| Question: | Using RIP, how do we configure R1 so that only R2 knows about the 192.168.5.x/24 network.
A. router rip network 192.168.1.0 network 192.168.5.0 neighbor 192.168.1.3
B. router rip passive-interface ethernet 0 network 192.168.1.0 network 192.168.5.0
C. router rip passive-interface ethernet 1 network 192.168.1.0 network 192.168.5.0 neighbor 192.168.1.3
D. router rip passive-interface ethernet 0 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: | D. 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: | We want to advertise only a default route via EIGRP. How do we achieve this?
A. R1(config)#router EIGRP 1000 R1(config-router)#neighbor 172.16.1.25 default-originate always
B. R1(config)#router EIGRP 1000 R1(config-router)#ip summary-address eigrp 1000 0.0.0.0 0.0.0.0
C. R1(config)#interface serial0 R1(config-if)#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: | C. 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. Neighbor table
B. Cost table
C. Topology table
D. Link-state table
E. Route/Forwarding table
F. EIGRP table
|
| Answer: | A. Neighbor table
C. Topology table
E. Route/Forwarding 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 ospf R1(config-router)#redistribute rip subnets
B. R1(config)#router rip R1(config-router)#redistribute ospf
C. R1(config)#router ospf 100 R1(config-router)#redistribute rip subnets
D. R1(config)#redistribute rip ospf
|
| 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. An election is held between all the Backup Designated Routers and the Backup Designated Router with the lowest priority becomes the Designated Router
B. 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
C. 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
D. An election is held between all the Backup Designated Routers and the Backup Designated Router with the highest priority becomes the Designated Router
|
| Answer: | B. 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 1
B. LSA type 3
C. LSA type 7
D. LSA type 5
|
| Answer: | D. 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 priority 220
B. R1(config)#interface ethernet0 R1(config-if)#ip ospf priority 0
C. R1(config)#interface ethernet0 R1(config-if)#ip ospf priority 220
D. R1(config)#router ospf 10 R1(config-router)#priority 220
|
| Answer: | C. 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 neighbor
B. Show ip ospf database summary
C. Show ip ospf detail
D. Show ip ospf database
|
| Answer: | A. 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 E1
B. O
C. O E2
D. O IA
|
| Answer: | C. 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. ABR
C. ASBR
D. BDR
|
| 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. Aggregator
B. Next_hop
C. Atomic_Aggregate
D. AS_path
E. Multi_Exit_Disc
F. Local_Pref
|
| Answer: | B. Next_hop
D. 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 R1(config-router)#network 192.168.1.0
B. 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
C. 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
D. 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
|
| Answer: | C. 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: | 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 a non client advertise the route to all the clients
C. If a route is received from an eBGP peer advertise the route to all clients but not to the non 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
B. 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 is described in RFC 1771
C. BGP does not support VLSM
D. BGP uses TCP port 179
E. Is a distance vector protocol.
|
| Answer: | B. BGP is described in RFC 1771
D. BGP uses TCP port 179
|
| 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. Version
B. Autonomous system number
C. Network Layer Reachability Information
D. Hello time
E. Path attributes
|
| Answer: | A. Version
B. 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: | 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-peer loopback0
B. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 update-interface loopback0
C. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 update-source loopback0
D. neighbor 10.1.1.1 remote-as 1 neighbor 10.1.1.1 peer loopback0
|
| Answer: | C. 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: | What is the origin code for a route originated on a BGP router?
A. 2
B. 3
C. 1
D. 0
|
| Answer: | D. 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: | When electing a DIS and the priorities are all equal what will be used to elect the DIS?
A. The highest numeric SNPA
B. The highest numeric IP Address
C. The lowest numeric IP Address
D. The highest value in the TLV
E. The lowest value in the TLV
F. The lowest numeric SNPA
|
| Answer: | A. 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. Checksum
B. Remaining lifetime
C. Sequence number
D. LAN ID
E. Version
F. Priority
G. Holding time
|
| Answer: | A. Checksum
B. Remaining lifetime
C. Sequence number
|
| 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 isis circuit-type level-1
B. interface ethernet0 isis circuit-type level-1
C. interface ethernet0 is-type level-1
D. router isis is-type level-1
|
| Answer: | D. 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: | When a new router is with a higher priority appears on a IS-IS network what will happen to the DIS?
