Juniper offers several validated EVPN-VXLAN campus fabrics that

cater to a range of network size, scale, and segmentation

requirements:

EVPN multihoming (on collapsed core or distribution): A collapsed

core architecture combines the core and distribution layers into a

single layer, turning the traditional three-tier hierarchal network into

a two-tier network. EVPN multihoming on a collapsed core

eliminates the need for Spanning Tree Protocol (STP) across campus

networks by providing link aggregation capabilities from the access

layer to the core layer. This topology is best suited for small to

medium distributed enterprise networks and allows for consistent

VLANs across the network. This topology uses ESI (Ethernet

Segment Identifier) LAG (Link Aggregation) and is a standards-based

protocol.

Campus Fabric Core distribution: When EVPN VXLAN is

configured across core and distribution layers, it becomes a campus

Fabric Core Distribution architecture that can be configured in two

modes: centrally or edge routed bridging overlay. This architecture

provides an opportunity for an administrator to move toward

campus-fabric IP Clos without a forklift upgrade of all access

switches in the existing network while bringing in the advantages of

moving to a campus fabric and providing an easy way to scale out

the network.

Campus fabric IP Clos: When EVPN VXLAN is configured on all

layers, including access, it is called the campus fabric IP Clos

architecture. This model is also referred to as “end-to-end,” given

that VXLAN tunnels are terminated at the access layer. Due to the

availability of VXLAN at access, it provides us with the opportunity

to bring policy enforcement to the access layer (closest to the

source) using GBP. Standards-based GBP tags bring the unique

option to segment traffic both at a micro and macro level. GBP tags

are assigned dynamically to clients as part of Radius transaction by

Mist Cloud NAC. This topology works for small to medium and

large campus architectures that need macro and

microsegmentation.

Figure 3: Campus fabrics showing Virtual Chassis and EVPN-VXLAN-based architectures

All three topologies are standards-based and interoperable with

third-party vendors. The EX4100-H switches can be deployed in

campus and branch access layer networks in the EVPN-VXLAN

architectures shown in Figure 3.

Managing AI-driven Campus Fabric with Juniper Mist Cloud

Juniper Mist Wired Assurance brings cloud management and Mist

AI to the campus fabric. It sets a new standard that moves away

from traditional network management toward AI-Native operations

while delivering better experiences to connected devices. Juniper

Mist Cloud streamlines deployment and management of campus

fabric architectures by allowing:

• Automated deployment and zero-touch provisioning (ZTP)

• Anomaly detection

• Root cause analysis

Figure 4: EVPN multihoming configuration via the Juniper Mist Cloud

Chassis-Class Availability

EX4100-H switches deliver high availability through redundant

power supplies, graceful Routing Engine switchover (GRES), and

nonstop bridging and routing when deployed in a Virtual Chassis

configuration. In a Virtual Chassis configuration, each EX4100-H

switch is capable of functioning as a Routing Engine (RE). When

two or more EX4100-H switches are interconnected, a single

control plane is shared among all Virtual Chassis member switches.

Junos OS automatically initiates an election process to assign a

primary (active) and backup (hot-standby) RE. An integrated L2 and

L3 GRES feature maintains uninterrupted access to applications,

services, and IP communications in the unlikely event of a primary

RE failure.

When more than two switches are interconnected in a Virtual

Chassis configuration, the remaining switch elements act as line

cards and are available to assume the backup RE position should

the designated primary RE fail. Primary, backup, and line card

priority status can be assigned to dictate the order of ascension.

This N+1 RE redundancy, coupled with the GRES, nonstop active

routing (NSR), and nonstop bridging (NSB) capabilities of Junos OS,

EX4100-H Line of Ethernet Switches Datasheet

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