Design Best Practice for Core Layer in Three-Tier Hierarchical Campus Networks

B.

In a three-tier hierarchical campus network design, the core layer is the backbone of the network, providing high-speed connectivity and fast forwarding of traffic between different parts of the network. The core layer typically connects the distribution layer switches and provides the aggregation point for traffic from the access layer switches.

The design best-practices for the core layer are:

A. Provide QoS prioritization services such as marking, queueing, and classification for critical network traffic: QoS (Quality of Service) is essential in a network to ensure that critical traffic such as voice and video is given higher priority than other types of traffic. The core layer should provide QoS services to ensure that critical traffic is given priority and is forwarded through the network with minimal delay or packet loss. The QoS services provided in the core layer should be based on the business requirements and the traffic patterns of the network.

B. Provide redundant Layer 3 point-to-point links between the core devices for more predictable and faster convergence: The core layer should be designed to provide high availability and fast convergence in case of a link or device failure. Redundant Layer 3 point-to-point links between the core devices can provide fast convergence and help ensure that traffic is not disrupted in case of a link or device failure. The links should be designed to provide equal-cost multipath (ECMP) routing and load balancing for efficient use of network resources.

C. Provide advanced network security features such as 802.1X, DHCP snooping, VACLs, and port security: Security is an essential aspect of any network design, and the core layer should provide advanced security features to protect against various threats such as unauthorized access, DHCP spoofing, and MAC address spoofing. The security features provided in the core layer should be based on the security policy of the organization and the level of security required for the network.

D. Provide redundant aggregation for access layer devices and first-hop redundancy protocols such as VRRP: Redundancy is a critical aspect of any network design, and the core layer should be designed to provide redundant aggregation for access layer devices and first-hop redundancy protocols such as VRRP (Virtual Router Redundancy Protocol) to ensure high availability and fast convergence in case of a device or link failure. The redundancy features provided in the core layer should be based on the business requirements and the criticality of the network.

In conclusion, the best practice for the core layer is to provide QoS prioritization services, redundant Layer 3 point-to-point links, advanced network security features, and redundant aggregation for access layer devices and first-hop redundancy protocols. These design best-practices help ensure that the core layer provides high availability, fast convergence, and efficient forwarding of traffic through the network.