.4 remote-as 789 no auto-summary
|
| Answer: | C. router bgp 123 no synchronization network 192.168.1.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 456 neighbor 10.1.1.4 remote-as 789 neighbor 10.1.1.2 default-originate no auto-summary
|
| Explanation: | Using the default-originate keyword with the neighbor command will let you inject a default route in that peer?s AS. The network 0.0.0.0 command will do the same but for all neighbors mentioned under the BGP process. |
|
| Question: | What is the origin code for a route originated on a BGP router?
A. 1
B. 2
C. 0
D. 3
|
| Answer: | C. 0
|
| Explanation: | Origin Code Origin Code name Description
0 IGP Route originated from a BGP router.
1 EGP Route originated from an EGP (not eBGP)
2 Incomplete Route originated from a routing process
other then BGP via redistribution . |
|
| Question: | The default BGP holdtime for a session is?
A. 60 seconds
B. 240 seconds
C. 120 seconds
D. 180 seconds
|
| Answer: | D. 180 seconds
|
| Explanation: | The default BGP holdtime, sent in the open message, is 180 seconds. |
|
| Question: | On a broadcast multiaccess OSPF network Hellos are send every _______ ?
A. 90 seconds
B. 10 seconds
C. 40 seconds
D. 30 minutes
E. 60 seconds
|
| Answer: | B. 10 seconds
|
| Explanation: | Hellos are send periodically every 10 seconds (default) on a broadcast multiaccess media. |
|
| Question: | An IPv6 address that is within the same site but might be on a different network is a ____________ address?
A. Site local
B. Link local
C. Network local
D. Area local
|
| Answer: | A. Site local
|
| Explanation: | A site local is unicast address that is within the same site but it could be on a different network. |
|
| Question: | Where in the Cisco hierarchical design would you find access lists?
A. Access layer
B. Core layer
C. Network layer
D. Transport layer
E. Distribution layer
|
| Answer: | E. Distribution layer
|
| Explanation: | The distribution layer is responsible for determining access across the backbone by filtering out unnecessary resource updates and selectively granting access to users and departments via access lists. |
|
| Question: | Which of the following routing protocols do support VLSM?
A. EIGRP
B. IS-IS
C. OSPF
D. RIPv2
E. BGP
F. RIPv1
G. EGP
H. IGRP
|
| Answer: | A. EIGRP
B. IS-IS
C. OSPF
D. RIPv2
E. BGP
|
| Explanation: | RIPv2, EIGRP, OSPF, IS-IS and BGP do support VLSM. |
|
| Question: | Given the network 192.168.1.0/24 what will be subnetmask if we only want 20 hosts on each subnet?
A. /28
B. /30
C. /29
D. /27
|
| Answer: | D. /27
|
| Explanation: | In order for us to get 20 hosts on each subnet we need 5 bits of the last octet this will give us 2^5 - 2 = 30 hosts on each subnet. We still have 3 bits left for available subnets. So the subnetmask is 255.255.255.224 or /27. |
|
| Question: | EIGRP uses which multicast address for updates?
A. 224.0.0.1
B. 224.0.0.5
C. 224.0.0.6
D. 224.0.0.9
E. 224.0.0.10
|
| Answer: | E. 224.0.0.10
|
| Explanation: | EIGRP uses 224.0.0.10 for sending out routing updates. |
|
| Question: | In IS-IS what best describes a pseudonode?
A. The LAN identifier for a broadcast subnetwork.
B. A router that is only connected to the backbone and provide transit traffic between areas.
C. A group of routers running the IS-IS protocol.
D. A service at the network layer to which the packet is to be directed.
|
| Answer: | A. The LAN identifier for a broadcast subnetwork.
|
| Explanation: | A pseudonode is the LAN identifier for a broadcast subnetwork. It makes the broadcast domain appear as a virtual router and the routers appear as connected interfaces. |
|
| Question: | When a router has multiple routes to a network what will be used to route a packet to that network?
A. The route that matches the longest prefix length.
B. The route that was learned last.
C. The route that uses the fastest interface.
D. The route that was learned first.
E. The route that matches the shortest prefix length.
|
| Answer: | A. The route that matches the longest prefix length.
|
| Explanation: | The forwarding process will use the route where the most number of subnet bits match that of the destination network. This is known as match to the longest prefix length. |
|
| Question: | Which of the following are part of the switching function in a router?
A. Check if the frame passes the crc.
B. Check if there is a layer 2 address.
C. Check if there are multiple equal-cost paths.
D. Check for the best path to the destination.
|
| Answer: | A. Check if the frame passes the crc.
