Oct-2023 FREE Juniper JN0-664 PRACTICE QUESTIONS AND ANSWERS UPDATES
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NEW QUESTION # 37
You are responding to an RFP for a new MPLS VPN implementation. The solution must use LDP for signaling and support Layer 2 connectivity without using BGP The solution must be scalable and support multiple VPN connections over a single MPLS LSP The customer wants to maintain all routing for their Private network In this scenario, which solution do you propose?
- A. BGP Layer 2 VPN
- B. LDP Layer 2 circuit
- C. circuit cross-connect
- D. translational cross-connect
Answer: B
Explanation:
Explanation
AToM (Any Transport over MPLS) is a framework that supports various Layer 2 transport types over an MPLS network core. One of the transport types supported by AToM is LDP Layer 2 circuit, which is a point-to-point Layer 2 connection that uses LDP for signaling and MPLS for forwarding. LDP Layer 2 circuit can support Layer 2 connectivity without using BGP and can be scalable and efficient by using a single MPLS LSP for multiple VPN connections. The customer can maintain all routing for their private network by using their own CE switches.
NEW QUESTION # 38
You are configuring a BGP signaled Layer 2 VPN across your MPLS enabled core network. Your PE-2 device connects to two sites within the s VPN In this scenario, which statement is correct?
- A. You must create a unique Layer 2 VPN routing instance for each site on the PE-2 device.
- B. By default on PE-2, the remote site IDs are automatically assigned based on the order that you add the interfaces to the site configuration.
- C. By default on PE-2, the site's local ID is automatically assigned a value of 0 and must be configured to match the total number of attached sites.
- D. You must use separate physical interfaces to connect PE-2 to each site.
Answer: B
Explanation:
Explanation
BGP Layer 2 VPNs use BGP to distribute endpoint provisioning information and set up pseudowires between PE devices. BGP uses the Layer 2 VPN (L2VPN) Routing Information Base (RIB) to store endpoint provisioning information, which is updated each time any Layer 2 virtual forwarding instance (VFI) is configured. The prefix and path information is stored in the L2VPN database, which allows BGP to make decisions about the best path.
In BGP Layer 2 VPNs, each site has a unique site ID that identifies it within a VFI. The site ID can be manually configured or automatically assigned by the PE device. By default, the site ID is automatically assigned based on the order that you add the interfaces to the site configuration. The first interface added to a site configuration has a site ID of 1, the second interface added has a site ID of 2, and so on.
Option D is correct because by default on PE-2, the remote site IDs are automatically assigned based on the order that you add the interfaces to the site configuration. Option A is not correct because by default on PE-2, the site's local ID is automatically assigned a value of 0 and does not need to be configured to match the total number of attached sites. Option B is not correct because you do not need to create a unique Layer 2 VPN routing instance for each site on the PE-2 device. You can create one routing instance for all sites within a VFI. Option C is not correct because you do not need to use separate physical interfaces to connect PE-2 to each site. You can use subinterfaces or service instances on a single physical interface.
NEW QUESTION # 39
Which two statements about IS-IS are correct? (Choose two.)
- A. CSNPs contain only descriptions of LSPs.
- B. PSNPs are flooded periodically.
- C. CSNPs are flooded periodically
- D. PSNPs contain only descriptions of LSPs.
Answer: C,D
Explanation:
Explanation
IS-IS is an interior gateway protocol that uses link-state routing to exchange routing information among routers within a single autonomous system. IS-IS uses two types of packets to synchronize link-state databases among routers: Link State Packets (LSPs) and Partial Sequence Number Packets (PSNPs). LSPs contain information about the state and cost of links in the network, and are flooded periodically throughout the network. PSNPs are used to acknowledge receipt of LSPs and request retransmission of missing or corrupted LSPs. PSNPs contain only descriptions of LSPs, such as their sequence numbers and checksums3. IS-IS also uses another type of packet called Complete Sequence Number Packets (CSNPs), which are used to summarize the entire link-state database at regular intervals or when a new adjacency is formed. CSNPs are flooded periodically throughout the network and contain only descriptions of LSPs4. Therefore, PSNPs contain only descriptions of LSPs and CSNPs are flooded periodically.
