Juniper Networks Certified Internet Associate docx

Exam : JN0-201

Title : Juniper Networks Certified Internet Associate

Ver : 09.21.2006
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QUESTION 1
Which two statements are true concerning the JUNOS software? (Choose two.)

A. Processes are tightly integrated with each other.
B. Processes are fully independent from each other.
C. Processes run in a protected memory environment.
D. Processes may fail and cause a failure of the entire system.

Answer: B, C
Explanation:
From Juniper.com, Benefits of the JUNOS operating system: Each user process runs in
its own protected memory space. This ensures that the failure of one subsystem will not
negatively impact the operation of other subsystems executing over the operating system.

QUESTION 2
Which boot device contains the primary copy of the JUNOS software?

A. hard drive
B. floppy drive
C. PCMCIA flash
D. internal flash drive

Answer: D
Explanation:
The router stores bootable copies of the JUNOS software in three possible locations: the
internal flash disk, the hard drive, or the removable media. The primary boot location is
the internal flash disk. The hard drive is the secondary boot location, while the removable
media is used for disaster-recovery purposes.

QUESTION 3
Which path will a packet follow within a Juniper Networks router after it enters an
interface and before a forwarding table lookup is performed?

A. PIC I/O Manager, Buffer Manager, I/O Manager, Internet Processor
B. PIC I/O Manager, Buffer Manager, Internet Processor, I/O Manager
C. PIC I/O Manager, I/O Manager, Buffer Manager, Internet Processor
D. PIC I/O Manager, I/O Manager, Internet Processor, Buffer Manager

Answer: C
Explanation:
When a data packet arrives on an interface, the PIC I/O Manager performs
error-checking, then transmits the packet to the I/O Manager. The I/O Manager removes
the layer 2 header and segments the packet into 64-byte J-cells. It then sends those J-cells
to the Inbound Distributed Buffer Manager. The Buffer Manager then sends a
notification cell to the Internet Processor, which performs a forwarding table lookup.
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QUESTION 4
Given the following configuration:
interfaces {
so-0/0/0 {
unit 0 {
family inet {
address 10.10.10.1/24;
}
}
}
so-0/0/1 {
unit 0
family inet {
address 20.20.20.1/24;

}
}
}
lo0 {
unit 0 {
family inet {
address 192.168.1.1/32;
}
}
}
}

Which is considered an exception packet?

A. IP packet addressed to 10.100.100.10
B. IP packet with the Router Alert option set
C. ICMP traceroute packet with TTL set to 5
D. ICMP echo request addressed to 172.16.1.1

Answer: B
Explanation:
The PFE can't process some data packets in its normal fashion. These packets are referred
to as exception packets. Examples of exception packets are: Routing protocol updates,
Packets addressed to the router, Packets requiring generation of ICMP error messages, or
Packets containing an IP Options field.
Answer B is correct because an IP Option field is set in the packet. A,C, and D are all
examples of packets that are be forwarded through the router as none of them are
destined for the router or require special attention.

QUESTION 5
From within the [edit] portion of the configuration, which command restores the
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number 2 rollback file?

A. rollback 2
B. run rollback 2
C. request system rollback 2
D. run request system rollback 2

Answer: A
Explanation:
The JUNOS software saves up to nine previous configuration files. The most recent
config file is called juniper.conf.1.gz and is number 1. The naming convention continues
with each older file incrementing by 1. You restore a config file with the rollback
command and the number of the config file to restore. Rollback is a configuration mode
command not an operation mode command, so within [edit] it is not necessary to precede
the command with the command "run".

QUESTION 6
A network administrator would like to verify the active alarms on the interface
so-0/0/0.0. Which command displays this information?

A. show alarms
B. show interfaces terse
C. show alarms extensive
D. show interfaces extensive

Answer: D
Explanation:
The "show interfaces extensive" command displays all possible information about every
interface including active alarms and any error conditions.

QUESTION 7
Which ASIC is responsible for segmenting a packet into 64-byte J-Cells?

A. PIC I/O ASIC
B. I/O Manager ASIC
C. Buffer Manager ASIC

D. Internet Processor ASIC

Answer: B
Explanation:
The I/O Manager ASIC removes the layer 2 header and segments the packet into 64-byte
J-cells.