A. The new router will become a backup DIS and will take over the role of the current DIS when it fails.
B. The new router will become to new DIS and the old DIS becomes a backup DIS.
C. Nothing will happen and the DIS remains the same.
D. The new router will become to new DIS after a new election.
|
| Answer: | D. The new router will become to new DIS after a new election.
|
| Explanation: | When a DIS has a problem or a new router with a higher priority comes online a new DIS is elected in the place of the old DIS. |
|
| Question: | Which of the 4 metrics defined by ISO 10589 for Integrated IS-IS is supported by Cisco and what is its value?
A. 100
B. 64
C. Delay
D. Error
E. Expense
F. 15
G. 10
H. Default
|
| Answer: | G. 10
H. Default
|
| Explanation: | The default or cost is the only out of the 4 metrics of IS-IS supported by Cisco. Its default value is 10 on all interfaces. |
|
| Question: | IGRP sends out periodic updates every _________ seconds?
A. 120
B. 630
C. 90
D. 30
E. 180
|
| Answer: | C. 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. variance
B. traffic-share min
C. traffic-share max
D. maximum-paths
|
| Answer: | A. 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. primary metric
C. secondary metric after the composite metric of bandwidth and delay
D. IGRP does not have a hop count
|
| 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. 120
B. 5
C. 90
D. 170
|
| Answer: | B. 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. OSPF
B. EGP
C. IS-IS
D. BGP
E. EIGRP
F. RIPv2
|
| Answer: | A. OSPF
C. IS-IS
E. EIGRP
F. RIPv2
|
| 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 triggered updates that contain only the change instead of the entire routing table.
C. By sending of the entire routing table in each update.
D. By using multicast updates.
E. By not using hop count as a metric.
|
| Answer: | B. By sending triggered updates that contain only the change instead of the entire routing table.
D. By using multicast updates.
|
| 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. attributes
D. composite metric
|
| Answer: | C. 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 route bgp
B. clear ip route *
C. clear ip bgp reset
D. clear ip bgp *
|
| Answer: | D. 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. backbone
B. area border
C. autonomous system boundary
D. internal
|
| Answer: | A. 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. RIP
B. OPSF
C. EIGRP
D. IS-IS
E. IGRP
F. BGP
|
| Answer: | A. RIP
C. EIGRP
E. IGRP
F. BGP
|
| 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. 5
B. 60 on access links with a speed lower then T1
C. 10
D. 120 on access links with a speed lower then T1
E. 30
F. 30 on access links with a speed lower then T1
|
| Answer: | A. 5
B. 60 on access links with a speed lower then T1
|
| 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 database
B. show ip protocols
C. show ip ospf neighbor
D. show ip ospf
|
| Answer: | C. 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. 01-08-c2-00-00-00
B. 01-00-5e-ff-ff-ff
C. 01-00-5e- followed by the MAC address of each switch in the spanning tree topology
D. ff-ff-ff-ff-ff-ff
|
| Answer: | A. 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 nonbroadcast
B. Broadcast multiaccess
C. Point-to-point
D. Nonbroadcast multiaccess
E. Point-to-multipoint
|
| Answer: | B. Broadcast multiaccess
D. Nonbroadcast 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. hop count
B. composite
C. cost
D. bandwidth
|
| Answer: | C. 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)#interface ethernet0 R1(config-if)#ip ospf router-id x.x.x.x
B. R1(config)#interface loopback0 R1(config-if)#ip address x.x.x.x y.y.y.y
C. R1(config)#router-id x.x.x.x
D. R1(config)#router ospf 100 R1(config-router)#router-id x.x.x.x
E. R1(config)#interface loopback0 R1(config-if)#ip ospf router-id x.x.x.x
|
| Answer: | B. R1(config)#interface loopback0 R1(config-if)#ip address x.x.x.x y.y.y.y