B. Check if there is a layer 2 address.
|
| Explanation: | The switching function on a router performs the following steps:
- checks the incoming frame for validity
- checks if it contains a layer 2 address to the router
- checks the size of the frame, not too big or too small
- checks if it passes the cyclic redundancy check
- strips the layer 2 header and trailer and checks the destination address against its cache
- creates the new frame header and trailer and places the frame in the outbound interface queue |
|
| Question: | Which of the following are routed procotols?
A. OSPF
B. NetBeui
C. SPX
D. TCP
E. BGP
F. IS-IS
G. AppleTalk
H. IP
I. IPX
|
| Answer: | G. AppleTalk
H. IP
I. IPX
|
| Explanation: | A routed protocol is the layer 3 protocol used to transfer data from one end device to another across the network. AppleTalk, IPX, IP, Vines, DECnet IV are examples of routed protocols. |
|
| Question: | What is described by the following:
A value assigned to each path based on the criteria specified in the routing protocol.
A. Metric
B. Administrative Distance
C. Bandwidth
D. Subnetmask
E. Prefix length
F. Path cost
|
| Answer: | A. Metric
|
| Explanation: | The metric is a value assigned to each path based on the criteria specified in the routing protocol. |
|
| Question: | Looking at the routing table we see routes marked with i, via which protocol are these routes learned?
A. EIGRP
B. OSPF
C. BGP
D. IGRP
E. IS-IS
|
| Answer: | E. IS-IS
|
| Explanation: | Routes that are marked with an i in the routing table are routes learned via IS-IS.
R1# show ip route
Codes:
I - IGRP derived, R - RIP derived, O - OSPF derived,
C - connected, S - static, E - EGP derived, B - BGP derived,
* - candidate default route, IA - OSPF inter area route,
i - IS-IS derived, ia - IS-IS, U - per-user static route,
o - on-demand routing, M - mobile, P - periodic downloaded static route,
D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route,
E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route,
N2 - OSPF NSSA external type 2 route |
|
| Question: | The maximum amount of equal-costs paths on a Cisco router is by default?
A. 6
B. 10
C. 2
D. 4
E. 8
|
| Answer: | D. 4
|
| Explanation: | On a Cisco router, if multiple equal-cost paths exist in IP up to 6 paths can be used to load balance traffic across the network in a round-robin manner. The default is 4 paths. |
|
| Question: | We want to enter a static route in the routing table that will stay there even if the interface shuts down. How do we achieve this?
A. ip route 192.168.1.0 255.255.255.0 172.16.1.1
B. ip route 192.168.1.0 255.255.255.0 serial0/1
C. ip route 192.168.1.0 255.255.255.0 172.16.1.1 persistent
D. ip route 192.168.1.0 255.255.255.0 172.16.1.1 permanent
|
| Answer: | D. ip route 192.168.1.0 255.255.255.0 172.16.1.1 permanent
|
| Explanation: | Using the permanent keyword with the ip route command ensures that the route will not be removed from the routing table even if the interface shuts down. |
|
| Question: | Which of the following are valid statements for implementing static routes?
A. The network administrator needs control over the link.
B. Using static routes makes scalability easier.
C. The network is a stub network.
D. Static routes are more reliable since there is no convergence in case of a failure.
E. Static routes are easier to confgure no matter what the size of the network is.
|
| Answer: | A. The network administrator needs control over the link.
C. The network is a stub network.
|
| Explanation: | Some reasons for implementing static routes are:
- low bandwidth link, e.g. dial-up links
- you need control over the link
- the link is a backup to the dynamically learned route
- there is only 1 path to the remote network, a stub network
- router has limited resources and can not run a routing protocol
|
|
| Question: | ODR uses which protocol to send prefixes from the remote router to the core router?
A. Static routing
B. EIGRP
C. CDP
D. IGRP
E. SNMP
|
| Answer: | C. CDP
|
| Explanation: | ODR or On Demand Routing uses Cisco Discovery Protocol (CDP) to send the prefixes of attached networks from the spoke or remote router to the hub or core router. |
|
| Question: | By default ODR sends updates every 60 seconds we want this to decrease to 30 seconds. How do we achieve this?
A. R1(config)#ODR timer 30
B. R1(config-if)#ODR timer 30
C. R1(config-if)#timer 30
D. R1(config-if)#cdp timer 30
|
| Answer: | D. R1(config-if)#cdp timer 30
|
| Explanation: | Because ODR, On Demand Routing, uses CDP (Cisco Discovery Protocol) we can change the update interval by changing the CDP timer to send out updates more or less frequently then every 60 seconds (default). |
|
| Question: | Networks logically grouped together under one administrative control is called a(n) _________ ?