QUESTION 8
During the boot sequence of the JUNOS software, which device is consulted first, by
default?
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A. hard drive
B. LAN server
C. removable media
D. internal flash drive

Answer: C
Explanation:
The removable media is the first boot location examined. If the router finds a copy of
the JUNOS software there, it loads the software on the router. This presents a possible
hazard in your network since all existing files and file systems on the router are erased
during this process. This type of boot process returns the router to a factory default-type
environment and should be used only for disaster recovery. If no removable media is
present, the router loads the software from the internal flash disk. This is considered the
normal boot operation and should occur at each router start.

QUESTION 9
Which protocol family is required prior to assigning an IP address to an interface?

A. family ip
B. family ip6
C. family inet
D. family inet4

Answer: C
Explanation:
Each logical interface in the JUNOS software has the ability to support one or more
protocol families. The inet protocol family supports IP version 4 (IPv4) packets.

QUESTION 10
The monitor traffic command closely resembles that UNIX based utility?

A. ps -x
B. passwd
C. ls -a-l
D. tcpdump

Answer: D
Explanation:
The "monitor traffic" command prints packet headers to your terminal screen for
information sent or receive by the routing engine. It is very similar in operation to the
Unix tcpdump utility.

QUESTION 11
Which command ensures that a configuration file on a backup Routing Engine is

identical to the file on the primary Routing Engine?
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A. commit check
B. commit and-quit
C. commit confirmed
D. commit synchronize

Answer: A
Explanation:
One of the options for the "commit" command is "synchronize". When you have a router
with two routing engines installed, this option tells the router to apply the candidate
configuration to both routing engines.

QUESTION 12
If there is a BGP next hop with equal preference in inet.0 and inet.3, which version
of the route will BGP use?

A. the route in inet.3
B. the route in inet.0
C. the route with the lower metric
D. It will randomly choose between inet.0 and inet.3.

Answer: A
Explanation:
The inet.0 routing table is used to store IPv4 routes. All routing protocols place

information into this table by default. The inet.3 routing table contains the egress IP
address of a MPLS lable switched path (LSP). Routes are inserted into inet.3 by the
RSVP protocol. In the case of a preference tie between the routing tables, the JUNOS
software prefers the inet.3 table and the LSP.

QUESTION 13
When a router receives a label of zero it will ____.

A. perform a label pop
B. perform a label swap
C. perform a label push
D. send an error message toward the ingress router

Answer: A
Explanation:
Popping the MPLS Label
Our definition of each router's role along the path of an LSP assumes the default JUNOS
software behavior of penultimate hop popping (PHP). In this case, the penultimate transit
router in the LSP performs the label pop operation. Another option exists for popping the
MPLS from the data packet- ultimate hop popping.
Ultimate hop popping occurs when the egress router itself performs the pop operation.
This requires the egress router to perform two operations on the data packet: the pop and
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an IPv4 lookup to forward the packet. This dual operation places a larger processing
burden on the egress router, which prompts the use of PHP.
The technical difference between PHP and ultimate hop popping comes in the action of

the egress router. Based on its current configuration, the egress router signals different
MPLS upstream to the penultimate router. A lvalue of 3 means the upstream router
should perform PHP and forward native IPv4 packets. A lvalue of 0, on the other hand,
tells the upstream router to perform a l-swap operation and to forward the data
with an MPLS header attached. (We discuss the definitions of the MPLS label values in
the "ls" section of this chapter.) A Juniper Networks router performs ultimate hop
popping when the explicit-null command is applied.

QUESTION 14
In normal operation, what is the job of the penultimate router?

A. It pops the label and sends the remaining data packet to the egress router.
B. It pushes an additional label on a packet and sends it to the egress router.
C. It swaps an incoming label with a label of 3 and sends it to the egress router.
D. It examines the IP packet and forwards the packet based on the destination IP address.

Answer: A
Explanation:
The penultimate router, which is second to last along the path of the LSP, often performs
a label pop operation to remove the MPLS information from the data packet. After
consulting the MPLS switching table, the router forwards the resulting data, a native IPv4
packet, to the egress router.

QUESTION 15
Where must you configure a static LSP?

