Juniper Juniper Certifications JN0-361 Questions & Answers

• Question 211:

  Click the Exhibit button.

  

  Which two statements are true regarding the output shown in the exhibit? (Choose two.)

  A. The ge-1/0/0 interface will transmit any outgoing frames associated with VLAN 55 as untagged frames.

  B. The ge-1/0/0 interface will associate any untagged frames that are received with VLAN 56.

  C. The ge-1/0/0 interface will associate any untagged frames that are received with VLAN 55.

  D. The ge-1/0/0 interface will transmit any outgoing frames associated with VLAN 56 as untagged frames.

  Correct Answer: BD

  *

  You can configure the router to receive and forward single-tag frames, dual-tag frames, or a mixture of

  single-tag and dual-tag frames. To configure the router to receive and forward single-tag frames with

  802.1Q VLAN tags, include the vlan-tagging statement at the [edit interfaces interface-name] hierarchy

  level:

  [edit interfaces interface-name]

  vlan-tagging;

  *

  You can configure mixed tagging support for untagged packets on a port. Untagged packets are

  accepted on the same mixed VLAN-tagged port. To accept untagged packets, include the native-vlan-id

  statement and the flexible-vlan-tagging statement at the [edit interfaces interface-name] hierarchy level:

  [edit interfaces ge-fpc/pic/port] flexible-vlan-tagging; native-vlan-id number;

  References: https://www.juniper.net/documentation/en_US/junos15.1/topics/usage-guidelines/interfacesenabling-vlan-tagging.html https://www.juniper.net/documentation/en_US/junos12.1x44/topics/concept/ security-interface-vlan-tagging-configuring.html

• Question 212:

  An IS-IS TLV includes which two attributes? (Choose two.)

  A. topology

  B. vector

  C. length

  D. value

  Correct Answer: CD

  Within data communication protocols, optional information may be encoded as a type-length-value or TLV element inside a protocol. TLV is also known as tag-length-value.

  The type and length are fixed in size (typically 1-4 bytes), and the value field is of variable size. These

  fields are used as follows: Type. A binary code, often simply alphanumeric, which indicates the kind of field that this part of the message represents;

  Length. The size of the value field (typically in bytes);

  Value. Variable-sized series of bytes which contains data for this part of the message.

  References: https://en.wikipedia.org/wiki/Type-length-value

• Question 213:

  An IS-IS router on a broadcast medium has detected its LSDB is missing an LS PDU.

  Which action will the router take?

  A. The router will send a CSNP to the router that sent it a PSNP with missing PDUs.

  B. The router will send a link-state request packet to its closest Level 1/Level2 router.

  C. The router will send a PSNP to the router that sent it a CSNP with missing PDUs.

  D. The router will send a link-state request packet to its DIS router.

  Correct Answer: C

  A Partial SNP (PSNP) is similar to CSNP except that it describes only some LSPs rather than the entire database. On a P2P network, PSNP is used to acknowledge received LSPs. On a LAN network, PSNP is used to request missing or latest LSPs.

  Incorrect Answers:

  A: IS-IS Sequence Number PDU (SNP)

  SNPs are used to maintain IS-IS LSDB by describing some or all of the LSPs in the database. The DIS

  periodically multicast Complete SNP (CSNP) to describe all the LSPs in the Pseudonode database.

  References: https://sites.google.com/site/amitsciscozone/home/is-is/is-is-packets

• Question 214:

  How many bytes does IP-IP tunneling add to an IP packet?

  A. 20

  B. 24

  C. 16

  D. 28

  Correct Answer: A

  Tunneling increases overhead, because it needs an extra set of IP headers. Typically this is 20 bytes per packet, so if the normal packet size (MTU) on a network is 1500 bytes, a packet that is sent through a tunnel can only be 1480 bytes big.

  References: http://cs.uccs.edu/~scold/iptunnel.htm

• Question 215:

  You are adding IPv6 to an existing IPv4 network running OSPF. Your plan is to use OSPFv3 to route both

  IPv4 and IPv6 prefixes.

  Which configuration will enable OSPFv3 to advertise prefixes for both IPv4 and IPv6?

  A. user@host# show protocols ospf3 realm ipv4-unicast { area 0.0.0.0 { interface ge-0/0/0.0; } } area 0.0.0.0 { interface ge-0/0/0.0; }

  B. user@host# show protocols ospf3 export ipv4; area 0.0.0.0 { interface ge-0/0/0.0; }

  C. user@host# show protocols ospf area 0.0.0.0 { interface ge-0/0/0.0; } user@host# show protocols ospf3 area 0.0.0.0 { interface ge-0/0/0.0; }

  D. user@host# show protocols ospf3 rib-group inet.0; area 0.0.0.0 { interface ge-0/0/0.0; }

  Correct Answer: A

  By default, OSPFv3 supports unicast IPv6 routes, but you can configure OSPFv3 to support multiple

  address families. To support an address family other than unicast IPv6, you configure a realm that allows

  OSPFv3 to advertise IPv4 unicast, IPv4 multicast, or IPv6 multicast routes.

