リアルJuniper JN0-664試験問題 [更新されたのは2023年]
JN0-664試験問題集で合格させるのは更新されたのは2023年年最新のService Provider, Professional (JNCIP-SP)
質問 # 34
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 site's local ID is automatically assigned a value of 0 and must be configured to match the total number of attached sites.
- C. 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.
- D. You must use separate physical interfaces to connect PE-2 to each site.
正解：C
解説：
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.
質問 # 35
Exhibit
Referring to the exhibit, PE-1 and PE-2 are getting route updates for VPN-B when neither of them service that VPN Which two actions would optimize this process? (Choose two.)
- A. Configure the resolution rib bgp . 13vpn . 0 resolution-ribs inet. 0 Statement on the PEs.
- B. Configure the resolution rib bgp.l3vpn.O resolution-ribs inet. 0 Statement on the RR
- C. Configure the family route-target statement on the RR
- D. Configure the family route-target statement on the PEs.
正解：B、C
解説：
Explanation
BGP route target filtering is a technique that reduces the number of routers that receive VPN routes and route updates, helping to limit the amount of overhead associated with running a VPN. BGP route target filtering is based on the exchange of the route-target address family, which contains information about the VPN membership of each PE device. Based on this information, a PE device can decide whether to accept or reject VPN routes from another PE device.
BGP route target filtering can be configured on PE devices or on route reflectors (RRs). Configuring BGP route target filtering on RRs is more efficient and scalable, as it reduces the number of BGP sessions and updates between PE devices. To configure BGP route target filtering on RRs, the following steps are required:
* Configure the family route-target statement under the BGP group or neighbor configuration on the RRs.
This enables the exchange of the route-target address family between the RRs and their clients (PE devices).
* Configure the resolution rib bgp.l3vpn.0 resolution-ribs inet.0 statement under the routing-options configuration on the RRs. This enables the RRs to resolve next hops for VPN routes using the inet.0 routing table.
* Configure an export policy for BGP route target filtering under the routing-options configuration on the RRs. This policy controls which route targets are advertised to each PE device based on their VPN membership.
質問 # 36
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. Both IPv4 and IPv6 are being used in the topology
- C. The interface specified a metric of 100 for L2.
- D. There are both narrow and wide metric devices in the topology
正解：D
解説：
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.
質問 # 37
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. To use this drop profile, you apply it directly to an interface.
- B. To use this drop profile, you reference it in a scheduler.
- C. The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full.
- D. The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to
75% full
正解：B、D
解説：
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; } }
質問 # 38
Which origin code is preferred by BGP?
- A. Incomplete
- B. External
- C. Internal
- D. Null
正解：A
解説：
Explanation
BGP uses several attributes to select the best path for a destination prefix. One of these attributes is origin, which indicates how BGP learned about a route. The origin attribute can have one of three values: IGP, EGP, or Incomplete. IGP means that the route was originated by a network or aggregate statement within BGP or by redistribution from an IGP into BGP. EGP means that the route was learned from an external BGP peer (this value is obsolete since BGP version 4). Incomplete means that the route was learned by some other means, such as redistribution from a static route into BGP. BGP prefers routes with lower origin values, so Incomplete is preferred over EGP, which is preferred over IGP.
質問 # 39
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-1.
- B. Configure the explicit-null statement on PE-2
- C. Configure VPN prefix mapping for the PE-1_to_PE-2 LSP
- D. Set a static CoS value for the PE-1_to_PE-2 LSP
正解：A
解説：
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.
質問 # 40
Exhibit.
Referring to the exhibit; the 10.0.0.0/24 EBGP route is received on R5; however, the route is being hidden.
What are two solutions that will solve this problem? (Choose two.)
- A. On R4, create a policy to change the BGP next hop to itself and apply it to IBGP as an export policy
- B. On R4, create a policy to change the BGP next hop to 172.16.1.1 and apply it to IBGP as an export policy
- C. Add the internal interface prefix to the BGP routing tables.
- D. Add the external interface prefix to the IGP routing tables
正解：A、D
解説：
Explanation
the default behavior for iBGP is to propagate EBGP-learned prefixes without changing the next-hop. This can cause issues if the next-hop is not reachable via the IGP. One solution is to use the next-hop self command on R4, which will change the next-hop attribute to its own loopback address. This way, R5 can reach the next-hop via the IGP and install the route in its routing table.
Another solution is to add the external interface prefix (120.0.4.16/30) to the IGP routing tables of R4 and R5.
This will also make the next-hop reachable via the IGP and allow R5 to use the route. According to 2, this is a possible workaround for a pure IP network, but it may not work well for an MPLS network.
質問 # 41
Your organization manages a Layer 3 VPN for multiple customers To support advanced route than one BGP community on advertised VPN routes to remote PE routers.
