Enterprise Routing and Switching, Specialist (JNCIS-ENT) v7.0 (JN0-346)

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Total 65 questions

Which two statements are true about a unified ISSU? (Choose two.)

  • A. It requires that Bidirectional Forwarding Detection be disabled.
  • B. It is only supported on platforms with redundant control planes.
  • C. It is only supported on platforms with redundant power supplies.
  • D. It requires that graceful Routing Engine switchover be enabled.


Answer : B,D

Explanation:
B: Recent development work by many router vendors has focused on an effort to provide hitless control plane switchovers, which means keeping the control plane states in sync between the active and standby control planes prior to a switchover. Many consider this capability to be a prerequisite to delivering ISSU. Hitless control planeswitchovers are usually implemented using the same version of code on both active and standby control plane components. However, ISSU design additionally requires different software versions running on active and standby control plane components.
D: Unified ISSU is supported only on dual Routing Engine platforms. In addition, the graceful Routing Engine switchover (GRES) and nonstop active routing (NSR) must be enabled.
References:
https://www.juniper.net/documentation/en_US/junos15.1/topics/reference/requirements/iss u-system-requirements.html https://www.juniper.net/kr/kr/local/pdf/whitepapers/2000280-en.pdf

Which state indicates that the BGP session is fully converged?

  • A. Connect
  • B. Up
  • C. Established
  • D. Active


Answer : C

Explanation:
In order to make decisions in its operations with peers, a BGP peer uses a simple finite state machine (FSM) that consists of six states: Idle; Connect; Active; OpenSent;
OpenConfirm; and Established.
In the Established state, the peers send Update messages to exchange information about each route being advertised to the BGP peer.


Click the Exhibit button.
In the exhibit, each IP subnet in the network is associated with a unique VLAN ID.
Which action will ensure that Host C will communicate with Host A and Host B?

  • A. Configure all switch ports connecting to the host devices as access ports associated with a common VLAN.
  • B. Configure an IRB interface for each VLAN and associate it with its corresponding VLAN.
  • C. Configure all switch ports connecting to the host devices as trunk ports associated with all VLANs.
  • D. Configure a port-based ACL that permits inter-VLAN routing for all configured VLANs.


Answer : B

Explanation:
Configuring Routing Between VLANs on One Switch
To segment traffic on a LAN into separate broadcast domains, you create separate virtual
LANs (VLANs).
Of course, you also want to allow these employees to communicate with people and resources in other VLANs. To forward packets between VLANs you normally you need a router that connects the VLANs. However, you can accomplish this on a Juniper Networks switch without using a router by configuring an integrated routing and bridging (IRB) interface (also known as a routed VLAN interfaceor RVIin versions of Junos OS that do not support Enhanced Layer 2 Software).
References: http://www.juniper.net/documentation/en_US/junos15.1/topics/example/RVIs- qfx-series-example1.html


Click to the exhibit button.
Referring to the exhibit, which configuration change is needed for an IS-IS Level 1 adjacency between R1 and R2?

  • A. Configure the Io0 family ISO address 49.0002.0010.0042.0002.00 on R1.
  • B. Disable Level 2 on R2’sge-0/0/1 interface.
  • C. Configure the Io0 family ISO address 49.0002.0010.0042.0002.00 on R2.
  • D. Enable Level 2 on R1’s ge-0/0/1 interface.


Answer : C

Explanation:
Level 1 adjacencies can be formed between routers that share a common area number.
We need to change ISOaddresses so that both routers have the same area number. If we change the ISO address on R2 49.0002.0010.0042.0002.00, both routers will have 0002 as area number.
Note: Level 2 adjacency can be formed between routers that might or might not share an areanumber.
References: http://www.juniper.net/techpubs/en_US/junos16.1/topics/example/isis-multi- level.html

An EBGP session sources its TCP connection from which IP address?

  • A. The IP address of the primary address assigned to the loopback interface.
  • B. The IP address assigned as the router ID.
  • C. The IP address of the preferred address assigned to the loopback interface.
  • D. TheIP address of the interface that connects the two BGP speakers.


Answer : D

Explanation:
The BGP session between two BGP peers is said to be an external BGP (eBGP) session if the BGP peers are in different autonomous systems (AS) . A BGP session between two
BGP peers is said to be an internal BGP (iBGP) session if the BGP peers are in the same autonomous systems.
By default, the peer relationship is established using the IP address of the interface closest to the peer router.
References:http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol- bgp/13751-23.html

Which two prefixes are martian routes by default? (Choose two.)

  • A. 127.0.0.0/16
  • B. 127.0.0.0/8
  • C. 192.0.0.0/16
  • D. 192.0.0.0/24


Answer : B,D

Explanation:
Martian addresses are host or network addresses about which all routing information is ignored. When received by the routing device, these routes are ignored. They commonly are sent by improperly configured systems on the network and have destination addresses that are obviously invalid.
To view the default and configured martian routes, run the show route martians command.

IPv4 Martian Addresses -
[email protected]> show route martians table inet.
inet.0:
0.0.0.0/0 exact -- allowed
0.0.0.0/8 orlonger -- disallowed
127.0.0.0/8 orlonger -- disallowed
192.0.0.0/24 orlonger -- disallowed
240.0.0.0/4 orlonger -- disallowed
224.0.0.0/4 exact -- disallowed
224.0.0.0/24 exact -- disallowed
inet.1:
0.0.0.0/0 exact -- allowed
0.0.0.0/8 orlonger -- disallowed
127.0.0.0/8 orlonger -- disallowed
192.0.0.0/24 orlonger -- disallowed
240.0.0.0/4 orlonger -- disallowed
Etc.
References:https://www.juniper.net/documentation/en_US/junos16.1/topics/concept/martia n-addresses-understanding.html

What are two interarea OSPF LSA types? (Choose two.)

