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source-packet-routing (Protocols IS-IS)

Syntax

Hierarchy Level

Description

Enable source packet routing in networking (SPRING) feature on IS-IS levels or OSPF areas.

Source packet routing for IPv6 is supported only for IS-IS. The adjacency-segment, explicit-null, and srgb statements are supported only for IS-IS.

The remaining statements are explained separately.

Default

Disabled.

Options

adjacency-segment <hold-time hold-time>

Configure attributes for adjacency segments in source packet routing in networking (SPRING), or configure segment routing (SR) to ensure that the adjacency segment identifiers are retained during adjacency or link flaps. The adjacency segments are not released immediately and are retained for the configured hold time duration.

  • hold-time hold-time—(Optional) Duration, in milliseconds, to retain adjacency segments after isolating from an interface. The range is 180,000 through 900,000, with the default being 300,000 milliseconds for IS-IS interfaces and 180,000 milliseconds for OSPF interfaces.

disable

Disable source packet routing from a specific level.

explicit-null

Configure E and P bits in all prefix segment identifier (SID) advertisements.

no-strict-spf

Disable strict spf algo 1 advertisement.

node-segment

Enable source packet routing in networking (SPRING) at all levels. SPRING or segment routing is a control-plane architecture that enables an ingress router to steer a packet through a specific set of nodes and links in the network without relying on the intermediate nodes in the network to determine the actual path it should take.

Provisioning the IPv4 and IPv6 node segment index is allowed per routing-instance, and will NOT be allowed per IS-IS level. Node segment index is attached to the IPv4 and IPv6 router-id, if the router-ids are configured on the loopback interface. Else, lowest IP address on the loopback is chosen to attach the node-sid.

index-range index range

Range of node segment indices allowed. The range is 32 through 16384, and the default is 4096.

ipv4-index index

IPv4 node segment index. The range is 0 through 199999.

Starting with Junos OS Release 17.2, the maximum index for IPv4 node segment index is 199999.

ipv6-index index

IPv6 node segment index. The range is 0 through 199999.

Starting with Junos OS Release 17.2, the maximum index for IPv6 node segment index is 199999.

udp-tunneling

Configure udp-tunneling option to enable SR-o-UDP feature. When this option is enabled, during route computation, IS-IS looks for routes whose next hop neighbor does not support segment routing. IS-IS creates UDP tunnel next hops to every route that does not support segment routing. The source address of UDP tunnel is set to self router-id and destination address of the UDP tunnel is set to the prefix for which route computation is being performed. The statement is introduced only at [edit protocols isis] hierarchy level.

encapsulation The encapsulation statement enables SR-over-UDP encapsulation, thus creates a tunnel to traverse an SR traffic across a non-SR core.
Note:

Configure a filter-based de-encapsulation on MX series router and an FTI-based de-encapsulation on PTX Series routers.

use-flex-algorithm-metric-always

Specify to indicate flex-algo path computations to always use the metric advertised in FAPM during path computation. By default, flex-algo path computation will use FAPM for readvertised prefixes, for which the R bit in prefix SID is considered. In a multi-vendor environment, if this check needs to be relaxed, you can use this option. Path computations will still use FAPM if the winner FAD in that level is set to M flag.

Required Privilege Level

routing—To view this statement in the configuration.

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

Release Information

Statement introduced in Junos OS Release 16.2R1.

Support for explicit-null and adjacency-segment statements introduced in Junos OS Release 17.2R1 for MX Series routers, PTX Series routers, QFX5100 switches and QFX10000 switches.

The udp-tunneling option is introduced in Junos OS Evolved Release 21.2R1.