单选题In IS-IS， how does the restarting router inform its helpers that a restarts event occurred？（）A Sending out a graceful restart PDUB Sending an LSP that contains no TLVs.C Sending out a restarts TLV with the RR bit set.D Reflooding its LSP with a maximum

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第2题：

What are the two benefits of graceful restart？（）

• A、Graceful restart allows session information recovery without disruption to the network.
• B、A node can perform a graceful restart to help a neighbor recover its state. The label bindings are kepton state information， which helps the failed node recover faster and does notaffect the current for wardtraffic.
• C、Graceful restart allows a node to recover state from its neighbor when there is no RP or before thedevice undergoes SSO.
• D、Graceful restart does not allow session information recovery.
• E、During a graceful restart， the router removes any stale prefixes after a timer for stale entries expires

第3题：

In which two ways does the BGP graceful capability preserve prefix information during a restart？（）

• A、The peer router immediately removes the BGP routers that it learned from the restarting router from itsBGP routing tables.
• B、The router establishes BGP sessions with other routers and relearns the BGP routes from others that are also capable of graceful restart. The restarting router waits to receive updates from the neighboringrouters. When the neighboring routers send end-of-RIB messages to indicate that they are donesending updates，the restarting router starts sending its own updates.
• C、The peer router sends an end-of-RIB message to the restarting router.
• D、The restarting router removes any stale prefixes after the timer for stale entries expires.
• E、The restarting router does not remove any stale prefixes after the timer for stale entries expires.

第4题：

You have a Level 1-only router (Router A) in IS-IS area 49.0001. How does Router A learn how to get to IP prefixes in other areas?（）

• A、Router A must have a Level 2 adjacency with the Level 1/Level 2 router in area 49.0001.
• B、The Level 1/Level 2 router in area 49.0001 sets the "attached" bit in the Level 1 link-state PDU (LSP) it floods into area 49.0001.
• C、The Level 1/Level 2 router in area 49.0001 sets the "attached" bit in the Level 2 LSP it floods into area 49.0001.
• D、The Level 1/Level 2 router in area 49.0001 advertises these prefixes into area 49.0001 using a Level 2 LSP it floods into the area.

第5题：

Within IS-IS, the restart helper performs which task?（）

• A、It sends CSNPs to the restarting router.
• B、It periodically sends TLV 211 to the restarting router.
• C、It informs other routers in the domain that a router has restarted.
• D、It tears down adjacency and sends its entire database after 30 seconds.

第6题：

In IS-IS， how long will the restart helper keep the restarting router in the up state？（）

• A、The hello dead timer expires.
• B、The restart duration timer expires.
• C、The restarting router sets the down bit.
• D、The restart helper sends out three CSNPs.

第7题：

In IS-IS, how long will the restart helper keep the restarting router in the up state?（）

• A、until the hello dead timer expires
• B、until the restart duration timer expires
• C、until the restarting router sets the down bit
• D、until the restart helper sends out three CSNPs

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第13题：

In which two ways does the BGP graceful restart capability preserve prefix information during a restart？（）

• A、The peer router sends an end-of RIB message to the restarting router
• B、The peer router immediately removes the BGP routes that it learned from the restarting router from its BGP routing table
• C、The restarting router does not remove any stale prefixes after the timer for stale entries expires
• D、The router establishes BGP sessions with other routers and relearns the BGP routes from other routers that are also capable of graceful restart. The restarting router waits to receive updates from the neighboring routers. When the neighboring routers send end-of-RIB messages to indicate that they are done sending updates， the restarting router starts sending its own updates
• E、The restarting router removes any stale prefixes after the timer for stale entries expires

第14题：

What does the LSP Holdtime field in an IS-IS database indicate?（）

• A、the LSP age
• B、the LSP refresh interval
• C、the LSP elapsed lifetime
• D、the LSP remaining lifetime

第15题：

By default, which IS-IS metric types does JUNOS software support?（）

• A、receiving of wide metrics only
• B、sending of narrow metrics only
• C、receiving of narrow metrics only
• D、sending and receiving of narrow and wide metrics

第16题：

During OSPF adjacency formation， what state is a router in when it is sending LSA header information to its neighbor？  （）

• A、 Init
• B、 2Way
• C、 ExStart
• D、 Exchange

第17题：

In IS-IS， how does the restarting router inform its helpers that a restarts event occurred？（）

• A、Sending out a graceful restart PDU
• B、Sending an LSP that contains no TLVs.
• C、Sending out a restarts TLV with the RR bit set.
• D、Reflooding its LSP with a maximum sequence number.

第18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

第19题：

In BGP graceful restart, how does a peer router indicate the end of a route exchange?（）

• A、an open message with the E bit set
• B、an update message with the E bit set
• C、an open message with an end-of-RIB marker
• D、an update message with an end-of-RIB marker

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