A. Area
B. Domain
C. Workgroup
D. Hierarchy
E. Backbone
F. Autonomous system
|
| Answer: | F. Autonomous system
|
| Explanation: | An autonomous system is a logical grouping of networks under one administrative control. |
|
| Question: | We want to create 15 subnets of the 172.16.0.0/16 address. How many hosts are available on each subnet?
A. 2046
B. 2048
C. 2050
D. 2044
|
| Answer: | A. 2046
|
| Explanation: | To give us 15 subnets we use 5 bits of the host portion giving us 30 available subnets [2^5 - 2 = 30]. This leaves us 11 bits available for hosts, 2^11 - 2 = 2046 hosts on each subnet. |
|
| Question: | What are some advantages of using prefix routing?
A. reduction in the size of the routing table.
B. eliminates the need for an exterior routing protocol.
C. greater flexibility in network addressing.
D. eliminates the need for route summarization
E. allows for complex routing protocols to be used on private networks.
|
| Answer: | A. reduction in the size of the routing table.
C. greater flexibility in network addressing.
|
| Explanation: | Following are some benefits of Prefix Routing/CIDR:
- reduces the routing table in size
- allows for more flexibility in network addressing
- less overhead in network traffic, CPU and Memory |
|
| Question: | Which of the following routing protocols do not support VLSM?
A. EGP
B. BGP-4
C. IGRP
D. RIPv2
E. OSPF
F. RIPv1
G. IS-IS
|
| Answer: | A. EGP
C. IGRP
F. RIPv1
|
| Explanation: | The following routing protocols support VLSM:
- RIPv2
- OSPF
- IS-IS
- EIGRP
- BGP-4
|
|
| Question: | Ciscos hierarchical design consists of which layers?
A. Access
B. Backbone
C. Distribution
D. Network
E. Core
F. Internetwork
|
| Answer: | A. Access
C. Distribution
E. Core
|
| Explanation: | The Cisco hierarchical design model has the following layers:
- The core layer
- The distribution layer
- The access layer
|
|
| Question: | Which of the following elements would find on the core layer of Ciscos hierarchical design?
A. Access-lists
B. QoS
C. NAT
D. Redundancy
E. Complex routing decisions
|
| Answer: | B. QoS
D. Redundancy
|
| Explanation: | The core layers main function is to connect the entire enterprise by interconnecting the distributions layer devices. To achieve maximum availability we need a highly redundant layer. Any services, e.g. filtering (Access lists), NAT etc. should be removed from this layer since they create a latency in the forwarding process. To ensure higher priority to certain traffic types QoS can be implemented at this layer. |
|
| Question: | A DIS sends out Hello Packets every __________ seconds?
A. 10
B. 45
C. 3
D. 15
E. 3.3
F. 30
|
| Answer: | E. 3.3
|
| Explanation: | A DIS sends out Hello packets every 3.3 seconds to maintain the adjacencies with the other routers. Other routers send out Hello Packets every 10 seconds. |
|
| Question: | When electing a DIS and the priorities are all equal what will be used to elect the DIS?
A. The highest value in the TLV
B. The lowest value in the TLV
C. The highest numeric SNPA
D. The lowest numeric SNPA
E. The highest numeric IP Address
F. The lowest numeric IP Address
|
| Answer: | C. The highest numeric SNPA
|
| Explanation: | A DIS election is based on priority (default is 64) if all priorities are the default value then the highest SNPA (Subnetwork Point of Attachment), the data-link address will determine the DIS. |
|
| Question: | Which fields in an LSP packet determine if the LSP is newer then the one in the database?
A. Sequence number
B. Holding time
C. Checksum
D. LAN ID
E. Version
F. Remaining lifetime
G. Priority
|
| Answer: | A. Sequence number
C. Checksum
F. Remaining lifetime
|
| Explanation: | The tree fields used in an LSP to determine if the LSP is newer then the one in the database are:
- Remaining lifetime
- Sequence number
- Checksum |
|
| Question: | How do we change the entire router to be Level 1 only IS-IS router?
A. router isis is-type level-1
B. router isis isis circuit-type level-1
C. interface ethernet0 isis circuit-type level-1
D. interface ethernet0 is-type level-1
|
| Answer: | A. router isis is-type level-1
|
| Explanation: | We use the is-type router configuration command to change the routing level the IS-IS routing process for the entire router or for the instance of IS-IS if there are more then 1 instances running. |
|
| Question: | Distribution lists can be used to achieve which of the following?
