Appendix A. Practice JNCIS Questions

This appendix is a great section and we are pleased to make it available. At the time of this writing, Boson Software (www.boson.com) is the only company selling any self-test software relating to the JNCIS. The questions and answers here are presented through the courtesy of Boson Software.

Currently Boson sells a practice test that was written by two CCNPs who work as part of JTAC. This sample test currently has 212 practice questions available for you and is identified as test number 70042.

The Boson testing software is extremely useful and has some advanced customizable features (see Figure A-1). The characteristics of the Boson Software worth mentioning include the following:

• By default, the question bank is segmented into smaller quizzes, thereby allowing you to pick the quiz you would like to practice on. You can adjust the number of questions to be asked.

• It allows you to focus practice on specific technical categories where you may need more practice.

• It tracks your historical scores to see how your learning has progressed. You can even have the software ask you only the questions you have gotten wrong.

• It randomizes the order of the questions and answers so you cannot memorize them very easily. This is an excellent option, and we highly recommend using it.

• It provides the ability to turn questions into flash cards, allowing you to use the questions as a learning aid.

• Its simulator mode allows you to take a timed practice quiz with the characteristics of the actual exam.

Figure A-1. Boson Test Configuration Screen

1:	Which is the shortest AS- Path ? (64515 65001 64972 65101) 172 178 182 172 (65101 64972) 190 172 (64972) 178 192 172
A1:	A. (64515 65001 64972 65101) 172 ASs included within parentheses are interior to a confederation. These ASs's numbers are not included in the total AS-Path length because they are affiliated with a confederation. Therefore, the (64515 65001 64972 65101) 172 path is the shortest because only one AS is included in its length.
2:	In IS-IS, what is used to limit excessive packet transmissions in a fully meshed NBMA network? IS-IS elects a DIS in such a situation IS-IS elects a DR in such a situation IS-IS cannot be used over ATM circuits IS-IS uses mesh groups to limit excessive packets
A2:	D. IS-IS uses mesh groups to limit excessive packets IS-IS can only be used on broadcast or point-to-point links. Broadcast links use a DIS to limit excessive packet transmissions, but there is no DIS elected for point-to-point links. To keep excessive packets from being transmitted over point-to-point links, mesh groups were created. When an IS-IS router receives an LSP from a member of its mesh group, it does not flood this LSP to other mesh- group members . This limits duplicate packets from being transmitted over an NBMA cloud.
3:	What is the maximum metric value that an IS-IS route can have if wide metrics are not used? 255 1023 63 65534
A3:	C. 63 The maximum metric value allowed for IS-IS routes is 63 unless wide metrics are specified to be used exclusively via the wide-metrics-only command.
4:	Assuming that all inet.3 routes have not been merged into inet.0 , which command, used under the [edit protocols mpls label-switch path NAME ] hierarchy will result in a route that can be pinged? Install 10.0.0.0/8 Install 10.0.0.0/8 active Install 10.0.0.0/8 rib inet.0 Install 10.0.0.0/8 enable ping
A4:	B. Install 10.0.0.0/8 active The install command causes a route, in addition to the standard host route to the egress of the LSP, to be installed into the inet.3 routing table. Routes in inet.3 are not installed into the forwarding table; therefore, it is not possible to ping these routes from another router, and they are only available for use by BGP as next -hops. By using the active keyword, you specify that a particular route should be installed into inet.0 , which will result in a route that can be used for BGP next-hops and can also be pinged by other routers.
5:	When configuring setup and hold priority for an LSP, what is true? Setup and hold priority are independent and can be configured as you like. Setup priority must be higher than hold priority. Hold priority must be higher than or equal to setup priority. They must be the same.
A5:	C. Hold priority must be higher than or equal to setup priority. When there is a lack of bandwidth, an LSP with a higher priority can cause a lower-priority LSP to be torn down to free up the necessary bandwidth. The setup priority is used to determine whether a given LSP should cause a less-important LSP to be torn down. The hold priority is used to determine if a given LSP will be allowed to remain up after it has been established. To prevent flapping of LSPs, it is required that the hold priority be equal to or greater than the setup priority.
6:	Which of the following OSPF routes will be chosen to reach a given destination? Intra-area route with a cost of 15 Inter-area route with a cost of 10 External type 1 route with a cost of 25 External type 2 route with a cost of 5
A6:	A. Intra-area route with a cost of 15 OSPF intra-area routes are always preferred over inter-area and external routes, no matter what the cost is.
7:	What is true about LSA type 4s? They describe the traffic-engineering information needed for CSPF. They are flooded throughout the entire OSPF domain just like LSA type 5s. They are only flooded throughout one area. They are allowed in every area type, including stub areas.
A7:	C. They are only flooded throughout one area. LSA type 4s are ASBR summary LSAs. They are used to indicate a path to an ASBR much like an LSA type 3. Summary LSA indicates a path to an inter-area network. They have nothing to do with traffic engineering and are only flooded throughout a single area. They are originated by ABRs and are not allowed in stub areas, just like LSA type 5s. See RFC 2328 Section 12.4.3.
