Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

 
 

Understanding Automatically Generated ESIs in EVPN Networks

Starting with Junos OS Release 18.4R1, you can configure aggregated Ethernet interfaces and aggregated Ethernet logical interfaces to automatically derive Ethernet segment identifiers (ESIs) from the Link Aggregation Control Protocol (LACP) configuration. Figure 1 shows a simple multihomed network with a customer edge (CE) device multihomed to two provider edge (PE) devices with Link Aggregation Control Protocol (LACP). This feature automatically derives the ESI from the system ID and the administrative key on the local PE device in the LACP link (actor). Starting in Junos OS Release 22.2R1, we support other automatic ESI derivation methods. See Other Methods to Auto-Derive the ESI.

Figure 1: Simple Multihomed Topology Simple Multihomed Topology

We support this feature in the following environments:

  • On Juniper Networks devices that support this feature and are multihomed in active-active mode in an EVPN-VXLAN overlay network.

  • On Juniper Networks devices that support this feature and are multihomed in active-standby or active-active mode in an EVPN-MPLS overlay network.

This topic includes the following information:

Benefits

  • In large EVPN-VXLAN and EVPN-MPLS overlay networks, frees you from manually configuring ESIs.

  • Eliminates the possibility of inadvertently configuring the same ESI for multiple Ethernet segments.

Automatic ESI Configuration

In general, you can configure ESIs on aggregated Ethernet interfaces and aggregated Ethernet logical interfaces using the following methods:

  • Method 1—You can configure automatic ESI on an aggregated Ethernet interface on which LACP is enabled. In this case, an ESI is generated, and that particular ESI is assigned to all logical interfaces on the aggregated Ethernet interface.

  • Method 2—You can configure automatic ESI on one or more logical interfaces of an aggregated Ethernet interface on which LACP is configured. In this case, an ESI is generated for each logical interface on which the feature is enabled and assigned to that particular logical interface.

  • Method 3—On an aggregated Ethernet interface on which LACP is enabled, you can manually configure an ESI using the esi identifier configuration statement at the [edit interfaces aeX] hierarchy level. On one or more logical interfaces on that particular aggregated Ethernet interface, you can configure automatic ESI. In this case, an ESI is generated for each logical interface on which the feature is enabled and assigned to that particular logical interface.

Table 1 outlines the automatic ESI configuration options, how to configure each option, and how the ESI is derived for each option.

Table 1: Automatic ESI Configuration Options

Configuration Options

How to Configure Automatic ESI

How ESI Is Derived

Configure automatic ESI on an aggregated Ethernet interface on which LACP is enabled.

Include the auto-derive and lacp configuration statements at the [edit interfaces aeX esi] hierarchy level.

The ESI is derived from the configured values for the system-id and admin-key configuration statements at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level.

Configure automatic ESI on an aggregated Ethernet logical interface. LACP is enabled on the parent aggregated Ethernet interface.

Include the auto-derive and lacp configuration statements at the [edit interfaces aeX unit logical-unit-number esi] hierarchy level.

The ESI is derived from the configured values for the system-id configuration statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level and the vlan-id configuration statement at the [edit interfaces aeX unit logical-unit-number] hierarchy level. If a logical interface is configured as a trunk interface (interface-mode trunk) and has a VLAN ID list associated with it, the lowest VLAN ID value is used.

Note:

Starting in Junos OS Release 22.2R1, the lacp configuration statement has been renamed and aliased to the lacp-pe-system-id-and-admin-key configuration statement.

When implementing the automatic ESI feature, keep the following in mind:

  • In your EVPN-VXLAN or EVPN-MPLS overlay network, you can configure automatic ESI using a mix of method 1, 2, and 3 configuration use cases.

  • If a local device is multihomed to two remote devices, we recommend that the aggregated Ethernet and aggregated Ethernet logical interfaces by which the three devices are multihomed have the automatic ESI feature enabled. If the automatic ESI feature is not enabled on one of the interfaces, that interface is not considered during the designated forwarder (DF) election process.

  • The automatically generated ESI is supported in both modulo operation- and preference-based DF election processes.

  • If you enable the automatic ESI feature and manually configure an ESI on a particular aggregated Ethernet interface or aggregated Ethernet logical interface, you will receive an error when you try to commit the configuration.

  • If you enable the automatic ESI feature on an aggregated Ethernet interface and one or more of the logical interfaces on that particular aggregated Ethernet interface, you will receive an error when you try to commit the configuration.