A. on the egress router only
B. on the ingress router only
C. on all routers along the LSP path
D. on the ingress and egress routers

Answer: A
Explanation:
A static label switched path requires that each router along the LSP be configured
explicitly.

QUESTION 16
You want to ensure that an LSP from router A to router D always goes through
router C, which is two hops away. The ERO is configured as ____.

A. C loose
B. D loose
C. C strict
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D. B strict

Answer: A
Explanation:
The explicit route object (ERO) allows the path message to traverse the network using
information that is independent of the IGP shortest path. An ERO configured with a loose
hop specifies that the LSP must transit the specified node(s) in the order given. The IGP
shortest path is used between the loose hop nodes.

QUESTION 17
Which RSVP object assigns a label to the LSP?

A. Label Object
B. Label Assign Object
C. Record Route Object
D. Label Request Object

Answer: A
Explanation:
Label Request Object
The label request object is encoded in the Path messages sent to the egress router. This
object allows each router to assign a label value to the requested LSP. When the Path
message is received, the local router allocates a label and stores it with the Path soft state
for that LSP. When the Resv message arrives from the downstream neighbor, the label is
advertised upstream in an RSVP label object.

QUESTION 18
If all OSPF routers on a broadcast network have the same OSPF priority, what
parameter is used to determine the new BDR at the same time of a DR failure?

A. area ID
B. router ID
C. loopback address
D. IP address of interface on broadcast network

Answer: A
Explanation:
The router priority of all participating routers is examined first, with the highest priority
router becoming the BDR. Any router reporting a priority value of 0 is ineligible to
become either the DR or BDR. In the event of a priority tie, the router ID of each router
is examined. The highest value results in that router becoming the BDR.

QUESTION 19
What is the purpouse of the OSPF link-state update packet?

A. describes a change to the OSPF hello timer
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B. carries one or more link-state advertisements
C. establishes and maintains neighbor relationships
D. describes the contents of the entire link-state database

Answer: A
Explanation:
Information in the link-state database is populated through a Link State Advertisement
(LSA). Each LSA contains routing, metric, and topology information to describe a
portion of the OSPF network. The local router advertises LSAs within a link-state update
packet to its neighboring routers.

QUESTION 20
Why would you make a non-backbone area a stub or not-so-stubby area?

A. to aggregate routes learned from the ABR
B. to lower the cost of routes advertised by the ABR
C. to connect a non-contiguous area to the backbone
D. to decrease the size of the link-state database in that area

Answer: A
Explanation:

The OSPF stub area provides for a smaller link-state database by restricting the presence
of AS external LSAs (type 5) within the area. A not-so-stubby area restricts type 5
external LSAs, but still allows for some external routes to be present in the database with
a new NSSA external LSA type 7.

QUESTION 21
What type of OSPF router is responsible for redistributing routes into OSPF?

A. ABR
B. ASBR
C. internal router
D. backbone router

Answer: A
Explanation:
An Autonomous System boundary router (ASBR) connects networks running different
routing protocols (autonomous systems). An ASBR injects external routing knowledge
into an OSPF network.

QUESTION 22
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
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D. show ospf link-state

Answer: A
Explanation:
The "show ospf database" command shows summary information about each LSA on a
per-area basis.

QUESTION 23
During OSPF adjacency formation, in what state is a router when it is negotiating to
be in charge of the database synchronization process?

A. Init
B. 2Way
C. ExStart
D. Exchange

Answer: A
Explanation:
In the ExStart state, the local router and its neighbor establish which router is in charge of
the database synchronization process. The higher router ID of the two neighbors controls
which router becomes the master.

QUESTION 24
Which three BGP states are associated with establishing TCP connectivity? (Choose
three.)

A. Idle
B. Active
C. Connect
D. Open Sent

E. Established

Answer: A, B, C
Explanation:
IDLE: After the BGP process starts, a TCP session is initiated with the remote peer. The
local router transitions to the Connect state and begins listening for a connection initiated
by the remote peer.
CONNECT: In this state, the local router is has seen a TCP connection attempt from a
peer and is waiting for the TCP session to be completed. If it is successful, the local
router sends an Open message to the peer and transitions to the OPENSENT state.
ACTIVE: In the active state, the local router is trying to establish a TCP session with its
peer. If the session establishes successfully, an Open message is sent and the local router
transitions to the OPENSENT state.
OPENSENT state is reached once TCP session is established. Established designates a
fully operational OSPF connection

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QUESTION 25
What are two ways that a valid IBGP peering session can be configured? (Choose
two.)

