Dell Brocade Adapters User Manual
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Brocade Adapters Installation and Reference Manual
53-1002144-01
Adapter features
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Failback mode is an extension of the Failover mode. In addition to the events that occur
during a normal failover, if the original primary port comes back up, that port again
becomes the primary port.
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802.3ad is an IEEE specification that includes Link Aggregation Control Protocol (LACP) as
a method to control how several physical ports bundle to form a single logical channel.
LACP allows a network device to negotiate automatic bundling of links by sending LACP
packets to the peer (a device directly connected to a device that also implements LACP).
This mode provides larger bandwidth in fault tolerance.
Configuration is required on the switch for NIC teaming to function.
Be aware when configuring ports for teaming that converged FCoE and network traffic is not
supported on ports that participate in an IEEE 802.3ad-based team. This must be enforced by
the user as there is no mechanism to control this in the software.
Teaming is implemented by Brocade in the intermediate drivers for Windows 2008 x86_64 and
R2, as well as Windows 2003 x86_64. Teaming is supported on Linux, Solaris, and VMware as
implemented by the specific operating system.
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Look ahead data split
Look ahead split is a security feature for using virtual machine shared memory for a virtual
machine queue, where the adapter splits the data packet so that look ahead data and post
look ahead data are transmitted to the shared memory allocated for this data.
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Multiple transmit (Tx) priority queues. Support for multiple transmit priority queues in the
network driver allows the driver to establish multiple transmit queues and specific priorities in
the ASIC. This feature enables Brocade CNAs and Fabric Adapter ports configured in CNA mode
to pass-link layer traffic using multiple transmit priorities without interfering with the assigned
priority for the FCoE or iSCSI traffic on the same port. This also allows handling of FCoE or iSCSI
priority changes propagated from the DCB switch. Multiple traffic priorities are used to ensure
that Quality of Service (QoS) is guaranteed across different traffic classes. The driver supports
one transmit queue on CNAs and eight on Fabric Adapters. If multiple vNICs are configured on
a Fabric Adapter, each vNIC instance has its own set of eight Tx Queues. To configure multiple
queues for sending priority tagged packets, refer to
Transmit NetQueues with multiple priorities allow VMware (version 4.1 or later) to assign
different priorities to transmit NetQueues to ensure QoS for different classes of traffic on an
ESX host. Multiple transmit priorities are supported in the following ways on Brocade adapters:
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On CNAs and Fabric Adapter ports configured in NIC mode, all eight priorities can be
assigned to transmit NetQueues by VMware.
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On CNAs only, every request to assign a priority different from the default network priority
will be denied. If a storage priority is reserved, one non-default priority could be assigned
to a transmit NetQueue.
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On Network Adapter ports configured in CNA mode, only allowed priorities can be assigned
to transmit NetQueues by VMware. Requests for a priority are denied if the priority
matches a reserved storage priority.
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Interrupt coalescing
Avoids flooding the host system with too many interrupts. This allows the system to reduce the
number of interrupts generated by generating a single interrupt for multiple packets.
Increasing the “coalescing timer” should lower the interrupt count and lessen CPU utilization.