D. R1(config)#router ospf 100 R1(config-router)#router-id x.x.x.x
|
| 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. dead timer 30 seconds
B. hello timer 40 seconds
C. hello timer 30 seconds
D. hello timer 10 seconds
E. dead timer 120 seconds
F. dead timer 40 seconds
G. dead timer 90 seconds
|
| Answer: | C. hello timer 30 seconds
E. 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 area 1056
B. network 192.168.1.0 0.0.0.255 area 1.0.5.6
C. network 192.168.1.0 0.0.0.255 area 0.0.10.56
D. network 192.168.1.0 0.0.0.255 area 1056
E. network 192.168.1.0 0.0.0.255 area 0.0.4.32
|
| Answer: | D. network 192.168.1.0 0.0.0.255 area 1056
E. 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 can we influence the metric of OSPF?
A. R1(config)#router ospf 10 R1(config-router)#cost 10
B. R1(config)#router ospf 10 R1(config-router)#ip cost 10
C. R1(config)#interface serial0 R1(config-if)#bandwidth 256k
D. R1(config)#interface serial0 R1(config-if)#ip ospf cost 10
E. R1(config)#interface serial0 R1(config-if)#bandwidth 256
|
| Answer: | D. R1(config)#interface serial0 R1(config-if)#ip ospf cost 10
E. R1(config)#interface serial0 R1(config-if)#bandwidth 256
|
| 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)#ospf auto-cost reference-bandwidth 1000
B. R1(config-router)#ospf reference-bandwidth 1000
C. R1(config-if)#ospf reference-bandwidth 1000
D. R1(config)#ospf reference-bandwidth 1000
E. R1(config)#ospf auto-cost reference-bandwidth 1000
F. R1(config-router)#ospf auto-cost reference-bandwidth 1000
|
| Answer: | F. 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: | 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 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
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 network non-broadcast R1(config)#router ospf 10 R1(config-router)#network 192.168.1.2 0.0.0.255 area 0
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 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 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
|
| Answer: | 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 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. |
|
| Question: | We want to know how many times the router has recalculated its routing table. Which command do we use?
A. show ip ospf database
B. show ip ospf neighbor
C. show ip ospf
D. show ip ospf interface
|
| Answer: | C. show ip ospf
|
| 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
|
|
| Question: | How can make sure that a router will not become a DR or BDR?
A. ip ospf priority 0
B. ip ospf cost 0
C. no ip ospf priority
D. ip ospf priority 255
|
| Answer: | A. ip ospf priority 0
|
| 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. |
|
| Question: | Which of the following IP Addresses is a Class C Private network address?
A. 11000000.10101000.00010001.00001001
B. 11000000.10101010.00010001.00001001
C. 11000000.11101000.00010001.00001001
D. 11000000.10101001.00010001.00001001
E. 10100000.10101000.00010001.00001001
|
| Answer: | A. 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. 224.0.0.6
B. 224.0.0.9
C. 224.0.0.10
D. 224.0.0.5
|
| Answer: | D. 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: | Which command would produce the following output?
System Id SNPA Interface State Holdtime Type Protocol
0000.0000.0007 aa00.0400.6408 Ethernet0 Init 277 IS ES-IS
0000.0C00.0C35 0000.0c00.0c36 Ethernet1 Up 91 L1 IS-IS
0800.2B16.24EA aa00.0400.2d05 Ethernet0 Up 29 L1L2 IS-IS
0800.2B14.060E aa00.0400.9205 Ethernet0 Up 1698 ES ES-IS
0000.0C00.3E51 DLCI 123 Serial1 Up 28 L2 IS-IS
0000.0C00.62E6 0000.0c00.62e7 Ethernet1 Up 22 L1 IS-IS
0A00.0400.2D05 aa00.0400.2d05 Ethernet0 Init 24 IS ES-IS
A. show isis neighbors detail
B. show clns snpa
C. show isis neighbors
D. show clns neighbors detail
E. show clns neighbors
F. show isis snpa
|
| Answer: | E. show clns neighbors
|
| Explanation: | R1# show clns neighbors
System Id SNPA Interface State Holdtime Type Protocol
0000.0000.0007 aa00.0400.6408 Ethernet0 Init 277 IS ES-IS
0000.0C00.0C35 0000.0c00.0c36 Ethernet1 Up 91 L1 IS-IS
0800.2B16.24EA aa00.0400.2d05 Ethernet0 Up 29 L1L2 IS-IS
0800.2B14.060E aa00.0400.9205 Ethernet0 Up 1698 ES ES-IS
0000.0C00.3E51 DLCI 123 Serial1 Up 28 L2 IS-IS
