> # In-Order Delivery

> In-order delivery (IOD) of data frames guarantees frame delivery to a destination in the same order that they were sent by the originator.

> Some Fibre Channel protocols or applications cannot handle out-of-order frame delivery. In these cases, switches in the Cisco MDS 9000 Family preserve frame ordering in the frame flow. The source ID (SID), destination ID (DID), and optionally the originator exchange ID (OX ID) identify the flow of the frame.

> On any given switch with IOD enabled, all frames received by a specific ingress port and destined to a certain egress port are always delivered in the same order in which they were received.

> Use IOD only if your environment cannot support out-of-order frame delivery.

> Tip If you enable the in-order delivery feature, the graceful shutdown feature is not implemented.

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