SRv6 Locator Summarization

SRv6 Prefix and Locator Summarization is a scalability feature that condenses SRv6 locators at domain boundaries, reducing the number of IGP routes required for inter-domain connectivity and minimizing unnecessary route advertisements.
Ensuring end-to-end reachability in a multi-domain network design requires loopback addresses to be re-advertised across domains. However, in  SRv6, simply providing connectivity between loopbacks is insufficient for service functionality. Instead, connectivity between SRv6 locators is essential for enabling VPN services it is crucial that  SRv6 locators are also leaked across domain boundaries to support service resolution.
In our tests, the advertised summarization included the local locator/prefix for each ABR alongside the summarized prefix/locator exchanged between Level-1 and Level-2 IS-IS areas in both directions. Additionally, we checked that  ABRs participating in summarization correctly advertised both ‘SRv6 Locator’ TLV and ‘IPv6 Reachability’ TLV for the SRv6 Locator summary since their presence ensures proper forwarding.
We verified that all PEs were able to resolve the summarized locators in their FIB database into functional forwarding paths by generating traffic end-to-end and checking that all traffic successfully reached its destination.