Templates Introduction

Rack-based Template

Rack-based templates define the type and number of racks to connect as top-of-rack (ToR) switches (or pairs of ToR switches). Rack-based templates include the following details:

Table 1: Rack-based Template Policies

Policy	Options
ASN Allocation Scheme (spine)	Unique - applies to 3-stage designs. Each spine is assigned a different ASN. Single - applies to 5-stage designs. All spine devices in each pod are assigned the same ASN, and all superspine devices are assigned another ASN.
Overlay Control Protocol	Defines the inter-rack virtual network overlay protocol in the fabric. Overlay control protocol on deployed blueprints can't be changed. Static VXLAN (renamed to Pure IP Fabric in Apstra version 4.2.1) - uses static VXLAN routing the Head End Replication (HER) flooding to distribute Layer 2 virtual network traffic between racks. MP-EBGP EVPN - uses EVPN family eBGP sessions between device loopbacks to exchange EVPN routes for hosts (Type 2) and networks (Type 5). Only homogeneous, single-vendor EVPN fabrics are supported. EVPN-VXLAN capabilities for inter-rack virtual networks are dependent on the make and model of network devices used. See Virtual Networks for more information. External systems must be connected to racks (not spine devices).
Spine to Leaf Links Underlay Type	IPv4 - uses addresses from IPv4 resource pools. IPv6 RFC-5549 - uses addresses from IPv6 resource pools. Not supported when overlay control protocol is MP-EBGP EVPN. IPv6-IPv6 Dual Stack

Table 2: Rack-based Template Structure

Structure	Options
Rack Types	Type of rack and number of each selected rack type. ESI-based rack types in rack-based templates without EVPN are invalid.
Spines	Spine Logical Device and Count - Type and number of spine logical devices Links per Superspine Count and Speed - Number and speed of links to any superspine devices Tags - User-specified. Select tags from drop-down list generated from global catalog or create tags on-the-fly (which then become part of the global catalog). Useful for specifying external routers. Tags used in templates are embedded, so any subsequent changes to tags in the global catalog do not affect templates.

Pod-based Template

Pod-based templates are used to create large, 5-stage Clos networks, essentially combining multiple rack-based templates using an additional layer of superspine devices. The following images show examples of 5-stage Clos architectures built using pod-based templates (Superspine links are not shown for readability purposes). See 5-Stage Clos Architecture for more information.

Single plane, dual superspine4 x plane, 4 x superspine

Pod-based templates include the following details:

Table 3: Pod-based Template Policies

Policy	Option
Spine to Superspine Links	IPv4 - uses addresses from IPv4 resource pools. IPv6 RFC-5549 - uses addresses from IPv6 resource pools. Not supported when overlay control protocol is MP-EBGP EVPN. IPv4-IPv6 Dual Stack
Overlay Control Protocol	Defines inter-rack virtual network overlay protocol used in the fabric. Overlay control protocol on deployed blueprints can't be changed. Static VXLAN (renamed to Pure IP Fabric in Apstra version 4.2.1) - uses static VXLAN routing the Head End Replication (HER) flooding to distribute Layer 2 virtual network traffic between racks. MP-EBGP EVPN - uses EVPN family eBGP sessions between device loopbacks to exchange EVPN routes for hosts (Type 2) and networks (Type 5). Only homogeneous, single-vendor EVPN fabrics are supported. EVPN-VXLAN capabilities for inter-rack virtual networks are dependent on the make and model of network devices used. See Virtual Networks for more information. External systems must be connected to racks (not spine devices).

Table 4: Pod-based Template Structure

Structure	Options
Pods	Type of rack-based template and number of each selected template
Superspines	Superspine Logical Device and Count Plane Count and Per Plane Count - Number of planes and number of superspine devices per plane Tags - User-specified. Select tags from drop-down list generated from global catalog or create tags on-the-fly (which then become part of the global catalog). Useful for specif.ying external routers. Tags used in templates are embedded, so any subsequent changes to tags in the global catalog do not affect templates.

Collapsed Template

Collapsed templates allow you to consolidate leaf, border leaf and spine functions into a single pair of devices. A full mesh topology is created at the leaf level instead of at leaf-spine connections. This spineless template uses L3 collapsed rack types. Collapsed templates have the following limitations:

• No support for upgrading collapsed L3 templates to L3 templates with spine devices (To achieve the same result you could move devices from the collapsed L3 blueprint to an L3 Clos blueprint.)
• Collapsed L3 templates can't be used as pods in 5-stage templates.
• You can't mix vendors inside redundant leaf devices - the two leaf devices must be from the same vendor and model.
• Leaf-to-leaf links can't be added, edited or deleted.
• Inter-leaf connections are limited to full-mesh.
• IPv6 is not supported.

Collapsed templates include the following details:

Table 5: Collapsed Template Policies

Policy

Options

Overlay Control Protocol

Defines the inter-rack virtual network overlay protocol used in the fabric. Overlay control protocol on deployed blueprints can't be changed. Static VXLAN (renamed to Pure IP Fabric in Apstra version 4.2.1) - uses static VXLAN routing the Head End Replication (HER) flooding to distribute Layer 2 virtual network traffic between racks. MP-EBGP EVPN - uses EVPN family eBGP sessions between device loopbacks to exchange EVPN routes for hosts (Type 2) and networks (Type 5). Only homogeneous, single-vendor EVPN fabrics are supported. EVPN-VXLAN capabilities for inter-rack virtual networks are dependent on make and model of network devices used. See Virtual Networks for more information. External systems must be connected to racks (not spine devices).

Table 6: Collapse Template Structure

Structure	Options
Rack Types	Type of L3 collapsed rack and number of each selected rack type.
Mesh Links Count and Speed	Defines the link set created between every pair of physical devices, including devices in redundancy groups (MLAG / ESI). These links are always physical L3. No logical links are needed at the mesh level.