H3C Technologies H3C S12500 Series Switches - Manual (Page 19)

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Figure 8 Multiple SPTs in an SPBM network
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.
Figure 9 ECT migration
Customer site B
Customer site A
Customer site F
Customer site E
Customer site C
BEB
BEB
BEB
BEB
BEB
Customer site D
BEB
BCB
BCB
SPBM
network
ECT 1 B-VLANs 100-200
ECT 2 B-VLANs 300-400
BCB 1
BCB 2
Customer
network
Customer
network
BEB 1 BEB 2
SPBM network
Path A (ECT 1)
Path B (ECT 2)
I-SID 400 B-VLAN 300
B-VLAN 300 ECT 1
B-VLAN 300 ECT 2
B-VLAN 300 ECT 1
B-VLAN 300 ECT 2
CNP
I-SID 400 B-VLAN 300
B-VLAN 300 ECT 1
B-VLAN 300 ECT 2
CNP