Configuring the Shortcut Function for Static SRv6 TE Flow Groups

Enable the shortcut function for static SRv6 TE flow groups so that an IGP uses an SRv6 TE flow group that is up to perform enhanced SPF calculation.

Prerequisites

Before configuring the shortcut function for static SRv6 TE flow groups, complete one of the following tasks:

Context

An SRv6 TE flow group is a set of SRv6 TE Policies and can be used to implement DSCP-based traffic steering. It contains multiple SRv6 TE Policies with the same endpoint but different color values. During service recursion, service traffic is matched against SRv6 TE Policies in the SRv6 TE flow group according to the DSCP values carried by the traffic.

The mapping between DSCP values and SRv6 TE Policies can be statically configured in an SRv6 TE flow group and applies to both IPv4 and IPv6 services. Only an SRv6 TE Policy in the up state can be mapped to a DSCP value.

In the implementation of the shortcut function for a static SRv6 TE flow group, the SRv6 TE flow group is considered a local direct link. An IGP uses the SRv6 TE flow group as an outbound interface to perform enhanced SPF calculation. If the headend and endpoint of the SRv6 TE flow group match the ingress and egress of a physical link on the SPF tree, respectively, the IGP uses the SRv6 TE flow group to replace the physical link, implementing the shortcut function for the SRv6 TE flow group. During data forwarding, a node steers data traffic into the corresponding SRv6 TE flow group based on DSCP values, thereby meeting SLA requirements.

Although a device on which the shortcut function for SRv6 TE flow groups is enabled uses an SRv6 TE flow group as an outbound interface, it does not advertise the SRv6 TE flow group to its neighbors. As such, other devices cannot use the SRv6 TE flow group.

Procedure

Run system-view
The system view is displayed.
Run segment-routing ipv6
SRv6 is enabled, and the SRv6 view is displayed.
Run srv6-te flow-group group-name
The SRv6 TE Policy view is displayed.
Run endpoint ipv6-address
An endpoint address is configured for the SRv6 TE flow group.

During route recursion, the device checks whether the next hop address of the route matches the endpoint address of the SRv6 TE flow group. If they match, route recursion succeeds.
Run igp shortcut isis [ route-policy route-policy-name ]
The shortcut function is enabled for the SRv6 TE flow group.

If the route-policy route-policy-name parameter is not configured, only 128-bit host routes can recurse to the SRv6 TE flow group by default. However, if the route-policy route-policy-name parameter is configured, the specified route-policy is used to selectively recurse routes to the SRv6 TE flow group after path calculation is complete.
Run isis ipv6 enable [ instanceId ]
IS-IS IPv6 is enabled for the SRv6 TE flow group and the ID of the IS-IS process to be associated is specified.
Run match-type dscp
The mapping type of the SRv6 mapping policy is set to DSCP.
Run index index-value dscp { { dscpBegin [ to dscpEnd ] } &<1-64> } match { srv6-te-policy color color-value | native-ip } or default match { srv6-te-policy color color-value | native-ip }
A rule is configured either for the mapping between the color values of SRv6 TE Policies in an SRv6 TE flow group and the DSCP values of packets or for the mapping between native IP links in an SRv6 TE flow group and the DSCP values of packets.

When packets with DSCP values enter an SRv6 TE flow group, they are matched against the following rules in sequence to achieve forwarding:
1. The packets are first strictly matched against the SRv6 TE Policy-specific or native IP link-specific rule configured with specified DSCP values.
2. If the matching fails, the packets are matched against the SRv6 TE Policy-specific or native IP link-specific rule configured with the default priority.
3. If the matching fails, the packets are matched against the SRv6 TE Policy-specific or native IP link-specific rule configured with the smallest DSCP value.
Only an SRv6 TE Policy in the up state can be mapped to a DSCP value.

The mapping rule takes effect for an SRv6 TE flow group only when it is up.
Run commit
The configuration is committed.

Verifying the Configuration

After the configuration is complete, verify the configuration.

Run the display srv6-te flow-group command to check SRv6 TE flow group details.
Run the display srv6-te flow-group last-down-reason command to check the records about SRv6 TE flow group down events.
Run the display srv6-te flow-group statistics command to check SRv6 TE flow group statistics.
Run the display isis route [ process-id ] ipv6 [ topology topology-name ] [ verbose | [ level-1 | level-2 ] | ipv6-address [ prefix-length ] ] ^* [ | count ] command to check IS-IS routing information.
Run the display ipv6 routing-table ipv6-address [ prefix-length ] [ longer-match ] verbose or display ipv6 routing-table brief command to check IPv6 routing table information.