A. via the accept x.x/y command
B. via the TCP reachable physical interface addresses
C. via remote loopbacks with the local-address command
D. via UDP with the neighbor x.x.x.x command at the group level

Answer: B, C
Explanation:
Unlike EBGP peers, there is no requirement for physical connectivity between IBGP
peers. TCP sessions are established based on the IP reachability between two peers. This
session can be established between any configured IP interfaces on the two routers.\

QUESTION 26
When configuring an IBGP peering session between loopback interfaces, why is the
local-address option required?

A. for VLSM support
B. for loop prevention
C. for TCP reachability
D. for MD5 authentication

Answer: A
Explanation:
When a router generates an IP packet, the source IP address becomes the address of the
outbound interface. The local-address command changes the source IP address of the
BGP messages to the configured IP address. Without this, a peer configured to use a
loopback address will never see a connection attempt from its configured neighbor. It is
expecting connections from the loopback IP address. The local router is attempting
connections from the egress interface IP address unless local-address is configured.

QUESTION 27
What is the first step in the BGP route selection?

A. The local router prefers the route with the shortest AS_PATH.
B. The router first verifies that it has a route to the BGP Next Hop IP address.
C. The local router prefers the route from the peer with the lowest peer ID address.

D. The local router prefers the route learned from an EBGP peer over a route learned
from an IBGP peer.

Answer: A
Explanation:
The order of BGP route selection:
1. The next hop must be reachable
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2. Highest local preference
3. Shortest AS Path
4. Smallest Origin attribute
5. Smallest Multiple Exit Discriminator (MED)
6. EGP routes preferred over IBGP routes
7. Smallest IGP metric to advertised BGP next-hop
8. Shortest cluster-list length if route reflection is used for IBGP
9. Smallest numerical ID
10. Smallest numerical IP address

QUESTION 28
Assume that a comparable configuration is applied to your peer in AS 11 and that
bi-directional TCP reachability has been achieved. Which EBGP configuration will
allow the BGP session to become established?

A. routing-options {
autonomoues-system 64;
}

protocols {
bgp {
group external-peer11 {
type external;
neighbor 10.0.3.6 {
peer as }
}
B. routing-options {
autonomous-system 11;
}
protocols {
bgp {
group external-peer 1 {
type external;
peer-as 11; {
neighbor 10.0.3.6;
}
}
C. routing-options {
autonomous-system 11;
}
protocols {
bgp {
group external-peer11 {
type external;
peer-as 64; {
neighbor 10.0.3.6;
}
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}
D. routing-options {
autonomous-system 64;
}
protocols {
bgp {
group external-peer101 {
peer-as 101;
neighbor 10.0.3.6;
}
}
}


Answer: A
Explanation:
The "autonomous system" command assigns the local AS number, so B and C aren't
correct since the peer is an EBGP peer in AS 11. The local AS must be 64. The "peer-as"
command defines the AS of the peer router. Answer D has the peer-as set to 101. Answer
A has the correct configuration.

QUESTION 29
Once the TCP connection is established, which message type initiates the BGP
peering process?

A. Open
B. Active

C. Update
D. Keepalive
E. Notification

Answer: A
Explanation:
The Open message is the first packet BGP sends to a peer after the TCP connection has
been established. It allows the two peers to negotiate the parameters of the peer session.

QUESTION 30
Which CLI command displays routes received from an EBGP peer?

A. show bgp received routes x.x.x.x
B. show bgp advertised routes x.x.x.x
C. show route receive-protocol bgp x.x.x.x
D. show route advertising-protocol bgp x.x.x.x

Answer: A
Explanation:
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You can view routes advertised by a BGP peer on the local router by using the "show
route receive-protocol bgp neighbor-address" command.

QUESTION 31
Which CLI command displays routes advertise to an EBG peer?

