This feature extends the traffic engineering capability with the support of IPv6 TE links and nodes.
This feature enhances IS-IS, BGP-LS and the TE database with the additional IPv6 link TLVs and TE link TLVs and provides the following three modes of operation of the IPv4 and IPv6 traffic engineering in a network:
legacy mode
This mode enables the existing traffic engineering behavior for IPv4 RSVP-TE and IPv4 SR-TE. Only the RSVP-TE attributes are advertised in the legacy TE TLVs that are used by both RSVP-TE and SR-TE LSP path computation in the TE domain routers. In addition, IPv6 SR-TE LSP path computation can now use these common attributes.
legacy mode with application indication
This mode is intended for cases where link TE attributes are common to RSVP-TE and SR-TE applications and have the same value, but the user wants to indicate on a per-link basis which application is enabled.
Routers in the TE domain use these attributes to compute path for IPv4 RSVP-TE LSP and IPv4/IPv6 SR-TE LSP.
application specific mode
This mode of operation is intended for use cases where TE attributes may have different values in RSVP-TE and SR-TE applications or are specific to one application (for example, RSVP-TE Unreserved Bandwidth and Max Reservable Bandwidth attributes). This mode is also used to advertise the TE attributes for the SR-TE application when RSVP-TE is disabled on the router.
SR OS does not support configuring TE attributes that are specific to the SR-TE application. As a result, enabling this mode advertises the common TE attributes as sub-TLVs of the new Application Specific Link Attributes TLV. Routers in the TE domain use these attributes to compute paths for IPv4 RSVP-TE LSP and IPv4/IPv6 SR-TE LSP.
See IS-IS IPv4 and IPv6 SR-TE and IPv4 RSVP-TE feature behavior for more details on the IPv4 and IPv6 Traffic Engineering modes of operation.
The feature also adds support of IPv6 destinations to the SR-TE LSP configuration. In addition, this feature also extends the MPLS path configuration with hop indexes that include IPv6 addresses.
IPv6 SR-TE LSP is supported with the hop-to-label and the local CSPF path computation methods. It requires the enabling of the IPv6 traffic engineering feature in IS-IS.