Designing Leaf-and-Spine Fabric


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Designing Leaf-and-Spine Fabric

In this module you'll learn how to design stable and scalable leaf-and-spine fabrics, regardless of whether they have to provide layer-2 or layer-3 transport.

Leaf-and-Spine Fabric Designs

1:25:50 Layer-3 Fabrics with Non-Redundant Server Connectivity

We're starting the design part of the webinar with the simplest possible scenario – each leaf switch is a single IP subnet – and focus on routing protocol selection, route summarization, leaf-to-spine link aggregation, and core link addressing.

44:27 Overview and Design Principles

Introduction to Leaf-and-Spine Designs 4:39 2017-02-09
Layer-3 Fabric with Non-Redundant Server Connectivity 6:52 2017-02-09
Routing Protocol Selection 19:50 2017-02-09
Route Summarization and Link Aggregation 6:40 2017-02-09
Core Link Addressing 6:26 2017-02-09
Slide deck 1.4M 2016-03-25

41:23 Using BGP in Leaf-and-Spine Fabrics

Based on the work done by Petr Lapukhov at Microsoft, every vendor talks about using BGP as the routing protocol in leaf-and-spine fabrics. Does it make sense? You'll find some of the answers in this section presented by Dinesh Dutt (Cumulus Networks).

Using BGP in Leaf-and-Spine Fabrics 10:19 2016-06-06
Simplifying BGP Configurations 19:30 2016-06-06
Troubleshooting and Managing BGP 8:19 2016-06-06
BGP in Data Centers - Sample Deployments 3:15 2016-06-06
Slide deck 1.9M 2016-03-04

Test your knowledge

Review Questions 202K 2017-11-06

32:38 Layer-3 Fabrics with Redundant Server Connectivity

After establishing the baseline in the Layer-3 fabrics with non-redundant server connectivity section we'll add complexity at the fabric edge: redundantly connected servers.

Layer-3 Fabrics with Redundant Server Connectivity 18:54 2018-01-17
Link Aggregation between Servers and Network 5:26 2018-01-17
Active-Standby Server Connectivity 8:18 2016-12-12
Slide deck 1.7M 2018-01-17

Test your knowledge

Review Questions 165K 2017-12-31

1:50:15 Layer-3-Only Data Centers

Is it possible to build a pure layer-3 data center fabric that supports redundant server connectivity and IP address mobility? You'll find out in this section.

6:53 Design Guidelines

Host Routing 6:53 2016-12-12
Slide deck 1.3M 2016-03-25

24:22 Building a Pure L3 Data Center with Cumulus Linux

Building a Pure L3 Data Center with Cumulus Linux 24:22 2016-12-12
Slide deck 949K 2016-03-29

Test your knowledge

Review Questions 157K 2018-01-17

1:19:00 More to explore

Layer-3-only Data Center Networks with Cumulus Linux on Software Gone Wild
Enterasys Robust Data Center Interconnect Solutions 1:19:00

This free webinar sponsored by Enterasys Networks describes a robust hybrid layer-2/layer-3 data center interconnect (DCI) solutions made possible with Fabric Routing and Host Routing technologies available in Enterasys’ OneFabric architecture.

29:27 Free items Routing on Servers

Another approach to building a pure layer-3 fabric is to extend the fabric routing protocol into the servers and announce servers' loopback IP addresses using BGP.

Runinng Routing Protocols on Servers 10:55 2016-12-12
Routing from Hosts - Deep Dive 10:24 2016-12-12
Examples from Real World 8:08 2016-12-12

Test your knowledge

Review Questions 153K 2017-12-31

1:53:15 Layer-2 Fabrics

We're leaving the stable world of L3-only fabrics and entering the realm of large VLANs that most enterprise data centers have to deal with. We'll cover numerous design scenarios, from traditional bridging to routing on layer 2 and MAC-over-IP encapsulation.

