Quality of Service Policy

Aquality of service (QoS) policy assigns a system class to the outgoing traffic for a vNIC or vHBA. This
systemclass determines the quality of service for that traffic. For certain adapters you can also specify additional
controlson the outgoing traffic, such as burst and rate.
Youmust include a QoS policy in a vNIC policy or vHBA policy and then include that policy in a service
profileto configure the vNICor vHBA.

Flow Control Policy

Flowcontrol policies determine whether the uplink Ethernet ports in a Cisco UCS domain send and receive
IEEE802.3x pauseframes when the receivebuffer for a port fills. These pause frames request that the
transmittingport stop sendingdata fora fewmilliseconds until thebuffer clears.
Forflow control to work between a LAN port and an uplink Ethernet port, you must enable the corresponding
receiveand send flow controlparameters for both ports. For Cisco UCS, the flow control policies configure
theseparameters.
Whenyou enable the send function, the uplink Ethernet port sends a pause request to the network port if the
incomingpacket rate becomes too high. The pause remains in effect for a few milliseconds before traffic is
resetto normal levels. If you enable the receive function, the uplink Ethernet port honors all pause requests
fromthe network port. All traffic is halted on that uplink port until the network port cancels the pause request.
Becauseyou assign the flow control policy to the port, changes to the policy have an immediate effect on how
theport reacts to a pause frame or a full receive buffer.
Opt-In Features
EachCisco UCS domain is licensed for all functionality. Depending upon how the system is configured, you
candecide to opt in to some features or opt out of them for easier integration into existing environment. If a
processchange happens, you can change your system configuration and include one or both of the opt-in
features.
Theopt-in featuresare as follows:
• Stateless computing, which takes advantage of mobile service profiles with pools and policies where
eachcomponent, such as a server or an adapter, is stateless.
• Multi-tenancy,which uses organizations and role-based access control to divide the system into smaller
logicalsegments.

Stateless Computing

Statelesscomputing allows you to use a service profile to apply the personality of one server to a different
serverin the same Cisco UCS domain. The personality of the server includes the elements that identify that
serverand make it unique in the Cisco UCS domain. If you changeany of theseelements, the server could
loseits abilityto access, use, or even achieve booted status.
Theelements that makeup aserver's personalityinclude the following:
• Firmware versions
• UUID (used for server identification)
Cisco UCS Manager GUI Configuration Guide, Release 2.0
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Opt-In Features