Which statement is true about the routing table?
A.
The routing table exists in the control plane only.
B.
The routing table exists in the control plane and in the forwarding plane.
C.
The routing table contains both active and inactive routes.
D.
The routing table is stored on compact flash.
Explanation:
Correct answer is B.
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Sorry, A is correct here.
Confused with question 131 where the answer is B.
Source: http://packetsanalyzed.blogspot.com/2011/06/junos-control-and-forwarding-plane.html
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http://www.juniper.net/techpubs/en_US/junos13.2/topics/concept/junos-software-routing-forwarding-table-overview.html
Junos OS Routing and Forwarding Tables
A major function of the Junos OS routing protocol process is to maintain the Routing Engine’s routing tables and use these tables to determine the active routes to network destinations. The routing protocol process then installs these routes into the Routing Engine’s forwarding table. The Junos OS kernel then copies this forwarding table to the Packet Forwarding Engine. (so RE populate routing table to Fw engine)
The routing protocol process maintains multiple routing tables. By default, it maintains the following three routing tables. You can configure additional routing tables to suit your requirements.
Unicast routing table—Stores routing information for all unicast routing protocols running on the router. BGP, IS-IS, OSPF, and RIP all store their routing information in this routing table. You can configure additional routes, such as static routes, to be included in this routing table. BGP, IS-IS, OSPF, and RIP use the routes in this routing table when advertising routing information to their neighbors.
Multicast routing table (cache)—Stores routing information for all the running multicast protocols. DVMRP and PIM both store their routing information in this routing table, and you can configure additional routes to be included in this routing table.
MPLS routing table—Stores MPLS path and label information.
With each routing table, the routing protocol process uses the collected routing information to determine active routes to network destinations.
For unicast routes, the routing protocol process determines active routes by choosing the most preferred route, which is the route with the lowest preference value. By default, the route’s preference value is simply a function of how the routing protocol process learned about the route. You can modify the default preference value using routing policy and with software configuration parameters.
For multicast traffic, the routing protocol process determines active routes based on traffic flow and other parameters specified by the multicast routing protocol algorithms. The routing protocol process then installs one or more active routes to each network destination into the Routing Engine’s forwarding table.
Published: 2
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http://www.juniper.net/documentation/en_US/junos14.2/topics/concept/routing-tables-understanding.html
Understanding Junos OS Routing Tables
Junos OS automatically creates and maintains several routing tables. Each routing table is used for a specific purpose. In addition to these automatically created routing tables, you can create your own routing tables.
Each routing table populates a portion of the forwarding table. Thus, the forwarding table is partitioned based on routing tables. This allows for specific forwarding behavior for each routing table. For example, for VPNs, each VPN-based routing table has its own VPN-specific partition in the forwarding table.
It is common for the routing software to maintain unicast routes and multicast routes in different routing tables. You also might have policy considerations that would lead you to create separate routing tables to manage the propagation of routing information.
Creating routing tables is optional. If you do not create any, Junos OS uses its default routing tables, which are as follows:
inet.0—For IP version 4 (IPv4) unicast routes. This table stores interface local and direct routes, static routes, and dynamically learned routes.
inet.1—For the IPv4 multicast forwarding cache. This table stores the IPv4 (S,G) group entries that are dynamically created as a result of join state information.
inet.2—For subsequent address family indicator (SAFI) 2 routes, when multiprotocol BGP (MBGP) is enabled. This table stores unicast routes that are used for multicast reverse-path-forwarding (RPF) lookup. The routes in this table can be used by the Distance Vector Multicast Routing Protocol (DVMRP), which requires a specific RPF table. In contrast, Protocol Independent Multicast (PIM) does not need this table because it can perform RPF checks against the inet.0 table. You can import routes from inet.0 into inet.2 using routing information base (RIB) groups, or install routes directly into inet.2 from a multicast routing protocol.
inet.3—For IPv4 MPLS. This table stores the egress address of an MPLS label-swiched path (LSP), the LSP name, and the outgoing interface name. This routing table is used only when the local device is the ingress node to an LSP.
inet6.0—For IP version 6 (IPv6) unicast routes. This table stores interface local and direct routes, static routes, and dynamically learned routes.
instance-name.inet.0—If you configure a routing instance, Junos OS creates the default unicast routing table instance-name.inet.0.
instance-name.inet.2—If you configure routing-instances instance-name protocols bgp family inet multicast in a routing instance of type VRF, Junos OS creates the instance-name.inet.2 table.
