If the IGP issues or receives an LSA/LSP containing a prefix SID sub-TLV for a node SID or a backup node SID with a SID value that is a duplicate of an existing SID or backup node SID, the resolution is indicated in the following table.
Equal/Old means the following:
If the prefix is duplicate, it is equal and no change is needed. Keep the old LSA/LSP.
If the prefix is not duplicate, still keep the old LSA/LSP.
If the prefix is duplicate, it is equal and no change is needed. Keep the old LSA/LSP.
If the prefix is not duplicate, pick a new prefix and use the new LSA/LSP.