Which of following is used to periodically multicast by DIS on a LAN to ensure IS-IS link state databaseaccuracy？（）A、LSPB、PSNPC、ISHD、CSNPE、IIH

第1题：

第2题：

Which of the following technologies can be used in distance vector routing protocols to prevent routing loops?（）

• A、Spanning Tree Protocol
• B、Shortest path first tree
• C、Link-state advertisements (LSA)
• D、Hold-down timers
• E、Split horizon
• F、VRP

正确答案:D,E

第3题：

While troubleshooting some connectivity issues， you issue the "show ip ospf database" in order toexamine the link state database. Which three of the statements below are true regarding theOSPF link state database？（）

• A、Each router has an identical link state database
• B、External routes are imported into a separate link state database
• C、Synchronization of link state databases is maintained via flooding of LSAs
• D、Information in the link state database is used to build a routing table by calculating a shortest-path tree
• E、By default， link state databases are refreshed every 10 minutes in the absence of topologychanges

正确答案:A,C,D

第4题：

Open Shortes t Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working group of the Internet Engineering Task Force (IETF). Which two statements best describe the OSPF link - state routing pro tocol?（）

• A、OSPF sends updates every 10 seconds
• B、OSPF sends triggered updates when a network change occurs
• C、When a link state is changed, the router that detected the change creates a link - state advertisement (LSA) and propagates it  to all OSPF devices using the 224.0.0.6 multicast address
• D、OSPF sends summaries of individual link- state entries every 30 minutes to ensure LSDB synchronization

正确答案:B,D

第5题：

Which of the following multicast mode does Auto-RP require？（）

• A、Link-mode
• B、Dense mode
• C、Sparse mode
• D、Sparse-dense mode

正确答案:B

第6题：

Which of the following is used to periodically multicast by DIS on a LAN to ensure IS-IS link state databaseaccuracy？（）

• A、CSNP
• B、LSP
• C、ISH
• D、Hello
• E、IIH
• F、PSNP

正确答案:A

第7题：

Which of the following devices is used to connect a WAN to a LAN?（）

• A、Basic router
• B、Basic switch
• C、Bridge
• D、Repeater

正确答案:A

第8题：

Which of the following are considered link state protocols?（）

• A、RIPv2 and EIGRP
• B、EGP and IGP
• C、OSPF and IS-IS
• D、RIP and BGP

正确答案:C

第9题：

Which two statements are correct regarding IS-IS？（）

• A、Routers maintain a single link-state database per area.
• B、Routers maintain a separate Level 1 link-state database.
• C、Routers maintain a separate Level 2 link-state database.
• D、Routers maintain a single Level 1 link-state database per area.

正确答案:B,C

第10题：

There are three routers on a Gigabit Ethernet LAN: Router A, Router B, and Router C. Router A is the Designated Intermediate System (DIS) at Level 1 for that LAN. Router A's DIS priority is 64. The LAN is a Level 1-only link. Router D has just been powered up on that same LAN and its DIS priority is 80. Which statement is true?（）

• A、Router A remains the DIS and generates a new pseudonode LSP for that LAN
• B、Router A remains the DIS and NO new pseudonode LSP is generated for that LAN
• C、Router D becomes the new DIS, generates a new pseudonode LSP for that LAN, and purges the old pseudonode LSP generated by Router A
• D、Router D becomes the new DIS, does NOT generate a new pseudonode LSP for that LAN, and does NOT purge the old pseudonode LSP generated by Router A

正确答案:C

第11题：

第12题：

第13题：

第14题：

What is periodically sent by a DIS on a LAN to ensure that all adjacent neighbors' IS - IS link - state databases are synchronized?（）

• A、complete SNP (CSNP)
• B、partial SNP (PSNP)
• C、database query
• D、database description packet (DDP)
• E、link - state summary
• F、hello

正确答案:A

第15题：

In Multicast VPN （MVPN） implementations， which two of the following statements are regarding the DefaultMDT Group？（）

• A、It is used for PIM control traffic
• B、It is optionally configured for a high bandwidth multicast source to reduce multicast traffic replication to uninterested PE routers
• C、Within the VPF configuration in the PE router， multiple Default MDT groups are configured so each VPF can support multiple multicast sources
• D、There is a reduced multicast state in the MPLS core P routers
• E、When multicast traffic exceeds a certain configured threshold， traffic from the Data MDT is switched to the Default MDT to conserve bandwidth

正确答案:A,D

第16题：

Which of the following OSI model layers is used for logical addressing?（）

• A、Physical
• B、Transport
• C、Network
• D、Data link

正确答案:C

第17题：

以下关于IS-IS协议Hello报文结构不正确的是？（）

• A、Level-1 LAN IIH报文结构和Level-2 LAN IIH报文结构是一致的
• B、LAN IIH固定长度为27个字节
• C、P-to-P IIH报文固定长度为20个字节
• D、LAN IIH有一个字节的优先级字段

正确答案:D

第18题：

What is periodically multicasted （every 10 seconds） by the DIS on a LAN to ensure IS-IS Link StateDatabase accuracy？（）

• A、PSNP
• B、CSNP
• C、LSP
• D、IIH
• E、ISH

正确答案:B

第19题：

Which of the following routing protocols is a link state and uses a backbone called area 0？（）

• A、OSPF
• B、EIGRP
• C、BGP
• D、IS-IS

正确答案:A

第20题：

Which of the following commands is used to observe the current state of the routing table？（）

• A、route
• B、lsattr
• C、netstat
• D、ifconfig

正确答案:C

第21题：

Which CLI command is used to see the current OSPF link-state database?（）

• A、show ospf database
• B、show ospf neighbor
• C、show protocols ospf
• D、show ospf link-state

正确答案:A

第22题：

第23题：