A. To change the metrics of routes redistributed in another routing protocol.
B. To tag routes being redistributed from one routing protocol in another.
C. To change the priority of a packet when it travels across the network.
D. Prevent routing loops when redistributing between multiple routing protocols.
E. Hide networks, e.g. labs, secure networks, to be advertised to the whole network.
|
| Answer: | D. Prevent routing loops when redistributing between multiple routing protocols.
E. Hide networks, e.g. labs, secure networks, to be advertised to the whole network.
|
| Explanation: | Distribute lists are access lists applied to the routing process to determine which networks will be accepted in the routing table or sent in updates. The can also function to control security, overhead and management reasons. |
|
| Question: | Which form of queuing has a threshold stating the number of bytes or packets that might be sent before servicing the next queue?
A. Custom queuing
B. Priority queuing
C. Class-Based weighted fair queuing
D. Low-Latency queuing
E. Cisco express forwarding
F. Weighted fair queuing
|
| Answer: | A. Custom queuing
|
| Explanation: | In custom queuing the interface buffer is divided into 16 queues. Each queue has a threshold stating the number of bytes or packets that might be sent before servicing the next queue. |
|
| Question: | Besides access lists we can use an another method to reduce network traffic that is not so demanding on resources as access lists. Which method is that?
A. null interface
B. offset list
C. distribution list
D. custom queueing
|
| Answer: | A. null interface
|
| Explanation: | A null interface is virtual or logical interface that exists only in the operating system of the router, any traffic send to it disappears because the interface has no physical layer. By disabling ICMP Unreachable messages sent in response to packets send to the null interface the packets are silently dropped, i.e. no error message is sent to the transmitting device. |
|
| Question: | Which are some features of IPv6?
A. Part of the IPv6 address is the NICs MAC address
B. Autoconfiguration
C. Complex header
D. No need for multicast addresses
E. Security
|
| Answer: | B. Autoconfiguration
E. Security
|
| Explanation: | IPv6 has the following, and more, benefits and features:
- larger address space
- autoconfiguration
- renumbering
- security
- mobility
- simple and efficient header
- ... |
|
| Question: | In NAT terminology what is described by the following: "These addresses allow hosts in the organization to communicate"
A. Inside global
B. Outside local
C. Inside local
D. Outside global
|
| Answer: | C. Inside local
|
| Explanation: | Inside local addresses allow for each end device in the organization to communicate. These addresses are unique within the enterprise but they are probably not globally unique. They are the inside addresses as seen locally within the enterprise. |
|
| Question: | What does ::1 represent in IPv6?
A. Link local
B. Aggregate global unicast
C. Unspecified and Loopback
D. Site local
|
| Answer: | C. Unspecified and Loopback
|
| Explanation: | The unspecified and loopback IPv6 unicast address is represented 0000.0000.0000.0000.0000.0000.0000.0000.0000.0000.0000.0001 or
0.0.0.0.0.0.0.0.0.0.0.1 or
::1
It is often uses to download software or requesting an address. The loopback address is used to test the interface in basic troubleshooting. |
|
| Question: | The first 48 bits of an IPv6 address are used for?
A. To create the aggregate global unicast.
B. To create the multicast range.
C. To enter the MAC Address of the host.
D. To create an easy transistion from IPv4
|
| Answer: | A. To create the aggregate global unicast.
|
| Explanation: | The first 48 bits of an IPv6 address is the header used by the IANA for external routing within the Internet to create the aggregate global unicast. If this 48-bit prefix is not used the addressing scheme is similar to IPv4 private addressing. |
|
| Question: | Which of the following routing protocols support IPV6 on a Cisco router?
A. BGP-4
B. OSPF
C. IS-IS
D. RIPng
E. EIGRP
F. RIPv1
G. IGRP
H. RIPv2
|
| Answer: | A. BGP-4
B. OSPF
C. IS-IS
D. RIPng
|
| Explanation: | From Ciscos IOS 12.2T and later release the following routing protocols support IPv6:
- RIPng
- OSPF
- IS-IS
- BGP-4
|
|
| Question: | Which of the following techniques do distance vector protocols use to avoid routing loops?