Another way to create the instance-name.inet.2 table is to use the rib-group statement. See Example: Exporting Specific Routes from One Routing Table Into Another Routing Table.
Note: Importing inet-vpn multicast routes from the bgp.l3vpn.2 table into the instance-name.inet.2 table does not create the instance-name.inet.2 table. The import operation works only if the instance-name.inet.2 table already exists.
instance-name.inetflow.0—If you configure a flow route, Junos OS creates the flow routing table instance-name.inetflow.0.
bgp.l2vpn.0—For Layer 2 VPN routes learned from BGP. This table stores routes learned from other provider edge (PE) routers. The Layer 2 routing information is copied into Layer 2 VPN routing and forwarding instances (VRFs) based on target communities.
bgp.l3vpn.0—For Layer 3 VPN routes learned from BGP. This table stores routes learned from other PE routers. Routes in this table are copied into a Layer 3 VRF when there is a matching route table.
mpls.0—For MPLS label switching operations. This table is used when the local device is a transit router.
iso.0—For IS-IS routes. When you are using IS-IS to support IP routing, this table contains only the local device’s network entity title (NET).
juniper_private—For Junos OS to communicate internally between the Routing Engine and PIC hardware.
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New JN0-102 Exam Questions and Answers (8/May/2017 Updated):
NEW QUESTION 358
Which two statements describe the default behavior for OSPF? (Choose two.)
A. OSPF imports all routes into the inet4.0 routing table.
B. OSPF exports all static routes into the OSPF database.
C. OSPF imports all routes into the inet.0 routing table.
D. OSPF does not export static routes into the OSPF database.
Answer: CD
NEW QUESTION 359
Which two ping command parameters whould be used to troubleshoot MTU issues? (Choose two.)
A. ping do-not-fragment
B. ping rapid
C. ping verbose
D. ping size
Answer: AD
NEW QUESTION 360
Which command prompt indicates that you are in operational mode?
A. user @ router &
B. user @ router #
C. user @ router $
D. user @ router >
Answer: D
NEW QUESTION 361
Which keystroke combination allows users to move the cursor to the beginning of the command line without deleting text?
A. Ctrl + u
B. Ctrl + w
C. Ctrl + a
D. Ctrl + b
Answer: C
NEW QUESTION 362
What is the subnet mask for the 172.45.32.6/19 address?
A. 255.255.224.0
B. 255.255.240.0
C. 255.224.0.0
D. 255.240.0.0
Answer: A
NEW QUESTION 363
Click the Exhibit button. Referring to the exhibit, what happens when ping packets are sent to the management interface address of the local router?
user@router> show route protocol static
inet.0: 15 destinations, 15 routes (15 active, 0 holddown, 0 hidden)
+ = Active Route, – = Last Active, * = Both
99.0.0.0/17 *[Static/5] 00:00:11
————— > to 10.1.1.2 via ge-0/0/1.0
99.0.0.0/19 *[Static/5] 00:00:11
————— > to 10.1.2.2 via ge-0/0/2.0
99.0.0.0/24 *[Static/5] 00:00:11
————— > to 10.1.3.2 via ge-0/0/3.0
99.0.0.0/26 *[Static/5] 00:00:11
————— > to 10.1.4.2 via ge-0/0/4.0
Referring to the exhibit, which next-hop interface will be used to reach the 10.21.14.16 destination?
A. ge-0/0/1.0
B. ge-0/0/0.0
C. ge-0/0/3.0
D. ge-0/0/2.0
Answer: A
NEW QUESTION 364
What is the default firewall filter behavior when a term is matched but no terminating action is specified?
A. an implicit deny and the filter evaluation terminates
B. an implicit accept and the filter evaluation terminates
C. an implicit accept and the filter evaluation continues to the next term
D. an implicit deny and the filter evaluation continues to the next term
Answer: C
NEW QUESTION 365
What are three interface prefixes for a 40-gigabit interface? (Choose three.)
A. et
B. es
C. fte
D. xe
E. xle
Answer: ABE
NEW QUESTION 366
Which source of routing information is preferred by default?
A. static
B. RIP
C. direct
D. BGP
Answer: C
NEW QUESTION 367
For the interface ge-1/2/3.4, what does “ge” represent?
A. SONET/SDH
B. Gigabit Ethernet
C. Aggregated Ethernet
D. GRE
Answer: B
NEW QUESTION 368
Which word starts a command to display the operational status of a Junos device?
A. put
B. set
C. show
D. get
Answer: C
NEW QUESTION 369
……
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