A. show bgp received routes x.x.x.x
B. show bgp advertised routes x.x.x.x
C. show route receive-protocol bgp x.x.x.x
D. show route advertising-protocol bgp x.x.x.x

Answer: A
Explanation:
You can view routes being advertised to a BGP peer on the local router by using the
command "show route advertising-protocol bgp neighbor-address" command.

QUESTION 32
What are two purposes of the AS_PATH attribute? (Choose two.)

A. route selection
B. loop avoidance
C. determining equal cost paths for reachability
D. defining the application of other BGP attributes

Answer: A, B
BGP uses the AS path as a method to prevent routing loops. It is also used as a
tie-breaker in the route selection process.

QUESTION 33
The ORIGIN attribute describes the source of the BGP prefix. Which three are
valid ORIGIN codes? (Choose three.)

A. IGP
B. BGP
C. EGP
D. Incomplete

E. Anonymous

Answer: A, C, D
The current BGP specification dictates three possible origin values:
IGP: The route was originally learned from an IGP on the source router. IGP is
displayed with the character "I" and is encoded as a value of 0.
EGP: The route was originally learned by the EGP protocol on the source router. EGP is
displayed with the character "E" and is encoded as a value of 1.
Incomplete: The route's source was unkown to the initial BGP router. Incomplete is
displayed with the character "?" and is encoded as a value of 2.
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QUESTION 34
When is the default routing policy applied?

A. only if no policies have been applied
B. prior to evaluating any applied policy
C. after all policies have been evaluated
D. during the evaluation of every applied policy

Answer: A
Explanation:
All policy chains have an implicit default policy at the end. This is the default action to
take if there is no match to any of the configured policies. The default policy does not
have a "next policy" result. It will always end the policy evaluation.

QUESTION 35
How do you send static routes to a RIP neighbor?

A. By default, RIP automatically sends static routes.
B. Configure the static route with a next hop of the RIP neighbor.
C. This is not possible, only RIP routes can be sent to a RIP neighbor.
D. Configure redistribute static under [edit protocols rip]
E. Apply an export policy within RIP that matches on the routes, and accepts it.

Answer: A
Explanation:
By default, the RIP protocol will have no knowledge of routes from other routing
protocols including static routes. On a Juniper router, routing policies are used to
redistribute routes from one protocol to another. To advertise any routes to a RIP
neighbor, an export policy must be created.

QUESTION 36
How can you identify all routes that are more specific than 10.0/16, excluding the
exact match?

A. route-filter 10.0/16 longer
B. route-filter 10.0.0/17 longer
C. route-filter 10.0/16 orlonger
D. route-filter 10.0.0/17 upto /32

Answer: A
Explanation:
The longer match type is similar to the orlonger match type. The difference between
them is that longer will only match routes that are more specific than the specified route.
It will exclude the specified route.

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QUESTION 37
Given the following configuration snippet:

[edit protocols bgp]
importremove-comm;
grouppeer-65521 {
type external;
export [ my-cust-tag add-as-path ];
peer-as 65221;
neighbor 192.168.20.1 {
import [ gold-cust silver-cust bronze-cust ];
export add-metric;
}
}

Which policy will be applied to inbound routes from this BGP neighbor?

A. gold-cust
B. add-metric
C. my-cust-tag
D. remove-comm

Answer: A
Explanation:

Inbound route policies are applied by the "import" command. Looking at the
configuration, the 3 policies gold-cust, silver-cust, and bronze-cust are applied to
inbound routes. Answer A is the only answer that matches any of these policies.

QUESTION 38
Given the following policy:

policy-statementlimit-cust {
from {
route-filter 10.0.0.0/8 orlonger reject;
route-filter 10.0.55.0/24 orlonger;
route-filter 10.0.0.0/16 orlonger accept;
route-filter 0.0.0.0/0 through 0.0.0.0/32 {
metric 5;
accept;
}
}
then {
metric 10;
accept;
}
}
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What happens to the route 10.0.56.0/24?

A. The route is rejected.
B. The route is accepted.
C. The metric is set to 5 and the route is accepted.
D. The metric is set to 10 and the route is accepted.

