Exhibit
You are examining an L3VPN route that includes the information shown in the exhibit Which statement is correct in this scenario?
Correct Answer:
B
The information shows a Type 0 route distinguisher, which is one of the three types of route distinguishers defined by RFC 4364. A route distinguisher is a 64-bit value that is prepended to an IPv4 address to create a VPN-IPv4 address, which is unique within a VPN routing and forwarding (VRF) table. A Type 0 route distinguisher has two fields: an administrator subfield (2 bytes) and an assigned number subfield (6 bytes). The administrator subfield can be an AS number or an IP address, and the assigned number subfield can be any value assigned by the administrator. In this example, the administrator subfield is 65530 (an AS number) and the assigned number subfield is 1.
Exhibit
You want to use both links between R1 and R2 Because of the bandwidth difference between the two links, you must ensure that the links are used as much as possible.
Which action will accomplish this goal?
Correct Answer:
D
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). In this question, we have two links between R1 and R2 with different bandwidths (10 Gbps and 1 Gbps). We want to use both links as much as possible for VPLS traffic. To achieve this, we need to enable per-prefix load balancing on both routers. Per-prefix load balancing is a feature that allows a router to distribute traffic across multiple equal-cost or unequal- cost paths based on the destination prefix of each packet. This improves the utilization of multiple links and provides better load sharing than per-flow load balancing, which distributes traffic based on a hash of source and destination addresses4. Per-prefix load balancing can be enabled globally or per interface using the load-balance per-packet command.
Reference: 4: https://www.cisco.com/c/en/us/support/docs/multiprotocol-label-switching-mpls/mpls/137544-technote-mpls-00.html
Exhibit
Click the Exhibit button-Referring to the exhibit, which two statements are correct about BGP routes on R3 that are learned from the ISP-A neighbor? (Choose two.)
Correct Answer:
AB
BGP is an exterior gateway protocol that uses path vector routing to exchange routing information among autonomous systems. BGP uses various attributes to select the best path to each destination and to propagate routing policies. Some of the common BGP attributes are AS path, next hop, local preference, MED, origin, weight, and community. BGP attributes can be classified into four categories: well-known mandatory, well-known discretionary, optional transitive, and optional nontransitive. Well-known mandatory attributes are attributes that must be present in every BGP update message and must be recognized by every BGP speaker. Well-known discretionary attributes are attributes that may or may not be present in a BGP update message but must be recognized by every BGP speaker. Optional transitive attributes are attributes that may or may not be present in a BGP update message and may or may not be recognized by a BGP speaker. If an optional transitive attribute is not recognized by a BGP speaker, it is passed along to the next BGP speaker. Optional nontransitive attributes are attributes that may or may not be present in a BGP update message and may or may not be recognized by a BGP speaker. If an optional nontransitive attribute is not recognized by a BGP speaker, it is not passed along to the next BGP speaker. In this question, we have four routers (R1, R2, R3, and R4) that are connected in a full mesh topology and running IBGP. R3 receives the 192.168.0.0/16 route from its EBGP neighbor and advertises it to R1 and R4 with different BGP attribute values. We are asked which statements are correct about the BGP routes on R3 that are learned from the ISP-A neighbor. Based on the information given, we can infer that the correct statements are:
✑ By default, the next-hop value for these routes is not changed by ISP-A before being sent to R3. This is because the default behavior of EBGP is to preserve the next-hop attribute of the routes received from another EBGP neighbor. The next- hop attribute indicates the IP address of the router that should be used as the next hop to reach the destination network.
✑ The BGP local-preference value that is used by ISP-A is not advertised to R3. This is because the local-preference attribute is a well-known discretionary attribute that is used to influence the outbound traffic from an autonomous system. The local- preference attribute is only propagated within an autonomous system and is not advertised to external neighbors.
References: : https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol- bgp/13753-25.html : https://www.cisco.com/c/en/us/support/docs/ip/border-gateway- protocol-bgp/13762-40.html : https://www.cisco.com/c/en/us/support/docs/ip/border- gateway-protocol-bgp/13759-37.html
Exhibit
The environment is using BGP All devices are in the same AS with reachability redundancy Referring to the exhibit, which statement is correct?
Correct Answer:
A
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.
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.)
Correct Answer:
BC
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
