IGP Extensions for Optimized SRv6 SID Advertisement

When the IGP runs SRv6 Flex-Algo or performs QoS resource allocation, it needs to assign a large number of END.X SIDs, which can significantly impact IGP LSDB advertisements and overall performance. This document proposes a simplified method for advertising a large number of SRv6 SIDs. This method is particularly useful in scenarios that require generating many END.X SIDs, such as when supporting numerous Flex-Algo algorithms. It helps reduce the size of LSDB advertisements and improves IGP advertisement efficiency and operational performance.