6.7

Table Of Contents
Physical Switch Configuration
To ensure that IP hash load balancing works correctly, you must have an Etherchannel configured on the
physical switch. An Etherchannel bonds multiple network adapters into a single logical link. When ports
are bound into an Etherchannel, every time the physical switch receives a packet from the same virtual
machine MAC address on different ports, the switch updates its content addressable memory (CAM) table
correctly.
For example, if the physical switch receives packets on ports 01 and 02 from MAC address A, the switch
makes a 01-A and a 02-A entry in its CAM table. As a result, the physical switch distributes the incoming
traffic to the correct ports. Without an Etherchannel, the physical switch first makes a record that a packet
from MAC address A is received on port 01, then updates the same record that a packet from MAC
address A is received on port 02. Hence, the physical switch forwards incoming traffic only on port 02,
and might result in packets not reaching their destination and overloading the corresponding uplink.
Limitations and Configuration Requirements
n
ESXi hosts support IP hash teaming on a single physical switch or stacked switches.
n
ESXi hosts support only 802.3ad link aggregation in Static mode . You can only use a static
Etherchannel with vSphere Standard Switches. LACP is not supported. If you enable IP hash load
balancing without 802.3ad link aggregation and the reverse, you might experience networking
disruptions.
n
You must use Link Status Only as network failure detection with IP hash load balancing.
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You must set all uplinks from the team in the Active failover list . The Standby and Unused lists must
be empty.
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The number of ports in the Etherchannel must be same as the number of uplinks in the team.
Considerations on Using Route Based on IP Hash
Considerations Description
Advantages
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A more even distribution of the load compared to Route
Based on Originating Virtual Port and Route Based on
Source MAC Hash, as the virtual switch calculates the
uplink for every packet.
n
A potentially higher throughput for virtual machines that
communicate with multiple IP addresses.
Disadvantages
n
Highest resource consumption compared to the other load
balancing algorithms.
n
The virtual switch is not aware of the actual load of the
uplinks.
n
Requires changes on the physical network.
n
Complex to troubleshoot.
vSphere Networking
VMware, Inc. 99