ECT migration

ECT migration enables an I-SID to migrate from one ECT algorithm to another with minimum traffic loss.

To prevent traffic loss, ECT migration was designed based on the idea of make-before-break. All nodes in the SPBM network maintain the old path for the I-SID before a new path is set up. The SPBM nodes remove the old path only after all affected traffic has been moved from the old path to the new path for the I-SID.

As shown in Figure 9, two paths (path A and path B) are available between BEB 1 and BEB 2. B-VLAN 300 has been using path A. As path A is getting congested, you can perform ECT migration to move part of B-VLAN traffic (for example, traffic in I-SID 400) to path B.