A. holddown
B. counting to infinity
C. hop count
D. split horizon
E. flooding
|
| Answer: | A. holddown
D. split horizon
|
| Explanation: | Distance vectors use the following techniques to avoid routing loops:
- Split horizon
- Poison reverse
- Holddown
- Triggered updates
- Aging of routes from the routing table
Counting to infinity is a condition that occurs when a route disappears from the network and is found in distance vector protocols but strictly speaking this is not a technique. |
|
| Question: | Which routing loop avoidance technique is described? "The routing process will not advertise a route out of the interface through which that route was learned"
A. Split horizon with poison reverse
B. Poison reverse
C. Triggered update
D. Split horizon
|
| Answer: | D. Split horizon
|
| Explanation: | The split horizon rule state that the routing process will not advertise networks out of the interface through which those networks were learned. With poison reverse the routing process will advertise those networks but the metric will be set to infinite. |
|
| Question: | Using RIP, how do we configure R1 so that only R2 knows about the 192.168.5.x/24 network.
A. router rip passive-interface ethernet 0 network 192.168.1.0 network 192.168.5.0 neighbor 192.168.1.3
B. router rip network 192.168.1.0 network 192.168.5.0 neighbor 192.168.1.3
C. router rip passive-interface ethernet 0 network 192.168.1.0 network 192.168.5.0
D. router rip passive-interface ethernet 1 network 192.168.1.0 network 192.168.5.0 neighbor 192.168.1.3
E. router rip passive-interface ethernet 1 network 192.168.1.0 network 192.168.5.0
|
| Answer: | A. router rip passive-interface ethernet 0 network 192.168.1.0 network 192.168.5.0 neighbor 192.168.1.3
|
| Explanation: | By using the passive-interface router configuration command we block the sending of broadcast updates on the network. Because R2 needs to know about the 192.168.5.0/24 network we use the neighbor command to send out unicast updates to R2. R2 needs also to be configured in a similar way otherwise R3 would learn about 192.168.5.0/24 network via R2. |
|
| Question: | IGRP sends out periodic updates every _________ seconds?
A. 90
B. 30
C. 180
D. 630
E. 120
|
| Answer: | A. 90
|
| Explanation: | By default IGRP sends out periodic updates every 90 seconds. |
|
| Question: | How do we achieve load balancing across unequal paths in EIGRP?
A. traffic-share max
B. variance
C. maximum-paths
D. traffic-share min
|
| Answer: | B. variance
|
| Explanation: | The variance command can be used to load balance across unequal cost paths. Traffic-share min needs the across-interfaces keyword to have the same result otherwise it uses equal cost paths. |
|
| Question: | Hop count in IGRP is used for?
A. limit the diameter of the network
B. IGRP does not have a hop count
C. primary metric
D. secondary metric after the composite metric of bandwidth and delay
|
| Answer: | A. limit the diameter of the network
|
| Explanation: | By default the hop count in IGRP is 100 but it can be configured to 255 and is used to limit the diameter of the network. |
|
| Question: | The administrative distance of an EIGRP summary route is?
A. 5
B. 90
C. 170
D. 120
|
| Answer: | A. 5
|
| Explanation: | | Source | Administrative Distance | | Connected Interface | 0 | | Static Route | 1 | | EIGRP Summary Route | 5 | | External BGP | 20 | | Internal EIGRP | 90 | | IGRP | 100 | | OSPF | 110 | | IS-IS | 115 | | RIP | 120 | | EGP | 140 | | On Demand Routing (ODR) | 160 | | External EIGRP | 170 | | Internal BGP | 200 | |
|
| Question: | Which of the following routing protocols are interior routing protocols?
A. EIGRP
B. EGP
C. IS-IS
D. BGP
E. RIPv2
F. OSPF
|
| Answer: | A. EIGRP
C. IS-IS
E. RIPv2
F. OSPF
|
| Explanation: | RIPv1 & v2, OSPF, IGRP, EIGRP and IS-IS are considered interior routing protcols because they run inside the enterprise. Exterior routing protocols like BGP and EGP are/were used to exchange routing information between enterprises. |
|
| Question: | Link-state routing protocols reduce the network overhead by using?
A. By using broadcast updates.
B. By sending of the entire routing table in each update.
C. By not using hop count as a metric.
D. By using multicast updates.
E. By sending triggered updates that contain only the change instead of the entire routing table.
|
| Answer: | D. By using multicast updates.
E. By sending triggered updates that contain only the change instead of the entire routing table.
|
| Explanation: | Link-state routing protocols some of the following techniques to reduce the network overhead:
- use of multicast addressing
- sending of triggered updates
- infrequently sending network summaries
- not sending the entire routing table with every updated |
|
| Question: | BGP uses which metric?