References: 3:
https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/concept/routing-policy-is-is-p
4:
https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/concept/routing-policy-is-is-c
NEW QUESTION # 40
Exhibit
Referring to the exhibit, a working L3VPN exists that connects VPN-A sites CoS is configured correctly to match on the MPLS EXP bits of the LSP, but when traffic is sent from Site-1 to Site-2, PE-2 is not classifying the traffic correctly What should you do to solve the problem?
- A. Configure the explicit-null statement on PE-2
- B. Set a static CoS value for the PE-1_to_PE-2 LSP
- C. Configure VPN prefix mapping for the PE-1_to_PE-2 LSP
- D. Configure the explicit-null statement on PE-1.
Answer: D
Explanation:
Explanation
The explicit-null statement enables the PE router to send an MPLS label with a value of 0 (explicit null) instead of an IP header for packets destined to the VPN customer sites. This allows the penultimate hop router (the router before the egress PE router) to preserve the EXP bits of the MPLS label and pass them to the egress PE router. The egress PE router can then use these EXP bits to classify the traffic according to the CoS policy2
. In this example, PE-1 should configure the explicit-null statement under [edit protocols mpls label-switched-path PE-1_to_PE-2] hierarchy level.
NEW QUESTION # 41
Exhibit
Referring to the exhibit, which three statements are correct about route 10 0 0.0/16 when using the default BGP advertisement rules'? (Choose three.)
- A. R4 will advertise 10 0.0 0/16 to R6 with 172.16 1 1 as the next hop
- B. R1 will advertise 10.0.0.0/16 to R2 with 192 168 1 1 as the next hop.
- C. R1 will prepend AS 65531 when advertising 10 0.0 0/16 to R2.
- D. R2 will advertise 10.0.0.0/16 to R3 with 192.168.1 1 as the next hop
- E. R2 will advertise 10.0.0.0/16 to R4 with 172.16.1.1 as the next hop
Answer: A,B,E
Explanation:
Explanation
The problem in this scenario is that R1 and R8 are not receiving each other's routes because of private AS numbers in the AS path. Private AS numbers are not globally unique and are not advertised to external BGP peers. To solve this problem, you need to do the following:
* Configure loops on routers in AS 65412 and advertise-peer-as on routers in AS 64498. This allows R5 and R6 to advertise their own AS number (65412) instead of their peer's AS number (64498) when sending updates to R7 and R8. This prevents a loop detection issue that would cause R7 and R8 to reject the routes from R5 and R62
* Configure remove-private on advertisements from AS 64497 toward AS 64498 and from AS 64500 toward AS 64499. This removes any private AS numbers from the AS path before sending updates to external BGP peers. This allows R2 and R3 to receive the routes from R1 and R4, respectively3.
NEW QUESTION # 42
Exhibit
You are running a service provider network and must transport a customer's IPv6 traffic across your IPv4-based MPLS network using BGP You have already configured mpis ipv6-tunneling on your PE routers.
Which two statements are correct about the BGP configuration in this scenario? (Choose two.)
- A. You must configure family inet6 add-path between PE and CE routers.
- B. You must configure family inet6 unicast between PE routers
- C. You must configure family inet6 labcled-unicast between PE routers.
- D. You must configure family inet6 unicaat between PE and CE routers.
Answer: C,D
Explanation:
Explanation
To transport IPv6 traffic over an IPv4-based MPLS network using BGP, you need to configure two address families: family inet6 labeled-unicast and family inet6 unicast. The former is used to exchange IPv6 routes with MPLS labels between PE routers, and the latter is used to exchange IPv6 routes without labels between PE and CE routers. The mpis ipv6-tunneling command enables the PE routers to encapsulate the IPv6 packets with an MPLS label stack and an IPv4 header before sending them over the MPLS network.