  Example of a configuration which support both Ipv4 and Ipv6 prefixes:

  user@host# show protocols ospf3

  realm ipv4-unicast {

  area 0.0.0.0 {

  interface fe-0/1/0.0;

  }

  }

  area 0.0.0.0 {

  interface fe-0/1/0.0;

  }

  References: http://www.juniper.net/documentation/en_US/junos15.1/topics/topic-map/ospfv3-multipleaddress-families.html

• Question 216:

  In an RSVP-based MPLS network, which ERO type specifies the exact order of routers through which an LSP must travel, without consulting the IGP?

  A. loose hop

  B. static hop

  C. next hop

  D. strict hop

  Correct Answer: D

  When a strict hop is configured, it identifies an exact path through which the LSP must be routed. Strict-hop EROs (Explicit Route Objects) specify the exact order of the routers through which the RSVP messages are sent.

  Incorrect Answers:

  A: When a loose hop is configured, it identifies one or more transit LSRs through which the LSP must be

  routed.

  The network IGP determines the exact route from the inbound router to the first loose hop, or from one

  loose hop to the next.

  The loose hop specifies only that a particular LSR be included in the LSP.

  References: https://forums.juniper.net/t5/Routing/loose-and-strict-option/td-p/164626

• Question 217:

  What are three well-known mandatory BGP attributes? (Choose three.)

  A. origin

  B. MED

  C. AS path

  D. next hop

  E. local preference

  Correct Answer: ACD

  ORIGIN is a well known mandatory attribute that indicates the origin of the prefix, or rather, the way in

  which the prefix was injected into BGP.

  The AS_PATH is a well-known mandatory attribute.

  The BGP NEXT_HOP is a well-known mandatory attribute.

  References: http://www.informit.com/articles/article.aspx?p=331613andseqNum=5

• Question 218:

  Your customer requests that you provide a transparent Layer 2 service between two of their remote locations. This service must allow the customer to pass tagged traffic from multiple VLANs. You decide to use Q-in-Q tunneling on the two provider edge MX Series routers that connect to the customer's CE devices.

  Which two statements are true? (Choose two.)

  A. As traffic enters the Q-in-Q tunnel on the core-facing interface on the ingress PE device, a push operation is performed.

  B. As traffic passes through intermediary P routers in the Q-in-Q tunnel, a push operation is performed.

  C. As traffic passes through intermediary P routers in the Q-in-Q tunnel, a swap operation is performed.

  D. As traffic enters the Q-in-Q tunnel on the core-facing interface on the ingress PE device, a swap operation is performed.

  Correct Answer: AC

  Q-in-Q tunneling adds a service VLAN tag before the customer's 802.1Q VLAN tags. The Juniper Networks Junos operating system implementation of Q-in-Q tunneling supports the IEEE 802.1ad standard. In Q-in-Q tunneling, as a packet travels from a customer VLAN (C-VLAN) to a service provider's or data center VLAN (S-VLAN), another 802.1Q tag for the appropriate S-VLAN is added before the CVLAN tag. The C-VLAN tag remains and is transmitted through the network. As the packet leaves the SVLAN in the downstream direction, the S-VLAN 802.1Q tag is removed.

  With the push option, a packet retains its tag and an additional VLAN tag is added.

  With the swap option, the incoming tag is replaced with an S-VLAN tag. (This is VLAN translation.)

  References: https://www.juniper.net/documentation/en_US/junos12.3/topics/concept/qinq-tunneling-qfxseries.html

• Question 219:

  Click the Exhibit button.

  

  Referring to the exhibit, which two statements are correct? (Choose two.)

  A. Type 2 LSAs are not created for this link.

  B. Type 2 LSAs are created for this link.

  C. Designated router election does not occur on this link.

  D. Designated router election occurs on this link.

  Correct Answer: AC

  A: Type 2 - Network LSA - the designated router (DR) on a broadcast segment (e.g. Ethernet) lists which routers are joined together by the segment. Type 2 LSAs are flooded across their own area only. The link-state ID of the type 2 LSA is the IP interface address of the DR.

  C: Designated router (DR) and BDR election is done via the Hello protocol. Hello packets are exchanged via IP multicast packets (Appendix B) on each segment. Multicast packets are not sent on p2p links.

  References: https://en.wikipedia.org/wiki/Link-state_advertisement http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html#t21

• Question 220:

  What are three IS-IS PDU types? (Choose three.)

  A. type length value

  B. link-state

  C. partial sequence number

  D. database description

  E. complete sequence number

  Correct Answer: BCE