A. cost
B. hop count
C. composite metric
D. attributes
|
| Answer: | D. attributes
|
| Explanation: | BGP has a complex metric called attributes by which traffic paths can be manipulated. |
|
| Question: | We want to reset all BGP sessions. How do we achieve this?
A. clear ip bgp *
B. clear ip route bgp
C. clear ip route *
D. clear ip bgp reset
|
| Answer: | A. clear ip bgp *
|
| Explanation: | The clear ip bgp * command will reset all BGP sessions. |
|
| Question: | A Level 2 IS-IS router can be compared to an OSPF ________ router.
A. area border
B. autonomous system boundary
C. backbone
D. internal
|
| Answer: | C. backbone
|
| Explanation: | IS-IS L1 routers can be compared to OSPF non-backbone internal routers.
IS-IS L2 routers can be compared to OSPF backbone routers.
IS-IS L1/L2 routers can be compared to OSPF area border routers. |
|
| Question: | Which of the following statements about IS-IS are true?
A. It is a classless protocol
B. It does not support VLSM.
C. Hellos are sent every 10 seconds on all media.
D. Hellos are sent every 10 seconds on a broadcast network and every 30 seconds on a non-broadcast network.
E. If there are no hellos for 40 seconds the neighbor is declared dead.
|
| Answer: | A. It is a classless protocol
C. Hellos are sent every 10 seconds on all media.
|
| Explanation: | IS-IS is a classless protocol that supports VLSM. Hellos are sent out every 10 seconds on all media (broadcast or non-broadcast) and a neighbor is declared dead after 30 seconds of silence. |
|
| Question: | Which of the following protocols support automatic summarization at the class boundary?
A. OPSF
B. IS-IS
C. RIP
D. IGRP
E. BGP
F. EIGRP
|
| Answer: | C. RIP
D. IGRP
E. BGP
F. EIGRP
|
| Explanation: | OSPF and IS-IS do not support automatic summarization at the class boundary but summarization can be configured manually. |
|
| Question: | In EIGRP hello packets are sent every ___________ seconds?
A. 10
B. 60 on access links with a speed lower then T1
C. 30 on access links with a speed lower then T1
D. 120 on access links with a speed lower then T1
E. 5
F. 30
|
| Answer: | B. 60 on access links with a speed lower then T1
E. 5
|
| Explanation: | On most networks EIGRP sends out hello packets via multicast every 5 seconds. On multipoint X.25, Frame-Relay or ATM interfaces with access speed lower or equal to T1, hello packets are send every 60 seconds using unicast.[on point-to-point subinterfaces hellos are send every 5 seconds] |
|
| Question: | Before the databases are synchronized and LSRs are being received the OSPF router goes through different states. What is the correct order?
A. First,Second,Third,Fouth,Fifth,Sixth,Seventh
B. Down,Init,Two-Way,Exstart,Exchange,Loading,Full
|
| Answer: | B. Down,Init,Two-Way,Exstart,Exchange,Loading,Full
|
| Explanation: | An OSPF router goes through the following states:
1 down state: sends out his own hello packet
2 init state: waits 4 times the hello interval to hear a reply
3 two-way state: the router sees it own ID in the list of neighbors, adjancency is formed
4 exstart state: neighbors determine the master/slave relationship
5 exchange state: both neighbors send out database description packets
6 loading state: the router wants more details using an LSR packet
7 full state: LSRs are received and databases are updated and synchronized, the neighbors are fully adjacent |
|
| Question: | After rebooting our router we want to view the state of our OSPF adjacencies. Which command do we use?
A. show ip ospf
B. show ip ospf database
C. show ip protocols
D. show ip ospf neighbor
|
| Answer: | D. show ip ospf neighbor
|
| Explanation: | R1# show ip ospf neighbor
ID Pri State Dead Time Address Interface
192.168.1.1 1 FULL/DROTHER 0:00:45 192.168.1.1 Ethernet0
172.16.4.15 1 FULL/DROTHER 0:00:45 172.16.4.15 Ethernet0
10.1.1.4 5 FULL/DR 0:00:44 192.168.1.3 Ethernet0
Show ip ospf neighbor will give a summary line for each neighbor. The show ip ospf interface command will also display the state of the interface running OSPF. |
|
| Question: | Spanning Tree is used to prevent?
A. Routing loops
B. Unidirectional links
C. Bridging loops
D. Broadcast storms
|
| Answer: | C. Bridging loops
|
| Explanation: | Spanning Tree is used to prevent bridging loops. |
|
| Question: | The destination address of a BPDU frame is?