NEW QUESTION # 43
You are a network architect for a service provider and want to offer Layer 2 services to your customers You want to use EVPN for Layer 2 services in your existing MPLS network.
Which two statements are correct in this scenario? (Choose two.)
- A. VXLAN must be configured on all PE routers.
- B. EVPN uses Type 3 routes to join a multicast tree to flood traffic.
- C. Segment routing must be configured on all PE routers.
- D. EVPN uses Type 2 routes to advertise MAC address and IP address pairs learned using ARP snooping
Answer: B,D
Explanation:
Explanation
EVPN is a technology that connects L2 network segments separated by an L3 network using a virtual Layer 2 network overlay over the Layer 3 network. EVPN uses BGP as its control protocol to exchange different types of routes for different purposes. Type 2 routes are used to advertise MAC address and IP address pairs learned using ARP snooping from the local CE devices. Type 3 routes are used to join a multicast tree to flood traffic such as broadcast, unknown unicast, and multicast (BUM) traffic.
NEW QUESTION # 44
After a recent power outage, your manager asks you to investigate ways to automatically reduce the impact caused by suboptimal routing in your OSPF and OSPFv3 network after devices reboot.
Which three configuration statements accomplish this task? (Choose three.)
- A. set protocols ospf3 overload
- B. set protocols ospf overload
- C. set protocols oapf3 overload timeout 900
- D. set protocols ospf overload timeout 900
- E. set protocols ospf3 realm ipv4-unicast overload timeout 900
Answer: A,D
Explanation:
Explanation
To reduce the impact of suboptimal routing in OSPF and OSPFv3 after devices reboot, you can use the overload feature to prevent a router from being used as a transit router for a specified period of time. This allows the router to stabilize its routing table before forwarding traffic for other routers. To enable the overload feature, you need to do the following:
* For OSPF, configure the overload statement under [edit protocols ospf] hierarchy level. You can also specify a timeout value in seconds to indicate how long the router should remain in overload state after it boots up. For example, set protocols ospf overload timeout 900 means that the router will be in overload state for 15 minutes after it boots up.
* For OSPFv3, configure the overload statement under [edit protocols ospf3] hierarchy level. You can also specify a realm (ipv4-unicast or ipv6-unicast) and a timeout value in seconds to indicate how long the router should remain in overload state after it boots up for each realm. For example, set protocols ospf3 realm ipv4-unicast overload timeout 900 means that the router will be in overload state for 15 minutes after it boots up for IPv4 unicast routing.
NEW QUESTION # 45
Exhibit
You want to implement the BGP Generalized TTL Security Mechanism (GTSM) on the network Which three statements are correct in this scenario? (Choose three)
- A. BGP GTSM requires a TTL of 255 to be configured between neighbors.
- B. You can implement BGP GTSM between R2 and R1.
- C. BGP GTSM requires a TTL of 1 to be configured between neighbors.
- D. BGP GTSM requires a firewall filter to discard packets with incorrect TTL.
- E. You can implement BGP GTSM between R2, R3, and R4
Answer: A,C,E
Explanation:
Explanation
BGP GTSM is a technique that protects a BGP session by comparing the TTL value in the IP header of incoming BGP packets against a valid TTL range. If the TTL value is within the valid TTL range, the packet is accepted. If not, the packet is discarded. The valid TTL range is from 255 - the configured hop count + 1 to
255. When GTSM is configured, the BGP packets sent by the device have a TTL of 255. GTSM provides best protection for directly connected EBGP sessions, but not for multihop EBGP or IBGP sessions because the TTL of packets might be modified by intermediate devices.
In the exhibit, we can see that R2, R3, and R4 are in the same AS (AS 20) and R1 is in a different AS (AS 10).
Based on this information, we can infer the following statements:
* You can implement BGP GTSM between R2, R3, and R4. This is not correct because R2, R3, and R4 are IBGP peers and GTSM does not provide effective protection for IBGP sessions. The TTL of packets between IBGP peers might be changed by intermediate devices or routing protocols.