1:00:15 Design Guidelines

Layer-2 Fabrics 14:49 2017-03-21
Traditional Bridging 10:05 2017-03-21
Routing on Layer-2 13:12 2017-03-21
MAC-over-IP Encapsulation 13:25 2017-03-21
Redundant Server-to-Network Connectivity 8:44 2017-03-21
Slide deck 1.8M 2016-04-01

53:00 Shortest Path Bridging in Avaya Fabric

Avaya is one of the few data center switching vendors that still uses routing on layer 2 (SPB) technology instead of VXLAN encapsulation. In this guest presentation Roger Lapuh (Avaya) explains how SPB works and how you can use it to build layer-2 or layer-2+3 data center fabrics.

Introduction to SPB and Avaya Fabric Connect 18:25 2017-03-21
SPB Deep Dive 18:17 2017-03-21
Building Data Center Fabrics with SPB 16:18 2017-03-21
Slide deck 2.1M 2016-04-06

Test your knowledge

Review Questions 179K 2017-12-31

1:49:57 Mixed Layer-2 + Layer-3 Fabrics

Most data center fabrics have to combine elements of large VLANs and routing. In this section we'll explore the various combinations, from traditional routing on spine switches to anycast routing on leaf switches.

31:05 Design Guidelines

Layer-2+3 Fabrics 6:45 2017-04-04
Routing on Spine Switches 9:04 2017-04-04
Routing on Leaf Switches 15:16 2017-04-04
Slide deck 1.4M 2016-04-20

1:18:52 VXLAN with BGP EVPN on Cisco Nexus OS

Major data center switching vendors use VXLAN to build large layer-2 domains across IP fabrics, and EVPN control plane to build flooding trees and exchange MAC address reachability information.

In this section Lukas Krattiger (guest speaker from Cisco Systems) explains how VXLAN transport and EVPN control plane work on Nexus switches.

Overlays in Data Center Fabrics 15:07 2017-04-04
Overview of VXLAN with BGP EVPN 15:59 2017-04-04
Introduction to BGP EVPN 15:29 2017-04-04
BGP EVPN Deep Dive 15:39 2017-04-04
EVPN Integrated Routing and Bridging 16:38 2017-04-04
Slide deck 12M 2016-04-21

Test your knowledge

Review Questions 169K 2017-12-31

19:31 QoS and Load Balancing in Leaf-and-Spine Fabrics

Do you need QoS in data center fabrics? How do you handle load balancing between elephant and mice flows? This section describes some of the answers.

The following video was recorded in the Autumn 2016 Q&A session of the Building Next-Generation Data Center online course

QoS and Load Balancing in Leaf-and-Spine Fabrics 19:31 2017-11-06

Design Assignment: Build a Robust Layer-2 Fabric

In this assignment you'll design a layer-2 fabric required to support a traditional enterprise data center with VLAN-based virtual networks.

Design Assignment: Design a Robust Layer-2 Fabric 236K 2017-12-30
Submit your solution

Advanced Topics

1:44:36 Leaf-and-Spine Fabrics: Q&A and Whiteboarding Discussions

During the networking Q&A session we discussed interesting aspects of stretched leaf-and-spine fabrics, QoS in data center fabrics, and the concepts of pods and superspines.

Networking Discussions 486K 2016-09-21
Leaf-Spine Fabrics 74:23 2016-09-22
QoS on Core Fabric Links 16:38 2017-04-21
Pods and Superspines 13:35 2016-11-16

1:06:50 Large-Scale Open Data Center Fabrics

In this section you'll learn how to build very large data center fabrics. The section covers:

  • planning and design
  • disaggregation of chassis switches into individual components
  • challenges and limitations of modern data center switches
  • pod architecture
  • sample single-SKU designs
Large Data Center Fabric Challenges 16:54 2017-10-20
Pod Architecture and Basic Access Topologies 6:39 2017-10-20
Single-SKU Data Center Networks 9:44 2017-10-20
Hardware Challenges 14:48 2017-10-20
Building Large Leaf-and-Spine Fabrics 18:45 2017-10-20

Additional resources

Slide deck 4.5M 2017-05-23

Test your knowledge

Review Questions 170K 2017-12-30

56:19 Data Center Fabric Architectures

As you analyze the vendor solutions, it quickly becomes obvious that every single one of them uses one of few typical control/management plane architectures, from completely decentralized model (sometimes heavily automated) to centralized control- or even data plane.