  • A. Type-4 ASBR summary LSAs
  • B. Type 3 summary LSAs
  • C. Type 1 router LSAs
  • D. Type 2 network LSAs


Answer : A,B

Explanation:
A: The fourth LSA type, network example:



In this example we have R1 that is redistributing information from the RIP router into OSPF.
This makes R1 anASBR (Autonomous System Border Router). What happens is that R1 will flip a bit in the router LSA to identify itself as an ASBR. When R2 who is an ABR receives this router LSA it will create a type 4 summary ASBR LSA and flood it into area 0.
This LSA will also be flooded in all other areas and is required so all OSPF routers know where to find the ASBR.
B: Example:


Router 2 can create a Type 3 summary LSA and flood it into area 0. This LSA will flood into all the other areas of our OSPF network. Thisway all the routers in other areas will know about the prefixes from other areas.
Note: The name summary LSA is very misleading. By default OSPF is not going to summarize anything for you. There is however a command that let you summarize inter- area routes. Take a look at my OSPF summarization tutorial if you are interested. If you are looking at the routing table of an OSPF router and see some O IA entries you are looking at
LSA type 3 summary LSAs. Those are your inter-area prefixes!

Depending on the link type, OSPF sends link state update packets to which two addresses? (Choose two.)

  • A. 224.0.0.8
  • B. 224.0.0.6
  • C. 224.0.0.9
  • D. 224.0.0.5


Answer : B,D

Explanation:
Every time a router sends an update, it sends it to the DR and BDR on the multicast address 224.0.0.6. The DR will then send the update out to all other routers in the area, to the multicast address 224.0.0.5.
References:https://en.wikipedia.org/wiki/Open_Shortest_Path_First

What information is included in the DHCP snooping database? (Choose two.)

  • A. client MAC address
  • B. DHCP server address
  • C. DHCP options
  • D. VLAN


Answer : A,D

Explanation:
When DHCP snooping is enabled, the lease information from the server is used tocreate the DHCP snooping table, also known as the binding table. The table shows current IP-
MAC bindings, as well as lease time, type of binding, names of associated VLANs, and associated interface.
References:http://www.juniper.net/techpubs/en_US/junos13.2/topics/concept/port-security- dhcp-snooping-els.html

Which protocol prevents loops and calculates the best path through a switched network that contains redundant paths?

  • A. VRRP
  • B. STP
  • C. DHCP
  • D. IS-IS


Answer : B

Explanation:
Spanning Tree Protocol (STP) is a Layer 2protocol that runs on bridges and switches. The main purpose of STP is to ensure that you do not create loops when you have redundant paths in your network

Which two statements are true about DIS elections in IS-IS? (Choose two.)

  • A. If a priority tie occurs, the router with the lower subnetwork point of attachment (SNPA) value becomes the DIS.
  • B. If a priority tie occurs,the router with the higher subnetwork point of attachment (SNPA) value becomes the DIS.
  • C. The router with the lower priority value becomes the DIS.
  • D. The router with the higher priority value becomes the DIS.


Answer : B,D

Explanation:
In IS-IS, deterministic DIS election makes the possibility of predicting the router that will be elected as DIS from the same set of routers. The router advertising the numerically highest priority wins, with numerically highest MAC address, also called a Subnetwork Point of
Attachment (SNPA), breaking the tie.
References:https://kb.juniper.net/kb/documents/public/junos/StudyGuides/Ch4_from_JNCI

P_studyguide.pdf -

Which two statements are correct about aggregate routes in the Junos OS? (Choose two.)

  • A. An active route can contribute only to a single aggregate route.
  • B. Only one aggregate route can be configured for each destination prefix.
  • C. An aggregate route has a default next hop of an IP address.
  • D. An aggregate route always shows as active in the routing table.


Answer : A,B

Explanation:
A route can contribute only to a single aggregate route.
You can configure only one aggregate route for each destination prefix.

You notice that there are currently two MAC addresses associated with a single access port in the bridge table on one of your EX Series switches.
What are two explanations for this behavior? (Choose two.)

  • A. The access port connects to an IP phone which connects to a host device.
  • B. The native VLAN feature has been associatedwith the access port.
  • C. Themac-move-limitfeature has been disabled on the access port.
  • D. The access port connects to multiple hosts through a rogue device.


Answer : B,D

Explanation:
MAC move limiting detects MAC movement and MAC spoofing on access interfaces. You enable this feature on VLANs.


Click the Exhibit button.
Referring to the exhibit, which type of route is displayed?

  • A. static
  • B. generate
  • C. aggregate
  • D. martian


Answer : C

Explanation:
From the exhibit we see:
109.0.0.0/8 *[Aggegate/130]


Click the Exhibit button.
Referring to the exhibit, which type of route is displayed?

  • A. generate
  • B. martian
  • C. aggregate
  • D. static


Answer : C

Explanation:
From the exhibit se see: Contributing Routes
Note: Route aggregation allows you to combine groups of routes with common addresses into a single entry in the routing table. This decreases the size of the routing table as well as the number of route advertisements sent by the routing device.
An aggregate route becomes active when it has one or more contributing routes. A contributing route is an active route that isa more specific match for the aggregate destination.
References: http://www.juniper.net/techpubs/en_US/junos15.1x49- d40/topics/concept/policy-aggregate-routes.html

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Total 65 questions