* BGP GTSM requires a firewall filter to discard packets with incorrect TTL. This is not correct because BGP GTSM does not require a firewall filter to discard packets with incorrect TTL. BGP GTSM uses TCP option 19 to negotiate GTSM capability between peers and uses TCP option 20 to carry the expected TTL value in each packet. The receiver checks the expected TTL value against the actual TTL value and discards packets with incorrect TTL values.
* You can implement BGP GTSM between R2 and R1. This is correct because R2 and R1 are EBGP peers and GTSM provides effective protection for directly connected EBGP sessions. The TTL of packets between directly connected EBGP peers is not changed by intermediate devices or routing protocols.
* BGP GTSM requires a TTL of 1 to be configured between neighbors. This is not correct because BGP GTSM requires a TTL of 255 to be configured between neighbors. The sender sets the TTL of packets to 255 and the receiver expects the TTL of packets to be 255 minus the configured hop count.
* BGP GTSM requires a TTL of 255 to be configured between neighbors. This is correct because BGP GTSM requires a TTL of 255 to be configured between neighbors. The sender sets the TTL of packets to 255 and the receiver expects the TTL of packets to be 255 minus the configured hop count.
NEW QUESTION # 46
Which two statements are correct about VPLS tunnels? (Choose two.)
- A. BGP-signaled VPLS tunnels can use either RSVP or LDP between the PE routers.
- B. BGP-signaled VPLS tunnels require manual provisioning of sites.
- C. LDP-signaled VPLS tunnels use auto-discovery to provision sites
- D. LDP-signaled VPLS tunnels only support control bit 0.
Answer: A,C
Explanation:
Explanation
VPLS is a Layer 2 VPN technology that allows multiple sites to connect over a shared IP/MPLS network as if they were on the same LAN. VPLS tunnels can be signaled using either Label Distribution Protocol (LDP) or Border Gateway Protocol (BGP). LDP-signaled VPLS tunnels use auto-discovery to provision sites, meaning that PE routers can automatically discover other PE routers that belong to the same VPLS instance
NEW QUESTION # 47
Exhibit
The environment is using BGP All devices are in the same AS with reachability redundancy Referring to the exhibit, which statement is correct?
- A. Client1 is peered to Client2 and Client3.
- B. Peering is dynamically discovered between all devices.
- C. RR1 is peered to Client2 and RR2
- D. RR2 is in an OpenConfirm State until RR1 becomes unreachable.
Answer: C
Explanation:
Explanation
BGP route reflectors are BGP routers that are allowed to ignore the IBGP loop avoidance rule and advertise IBGP learned routes to other IBGP peers under specific conditions. BGP route reflectors can reduce the number of IBGP sessions and updates in a network by eliminating the need for a full mesh of IBGP peers.
BGP route reflectors can have three types of peerings:
* EBGP neighbor: A BGP router that belongs to a different autonomous system (AS) than the route reflector.
* IBGP client neighbor: An IBGP router that receives reflected routes from the route reflector. A client does not need to peer with other clients or non-clients.
* IBGP non-client neighbor: An IBGP router that does not receive reflected routes from the route reflector. A non-client needs to peer with other non-clients and the route reflector.
In the exhibit, we can see that RR1 and RR2 are route reflectors in the same AS with reachability redundancy.
They have two types of peerings: EBGP neighbors (R1 and R4) and IBGP client neighbors (Client1, Client2, and Client3). RR1 and RR2 are also peered with each other as IBGP non-client neighbors.
NEW QUESTION # 48
Exhibit
Referring to the exhibit, PIM-SM is configured on all routers, and Anycast-RP with Anycast-PIM is used for the discovery mechanism on RP1 and RP2. The interface metric values are shown for the OSPF area.
In this scenario, which two statements are correct about which RP is used? (Choose two.)
- A. Source2 will use RP2 and Received will use RP2 for group 224.2.2.2.
- B. Source2 will use RP1 and Receiver2 will use RP1 for group 224.2.2.2.
- C. Source1 will use RP1 and Receiver1 will use RP2 for group 224.1 1 1
- D. Source1 will use RP1 and Receiver1 will use RP1 for group 224.1.1.1.