0000.0C00.62E6 0000.0c00.62e7 Ethernet1 Up 22 L1 IS-IS 0A00.0400.2D05 aa00.0400.2d05 Ethernet0 Init 24 IS ES-IS |
|
| Question: | Looking at the following output:
R1# show isis database
IS-IS Level-1 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
0000.0C00.0C35.00-00 0x0000000C 0x5696 792 0/0/0
0000.0C00.40AF.00-00* 0x00000009 0x8452 1077 1/0/0
0000.0C00.62E6.00-00 0x0000000A 0x38E7 383 0/0/0
0000.0C00.62E6.03-00 0x00000006 0x82BC 384 0/0/0
0800.2B16.24EA.00-00 0x00001D9F 0x8864 1188 1/0/0
0800.2B16.24EA.01-00 0x00001E36 0x0935 1198 1/0/0
IS-IS Level-2 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
0000.0C00.0C35.03-00 0x00000005 0x04C8 792 0/0/0
0000.0C00.3E51.00-00 0x00000007 0xAF96 758 0/0/0
0000.0C00.40AF.00-00* 0x0000000A 0x3AA9 1077 0/0/0A. That that entry comes from a Pseudonode
B. That that entry comes from a Level 1 only router
C. That that entry comes from a new router still in the process of forming the adjacency
D. That that entry comes from a Level 1-2 router
|
| Answer: | D. That that entry comes from a Level 1-2 router
|
| Explanation: | ATT represents the attach bit. It indicates that the router is also a Level 2 router and it can reach other areas. Level 1 routers use the presence of this bit to identify the closest Level 1-2 router to send their out-of-area data. |
|
| Question: | In Integrated IS-IS, TLV stands for?
A. Time
B. Version
C. Lifetime
D. Packet length
E. Type
F. Length
G. Value
H. Local ciruict ID
I. Length indication
|
| Answer: | E. Type
F. Length
G. Value
|
| Explanation: | The structure of the TLV is:
- Type or Code, the type of TLV that identifies it and the characteristics that are related to it
- Length, the length of the following field
- Value, IP routes, IS-IS neighbors or authentication |
|
| Question: | We want to summarize our IP routes for Integrated IS-IS. How do we configure this?
A. interface ethernet 0 ip router isis summary-address address mask
B. router isis summary-address ip address mask
C. interface ethernet 0 ip router isis summary-address ip address mask
D. router isis summary-address address mask
|
| Answer: | D. router isis summary-address address mask
|
| Explanation: | To create IP routes summarization for Integrated IS-IS we use the summary-address address mask router configuration command. |
|
| Question: | How do we configure over NMBA in broadcast configuration?
A. interface serial1 ip address 10.1.1.1 255.255.255.0 ip router isis encapsulation frame-relay frame-relay map clns 123 frame-relay map ip 10.1.1.2 123
B. interface serial1 ip address 10.1.1.1 255.255.255.0 ip router isis encapsulation frame-relay frame-relay map isis 123 broadcast frame-relay map ip 10.1.1.2 123 broadcast
C. interface serial1 ip address 10.1.1.1 255.255.255.0 encapsulation frame-relay frame-relay map clns 123 broadcast frame-relay map ip 10.1.1.2 123
D. interface serial1 ip address 10.1.1.1 255.255.255.0 ip router isis encapsulation frame-relay frame-relay map clns 123 broadcast frame-relay map ip 10.1.1.2 123 broadcast
|
| Answer: | D. interface serial1 ip address 10.1.1.1 255.255.255.0 ip router isis encapsulation frame-relay frame-relay map clns 123 broadcast frame-relay map ip 10.1.1.2 123 broadcast
|
| Explanation: | We are using the frame-relay map interface configuration command. The keyword IP is used to map the IP destination address to the DLCI and we define the interface as broadcast. Without the CLNS keyword no router appear in the IP routing table because IS-IS does not receive IS-IS frames to populate the IP routing table. |
|
| Question: | Given the following NSAP Address: 49.0005.80.0000a7.0000.ffdd.0004.1921.6801.1005.00 What is the system ID?
A. 1921.6801.1005
B. 0004
C. 49
D. 0004.1921.6801.1005.00
E. 0004.1921.6801
F. 0005.80.0000a7.0000
|
| Answer: | A. 1921.6801.1005
|
| Explanation: | The address is a GOSIP NSAP format:
49.0005.80.0000a7.0000.ffdd.0004.1921.6801.1005.00
__.____.__.______.____.____.____.______________.__
AFI.ICD.DFI.AAI.Reserved.RDI.Area.SystemID.SEL
AFI: Authority and Format Identifier
ICD: International Code Designator
DFI: Domain specific part (DSP) Format Identifier
AAI: Administrative Authority Identifier
RDI: Routing Domain Identifier (Autonomous System Number)
SEL: Network Service Access Point (NSAP) Selector
|
|
| Question: | Wich IS-IS show command will display the metric?