Which routing-instance configuration parameter would support this requirement?
- A. vrf-target import
- B. vrf-import
- C. vrf-export
- D. vrf-target export
正解：D
解説：
Explanation
The vrf-target export parameter is used to specify one or more BGP extended community attributes that are attached to VPN routes when they are exported from a VRF routing instance to remote PE routers. This parameter allows you to control which VPN routes are accepted by remote PE routers based on their import policies. You can specify more than one vrf-target export value for a VRF routing instance to support advanced route filtering or route leaking scenarios.
質問 # 42
Which two statements are correct about reflecting inet-vpn unicast prefixes in BGP route reflection? (Choose two.)
- A. Route reflectors do not change any existing BGP attributes by default when advertising routes.
- B. A BGP peer does not require any configuration changes to become a route reflector client.
- C. Route reflectors add their cluster ID to the AS path when readvertising client routes.
- D. Clients add their originator ID when advertising routes to their route reflector
正解：A、B
解説：
Explanation
Route reflection is a BGP feature that allows a router to reflect routes learned from one IBGP peer to another IBGP peer, without requiring a full-mesh IBGP topology. Route reflectors do not change any existing BGP attributes by default when advertising routes, unless explicitly configured to do so. A BGP peer does not require any configuration changes to become a route reflector client, only the route reflector needs to be configured with the client parameter under [edit protocols bgp group group-name neighbor neighbor-address] hierarchy level.
質問 # 43
When building an interprovider VPN, you notice on the PE router that you have hidden routes which are received from your BGP peer with family inet labeled-unica3t configured.
Which parameter must you configure to solve this problem?
- A. Under the protocols ospf hierarchy, add the traffic-engineering parameter.
- B. Under the family inet labeled-unicast hierarchy, add the resolve-vpn parameter.
- C. Under the protocols mpls hierarchy, add the traffic-engineering parameter
- D. Under the family inet labeled-unicast hierarchy, add the explicit null parameter.
正解：B
解説：
Explanation
The resolve-vpn parameter is a BGP option that allows a router to resolve labeled VPN-IPv4 routes using unlabeled IPv4 routes received from another BGP peer with family inet labeled-unicast configured. This option enables interprovider VPNs without requiring MPLS labels between ASBRs or using VRF tables on ASBRs. In this scenario, you need to configure the resolve-vpn parameter under [edit protocols bgp group external family inet labeled-unicast] hierarchy level on both ASBRs.
質問 # 44
Which two statements about IS-IS are correct? (Choose two.)
- A. CSNPs are flooded periodically
- B. CSNPs contain only descriptions of LSPs.
- C. PSNPs contain only descriptions of LSPs.
- D. PSNPs are flooded periodically.
正解：A、C
解説：
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
質問 # 45
Exhibit
Which two statements about the output shown in the exhibit are correct? (Choose two.)
- A. The PE is attached to a single local site.
- B. The connection has not flapped since it was initiated.
- C. The PE router has the capability to pop flow labels
- D. There has been a VLAN ID mismatch.
正解：A、C
解説：
Explanation
According to 1 and 2, 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 the output shown in the exhibit, we can see some information about the L2VPN RIB and the pseudowire state. Based on this information, we can infer the following statements:
* The PE is attached to a single local site. This is correct because the output shows only one local site ID (1) under the L2VPN RIB section. A local site ID is a unique identifier for a site within a VPLS domain.
If there were multiple local sites attached to the PE, we would see multiple local site IDs with different prefixes.
* The connection has not flapped since it was initiated. This is correct because the output shows that the uptime of the pseudowire is equal to its total uptime (1w6d). This means that the pseudowire has been up for one week and six days without any interruption or flap.
* There has been a VLAN ID mismatch. This is not correct because the output shows that the remote and local VLAN IDs are both 0 under the pseudowire state section. A VLAN ID mismatch occurs when the remote and local VLAN IDs are different, which can cause traffic loss or misdelivery. If there was a VLAN ID mismatch, we would see different values for the remote and local VLAN IDs.
* The PE router has the capability to pop flow labels. This is correct because the output shows that the flow label pop bit is set under the pseudowire state section. The flow label pop bit indicates that the PE router can pop (remove) the MPLS flow label from the packet before forwarding it to the CE device.
The flow label is an optional MPLS label that can be used for load balancing or traffic engineering purposes.
質問 # 46
Exhibit
Referring to the exhibit, which statement is correct?
- A. The vrf-target configuration will stop routes from being shared between CE-1 and CE-2.
- B. The route-distinguisher configuration will allow overlapping routes to be shared between CE-1 and CE-2.
- C. The vrf-target configuration will allow routes to be shared between CE-1 and CE-2.
- D. The route-diatinguisher configuration will stop routes from being shared between CE-1 and CE-2.