Answer: A,D
Explanation:
Explanation
A sham link is a logical link between two PE routers that belong to the same OSPF area but are connected through an L3VPN. A sham link makes the PE routers appear as if they are directly connected, and prevents OSPF from preferring an intra-area back door link over the VPN backbone. A sham link creates an OSPF multihop neighborship between the PE routers using TCP port 646. The PEs exchange Type 1 OSPF LSAs instead of Type 3 OSPF LSAs for the L3VPN routes, which allows OSPF to use the correct metric for route selection1.
NEW QUESTION # 49
You are asked to protect your company's customers from amplification attacks. In this scenario, what is Juniper's recommended protection method?
- A. ASN prepending
- B. destination-based Remote Triggered Black Hole
- C. unicast Reverse Path Forwarding
- D. BGP FlowSpec
Answer: B
Explanation:
Explanation
amplification attacks are a type of distributed denial-of-service (DDoS) attack that exploit the characteristics of certain protocols to amplify the traffic sent to a victim. For example, an attacker can send a small DNS query with a spoofed source IP address to a DNS server, which will reply with a much larger response to the victim. This way, the attacker can generate a large amount of traffic with minimal resources.
One of the methods to protect against amplification attacks is destination-based Remote Triggered Black Hole (RTBH) filtering. This technique allows a network operator to drop traffic destined to a specific IP address or prefix at the edge of the network, thus preventing it from reaching the victim and consuming bandwidth and resources. RTBH filtering can be implemented using BGP to propagate a special route with a next hop of
192.0.2.1 (a reserved address) to the edge routers. Any traffic matching this route will be discarded by the edge routers.
NEW QUESTION # 50
In IS-IS, which two statements are correct about the designated intermediate system (DIS) on a multi-access network segment? (Choose two)
- A. A router with a priority of 1 wins the DIS election over a router with a priority of 10.
- B. On the multi-access network, each router only forms an adjacency to the DIS.
- C. On the multi-access network, each router forms an adjacency to every other router on the segment
- D. A router with a priority of 10 wins the DIS election over a router with a priority of 1.
Answer: B,D
Explanation:
Explanation
In IS-IS, a designated intermediate system (DIS) is a router that is elected on a multi-access network segment (such as Ethernet) to perform some functions on behalf of other routers on the same segment. A DIS is responsible for sending network link-state advertisements (LSPs), which describe all the routers attached to the network. These LSPs are flooded throughout a single area. A DIS also generates pseudonode LSPs, which represent the multi-access network as a single node in the link-state database. A DIS election is based on the priority value configured on each router's interface connected to the multi-access network. The priority value ranges from 0 to 127, with higher values indicating higher priority. The router with the highest priority becomes the DIS for the area (Level 1, Level 2, or both). If routers have the same priority, then the router with the highest MAC address is elected as the DIS. By default, routers have a priority value of 64. On a multi-access network, each router only forms an adjacency to the DIS, not to every other router on the segment. This reduces the amount of hello packets and LSP
NEW QUESTION # 51
Exhibit
You are attempting to summarize routes from the 203.0.113.128/25 IP block on R8 to AS 64500. You implement the export policy shown in the exhibit and all routes from the routing table stop being advertised.
In this scenario, which two steps would you take to summarize the route in BGP? (Choose two.)
- A. Replace exact in the export policy with orlonger.
- B. Add the set protocols bgp family inet unicast add-path command to allow additional routes to the RIB tables. -
- C. Add the set routing-options static route 203.0.113.123/25 discard command.
- D. Remove the from protocol bgp command from the export policy.
Answer: A,C
Explanation:
Explanation
To summarize routes from the 203.0.113.128/25 IP block on R8 to AS 64500, you need to do the following:
* Add the set routing-options static route 203.0.113.128/25 discard command. This creates a static route for the summary prefix and discards any traffic destined to it. This is necessary because BGP can only advertise routes that are present in the routing table.
