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    <title>VRRP Load Balancing Algorithm For Selecting Gigabit Ethernet Interfaces  </title>
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<a name="wp1084619"> </a><h1 class="pTitle">
VRRP Load Balancing Algorithm For Selecting Gigabit Ethernet Interfaces 

</h1>
<a name="wp1084620"> </a><p class="pBody">
When the VRRP master receives an iSCSI session request from an initiator, it first checks for an existing 
mapping to one of the interfaces in that VRRP group. If such a mapping exists, the VRRP master 
redirects the initiator to that interface. If no such mapping exists, the VRRP master selects the least 
loaded interface and updates the selected interface’s load with the initiator’s iSLB metric (weight). 

</p>
<a name="wp1084622"> </a><p class="pBodyAutonumNoRule">
<strong>Note	&nbsp;&nbsp;&nbsp;</strong> The VRRP master interface is treated specially and it needs to take a lower load compared to the other 
interfaces. This is to account for the redirection work performed by the master interface for every 
session. A new initiator is assigned to the master interface only if the following is true for every other 
interface:<br />
<br />
VRRP backup interface load &gt; [2 * VRRP master interface load + 1] 

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<hr /><br><p class="pBody">Copyright 2010-2013, Cisco Systems, Inc. All rights reserved.</p> 

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