Design Review Template - NETS

Hierarchical (MultiLayer) Network Design
- User ports to be configured with PortFast (See best practices section below)
- ISL or dot1Q trunks to the Distribution layer. Allow only Access Layer VLANs on the trunk.
- The ability to load-balance traffic over the Access-Distribution trunks. (This is done using HSRP).
If VLANs span multiple switches or buildings, then we can achieve load balancing using STP by
alternating “Root” configuration between Distribution Switches.
- If STP is the choice for redundancy, the UplinkFast feature is utilized to offer almost instantaneous
fail-over of uplinks.
At the Distribution Layer:
- Two Distribution switches per building to provide maximum redundancy and performance. The
two distribution switches are also directly connected to the Core using L3 connections.
- Terminate and limit the size of broadcast domains. With unique VLANs configured at the Access
switches, the link between the two Distribution in every building can be an L3 connections.
- A failure in one of the closets will only be limited to that closet.
- Configure HSRP with alternating priority levels between the two Distribution-MSFCs to provide
redundancy as well as load balancing of the Uplinks.
- Easy to manage and troubleshoot
- Root bridges are local and known. No Root is across the WAN links.
At the Core Layer:
- Layer 3 Core
- Highly redundant
- Simple Design
- Point-to-Point L3 connections
NCAR Design Review and Recommendations v1.0 15