Answer: A
Explanation:
Specifying multiple match conditions in a policy imposes a logical AND on the
conditions on the candidate route. It will match the policy only if it also matches all of
the specified conditions. Within a policy term, multiple route filters can be paired with
other types of match conditions. Multiple route-filters are evaluated with a logical OR.
So for this configuration, 10.0.56.0/24 matches the route-filter "10.0.0.0/16 orlonger". As
long as the metric on the route is "5" it will be accepted. Answer B is the most correct.

QUESTION 39
What are three characteristics of RIPv2? (Choose three.)

A. supports VLSM
B. supports Kerberos authentication
C. is backward compatible with RIPv1
D. multicasts messages to RIP neighbors
E. uses Hello Protocol for neighbor discovery

Answer: A, C, D
RIP version 2 adds some extensions to the RIP protocol. Because it uses the same packet
types and formats as RIPv1, RIPv2 is backward compatible with RIPv1. By default, all
RIPv2 response updates include the subnet mask, which allows for support of VLSM.
RIPv2 sends all request and response messages to a multicast address instead of a
broadcast address.
RIPv2 does support authentication, but only using plain-text or MD5 passwords. There is

also no Hello mechanism with RIP.

QUESTION 40
What are three characteristics of RIP? (Choose three.)

A. uses Bellman-Ford algorithm
B. uses hop count as the metric
C. supports maximum allowable hop count of 15
D. floods updates to all RIP routers in the network
E. sends updates only when a route metric changes

Answer: A, B, C
Explanation.
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D incorrect because it floods updates to all connected neighbors only. Not all routers in
the network.
E. Triggered updates. E is incorrect because updates are sent every 30 seconds regardless
of any route changes.

QUESTION 41
Which two steps are required for RIP to redistribute IS-IS routes? (Choose two.)

A. apply the redistribution policy to RIP as import
B. apply the redistribution policy to RIP as export
C. apply the redistribution policy to IS-IS as import
D. apply the redistribution policy to IS-IS as export

E. create a redistribution policy accepting the RIP routes
F. create a redistribution policy accepting the IS-IS routes

Answer: B, F
By default, the RIP protocol will have no knowledge of routes from other routing
protocols including static routes. On a Juniper router, routing policies are used to
redistribute routes from one protocol to another. For RIP to learn the ISIS routes, a policy
must be configured to accept the ISIS routes. For RIP to advertise the routes, a RIP
export policy must be configured accepting the new RIP routes.

QUESTION 42
Which RIP message type is used to ask neighbors for updates?

A. Hello message
B. Query message
C. Request message
D. Response message

Answer: A
Explanation:
A RIP request packet is sent to a neighbor to request that the neighbor send all or part of
the neighbor's routing table.

QUESTION 43
During all initial traffic flow, which routers do dense mode multicast protocols
assume want to receive multicast traffic?

A. all routers in the network
B. only routers with receivers attached
C. only routers along the core based tree

D. all routers along the shortest-path tree

Answer: A
Explanation:
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Dense mode multicast routing protocols assume that every user segment in the network
wants to receive the data stream. As the source begins transmitting data traffic destined
for the multicast group address, the routers in the network flood the traffic to each
segment in the network.

QUESTION 44
By default, which routing table do multicast-enabled routers use to perform an RPF
check?

A. inet.0
B. inet.1
C. inet.2
D. inet.3

Answer: A
Explanation:
As multicast traffic is received, a router checks the source IP address of the packets
against the RPF table. If it finds that the receiving interface is in fact the best path back to
the source, it assumes that a routing loop doesn't exist and continues to forward the
traffic. By default, JUNOS uses the inet.0 routing table to perform RPF checks.

QUESTION 45
What type of multicast distribution tree is created in both PIM-DM and PIM-SM?

A. root-based tree
B. core-based tree
C. shortest-path tree
D. receiver-based tree

Answer: A
Explanation:
There are two different types of trees created by multicast networks: shared trees, and
source-based trees. Both trees create a shortest-path tree from the receiver back to the
source.

QUESTION 46
What type of IGMP message is sent by a host to describe the multicast traffic it
would like to receive?

A. join
B. query
C. report
D. update

Answer: A
Explanation:
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There are two types of IGMP message of concern to hosts: Host Membership Query, and
Host Membership Report. Multicast routers send Host Membership Query messages to
discover which host groups have members on their attached local networks. Hosts
respond to a Query by generating Host Membership Reports reporting each host group to
which they belong on the network interface from which the Query was received.