This section describes most of the architectures you might encounter in real life and documents their benefits and drawbacks.

Fabric Architectures - Introduction 15:08 2017-01-18
Independent Devices 4:42 2017-01-18
Shared Management Plane 7:49 2017-01-18
Centralized Control Plane 13:13 2017-01-18
Centralized Control Plane with Local Offload 6:37 2017-01-18
Centralized Data Plane 6:17 2017-01-18
Conclusions 2:33 2017-01-18

Slide Deck

Data Center Fabrics - Architectures 2.3M 2016-05-30

Test your knowledge

Review Questions 198K 2017-12-30

1:11:40 Fabrics, Buffers and Drops

Buffering is a confusing and sometimes controversial topic when it comes to data center fabrics. In this short section JR Rivers discusses some of the related theory and practicalities as well as gives insight into tools that are available to networking specialists.

Switch Buffer Architectures 28:54 2017-09-16
Small Buffer or Big Buffer Switches 5:36 2017-09-16
Tools and Knobs 17:50 2017-09-16
Questions and Answers 19:20 2017-09-16

Reference material

Slide deck 2.5M 2016-11-09
Data Center TCP (Alizadeh, 2010)
Data Center TCP IETF draft
On the Data Path Performance of Leaf-Spine Datacenter Fabrics
BufferBloat wiki

Test your knowledge

Review Questions 192K 2017-12-30

Optional Self-Study and Reference Materials

Whiteboarding and Q&A from Live Sessions

This section contains recordings of live Q&A and whiteboarding sessions from courses run in 2016 - 2018. In these sessions we covered a wide range of topics, from pods and superspines to RIFT, OpenFabric and Segment Routing.

Overlay virtual networking, leaf-and-spine fabrics, pods and superspines (2016)
Infrastructure complexity, QoS, Contrail, NSX, ACI (2017)
OpenFabric, RIFT, Traffic Engineering and Segment Routing in data centers (2018)

4:12:00 EVPN Technical Deep Dive

This webinar will help you grasp the EVPN fundamentals, potential use cases, and its benefits and drawbacks. The deep dive part of the webinar discussed technical details that will enable you to deploy and troubleshoot EVPN in multi-vendor environments.

Reference: Data Center Fabric solutions

You'll find the information on switch models and vendor-specific software functionality you might need to complete the design assignment in the reference section of the previous module.

Relevant Webinars

All webinars in this section are included with your online course. Some of them are part of the core course content, others are included as reference material.

Data Center Fabric Architectures 16:38:00

The webinar describes the data center networking requirements and various approaches to data center fabric networks. It includes in-depth analysis of fabric architectures used by major data center networking vendor and compares their scalability and ease-of-use.

Leaf-and-Spine Fabric Architectures 10:52:00

The Leaf-and-Spine Fabric Architectures webinar describes the leaf-and-spine (Clos fabric) concepts, architecture, and single- and multistage designs that can be used to build large layer-2 or layer-3 all-point-equidistant Data Center networks.

Data Center Infrastructure for Networking Engineers 6:57:00

A broad overview of modern data center architectures and technologies covering server and LAN virtualization, LAN reference architectures and emerging fabric architectures, storage area networks and basics of data center interconnects.

Open Networking for Large-Scale Networks 2:22:00

This webinar will cover the design components involved in building a data center or cloud fabric using a single, disaggregated device—the way some hyperscale and web scale operators build their networks.

Networks, Buffers, and Drops 1:12:00

Buffering is a confusing and sometimes controversial topic when it comes to networking. In this short webinar JR Rivers discusses some of the related theory and practicalities as well as gives insight to tools that are available to networking specialists.

ExpertExpress Case Studies

The ExpertExpress case studies describe network design or deployment problems typically discussed during ExpertExpress sessions. They're based on real-life queries and consulting engagements but never represent an actual customer network.

Introduction to Virtualized Networking 1:57:00

Introductory webinar describing the networking requirements of server virtualization and IaaS cloud services, workload mobility, large-scale virtual networking solutions and multi-tenant isolation. This webinar is the recommended entry-level starting point for networking engineers interested in virtualization and cloud services.

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