Hi @Ahmed Ashfaque ,
Load balancing for Virtual Port Channels in ACI is determined by the Port Channel Policy assigned to the Virtual Interface Port Channel Group.
The mode can be:
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Static Channel - Mode On— All static port channels (that are not running LACP) remain in this mode. If you attempt to change the channel mode to active or passive before enabling LACP, the device displays an error message.
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Active—LACP mode that places a port into an active negotiating state in which the port initiates negotiations with other ports by sending LACP packets.
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Passive—LACP mode that places a port into a passive negotiating state in which the port responds to LACP packets that it receives but does not initiate LACP negotiation. Passive mode is useful when you do not know whether the remote system, or partner, supports LACP.
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MAC Pinning—Used for pinning VM traffic in a round-robin fashion to each uplink based on the MAC address of the VM. MAC Pinning is the recommended option for channeling when connecting to upstream switches that do not support multichassis EtherChannel (MEC).
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MAC Pinning-Physical-NIC-load—Pins VM traffic in a round-robin fashion to each uplink based on the MAC address of the physical NIC.
The default is Static Channel - Mode On.
I hope this helps.
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Hi @Ahmed Ashfaque ,
OK - bit more detail needed.
The answer is still in the Port Channel Policy assigned to the Virtual Interface Port Channel Group - clearly for the MAC Pinning options, the balancing is done based on MAC addresses. But if LACP is used, LACP will negotiate the hashing as set by the other options that are found in the Control field.
And the control field has a few values that can be set. The help explains them
Control:
The LAG control properties. The control state can be:
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Fast Select Hot Standby Ports—Configures fast select for hot standby ports. Enabling this feature will allow fast selection of a hot standby port when last active port in the port-channel is going down.
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Graceful Convergence—Configures port-channel LACP graceful convergence. Disable this only with LACP ports connected to a Non-Nexus peer. Disabling this with Nexus peer can lead to port suspension.
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Load Defer Member Ports—Configures the load-balancing algorithm for port channels that applies to the entire device or to only one module.
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Suspend Individual Port—LACP sets a port to the suspended state if it does not receive an LACP bridge protocol data unit (BPDU) from the peer ports in a port channel. This can cause some servers to fail to boot up as they require LACP to logically bring up the port.
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Symmetric Hashing—Bidirectional traffic is forced to use the same physical interface and each physical interface in the port channel is effectively mapped to a set of flows.
And if Symmetric Hashing is used:
When symmetric hashing is enabled, the parameters used for hashing, such as the source and destination IP address, are normalized before they are entered into the hashing algorithm. This process ensures that when the parameters are reversed (the source on the forward traffic becomes the destination on the reverse traffic), the hash output is the same. Therefore, the same interface is chosen.
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Destination IP
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Layer4 Dest Port
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Layer4 Src Port
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Source IP
You won't actually see those options UNLESS you select Symmetric Hashing
Also be aware that only one hashing method can be deployed per switch.