A. show clns databse detail
B. show isis interface
C. show clns neighbor detail
D. show isis neighbor detail
E. show isis database
F. show clns interface
|
| Answer: | F. show clns interface
|
| Explanation: | The show clns interface command will display the Level 1 and Level 2 metric of the outbound interface.
R1# show clns interface ethernet 0
Ethernet0 is up, line protocol is up
Checksums enabled, MTU 1497, Encapsulation SAP
Routing Protocol: ISIS
Circuit Type: level-1-2
Interface number 0x0, local circuit ID 0x1
Level-1 Metric: 10, Priority: 64, Circuit ID: R2.01
Number of active level-1 adjacencies: 1
Level-2 Metric: 10, Priority: 64, Circuit ID: R2.01
Number of active level-2 adjacencies: 1
Next ISIS LAN Level-1 Hello in 5 seconds
Next ISIS LAN Level-2 Hello in 1 seconds
|
|
| Question: | What is the function of a Level 2 IS-IS router?
A. To route traffic between Level 1/2 routers.
B. To locate the destination within an area.
C. To route traffic between areas.
D. To maintain the database.
|
| Answer: | C. To route traffic between areas.
|
| Explanation: | The function of a Level 2 router is to route traffic between areas. |
|
| Question: | Which EIGRP table is build using Hellos?
A. Neighbor table
B. Topology table
C. Routing table
D. Link-state database.
|
| Answer: | A. Neighbor table
|
| Explanation: | The neighbor table is build from information on Hellos received from adjacent routers (neighbors). |
|
| Question: | This state is reached when a router has sent out network packets and is waiting for ACKs from all its neighbors.
A. Passive
B. Dead
C. Active
D. Stuck in Active
|
| Answer: | C. Active
|
| Explanation: | When a router has send out network packets because of a topology change and no Feasible Successor was found it will wait for ACKs from its neighbors. The route is set to active mode. |
|
| Question: | In the EIGRP composite metric the K1 value represents?
A. MTU
B. Bandwidth
C. Loading
D. Delay
E. Reliability
|
| Answer: | B. Bandwidth
|
| Explanation: | The EIGRP Metrics are as follows:
| Symbol | Value | | K1 | Bandwidth | | K2 | Loading | | K3 | Delay | | K4 | Reliability | | K5 | MTU | |
|
| Question: | In order for EIGRP to make adjacencies which conditions have to be met?
A. The sending router must have a different AS number then the receiving one.
B. The data-link layer protocols must match.
C. The SRTT must be lower then 10 milliseconds.
D.
E. The router must hear a Hello packet or ACK from the neighbor.
F. The metric settings need to be the same
|
| Answer: | E. The router must hear a Hello packet or ACK from the neighbor.
F. The metric settings need to be the same
|
| Explanation: | In order for adjacencies to be formed the following conditions need to be met:
- The router must hear a Hello packet or an ACK from a neighbor
- The AS number in the packet header must be the same as that of the receiving router
- The metric settings need to be same. |
|
| Question: | When a route in the EIGRP topology goes down a __________ is sent when there is no FS.
A. Update
B. ACK
C. Query
D. Hello
|
| Answer: | C. Query
|
| Explanation: | Queries are sent out when a route in the topology table goes down and there is no feasible successor. |
|
| Question: | What could cause an EIGRP topology table to be recalculated?
A. The neighbor table received a reply or a query from a neighbor
B. The topology table does not receive a Hello within the holdtime
C. The routing table has removed the routes from the topology table to be put in the routing table
D. The topology table received a reply or a query from a neighbor
E. The neighbor table does not receive a Hello within the holdtime
|
| Answer: | D. The topology table received a reply or a query from a neighbor
E. The neighbor table does not receive a Hello within the holdtime
|
| Explanation: | The following reasons could cause a topology table to be recalculated: - New network is available
- topology table receives an update containing the new network
- interface for a directly connected EIGRP network comes online
- Successor is changed in the topology table and in the routing table
- topology table receives a reply or a query from a neighbor
- the cost of the link changes
- A change from a neighbor when a network has become unavailable
- topology table receives a query, reply or update the remote network is down
- neighbor table does not receive a Hello within the holdtime
- the network is directly connected and the router senses a loss of carrier |
|
| Question: | A router will be marked dead in EIGRP after _____ attempts of sending a unicast query.
