300-420 Question 44
Select 3An enterprise network is configured with two redundant WAN links to connect its branch offices to the data center. The network engineer wants to implement load sharing across these links to optimize bandwidth utilization while ensuring traffic is distributed proportionally based on link capacity. Which of the following approaches can achieve this objective?
- A
Configure Equal-Cost Multi-Path (ECMP) routing on the branch routers.
- B
Use Policy-Based Routing (PBR) to direct specific types of traffic based on source or destination.
- C
Implement Weighted Static Routes with metrics proportional to link capacities.
- D
Enable per-packet load balancing on the branch routers.
- E
Deploy Border Gateway Protocol (BGP) with weight or local preference attributes for traffic distribution.
Show answer and explanation
Correct answers: B, C, E
Explanation
To achieve proportional load sharing, the network engineer can use approaches that allow for granular control over traffic distribution. Policy-Based Routing (PBR) enables custom traffic policies, Weighted Static Routes adjust traffic based on link capacities, and BGP attributes such as weight or local preference can control traffic paths effectively. ECMP and per-packet load balancing are less suitable for proportional bandwidth sharing across links with different capacities.
- A. Incorrect.
Equal-Cost Multi-Path (ECMP) routing is effective for distributing traffic across equal-capacity links, but it does not consider proportional bandwidth sharing for links with different capacities.
- B. Correct.
Policy-Based Routing (PBR) allows traffic to be directed based on criteria such as source or destination, which can be tailored to achieve load sharing across links.
- C. Correct.
Weighted Static Routes can be used to assign different metrics to links, ensuring traffic is distributed in proportion to their capacities.
- D. Incorrect.
Per-packet load balancing can lead to out-of-order packets, especially in WAN environments, and is not recommended for optimizing link utilization in enterprise networks.
- E. Correct.
BGP with weight or local preference attributes provides granular control over traffic distribution, enabling proportional load sharing based on link capacity.