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Source Packet Routing in Networking (SPRING) or Segment Routing

  • SRv6 support for static SR-TE policy (MX204, MX960, MX10003, and MX10008)—Starting in Junos OS Release 21.3R1, you can configure static segment routing–traffic engineering (SR-TE) tunnels over an SRv6 data plane.

    Use the following configuration commands to enable SRv6 support:

    • For an SR-TE policy: set protocols source-packet-routing srv6

    • For an SR-TE tunnel: set protocols source-packet-routing source-routing-path lsp name srv6

    • For an SR-TE segment list: set protocols source-packet-routing source-routing-path segment-list srv6

    [See Understanding SR-TE Policy for SRv6 Tunnel.]

  • Avoid microloops in IS-IS segment routing MPLS networks (MX Series routers with MPC7E, MPC8E and MPC9E line cards) —Starting in Junos OS Release 21.3R1, you can enable post-convergence path calculation on a device to avoid microloops between network devices. Microloops form when a network change such as a link or metric change occurs in a segment routing MPLS network. A network change might trigger a loop between upstream and downstream routers for a brief time period because the routers do not update their forwarding state simultaneously.

    To configure microloop avoidance in a segment routing MPLS network, include the maximum-labels and the maximum-srv6-sids statements at the [edit protocols isis spf-options microlooop-avoidance post-convergence-path]hierarchy level.

    [See Understanding Microloop Avoidance}.]

  • Support for Application Specific Link Attributes (ASLA) for flexible algorithms (ACX710, MX204, MX240, MX480, MX960, MX10003, MX 10008, MX10016, MX2008, MX2010, MX2020, PTX1000, PTX5000, PTX10002, PTX10008, PTX10016, VMX): IS-IS supports advertising different te-metric and admin-groups for RSVP and flexible algorithm on the same link using flexible-algorithm specific ASLA as defined in RFC 8919.

    [See strict-asla-based-flex-algorithm]