* Replace exact in the export policy with orlonger. This allows R8 to match and advertise any route that is equal or more specific than the summary prefix. The exact term only matches routes that are exactly equal to the summary prefix, which is not present in the routing table.
NEW QUESTION # 52
Exhibit
The network shown in the exhibit is based on IS-IS
Which statement is correct in this scenario?
- A. The routers are using unnumbered interfaces
- B. The system IDofR1_2 is 192.168.16.1
- C. The area address is two bytes.
- D. The NSEL byte for Area 0001 is 00.
Answer: D
Explanation:
Explanation
IS-IS is an interior gateway protocol that uses link-state routing to exchange routing information among routers within a single autonomous system. IS-IS uses two types of addresses to identify routers and areas:
system ID and area address. The system ID is a unique identifier for each router in an IS-IS domain. The system ID is 6 octets long and can be derived from the MAC address or manually configured. The area address is a variable-length identifier for each area in an IS-IS domain. The area address can be 1 to 13 octets long and is composed of high-order octets of the address. An IS-IS instance may be assigned multiple area addresses, which are considered synonymous. Multiple synonymous area addresses are useful when merging or splitting areas in the domain1. In this question, we have a network based on IS-IS with four routers (R1_1, R1_2, R2_1, and R2_2) belonging to area 0001. The area address for area 0001 is 49.0001. The NSEL byte for area 0001 is the last octet of the address, which is 01. The NSEL byte stands for Network Service Access Point Selector (NSAP Selector) and indicates the type of service requested from the network layer2. Therefore, the correct statement in this scenario is that the NSEL byte for area 0001 is 01.
References: 1:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_isis/configuration/xe-16/irs-xe-16-book/irs-ovrvw-cf.
2:
https://www.juniper.net/documentation/us/en/software/junos/is-is/topics/concept/is-is-routing-overview.html
NEW QUESTION # 53
Exhibit
user@Rl show configuration interpolated-profile { interpolate {
fill-level [ 50 75 drop-probability [ > }
class-of-service drop-profiles
];
20 60 ];
Which two statements are correct about the class-of-service configuration shown in the exhibit? (Choose two.)
- A. The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to
75% full - B. To use this drop profile, you apply it directly to an interface.
- C. The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full.
- D. To use this drop profile, you reference it in a scheduler.
Answer: A,D
Explanation:
Explanation
class-of-service (CoS) is a feature that allows you to prioritize and manage network traffic based on various criteria, such as application type, user group, or packet loss priority. CoS uses different components to classify, mark, queue, schedule, shape, and drop traffic according to the configured policies.
One of the components of CoS is drop profiles, which define how packets are dropped when a queue is congested. Drop profiles use random early detection (RED) algorithm to drop packets randomly before the queue is full, which helps to avoid global synchronization and improve network performance. Drop profiles can be discrete or interpolated. A discrete drop profile maps a specific fill level of a queue to a specific drop probability. An interpolated drop profile maps a range of fill levels of a queue to a range of drop probabilities and interpolates the values in between.
In the exhibit, we can see that the class-of-service configuration shows an interpolated drop profile with two fill levels (50 and 75) and two drop probabilities (20 and 60). Based on this configuration, we can infer the following statements:
* The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full. This is not correct because the drop profile is interpolated, not discrete. This means that the drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to 75% full. The drop probability for any fill level between 50% and 75% can be calculated by using linear interpolation formula.
* The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to
75% full. This is correct because the drop profile is interpolated and uses linear interpolation formula to calculate the drop probability for any fill level between 50% and 75%. For example, if the fill level is
60%, the drop probability is 28%, which is calculated by using the formula: (60 - 50) / (75 - 50) * (60 -
20) + 20 = 28.