A. 15
B. 7
C. 5
D. 16
E. 30
|
| Answer: | D. 16
|
| Explanation: | When a router does not hear an acknowledgment within the alloted time it will retransmit the qeury as a unicast. If after 16 attempts there is no reponse the neighbor will be marked as dead. |
|
| Question: | When can a neighbor become a feasible successor?
A. The topology table hold all routes so all neighbors are feasible successors.
B. If the feasible distance is lower then the advertised distance.
C. If the advertised distance is lower then the feasible distance.
D. If the RTO is lower then the RTP.
|
| Answer: | C. If the advertised distance is lower then the feasible distance.
|
| Explanation: | A neighbor can become a feasible successor only when its advertised distance is less than the feasible distance. This is DUALs key to remain loopfree. |
|
| Question: | This timer is used in EIGRP to determine how long the router waits for an ACK before retransmitting.
A. RTO
B. Hello
C. RTP
D. SRTT
|
| Answer: | A. RTO
|
| Explanation: | The RTO or ReTransmission Timeout is used to determine how long the router waits for an ACK before retransmitting the packet. This timer is calculated in reference to the SRTT (smooth Round-Trip Time). |
|
| Question: | EIGRP uses by default ______ % of the bandwidth.
A. 10
B. 25
C. 75
D. 100
E. 50
|
| Answer: | E. 50
|
| Explanation: | By default EIGRP uses 50% of the bandwidth of the link for its traffic, this value can be configured. |
|
| Question: | We want to see how many EIGRP Updates have been sent and received. Which command do we use?
A. show ip eigrp neigbors detail
B. show ip eigrp traffic
C. show ip eigrp interfaces
D. show ip eigrp neigbors
|
| Answer: | B. show ip eigrp traffic
|
| Explanation: | R1# show ip eigrp traffic
IP-EIGRP Traffic Statistics for process 10
Hellos sent/received: 175/165
Updates sent/received: 9/25
Queries sent/received: 4/0
Replies sent/received: 0/4
Acks sent/received: 15/10
|
|
| Question: | Which of the following messages will not use multicast in EIGRP?
A. Hello
B. Update
C. Query
D. ACK
|
| Answer: | D. ACK
|
| Explanation: | ACK are always sent unicast, it is a Hello packet with no data but the acknowledgment field has a positive number.
Updates can be multicast if there is a change in the topology and unicast if its a reply to a single router.
Hellos and Queries are always multicast. |
|
| Question: | In OSPF interarea summarization is communicated via which LSA(s)?
A. Type 5
B. Type 4
C. Type 2
D. Type 7
E. Type 3
F. Type 1
|
| Answer: | B. Type 4
E. Type 3
|
| Explanation: | LSA type 3 include the networks or subnets within an area that might have been summarized and that are sent to the backbone and between ABRs. Type 4 is information set to the ASBR from the ABR. |
|
| Question: | How do we change the time that Hellos are being sent?
A. R1(config)#interface ethernet 0 R1(config-if)#ip hello-timer eigrp 10 25
B. R1(config)#interface ethernet 0 R1(config-if)#ip hello-interval eigrp 25
C. R1(config)#interface ethernet 0 R1(config-if)#ip hello-interval eigrp 10 25
D. R1(config)#router eigrp 10 R1(config-router)#hello-interval 25
|
| Answer: | C. R1(config)#interface ethernet 0 R1(config-if)#ip hello-interval eigrp 10 25
|
| Explanation: | The ip hello-interval eigrp AS_number seconds interface configuration command will change the how often Hellos are sent to neighbors out of that interface. |
|
| Question: | What does r stand for in the output of show ip eigrp topology?
A. A reply packet was sent to this destination
B. A query packet was sent to this destination
C. An update packet was sent to this destination
D. A query has been sent and the router is waiting for a reply
|
| Answer: | D. A query has been sent and the router is waiting for a reply
|
| Explanation: | Lower case r in the show ip eigrp topology table means that the flag has been set by the software after a query packet was sent and the router is now waiting for a reply.
