Top-of-rack, end-of-row and leaf-spine layouts

Skills you'll practise

• Describe top-of-rack, end-of-row and middle-of-row switch placement and the cabling each implies
• Explain the leaf-spine topology, including why every leaf connects to every spine and how traffic is spread across spines
• Calculate a leaf switch's oversubscription ratio from its downlink and uplink capacity
• Predict the effect of losing a spine, a leaf or an uplink, and check dual-homing before maintenance on a leaf

Course outline

1. 1.Top-of-rack, end-of-row and leaf-spineVideo · 2 min
2. 2.Where the switches sit: top-of-rack, end-of-row, middle-of-rowLesson · 17 min
3. 3.Leaf-spine: every leaf to every spineLesson · 20 min
4. 4.Leaf pairs, dual-homing and failure effectsLesson · 18 min
5. 5.Top-of-rack, end-of-row and leaf-spine layouts: knowledge checkKnowledge check · 18 questions
6. 6.Final exam8 questions · passing it completes the course, so people who already know the material can test out

Sources it draws on

The lessons and questions are written from these references, so learners can go back to the original.

• IETF RFC 7938: Use of BGP for Routing in Large-Scale Data Centers (section 3: traditional three-tier and folded Clos / leaf-and-spine topologies, ECMP, oversubscription N/M)
• NVIDIA Cumulus Linux EVPN reference design: Data Center Networking Concepts (two-tier leaf-spine, MLAG pairs and peer link, EVPN multihoming)
• ANSI/TIA-942: Telecommunications Infrastructure Standard for Data Centers (overview)
• General data-center network operations practice