About Reordering Portchannel Frames - Cisco AP775A - Nexus Converged Network Switch 5010 Configuration Manual

In-Order Delivery
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Figure 32-13
Switch 1
In Figure
4 may be delivered before Frame 1 and Frame 2.
If the in-order guarantee feature is enabled, the frames within the network are treated as follows:
•
•

About Reordering PortChannel Frames

When a link change occurs in a PortChannel, the frames for the same exchange or the same flow can
switch from one path to another faster path.
Figure 32-14
Switch 1
In Figure
can be delivered before Frame 1 and Frame 2.
The in-order delivery feature attempts to minimize the number of frames dropped during PortChannel
link changes when the in-order delivery is enabled by sending a request to the remote switch on the
PortChannel to flush all frames for this PortChannel.
Both switches on the PortChannel must be running Cisco SAN-OS Release 3.0(1) for this IOD
Note
enhancement. For earlier releases, IOD waits for the switch latency period before sending new frames.
When the in-order delivery guarantee feature is enabled and a PortChannel link change occurs, the
frames crossing the PortChannel are treated as follows:
•
Cisco MDS 9000 Family Fabric Manager Configuration Guide
32-16
Route Change Delivery
Switch 2
Frame 2
32-13, the new path from Switch 1 to Switch 4 is faster. In this scenario, Frame 3 and Frame
Frames in the network are delivered in the order in which they are transmitted.
Frames that cannot be delivered in order within the network latency drop period are dropped inside
the network.
Link Congestion Delivery
Frame 2
Frame 4
32-14, the port of the old path (red dot) is congested. In this scenario, Frame 3 and Frame 4
Frames using the old path are delivered before new frames are accepted.
Chapter 32 Configuring Fibre Channel Routing Services and Protocols
Switch 3
Frame 1
Frame 4 Frame 3
Switch 2
Frame 1
Frame 3
Old path
New path
Switch 4
Old path
New path
OL-17256-03, Cisco MDS NX-OS Release 4.x