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domain-path-id

Syntax

Hierarchy Level

Description

Note:

In Junos OS Release 22.2R1 and 22.3R1, and Junos OS Evolved Releases and 22.2R1 and 22.3R1, the dpath-domain-id statement was called uniform-propagation-mode with a domain-id option. The uniform-propagation-mode statement with the domain-id option has the same functionality as the dpath-domain-id statement.

Starting in Junos OS Release 22.3R2 and Junos OS Evolved Release 22.3R2, the dpath-domain-id statement is now called domain-path-id.

Starting in Junos OS Release 23.2R1 and Junos OS Evolved Release 23.2R1, the domain-path-id is neither exported nor imported by default. Refer to domain-path-id (Protocols BGP) for more information.

When you configure the domain-path-id statement on a gateway provider edge (PE) device, you're enabling the BGP D-PATH attribute for all of the gateway PE's virtual routing and forwarding (VRF) instances. You can use the BGP D-PATH attribute for intersubnet forwarding (ISF) and subsequent address family identifiers (SAFIs) that advertise IP prefix routes. The BGP D-PATH attribute supports EVPN Type 5 and IP-VPN routes.

The BGP D-PATH attribute enables a gateway provider edge (PE) device to add a domain ID to a BGP route. In many situations, a tenant system is located in different data centers, where an IP Virtual Private Network (IP-VPN) is configured in the WAN. In this situation, gateway PEs aren't aware of the domains they traverse and can install suboptimal routes or routing loops in their IP virtual routing and forwarding (IP-VRF) tables. Gateway PEs can then send BGP updates that advertise those routes to other gateway PEs.

The BGP D-PATH attribute extends its path selection algorithm to prevent routing loops. This attribute also ensures that the gateway PEs install the best routes in their IP-VRF tables. When a gateway PE receives an ISF route, it imports the route into its IP-VRF table and adds the BGP D-PATH attribute to its existing path attributes. The gateway PE uses the information in the BGP D-PATH attribute and the ISF routes in its IP-VRF table to identify the domains through which EVPN IP prefix routes and IP-VPN routes have traversed. With this information, the gateway PE determines if a route should be installed in its IP-VRF table. If the route forms a loop, the gateway PE doesn't install the route in its IP-VRF table.

The BGP D-PATH attribute contains a sequence of domain segments. Each domain segment includes the following fields:

  • Domain segment length

    This segment is a 1-octet field that contains the number of domains in a domain segment.

  • Domain ID

    This segment is a 6-octet field that represents a particular domain. This segment also contains a 4-octet global administrator sub-field and a 2-octet local administrator sub-field. The global administrator sub-field can contain an AS number, an IPv4 address, or any other value that guarantees the uniqueness of the domain ID.

  • ISF_SAFI_TYPE

    This segment is a 1-octet field that identifies the ISF route and the SAFI.

    Table 1: ISF_SAFI Types and Values
    ISF_SAFI Types Values
    IPVPN (SAFI 128) 128
    EVPN (SAFI 128) 70

Required Privilege Level

routing—To view this statement in the configuration.

routing-control—To add this statement to the configuration.

Options

domain-id-string—(Required) Specify the domain ID type and value.

Note:

You can configure only two domain IDs.

The domain ID contains the following elements:

  • Autonomous system (AS) number, IPv4 address, or 4-octet value.

    Note:

    If you use a 4-octet value instead of the AS number or IPv4 value, the value needs to be unique.

  • Local administration subfield.

    Configure a local 2-octet value between 0 to 65535 (0xFFFF) for your local data center.

  • Inter-subnet forwarding identifier (ISF).

  • Subsequent address family identifier (SAFI).

Use this format to create the domain ID type: <ASN | IPv4 address | 4-octet value>:local administration subfield:ISF_SAFI_TYPE.

Here's an example that configures two EVPN ISF_SAFI_TYPE domain IDs with AS number 6500, and local administration subfields 1 and 2 for ISF_SAFI types EVPN and IPVPN, respectively:

Release Information

Statement introduced in Junos OS Release 22.2R1.