8:	When a BGP route has the no_export community added to it, what effect does that have on the route? A router will never advertise a no_export route to any of its neighbors. A router will never allow a no_export route to be exported into an IGP. A router will never allow a no_export route to leave the sub_as within a confederation. A router will never allow a no_export route to leave the AS (or confederation, if confederations are used).
A8:	D. A router will never allow a no_export route to leave the AS (or confederation, if confederations are used). There are a number of well-defined communities that can be used to indicate with whom a route should be distributed. The no_export community indicates that a route should not leave the confederation (or AS if confederations aren't used).
9:	MSDP is used to link the domains of which protocol? MOSPF IS-IS DVMRP PIM
A9:	D. PIM MSDP is used to interconnect PIM routing domains. Two MSDP routers establish adjacencies similar to EBGP. Multicast source information is then transferred back and forth between the two PIM domains.
10:	What is true about the BGP path attribute Local Preference ? The lower the number, the more preferred the route. It can be used to affect the routing of peer-AS s. It can only be used to affect your local-AS . It can only be used to affect the routing of the local router.
A10:	C. It can only be used to affect your local-AS . Local Preference is a BGP attribute that is shared within an AS. The higher the local preference, the more preferred the route is. It does not leave the AS, but it is shared between all members of the AS.
11:	While monitoring an RSVP session, you notice that one of your routers is periodically sending a PATH message. What is the likely cause of this? Your link is flapping. Your bandwidth allocation is changing too frequently. This is standard RSVP behavior. Your LSP never initialized correctly.
A11:	C. This is standard RSVP behavior. In a correctly functioning network, RSVP will send PATH messages every 30 seconds (the default refresh time) to maintain the state of the LSP. Without these periodic PATH messages, the LSP would age out and be removed by all the routers in the path.
12:	What command must be used to cause an ABR of a stub area to inject a default LSA type 3 route into an area? No command is necessary; this is done by default Stub default-metric Stub generate-default Stub summary
A12:	B. Stub default-metric Juniper Networks stub ABRs do not automatically inject a default LSA type 3 into the area. To generate this LSA you must use the default-metric command and specify a metric to be used for the LSA.
13:	If you have a route to the same destination from the following four sources, which will be picked? OSPF External route IS-IS Level 1 External route BGP RIP
A13:	D. RIP Of the IGPs, RIP has the worst preference value (100); however, external routes from OSPF and IS-IS level 1 have worse preference than RIP does (150 and 160 respectively). BGP has the worst of all: 170. The lower the preference, the more preferred the protocol.
14:	What is the default encapsulation on a SONET link? PPP Cisco-HDLC Frame-Relay Juniper-HDLC
A14:	A. PPP The default encapsulation on a SONET link is PPP. There is no Juniper-HDLC.
15:	Two Juniper Networks routers are advertising their presence via IRDP (ICMP router discovery protocol). Router A is using the default preference and router B is using a preference of 50. Which router will become the default router for the network? Router A Router B Neither They will load balance
A15:	B. Router B The default preference value for IRDP is 0 and the default router is determined by which router has the greatest preference. In this case router A has a preference of 0 (the default preference) and router B has a preference of 50, so router B will become the default router.
16:	You have an AS-Path of 65425 65126 4285 196 . In your external peering session, you have remove-private configured. Which AS-Path will be advertised to the external peer? 65425 65126 4285 196 65126 4285 196 4285 196 65425 65126
A16:	C. 4285 196 The remove-private command will strip the private ASNs off of the AS-Path before transmitting the path information to the external neighbor.
17:	What is the default half-life value for route dampening ? 10 15 20 40 50
A17:	B. 15 Route dampening is used to limit the disturbance caused by flapping routes. Every time a route flaps, it will be penalized by having its figure of metric added to. Once its figure of metric reaches a certain level, the route will be suppressed. The route will not be eligible for use until the figure of metric has been lowered below the reuse level. After every half-life elapses, the figure of metric will be cut in half. The default is 15 minutes.
18:	What is the result of the following configuration statement: set system ntp boot-server 192.168.20.1 Tells the system to advertise the address 192.168.20.1 as a boot server Tells the system to synchronize its time with the NTP time server at address 192.168.20.1 when the router boots Tells the system to only allow host 192.168.20.1 to connect to the boot server Provides NTP relay processes and directs all NTP messages to 192.168.20.1
A18:	B. Tells the system to synchronize its time with the time server at address 192.168.20.1 when the router boots It sets a designated server to provide a time to the router when it boots. At boot, the router issues an ntpdate request, which polls the network server to determine the local date and time.