Router# show ip eigrp topology
IP-EIGRP Topology Table for process 10
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - Reply status
P 192.168.1.0 255.255.255.0, 2 successors, FD is 0
via 172.16.80.28 (46251776/46226176), Ethernet0
via 172.16.81.28 (46251776/46226176), Ethernet1
via 172.16.80.31 (46277376/46251776), Serial0
|
|
| Question: | What is the difference between a NET and a NSAP address?
A. A NET address is the address of the host where the value of the NSEL is set to 0x00.
B. A NSAP address is the address of the host where the value of the NSEL is set to 0x00.
C. A NET address is the address of the host where the value of the NSEL is set to 0x01.
D. A NET address is the address of the host where the value of the AFI is set to 49.
|
| Answer: | A. A NET address is the address of the host where the value of the NSEL is set to 0x00.
|
| Explanation: | A NET address is the address of the host where the value of the NSEL is set to 0x00. The NSAP is the full ISO address, the NSEL field specifies the upper-layer protocol. |
|
| Question: | Which of the following statements are true about Layer 2 devices?
A. Broadcasts and multicast frames are flooded out of all ports.
B. Frames destined to an unknown location are discarded.
C. Frames destined to an unknown location are send to the default gateway.
D. Bridges and switches use a routing protocol to avoid loops.
E. Broadcasts and multicast frames are flooded out of all ports except the port it came from.
F. Bridges and switches use spanning tree to avoid loops.
|
| Answer: | E. Broadcasts and multicast frames are flooded out of all ports except the port it came from.
F. Bridges and switches use spanning tree to avoid loops.
|
| Explanation: | Layer 2 devices have the following functions:
- MAC addresses are learned from incoming frames source address
- A table of MAC addresses and their associated bridge and switch ports is build and maintained
- Broadcast and multicast frames are flooded out of all ports except the one the frame came from
- Frames destined to an unknown destination are flooded out of all ports except the one the frame came from
- Bridges and switches use spanning tree to avoid loops |
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| Question: | How can we divide a broadcast domain?
A. Implement Layer 2 switching
B. Implement Layer 2 bridging
C. Implement VLANs
D. Implement Layer 3 routing
E. Implement Layer 3 bridging
|
| Answer: | C. Implement VLANs
D. Implement Layer 3 routing
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| Explanation: | We can divide broadcast domains by implementing VLANs or by segmenting the network using routers or Layer 3 switches. |
|
| Question: | The traditional 80/20 rule specifies that:
A. 80 percent of network traffic is local to the segment and 20 percent is to be routed via the network backbone.
B. 20 percent of network traffic is local to the segment and 80 percent is to be routed via the network backbone.
C. 80 percent of network traffic is unicast traffic and 20 percent is broadcast/multicast traffic.
D. 20 percent of network traffic is unicast traffic and 80 percent is broadcast/multicast traffic.
|
| Answer: | A. 80 percent of network traffic is local to the segment and 20 percent is to be routed via the network backbone.
|
| Explanation: | The 80/20 rule specifies that 80 percent of the network traffic on a segment is local (switched) traffic and 20 percent of the network traffic needs to be routed via the network backbone. |
|
| Question: | What can we do if the network backbone becomes congested because of the traditional 80/20 rule?
A. Implement MLS
B. Bring resources closer to the users
C. Move all resources to 1 big datacentre
D. Move users logically (VLANs) and physically to stay near their workgroup
E. Implement faster links between the different networks
|
| Answer: | B. Bring resources closer to the users
D. Move users logically (VLANs) and physically to stay near their workgroup
|
| Explanation: | The following are a few solutions a network administrator can implement to reduce the traffic of the network backbone:
- reassign resources to bring the users and servers closer together
- move applications and files to a different server to stay within the workgroup
- move users logically and physically to stay near their workgroup
- add more servers, which can bring resources closer to the workgroups |
|
| Question: | What are the three layers of Ciscos Hierarchical Network Design?
A. Access
B. Network
C. Core
D. Backbone
E. Distribution
F. Host-to-Host
G. Internetwork
|
| Answer: | A. Access
C. Core
E. Distribution
|
| Explanation: | The three layers are: | core | backbone | | distribution | routing takes place here | | access | switching takes place here | |
|
| Question: | Which of the following functions relate to the Access layer of Ciscos hierarchical network design?
A. High throughput at Layer 3
B. High port density
C. Advanced QoS
D. Security
E. Low cost per switch port
|
| Answer: | B. High port densi |