* To use this drop profile, you reference it in a scheduler. This is correct because a scheduler is a component of CoS that determines how packets are dequeued from different queues and transmitted on an interface. A scheduler can reference a drop profile by using the random-detect statement under the
[edit class-of-service schedulers] hierarchy level. For example: scheduler test { transmit-rate percent 10; buffer-size percent 10; random-detect test-profile; }
* To use this drop profile, you apply it directly to an interface. This is not correct because a drop profile cannot be applied directly to an interface. A drop profile can only be referenced by a scheduler, which can be applied to an interface by using the scheduler-map statement under the [edit class-of-service interfaces] hierarchy level. For example: interfaces ge-0/0/0 { unit 0 { scheduler-map test-map; } }
NEW QUESTION # 54
Which two statements describe PIM-SM? (Choose two)
- A. Traffic is initially flooded to all routers and an S,G is maintained for each group
- B. Traffic is only forwarded to routers that request to join the distribution tree.
- C. Routers without receivers must periodically prune themselves from the SPT.
- D. Routers with receivers send join messages to their upstream neighbors.
Answer: B,D
Explanation:
Explanation
PIM sparse mode (PIM-SM) is a multicast routing protocol that uses a pull model to deliver multicast traffic.
In PIM-SM, routers with receivers send join messages to their upstream neighbors toward a rendezvous point (RP) or a source-specific tree (SPT). The RP or SPT acts as the root of a shared distribution tree for a multicast group. Traffic is only forwarded to routers that request to join the distribution tree by sending join messages.
PIM-SM does not flood traffic to all routers or prune routers without receivers, as PIM dense mode does.
NEW QUESTION # 55
Exhibit
A network designer would like to create a summary route as shown in the exhibit, but the configuration is not working.
Which three configuration changes will create a summary route? (Choose three.)
- A. delete protocols isis export summary-v6
- B. set policy-options policy-statement leak-v6 term DC-routes from route-filter 2001:db9:a:faOO::/61 exact
- C. set policy-options policy-statement leak-v6 term DC-routes then reject
- D. set protocols isis import summary-v6
- E. delete policy-options policy-statement leak-v6 term DC-routes from route-filter 2001: db9 :a: fa00 : :/6l longer
Answer: A,B,E
Explanation:
Explanation
To create a summary route for IS-IS, you need to configure a policy statement that matches the prefixes to be summarized and sets the next-hop to discard. You also need to configure a summary-address statement under the IS-IS protocol hierarchy that references the policy statement. In this case, the policy statement leak-v6 is trying to match the prefix 2001:db9:a:fa00::/61 exactly, but this prefix is not advertised by any router in the network. Therefore, no summary route is created. To fix this, you need to delete the longer keyword from the route-filter term and change the prefix length to /61 exact. This will match any prefix that falls within the /61 range. You also need to delete the export statement under protocols isis, because this will export all routes that match the policy statement to other IS-IS routers, which is not desired for a summary route.
NEW QUESTION # 56
What is the correct order of packet flow through configurable components in the Junos OS CoS features?
- A. Multifield Classifier -> Behavior Aggregate Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Rewrite Marker -> Scheduler/Shaper/RED
- B. Behavior Aggregate Classifier -> Input Policer -> Multifield Classifier -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker
- C. Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker
- D. Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Scheduler/Shaper/RED -> Output Policer -> Rewrite Marker
Answer: B
Explanation:
Explanation
The correct order of packet flow through configurable components in the Junos OS CoS features is as follows:
* Behavior Aggregate Classifier: This component uses a single field in a packet header to classify traffic into different forwarding classes and loss priorities based on predefined or user-defined values.
* Input Policer: This component applies rate-limiting and marking actions to incoming traffic based on the forwarding class and loss priority assigned by the classifier.
* Multifield Classifier: This component uses multiple fields in a packet header to classify traffic into different forwarding classes and loss priorities based on user-defined values and filters.
* Forwarding Policy Options: This component applies actions such as load balancing, filtering, or routing to traffic based on the forwarding class and loss priority assigned by the classifier.
* Fabric Scheduler: This component schedules traffic across the switch fabric based on the forwarding class and loss priority assigned by the classifier.
* Output Policer: This component applies rate-limiting and marking actions to outgoing traffic based on the forwarding class and loss priority assigned by the classifier.
