en-US/using-netscaler-load-balancers.xml

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<section id="using-netscaler-load-balancers">
  <title>About Using a NetScaler Load Balancer</title>
  <para>Citrix NetScaler is supported as an external network element for load balancing in zones
    that use isolated networking in advanced zones. Set up an external load balancer when you want
    to provide load balancing through means other than &PRODUCT;’s provided virtual router.</para>
  <note>
    <para>In a Basic zone, load balancing service is supported only if Elastic IP or Elastic LB
      services are enabled.</para>
  </note>
  <para>When NetScaler load balancer is used to provide EIP or ELB services in a Basic zone, ensure
    that all guest VM traffic must enter and exit through the NetScaler device. When inbound traffic
    goes through the NetScaler device, traffic is routed by using the NAT protocol depending on the
    EIP/ELB configured on the public IP to the private IP. The traffic that is originated from the
    guest VMs usually goes through the layer 3 router. To ensure that outbound traffic goes through
    NetScaler device providing EIP/ELB, layer 3 router must have a policy-based routing. A
    policy-based route must be set up so that all traffic originated from the guest VM's are
    directed to NetScaler device. This is required to ensure that the outbound traffic from the
    guest VM's is routed to a public IP by using NAT.For more information on Elastic IP, see <xref
      linkend="elastic-ip"/>. </para>
  <para>The NetScaler can be set up in direct (outside the firewall) mode. It must be added before
    any load balancing rules are deployed on guest VMs in the zone.</para>
  <para>The functional behavior of the NetScaler with &PRODUCT; is the same as described in the
    &PRODUCT; documentation for using an F5 external load balancer. The only exception is that the
    F5 supports routing domains, and NetScaler does not. NetScaler can not yet be used as a
    firewall.</para>
  <para>To install and enable an external load balancer for &PRODUCT; management, see <phrase
      condition="install"><xref linkend="external-guest-lb-integration"/>.</phrase>
    <phrase condition="admin">External Guest Load Balancer Integration in the Installation
      Guide.</phrase>
  </para>
  <para>The Citrix NetScaler comes in three varieties. The following table summarizes how these
    variants are treated in &PRODUCT;.</para>
  <informaltable>
    <tgroup cols="3" align="left" colsep="1" rowsep="1">
      <thead>
        <row>
          <entry><para>NetScaler ADC Type</para></entry>
          <entry><para>Description of Capabilities</para></entry>
          <entry><para>&PRODUCT; Supported Features</para></entry>
        </row>
      </thead>
      <tbody>
        <row>
          <entry><para>MPX</para></entry>
          <entry><para>Physical appliance. Capable of deep packet inspection. Can act as application
              firewall and load balancer</para></entry>
          <entry><para>In advanced zones, load balancer functionality fully supported without
              limitation. In basic zones, static NAT, elastic IP (EIP), and elastic load balancing
              (ELB) are also provided.</para></entry>
        </row>
        <row>
          <entry><para>VPX</para></entry>
          <entry><para>Virtual appliance. Can run as VM on XenServer, ESXi, and Hyper-V hypervisors.
              Same functionality as MPX</para></entry>
          <entry><para>Supported on ESXi and XenServer. Same functional support as for MPX.
              &PRODUCT; will treat VPX and MPX as the same device type.</para></entry>
        </row>
        <row>
          <entry><para>SDX</para></entry>
          <entry><para>Physical appliance. Can create multiple fully isolated VPX instances on a
              single appliance to support multi-tenant usage</para></entry>
          <entry><para>&PRODUCT; will dynamically provision, configure, and manage the life cycle of
              VPX instances on the SDX. