Diving into Ethernet VPN (EVPN) on Junos

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Ethernet VPN (EVPN) is a technology that provides an overlay solution for Ethernet multipoint services over a MPLS network. It is a key topic in the JNCIS-ENT certification and this blog post will provide a deep dive into EVPN on Junos devices.

What is EVPN?

EVPN is a standards-based technology that provides Layer 2 and Layer 3 VPN services over an IP/MPLS network. It uses BGP as the control plane protocol and MPLS for forwarding. EVPN provides several benefits over traditional Ethernet VPN solutions, including:

All-active multihoming: This allows for load balancing and redundancy across multiple PE devices.
Aliasing: This reduces the amount of traffic sent to the CE devices.
Fast convergence: EVPN provides faster convergence times in the event of a failure.

Configuring EVPN on Junos

Let's look at how to configure EVPN on a Junos device. We'll use a simple topology with two PE devices (PE1 and PE2) and a CE device.

First, we need to configure the MPLS and BGP settings on the PE devices. Here's an example configuration for PE1:

set protocols mpls interface ge-0/0/0.0
set protocols bgp group EVPN type internal
set protocols bgp group EVPN local-address 10.0.0.1
set protocols bgp group EVPN family evpn signaling
set protocols bgp group EVPN neighbor 10.0.0.2

Next, we need to configure the EVPN instance. Here's an example configuration:

set routing-instances EVPN-Instance instance-type evpn
set routing-instances EVPN-Instance route-distinguisher 10.0.0.1:100
set routing-instances EVPN-Instance vrf-target target:1:100
set routing-instances EVPN-Instance protocols evpn extended-vlan-list 100
set routing-instances EVPN-Instance interface ge-0/0/1.0

This configuration creates an EVPN instance with a route distinguisher and target of 10.0.0.1:100 and 1:100 respectively. It also specifies VLAN 100 for the EVPN instance and assigns interface ge-0/0/1.0 to the instance.

The configuration for PE2 is similar, but with the appropriate IP addresses and route distinguisher/target values.

Finally, we need to configure the CE device. This involves configuring the interface that connects to the PE device and assigning it to the appropriate VLAN. Here's an example configuration:

set interfaces ge-0/0/0 unit 0 family ethernet-switching interface-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members 100

Verifying EVPN Operation

Once the configuration is complete, we can verify the operation of EVPN using several show commands. Here are a few examples:

show evpn instance: This command displays information about the EVPN instances.
show evpn database: This command displays the EVPN database, which includes information about the MAC addresses learned by EVPN.
show bgp summary: This command displays a summary of the BGP neighbors, which should include the EVPN peer.

Conclusion

EVPN is a powerful technology that provides flexible and scalable Ethernet VPN solutions. It is a key topic in the JNCIS-ENT certification and understanding it is crucial for anyone working with Junos devices in a service provider or large enterprise environment.