* Scheduler/Shaper/RED: This component schedules, shapes, and drops traffic at the egress interface based on the forwarding class and loss priority assigned by the classifier.
* Rewrite Marker: This component rewrites the code-point bits of packets leaving an interface based on the forwarding class and loss priority assigned by the classifier.
NEW QUESTION # 57
Exhibit
A network is using IS-IS for routing.
In this scenario, why are there two TLVs shown in the exhibit?
- A. Wide metrics have specifically been requested
- B. The interface specified a metric of 100 for L2.
- C. Both IPv4 and IPv6 are being used in the topology
- D. There are both narrow and wide metric devices in the topology
Answer: D
Explanation:
Explanation
TLVs are tuples of (Type, Length, Value) that can be advertised in IS-IS packets. TLVs can carry different kinds of information in the Link State Packets (LSPs). IS-IS supports both narrow and wide metrics for link costs. Narrow metrics use a single octet to encode the link cost, while wide metrics use three octets. Narrow metrics have a maximum value of 63, while wide metrics have a maximum value of 16777215. If there are both narrow and wide metric devices in the topology, IS-IS will advertise two TLVs for each link: one with the narrow metric and one with the wide metric. This allows backward compatibility with older devices that only support narrow metrics12.
NEW QUESTION # 58
You are configuring a BGP signaled Layer 2 VPN across your MPLS enabled core network. In this scenario, which statement is correct?
- A. You must use the same route-distinguiaher value on both PE devices.
- B. You must assign a unique site number to each attached site's configuration.
- C. This type of VPN only supports Ethernet interfaces when connecting to CE devices.
- D. This type of VPN requires the support of the inet-vpn NLRI on all core BGP devices
Answer: D
Explanation:
Explanation
BGP signaled Layer 2 VPN is a type of VPN that uses BGP to distribute VPN labels and information for Layer 2 connectivity between sites over an MPLS network. BGP signaled Layer 2 VPN requires the support of the l2vpn NLRI on all core BGP devices . The l2vpn NLRI is a new address family that carries Layer 2 VPN information such as the VPN identifier, the attachment circuit identifier, and the route distinguisher. The l2vpn NLRI is used for both auto-discovery and signaling of Layer 2 VPNs . In this scenario, we are configuring a BGP signaled Layer 2 VPN across an MPLS enabled core network. Therefore, we need to ensure that all core BGP devices support the l2vpn NLRI.
References: 1:
https://www.juniper.net/documentation/us/en/software/junos/vpn-l2/topics/concept/vpn-layer-2-overview.html
2:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_l2_vpns/configuration/xe-16/mp-l2-vpns-xe-16-book/vpl
NEW QUESTION # 59
Exhibit
R1 and R8 are not receiving each other's routes
Referring to the exhibit, what are three configuration commands that would solve this problem? (Choose three.)
- A. Configure loops on routers in AS 65412 and advertise-peer-as on routers in AS 64498.
- B. Configure as-override on advertisement from AS 64500 toward AS 64512.
- C. Configure remove-private on advertisements from AS 64500 toward AS 64499
- D. Configure remove-private on advertisements from AS 64497 toward AS 64498
- E. Configure loops and advertise-peer-as on routers in AS 64497 and AS 64450.
Answer: A,C,D
Explanation:
Explanation
The problem in this scenario is that R1 and R8 are not receiving each other's routes because of private AS numbers in the AS path. Private AS numbers are not globally unique and are not advertised to external BGP peers. To solve this problem, you need to do the following:
* Configure loops on routers in AS 65412 and advertise-peer-as on routers in AS 64498. This allows R5 and R6 to advertise their own AS number (65412) instead of their peer's AS number (64498) when sending updates to R7 and R8. This prevents a loop detection issue that would cause R7 and R8 to reject the routes from R5 and R62.
* Configure remove-private on advertisements from AS 64497 toward AS 64498 and from AS 64500 toward AS 64499. This removes any private AS numbers from the AS path before sending updates to external BGP peers. This allows R2 and R3 to receive the routes from R1 and R4, respectively3.
NEW QUESTION # 60
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