Method 1 Sample Configuration—Automatic ESI on An Aggregated Ethernet Interface

The following example shows the configuration of automatic ESI on aggregated Ethernet interface ae0, which is multihomed in active-active mode. This configuration results in an ESI that is automatically generated based on the LACP configuration and assigned to logical interfaces ae0.0, ae0.100, ae0.101, and ae0.102.

Method 2 Sample Configuration—Automatic ESI On Aggregated Ethernet Logical Interfaces

The following example shows the configuration of automatic ESI on aggregated Ethernet logical interfaces ae0.0, ae0.100, ae0.101, and ae0.102, all of which are multihomed in active-active mode. This configuration results in ESIs that are automatically generated based on the LACP and VLAN ID configurations and assigned to each respective logical interface.

Method 3 Sample Configuration—Manual ESI on Aggregated Ethernet Interface and Automatic ESI on Logical Interfaces

The following example shows the manual configuration of an ESI on aggregrated Ethernet interface ae0, and the configuration of automatic ESI on logical interfaces ae0.0, ae0.100, ae0.101, and ae0.102. All interfaces are multihomed in active-active mode. This configuration results in ESI 00:11:22:33:44:55:66:77:88:99 being assigned to ae0, and ESIs that are automatically generated based on the LACP and VLAN ID configurations and assigned to the respective logical interfaces.

Other Methods to Auto-Derive the ESI

Network operators might not be managing all the devices in an EVPN-VXLAN network but they must still ensure that the ESI is unique. Juniper provides other methods to automatically derive an ESI.

Include the following statements at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level.

  • type-1-lacp—Type 1 uses the system ID and the administrative key on the remote CE device in the LACP link (partner).

  • type-3-system-mac—Type 3 uses the mac and local-discriminator values that are configured on the PE device.

We support configuring type 1 and type 3 auto-derived ESI on multihomed devices in the all-active mode in an EVPN-VXLAN network.

ESI Value Format

When the automatic ESI feature is configured, the aggregated Ethernet and aggregated Ethernet logical interfaces derive the ESIs from various configurations on the aggregated Ethernet interface. The 10-byte ESI value for the different auto-derived ESI options is shown in Figure 2 and described in Table 2.

Figure 2: ESI Value Format ESI Value Format
Table 2: ESI Value Format
Auto-Derived Option T (ESI Type) ESI Value
lacp-pe-system-id-and-admin-key

Type 1—The first octet is encoded as 0x01.

The next eight octets are generated from the LACP configuration on the local PE device (actor):

  • The LACP system MAC address includes the system-id configuration statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level.
  • The Port Key field consists of a two octet field from either:

    • The value of the admin-key configuration statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level.

    • The value of the vlan-id configuration statement at the [edit interfaces aeX unit logical-unit-number] hierarchy level.

The last octet is encoded as 0x00.

type-1-lacp

Type 1—The first octet is encoded as 0x01.

The next eight octets are generated from the LACP configuration on the remote CE device (partner):

  • The LACP system MAC address includes the system-id configuration statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level.
  • The Port Key field consists of a two octet field from either:

    • The value of the admin-key configuration statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level.

    • The value of the vlan-id configuration statement at the [edit interfaces aeX unit logical-unit-number] hierarchy level.

Note:

The system-id and admin-key are optional on the CE device. If you do not configure these options, the device will derive the ESI from the interface of the CE device and a system generated number.

The last octet is encoded as 0x00.

type-3-system-mac

Type 3—The first octet is encoded as 0x03.

The remaining octets are generated from the values of the mac and local-discriminator values at the [edit interfaces aeX esi auto-derive] hierarchy level.

Configuring Type 1 and Type 3 Automatic Derivation

Figure 3 show a simple multihomed topology with PE1 and PE2 multihomed to CE1.

Figure 3: Multihomed Topology Multihomed Topology

Configure Automatic Derivation Using Type 1

The following example shows a type 1 configuration on the aggregated Ethernet interfaces on CE1 and one PE device. The result is an ESI that is derived from the LACP configuration on CE1.

Configure Automatic Derivation Using Type 3

The following example shows the configuration of automatic ESI on the aggregated Ethernet interface that is using the locally configure system mac and local discriminator options on the PE1 device.

Release History Table
Release
Description
22.2R1
Starting in Junos OS Release 22.2R1, you can configure the ESI to be derived from the system ID and the administrative key on the remote CE device in the LACP link or from the mac and local discriminator values on the PE device.
18.4R1
Starting with Junos OS Release 18.4R1, you can configure aggregated Ethernet interfaces and aggregated Ethernet logical interfaces to automatically derive Ethernet segment identifiers (ESIs) from the Link Aggregation Control Protocol (LACP) configuration.