正解：B
解説：
Explanation
The route distinguisher (RD) is a BGP attribute that is used to create unique VPN IPv4 prefixes for each VPN in an MPLS network. The RD is a 64-bit value that consists of two parts: an administrator field and an assigned number field. The administrator field can be an AS number or an IP address, and the assigned number field can be any arbitrary value chosen by the administrator. The RD is prepended to the IPv4 prefix to create a VPN IPv4 prefix that can be advertised across the MPLS network without causing any overlap or conflict with other VPNs. In this question, we have two PE routers (PE-1 and PE-2) that are connected to two CE devices (CE-1 and CE-2) respectively. PE-1 and PE-2 are configured with VRFs named Customer-A and Customer-B respectively.
質問 # 47
An interface is configured with a behavior aggregate classifier and a multifield classifier How will the packet be processed when received on this interface?
- A. The packet will be processed by the MF classifier first, then the BA classifier.
- B. The packet will be forwarded with no classification changes.
- C. The packet will be processed by the BA classifier first, then the MF classifier.
- D. The packet will be discarded.
正解：B
解説：
Explanation
behavior aggregate (BA) classifiers and multifield (MF) classifiers are two types of classifiers that are used to assign packets to a forwarding class and a loss priority based on different criteria. The forwarding class determines the output queue for a packet. The loss priority is used by a scheduler to control packet discard during periods of congestion.
A BA classifier maps packets to a forwarding class and a loss priority based on a fixed-length field in the packet header, such as DSCP, IP precedence, MPLS EXP, or IEEE 802.1p CoS bits. A BA classifier is computationally efficient and suitable for core devices that handle high traffic volumes. A BA classifier is useful if the traffic comes from a trusted source and the CoS value in the packet header is trusted.
An MF classifier maps packets to a forwarding class and a loss priority based on multiple fields in the packet header, such as source address, destination address, protocol type, port number, or VLAN ID. An MF classifier is more flexible and granular than a BA classifier and can match packets based on complex filter rules. An MF classifier is suitable for edge devices that need to classify traffic from untrusted sources or rewrite packet headers.
You can configure both a BA classifier and an MF classifier on an interface. If you do this, the BA classification is performed first and then the MF classification. If the two classification results conflict, the MF classification result overrides the BA classification result.
Based on this information, we can infer the following statements:
* The packet will be discarded. This is not correct because the packet will not be discarded by the classifiers unless it matches a filter rule that specifies discard as an action. The classifiers only assign packets to a forwarding class and a loss priority based on their match criteria.
* The packet will be processed by the BA classifier first, then the MF classifier. This is correct because if both a BA classifier and an MF classifier are configured on an interface, the BA classification is performed first and then the MF classification. If they conflict, the MF classification result overrides the BA classification result.
* The packet will be forwarded with no classification changes. This is not correct because the packet will be classified by both the BA classifier and the MF classifier if they are configured on an interface. The final classification result will determine which output queue and which discard policy will be applied to the packet.
* The packet will be processed by the MF classifier first, then the BA classifier. This is not correct because if both a BA classifier and an MF classifier are configured on an interface, the BA classification is performed first and then the MF classification. If they conflict, the MF classification result overrides the BA classification result.
質問 # 48
Exhibit
R4 is directly connected to both RPs (R2 and R3) R4 is currently sending all ,o,ns upstream to R3 but you want all joins to go to R2 instead Referring to the exhibit, which configuration change will solve this issue?
- A. Change the group-range to be more specific on R2 than R3.
- B. Change the local address on R2 to be higher than R3.
- C. Change the bootstrap priority on R2 to be higher than R3
- D. Change the default route in inet.2 on R4 from R3 as the next hop to R2
正解：C
解説：
Explanation
PIM Bootstrap Router (BSR) is a mechanism that allows PIM routers to discover and announce rendezvous point (RP) information for multicast groups. BSR uses two roles: candidate BSR and candidate RP. Candidate BSR is the router that collects information from all available RPs in the network and advertises it throughout the network. Candidate RP is the router that wants to become the RP and registers itself with the BSR. There can be only one active BSR in the network, which is elected based on the highest priority or highest IP address if the priority is the same. The BSR priority can be configured manually or assigned automatically. The default priority is 0 and the highest priority is 2551. In this question, R4 is directly connected to both RPs (R2 and R3) and is currently sending all joins upstream to R3 but we want all joins to go to R2 instead. To achieve this, we need to change the BSR priority on R2 to be higher than R3 so that R2 becomes the active BSR and advertises its RP information to R4.
質問 # 49
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 requires the support of the inet-vpn NLRI on all core BGP devices
- D. This type of VPN only supports Ethernet interfaces when connecting to CE devices.