QUESTION 47
For what mode must an interface be configured in order to run Auto-RP?

A. dense
B. sparse
C. full-mesh
D. sparse-dense

Answer: A
Explanation:
The JUNOS software provides the ability for a PIM interface to operate in both sparse
and dense modes simultaneously. Sparse-dense mode is a requirement when you're using
Auto-RP as a rendezvous point election mechanism.

QUESTION 48
By default, which routing table is used to store unicast IPv4 routes?

A. inet.0
B. inet.1
C. inet.2
D. inet.3

Answer: A
Explanation:

The inet.0 routing table is the table used to store IPv4 unicast routes. The inet.1 routing
table is used to store IPv4 multicast routes. The inet.2 table is also used to store IPv4
unicast routes, however these routes are used by multicast routing protocols to prevent
routing loops. The inet.3 routing table contains the egress IP address of a MPLS label
switched path (LSP).

QUESTION 49
Which statement is true about static routes?

A. Static routes are never removed from the forwarding table.
B. By default, static routes are placed in the inet.1 routing table.
C. By default, a static route to a single destination prefix is assigned a preference value of
20.
D. Static routes are removed from the forwarding table when their nexthops are no longer
reachable.

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Answer: A
Explanation:
Static routes are assigned a preference of 5. The inet.0 routing table is used to store all
IPv4 unicast routes. For a static route to be placed in the inet.0 routing table, the next hop
must be valid. If a next-hop becomes unreachable, the route will be removed from the
routing table.

QUESTION 50
Without using policy, the default for load balancing traffic to equal-cost destination

is to _____.

A. randomly select one of the available next hops
B. load balance per packet across all available next hops
C. load balance per layer 3 microflow across all available next hops
D. load balance per layer 4 microflow across all available next hops

Answer: A
Explanation:
The default installation of data in the forwarding table is one next hop per destination.
Random selection places one of the equal cost routes in the routing table. To change the
default configuration and enable load balancing, a policy must be configured.

QUESTION 51
What is the default route preference for directly connected routes?

A. 0
B. 1
C. 5
D. 17

Answer: A
Explanation:
Directly connected routes have a preference value of 0. Static routes have a default
preference of 5. There are no routing protocols with default preferences of 1 or 17.

QUESTION 52
How do you enable interface fe-0/0/0 under the [edit protocols isis] level to form
both a Level 1 and Level 2 adjacency?

A. set interface fe-0/0/0.0
B. set interface fe-0/0/0.0 all level
C. set interface fe-0/0/0.0 level 3 enable
D. set interface fe-0/0/0.0 level 1 level 2

Answer: A
Explanation:
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The JUNOS software default configuration for ISIS is for the router to be configured as a
Level 1 and Level 2 (L1/L2) router. To enable (L1/L2) adjacencies on the router, the isis
protocol just needs to be enabled on an interface.

QUESTION 53
How often are IS-IS Hello packets transmitted?

A. 3 seconds for DIS; 9 seconds for non-DIS
B. 9 seconds for DIS; 3 seconds for non-DIS
C. 10 seconds for DIS; 3 seconds for non-DIS
D. 10 seconds for all routers

Answer: A
Explanation:
The default hold time for JUNOS software on LAN interfaces is 27 seconds unless the
router is the DIS. The Hello time is (hold time / 3) so the default hello timer is 9 seconds.
For DIS routers, the hold time is reduced to 9 seconds. The hello timer is still (hold time /
3), so the default hello timer for a DIS router is 3 seconds.

QUESTION 54
What are the three components of the ISO NET address? (Choose three.)

A. Area ID
B. N-selector
C. System ID
D. AS number
E. ISO number
F. MAC address

Answer: A, B, C
ISIS uses standard NSAP addressing as defined in ITU X.213. The first part of the
address indicates the ISIS area. The field containing the system ID appears immediately
after the area field. This can be thought of as the host portion of the address. The last
portion of the NET address is the N-selector (SEL) byte.

QUESTION 55
Two Level 2 routers are exchanging Hello packets with different Area IDs. What
occurs between these routers?

