A service provider is in the process of implementing Unified MPLS on an enterprise network with many nodes. After the migration, several new customers will be added to the environment. RFC 3107 is used to build BGP LSPs across the domains. Which action must the networking team take to reduce the full-mesh requirement for iBGP?
Answer(s): C
In a Unified MPLS architecture, using route reflectors (RRs) is a common way to reduce the full-mesh iBGP requirement. Deploying RRs on all Area Border Routers (ABRs) allows them to manage BGP routes within their respective areas or domains, avoiding the need for a full iBGP mesh between all routers. RFC 3107, which defines carrying label information in BGP, complements this setup by enabling labeled BGP LSPs across the domains efficiently. By implementing route reflectors on ABRs, scalability is improved, and management complexity is reduced.
Refer to the exhibit. A network engineer is implementing iBGP and eBGP between AS 600 and AS 500 with these requirements:R2 must establish eBGP peering on 192.168.3.0/30 with R5 for sending unicast and multicast traffic.R2 must wait for 30 seconds before sending BGP updates to R5 for multicast traffic.Which action must be taken on R2 to meet the requirement?
Answer(s): D
The advertisement-interval command in the BGP configuration is used to set the minimum interval (in seconds) between sending BGP updates for a specific address family. To meet the requirement of waiting 30 seconds before sending multicast BGP updates from R2 to R5, the engineer must configure the advertisement-interval 30 under the address-family ipv4 multicast on R2.
How does TI-LFA reduce packet loss in segment routing?
TI-LFA (Topology Independent Loop-Free Alternate) reduces packet loss in segment routing by precomputing loop-free backup paths for each possible link or node failure. These backup paths are calculated using the network topology and are immediately implemented upon detection of a failure. This ensures near- instantaneous traffic rerouting without requiring full reconvergence of the IGP, significantly minimizing packet loss during failures.
Refer to the exhibit. IS-IS is running as the IGP in the network, and the routers have established BGP peering relationships. Because the network carries mission-critical data, the routers must be able to operate with minimal downtime. The networking team decided to implement graceful restart to improve network stability. Which action must the team take so that all BGP peers can use their BGP routes during a failover?
Answer(s): B
Graceful Restart (GR) with Non-Stop Forwarding (NSF) ensures that during a router failover or software upgrade, BGP peers retain their routing table and continue forwarding traffic based on preexisting routes. By enabling NSF globally on all BGP peers, the routers can maintain their BGP routes during a failover, reducing downtime and ensuring the stability of mission-critical data traffic. This approach minimizes the impact of control plane disruptions on the data plane.
What is the primary purpose of the flexible algorithm in a segment-routing environment?
The flexible algorithm in a segment-routing environment enables the network to adaptively select paths based on predefined optimization criteria, such as latency, bandwidth, or administrative constraints. This allows traffic to be routed dynamically in response to real-time network conditions, improving overall performance and efficiency. By enabling this functionality, flexible algorithms help meet application-specific requirements while maximizing resource utilization.
Refer to the exhibit. MPLS is configured within the network. The routers use OSPF to exchange routing information. Hosts that are connected to routers R1 and R3 use routers R2 and R4 to access servers that run a variety of intranet applications. A network engineer must ensure that R1 and R3 maintain an LDP session between them to support the flow of traffic between hosts and servers. Which task should the engineer perform to provide LDP bindings in case of failure on the path between R1 and R3?
Answer(s): A
LDP (Label Distribution Protocol) session protection ensures that LDP sessions are maintained even if the direct path between two LSRs (Label Switch Routers) is lost. By enabling session protection, targeted hellos are sent between routers R1 and R3, allowing them to maintain their LDP session via alternate paths (through R2 and R4) in case of a link failure. This guarantees that MPLS label bindings remain intact, ensuring uninterrupted traffic flow between hosts and servers.
Refer to the exhibit. MPLS is running in the network with OSPF as the IGP. Full routes are shared between the routers, and each connected link has an MPLS neighbor relationship. A network engineer must update the network configuration so that it will maintain LDP neighbor relationships if a directly connected link goes down. Which action must the engineer take as part of the process?
LDP session protection ensures that Label Distribution Protocol (LDP) neighbor relationships are maintained even if a directly connected link goes down. This is achieved by enabling targeted LDP hellos, allowing the LDP session to persist over an alternate path if a direct link fails. This configuration is particularly useful in MPLS networks where maintaining label bindings during failures is critical for uninterrupted service. By implementing LDP session protection, the network can provide enhanced resilience and prevent disruption to MPLS traffic.
Refer to the exhibit. Routers R1 and R2 support traffic between multiple departments at a company's remote office and exchange routes using OSPF. The link between R1 and R2 has been providing inconsistent performance, particularly during times of peak usage. To help Identify the cause, an engineer was asked to implement BFD to detect failures on the link. Which task must the engineer perform?
Bidirectional Forwarding Detection (BFD) is used to detect failures on links quickly. Echo mode is a feature of BFD that can detect failures in asymmetric routing environments by sending echo packets between the devices.This mode operates independently of the control plane and ensures accurate detection even during high traffic or network asymmetries. Enabling echo mode on both R1 and R2 will help identify and resolve the inconsistency in link performance during peak usage.
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