A. 01-00-5e-ff-ff-ff
B. 01-00-5e- followed by the MAC address of each switch in the spanning tree topology
C. 01-08-c2-00-00-00
D. ff-ff-ff-ff-ff-ff
|
| Answer: | C. 01-08-c2-00-00-00
|
| Explanation: | BPDU frames are send to the well-known STP multicast address 01-80-c2-00-00-00. |
|
| Question: | On which OSPF network topologies do we find a DR and BDR?
A. Point-to-point
B. Nonbroadcast multiaccess
C. Point-to-multipoint
D. Broadcast multiaccess
E. Point-to-point nonbroadcast
|
| Answer: | B. Nonbroadcast multiaccess
D. Broadcast multiaccess
|
| Explanation: | We find Designated Routers (DR) and Backup Designated Routers on broadcast multiaccess networks and nonbroadcast multiaccess networks. |
|
| Question: | The metric of OSPF is?
A. bandwidth
B. cost
C. hop count
D. composite
|
| Answer: | B. cost
|
| Explanation: | OSPF uses the cost as its metric, the cost is calculated by the following formula 10^8/bandwidth. |
|
| Question: | How can we set the RID on an OSPF router?
A. R1(config)#router ospf 100 R1(config-router)#router-id x.x.x.x
B. R1(config)#interface ethernet0 R1(config-if)#ip ospf router-id x.x.x.x
C. R1(config)#interface loopback0 R1(config-if)#ip address x.x.x.x y.y.y.y
D. R1(config)#router-id x.x.x.x
E. R1(config)#interface loopback0 R1(config-if)#ip ospf router-id x.x.x.x
|
| Answer: | A. R1(config)#router ospf 100 R1(config-router)#router-id x.x.x.x
C. R1(config)#interface loopback0 R1(config-if)#ip address x.x.x.x y.y.y.y
|
| Explanation: | If a loopback interface is configured on the router, the highest IP Address of the configured loopback interface(s) will be used as the router ID. We can also use the router-id command in router configuration mode. |
|
| Question: | On a frame-relay circuit the OSPF timers are?
A. hello timer 30 seconds
B. dead timer 120 seconds
C. dead timer 90 seconds
D. dead timer 30 seconds
E. hello timer 40 seconds
F. hello timer 10 seconds
G. dead timer 40 seconds
|
| Answer: | A. hello timer 30 seconds
B. dead timer 120 seconds
|
| Explanation: | Serial interfaces with frame relay encapsulation are nonbroadcast network types so the hello timer is 30 seconds and the dead timer is 120 seconds. |
|
| Question: | Which of the following OSPF network statements are the same?
A. network 192.168.1.0 0.0.0.255 area 1056
B. network 192.168.1.0 area 1056
C. network 192.168.1.0 0.0.0.255 area 0.0.4.32
D. network 192.168.1.0 0.0.0.255 area 1.0.5.6
E. network 192.168.1.0 0.0.0.255 area 0.0.10.56
|
| Answer: | A. network 192.168.1.0 0.0.0.255 area 1056
C. network 192.168.1.0 0.0.0.255 area 0.0.4.32
|
| Explanation: | The area parameter can be represented in either a decimal or dotted decimal format. The dotted decimal format should be read as one binary string, e.g. decimal 1056 = 00000000.00000000.00000100.00100000 = 0.0.4.32 in dotted decimal format. |
|
| Question: | How do we configure OSPF on R1 in NBMA mode?