A. An Adjacency forms.
B. An Adjacency does not form.
C. An Adjacency forms but traffic is not forwarded.
D. No IS-IS PDUs are sent.

Answer: A
Explanation:
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The only requirement to form a Level 2 adjacency is that each end of the link reside
within Level 2. Level 1 adjacencies require that the area value of the two routers be
identical. If the areas are different, only Level 2 adjacencies can form between the
routers.

QUESTION 56
What command would you use to view an IS-IS adjacency?

A. show iso neighbor
B. show isis neighbor
C. show iso adjacency
D. show isis adjacency

Answer: A
Explanation:
You can verify ISIS adjacencies are working by using the "show isis adjacency"
command. The other 3 commands are not valid show commands in JUNOS.

QUESTION 57
Three IS-IS routers on a broadcast segment have different priority values
configured. Which router is elected the DIS on that broadcast segment?

A. the router with the lowest priority
B. the route with the highest priority
C. the router with the highest System ID
D. the router with the highest IP address

Answer: A
Explanation:
Within ISIS, a pseudonode is elected to represent the broadcast link to the rest of the
network. The pseudonode is called the DIS. The router with the highest criteria is always
the DIS. The first criteria checked is the DIS priority. When two or more nodes share
priority values, the second criteria checked is the MAC address of the advertising router.

QUESTION 58
Firewall filters can be used to accept, discard or reject packets based on _____.
(Choose three.)

A. protocol type
B. MAC address
C. TCP or UDP port
D. source and destination IP address

Answer: A, C, D
JUNOS uses the term firewall filter to describe the function of examining only the Layer
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3 and Layer 4 headers on a packet-by-packet basis. The mac-address is a layer 2 address,
so cannot be examined by a firewall filter.

QUESTION 59
A firewall filter is applied as an input filter on a transit interface. What three types
of traffic will this affect?

A. inbound traffic transiting the router
B. outbound traffic transiting the router
C. traffic destined to the Routing Engine
D. traffic destined to the interface address on which the filter is applied

Answer: A, C, D
Input filter apply only to inbound traffic, regardless of its destination.

QUESTION 60
By default, which command can be used to display information about packets that
have been logged with the syslog firewall filter action?

A. show log
B. show firewall
C. show log messages
D. show firewall log

Answer: A
Explanation:
The "syslog" filter action sends information to the hard drive storage file called
messages. You can view the file with the "show log messages" command.

QUESTION 61
In a multicast network, what is the process called when a router examines the
source address of a packet to see if it arrived on the correct interface?

A. unicast routing check
B. reverse routing check
C. source forwarding check
D. reverse path forwarding check

Answer: A
Explanation:
As a router receives multicast traffic, it examines the source IP address in the IP header.
A lookup is the performed in a special RPF routing table for that address. When the result
of this query affirms that the receiving interface is the best path back to the source, the
router is assured that a forwarding loop is not forming, and forwards the data stream out
all of its downstream interfaces.

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QUESTION 62
During initial traffic flow, which routers do dense mode multicast protocols assume
want to receive multicast traffic?

A. all routers in the network
B. only routers with receivers attached
C. only routers along the core based tree
D. all routers along the shortest-path tree

Answer: A
Explanation:
Dense mode multicast routing protocols assume that every user segment in the network
wants to receive the data stream. As the source begins transmitting data traffic destined
for the multicast group address, the routers in the network flood the traffic to each
segment in the network.

QUESTION 63
What version of IGMP is used default on juniper Networks routers?

A. version 1 only
B. version 2 only
C. version 3 only
D. version 4 only

Answer: A
Explanation:
The basic configuration of IGMP within the JUNOS software is quite simple: do nothing.
Each operational broadcast interface on the router that is running PIM automatically
enables IGMPv2.

QUESTION 64
What type of multicast distribution tree is created in both PIM-DM and PIM-SM?

A. root-based tree
B. core-based tree
C. shortest-path tree
D. receiver-based tree

Answer: A
Explanation:
There are two different types of trees created by multicast networks: shared trees, and
source-based trees. Both trees create a shortest-path tree from the receiver back to the
source.

QUESTION 65
Which RP election mechanism can load balance among multiple candidate RPs by