19:	Juniper Networks routers consist of two main units. They are Packet forwarding engine (PFE) Routing engine Packet forwarding module (PFM) Central routing unit (CRU) Forwarding engine module (FEM) Routing table manager (RTM)
A19:	A. Packet forwarding engine (PFE) B. Routing engine Juniper Networks routers consist of two main units that are interconnected . These units are the PFE, which forwards traffic through the interfaces and does route lookups, and the routing engine, which handles router management and protocol management and contains the storage devices (Flash drive and hard drive).
20:	The inet.3 routing table is used for Default unicast routing table Unicast routing table for a particular routing-instance Multicast forwarding cache Unicast routes used for multicast reverse-path-forwarding RPF lookup MPLS routing table for path information MPLS routing table for label-switched path (LSP) next-hops
A20:	E. MPLS routing table for path information The inet.3 routing table contains MPLS LSP information.
21:	Which of the following will match this routing-policy statement: route-filter 192.168.231.0/24 exact 192.168.231.0 192.168.231.0/16 192.168.231.0/30 192.168.231.0/24
A21:	D. 192.168.231.0/24 The exact statement requires that the prefix length be exactly 24 bits; therefore the /16 and /30 routes would not fit this description. Even though 192.168.231.20 is a Class C network address, there is no prefix length associated with it, so a default prefix of /32 is assumed. Therefore the /32 does not match the filter rules.
22:	Which of the following matches the AS regular expression ( 1485 193+ 425? 1226*.) ? 1485 193 193 482 1485 193 425 1226 485 193 1226 1485 425 1356
A22:	A. 1485 193 193 482 B. 1485 193 425 1226 485 1485 must be present. 193+ means 1 or more repetition of 193, so at least 1 instance of 193 must be present. 425? means 0 or 1 repetitions of 425, so it can be present or missing. 1226* means 0 or more repetitions of 1226, so it can be present or missing. The . signifies that there must be a term following the previous terms, but it doesn't matter what it is.
23:	Where would you specify SDH framing for a SONET interface? At the [interface so-x/y/z sonet-options] level At the [interface so-x/y/z] level At the [chassis fpc (slot-number) pic (pic-number)] level At the [chassis fpc (slot-number)] level
A23:	C. At the [chassis fpc (slot-number) pic (pic-number)] level SONET framing is set at the [chassis fpc (slot) pic (pic)] level of the configuration. [edit chassis] user@host# set fpc slot-number pic pic-number framing sdh
24:	Which version(s) of RSVP are supported by Juniper (up to v5.4)? RSVPv1 RSVPv2 RSVPv1 and v2 RSVP support was not added until JUNOS 5.0
A24:	A. RSVPv1 JUNOS currently supports RSVPv1 only (up through v4.4). Future implementations may change the level of RSVP support.
25:	In what mode must PIM be running for auto-rp to function (assuming you have not configured a static RP)? Sparse mode Dense mode Sparse-dense mode Multicast mode
A25:	C. Sparse-dense mode In order for auto-rp to function, the router must be operating in sparse-dense mode. This allows the control traffic to reach the router via the dense groups 224.0.1.39 and 224.0.1.40 , while allowing the rest of the groups to remain in static mode as long as they have an RP dynamically configured for them. Another option would be to leave the router in sparse mode and statically configure an RP for the 224.0.1.3 9 and 224.0.1.40 multicast groups.
26:	Router A receives an MPLS encapsulated packet with a label of 100020, which is not included in the routing table. What does router A do with the packet? Checks second to top label; if recognized, forwards accordingly Drops the packet Removes label stack and forwards according to the network address Creates a new label and forwards to all routers
A26:	B. Drops the packet When an LSR does not recognize the top label of a label stack, it will drop the packet.
27:	If a firewall filter is defined on an interface and a packet does not match any of the terms, what action is taken? The packet is accepted. The packet is discarded. The packet is rejected. The packet is stored.
A27:	B. The packet is discarded. The default action for a firewall filter is to discard all packets that do not match any of the defined terms. The difference between discarding and rejecting a packet is that discard is a silent discard ”no ICMP message is returned ”but reject causes an ICMP "Destination Unreachable" message to be returned.
28:	If traffic-engineering bgp is enabled for MPLS, and there are two routes to the next-hop, one in inet.0 and one in inet.3 , that have equal preference, which next-hop will be chosen? inet.0 inet.3 They will be load balanced This will be randomly determined
A28:	B. inet.3 The traffic-engineering bgp command causes routes to MPLS LSPs to be installed in the inet.3 routing table only. When selecting next-hop, BGP always gives preference to routes in inet.3 when they are equal to routes in inet.0 .
29:	MPLS provides what type of functioning to a router? Multiprotocol Label Switching functionality Multiple Protocol Layered System Switch-like forwarding capabilities in a router A system for running multiple protocols on a router
A29:	A. Multiprotocol Label Switching functionality C. Switch-like forwarding capabilities in a router MPLS stands for multiprotocol label switching, which is a label switching function on a router. It is designed to provide switch-like forwarding capabilities on a router where forwarding decisions are based on labels rather than IP-route lookup information.
30:	Which Juniper Networks routers support redundant routing engines? M5 M10 M20 M40 M160
A30:	C. M20 E. M160 Only the M20 and M160 support redundant routing engines.