A. R1(config)#interface serial 0 R1(config-if)# ip address 192.168.1.2 255.255.255.0 R1(config-if)#encapsulation frame-relay R1(config-if)#ip ospf network non-broadcast R1(config)#router ospf 10 R1(config-router)#network 192.168.1.2 0.0.0.255 area 0
B. R1(config)#interface serial 0 R1(config-if)# ip address 192.168.1.2 255.255.255.0 R1(config-if)#encapsulation frame-relay R1(config-if)#ip ospf non-broadcast R1(config)#router ospf 10 R1(config-router)#network 192.168.1.2 0.0.0.255 area 0 R1(config-router)#neighbor 192.168.1.4 R1(config-router)#neighbor 192.168.1.6
C. R1(config)#interface serial 0 R1(config-if)# ip address 192.168.1.2 255.255.255.0 R1(config-if)#encapsulation frame-relay R1(config-if)#ip ospf network non-broadcast R1(config)#router ospf 10 R1(config-router)#network 192.168.1.2 0.0.0.255 area 0 R1(config-router)#neighbor 192.168.1.4 R1(config-router)#neighbor 192.168.1.6
D. R1(config)#interface serial 0 R1(config-if)# ip address 192.168.1.2 255.255.255.0 R1(config-if)#encapsulation frame-relay R1(config-if)#ip ospf network non-broadcast R1(config)#router ospf R1(config-router)#network 192.168.1.2 0.0.0.255 area 0 R1(config-router)#neighbor 192.168.1.4 R1(config-router)#neighbor 192.168.1.6
|
| Answer: | C. R1(config)#interface serial 0 R1(config-if)# ip address 192.168.1.2 255.255.255.0 R1(config-if)#encapsulation frame-relay R1(config-if)#ip ospf network non-broadcast R1(config)#router ospf 10 R1(config-router)#network 192.168.1.2 0.0.0.255 area 0 R1(config-router)#neighbor 192.168.1.4 R1(config-router)#neighbor 192.168.1.6
|
| Explanation: | The ip ospf network non-broadcast command is not necessary because this is the default used in nonbroadcast multiaccess environments. There is the need however to use the neighbor statements so adjacencies can be formed. |
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| Question: | We want to know how many times the router has recalculated its routing table. Which command do we use?
A. show ip ospf neighbor
B. show ip ospf
C. show ip ospf interface
D. show ip ospf database
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| Answer: | B. show ip ospf
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| Explanation: | The show ip ospf command will show how many times the SPF algorithm has been executed.
R1#show ip ospf
Routing Process "ospf 10" with ID 10.1.1.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
LSA group pacing timer 100 secs
Interface flood pacing timer 55 msecs
Retransmission pacing timer 100 msecs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 2 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2
Area has message digest authentication
SPF algorithm executed 4 times
Area ranges are
Number of LSA 4. Checksum Sum 0x29BEB
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 3
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
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|
| Question: | How can make sure that a router will not become a DR or BDR?
A. ip ospf priority 0
B. ip ospf priority 255
C. ip ospf cost 0
D. no ip ospf priority
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| Answer: | A. ip ospf priority 0
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| Explanation: | The default priority is 1, this can be changed using the ip ospf priority command, setting the priority to 0 ensures that the router will not participate in DR or BDR elections. |
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| Question: | EIGRP uses what algorithm to determine path selection?
A. Diffusing update algorithm
B. Bellman Ford
C. Dijkstra
D. Diffie-Hellman
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| Answer: | A. Diffusing update algorithm
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| Explanation: | EIGRP uses DUAL or Diffusing Update Algorithm to make path selections. |
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| Question: | Which of the following requirements have to be fulfilled in order to create a virtual link?
A. The transit area can not be a stub area
B. The transit area can be a not-so-stubby area
C. The virtual link can be terminated on an interior router
D. The tranist area needs to have full routing information
E. The transit area can be a stub area
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| Answer: | A. The transit area can not be a stub area
D. The tranist area needs to have full routing information
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| Explanation: | The area through which you configure the virtual link, known as a transit area, must have full routing information and this transit area cannot be a stub area. Virtual links are configured between ABRs and one of them must have a connection to the backbone. |
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| Question: | Area 1 needs to be configured so no external LSAs or summary LSAs are send into the area. How do we achieve this? [click exhibit for topology]
A. R4 router ospf 10 network 192.168.1.1 0.0.0.0 area 0 network 172.16.1.1 0.0.0.0 area 1 area 1 stub no-summary R5 router ospf 10 network 0.0.0.0 255.255.255.255 area 1
B. R4 router ospf 10 network 192.168.1.1 0.0.0.0 area 0 network 172.16.1.1 0.0.0.0 area 1 area 1 stub R5 router ospf 10 network 0.0.0.0 255.255.255.255 area 1 area 1 stub
C. R4 router ospf 10 network 192.168.1.1 0.0.0.0 area 0 network 172.16.1.1 0.0.0.0 area 1 area 1 stub no-summary R5 router ospf 10 network 0.0.0.0 255.255.255.255 area 1 area 1 stub
D. R4 router ospf 10 network 192.168.1.1 0.0.0.0 area 0 network 172.16.1.1 0.0.0.0 area 1 area 1 stub no-summary
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| Answer: | C. R4 router ospf 10 network 192.168.1.1 0.0.0.0 area 0 network 172.16.1.1 0.0.0.0 area 1 area 1 stub no-summary R5 router ospf 10 network 0.0.0.0 255.255.255.255 area 1 area 1 stub
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| Explanation: | |
