Lets Design, Implement and do Administration of ESX3

Virtualization with VMWare Infrastructure 3.0

Network Policy: NIC TEAMING

Posted by Preetam on February 16, 2007

NIC Teaming policies, which includes load balancing and failover settings, allow you to determine how network traffic is distributed between adapters and how to re-route traffic in the event of adapter failure. Default NIC teaming policies are set for the entire virtual switch. And of course can be overridden at port group level.

To modify NIC teaming policies of a port group, click your ESX server’s configuration ->Networking ->Properties link next to virtual switch on which port group is allocated, select port group in the list of ports, Edit and under port group properties NIC Teaming

Load balancing Methods:

Route based on the originating port ID (default) [PortBased] : With this method, VM’s outbound traffic is mapped to specific PhyNIC based on the portID of Virtual Port, to which this virtual machine is connected.This method is simple and fast and doesn’t require VMKernel to examine the frame for necessary information.

Route based on IP hash [IPBased]:In this case NIC card is choosing based upon source and destination address of hte outbound packet. This method has slightly overhead and is not compatible with all switches. but traffic is distributed across NICS

Route based on source MAC hash: Each virtual machine outbound traffic is mapped to phyNIC based upon the VM’s NIC MAC address. It has low overhead and is compatible with all switches but may not spread traffic evenly.

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Detecting and Handling failover

Network Failover Detection: Network failure is detected by VMkernel , which monitors Link state /+ beaconing. Monitoring link state will helps us detect cable pulls or switch failures.Beaconing, VMKernel sends out and listen probe packets on all NICS in team.

Notify Switches: Whenever failure occurs, virtual NIC’s traffic is routed to different NIC, notification is send to switch to modify routing table, in most cases it is desirable to avoid network latency after failovers and VMotion

Rolling failover : Determines how a physical network is returned to active duty after recovering from a failure. If rolling is set toNo, the adapter is returned to active duty immediately upon recovery.


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