正解：C
解説：
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
質問 # 50
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 unicast between PE routers
- B. You must configure family inet6 unicaat between PE and CE routers.
- C. You must configure family inet6 add-path between PE and CE routers.
- D. You must configure family inet6 labcled-unicast between PE routers.
正解：B、D
解説：
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.
質問 # 51
When using OSPFv3 for an IPv4 environment, which statement is correct?
- A. OSPFv3 only supports IPv4.
- B. OSPFv3 supports IPv4 only on interfaces with family inet6 defined
- C. OSPFv3 is not backward compatible with IPv4
- D. OSPFv3 supports both IPv6 and IPv4, but not in the same routing instance.
正解：C
解説：
Explanation
OSPFv3 is an extension of OSPFv2 that supports IPv6 routing and addressing. OSPFv3 is not backward compatible with IPv4 because it uses a different packet format and a different link-state advertisement (LSA) structure than OSPFv2. OSPFv3 also uses IPv6 link-local addresses as router IDs and neighbor addresses, instead of IPv4 addresses. To use OSPFv3 for an IPv4 environment, you need to enable the IPv4 unicast address family under [edit protocols ospf3] hierarchy level and configure IPv4 addresses on the interfaces.
質問 # 52
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. RR1 is peered to Client2 and RR2
- B. Client1 is peered to Client2 and Client3.
- C. Peering is dynamically discovered between all devices.
- D. RR2 is in an OpenConfirm State until RR1 becomes unreachable.
正解：A
解説：
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.
質問 # 53
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 remove-private on advertisements from AS 64500 toward AS 64499
- C. Configure as-override on advertisement from AS 64500 toward AS 64512.
- D. Configure loops and advertise-peer-as on routers in AS 64497 and AS 64450.
- E. Configure remove-private on advertisements from AS 64497 toward AS 64498
正解：A、B、E
解説：
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.
質問 # 54
Which two statements are correct regarding bootstrap messages that are forwarded within a PIM sparse mode domain? (Choose two.)
- A. Bootstrap messages are used to notify which router is the PIM RP
- B. Bootstrap messages distribute RP information dynamically during an RP election.
- C. Bootstrap messages are forwarded to all routers within a PIM sparse-mode domain.
- D. Bootstrap messages are forwarded only to routers that explicitly requested the messages within the PIM sparse-mode domain
正解：B、C
解説：
Explanation
Bootstrap messages are PIM messages that are used to distribute rendezvous point (RP) information dynamically during an RP election. Bootstrap messages are sent by bootstrap routers (BSRs), which are routers that are elected to perform the RP discovery function for a PIM sparse-mode domain. Bootstrap messages contain information about candidate RPs and their multicast groups, as well as BSR priority and hash mask length. Bootstrap messages are forwarded to all routers within a PIM sparse-mode domain using hop-by-hop flooding.
質問 # 55
Exhibit
CE-1 must advertise ten subnets to PE-1 using BGP Once CE-1 starts advertising the subnets to PE-1, the BGP peering state changes to Active.
Referring to the CLI output shown in the exhibit, which statement is correct?
- A. CE-1 is configured with an incorrect peer AS
- B. The prefix limit has been reached on PE-1
- C. CE-1 is advertising its entire routing table.
- D. CE-1 is unreachable
正解：A
解説：
Explanation
The problem in this scenario is that CE-1 is configured with an incorrect peer AS number for its BGP session with PE-1. The CLI output shows that CE-1 is using AS 65531 as its local AS number and AS 65530 as its peer AS number. However, PE-1 is using AS 65530 as its local AS number and AS 65531 as its peer AS number. This causes a mismatch in the BGP OPEN messages and prevents the BGP session from being established. To solve this problem, CE-1 should configure its peer AS number as 65530 under [edit protocols bgp group external] hierarchy level.
質問 # 56
Which two statements are correct about VPLS tunnels? (Choose two.)
- A. LDP-signaled VPLS tunnels use auto-discovery to provision sites
- B. BGP-signaled VPLS tunnels can use either RSVP or LDP between the PE routers.
- C. LDP-signaled VPLS tunnels only support control bit 0.
- D. BGP-signaled VPLS tunnels require manual provisioning of sites.
正解：A、B
解説：
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
質問 # 57
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. set policy-options policy-statement leak-v6 term DC-routes from route-filter 2001:db9:a:faOO::/61 exact
- B. delete policy-options policy-statement leak-v6 term DC-routes from route-filter 2001: db9 :a: fa00 : :/6l longer
- C. set policy-options policy-statement leak-v6 term DC-routes then reject
- D. delete protocols isis export summary-v6
- E. set protocols isis import summary-v6
正解：A、B、D
解説：
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.
質問 # 58
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Juniper JN0-664 認定試験の出題範囲：
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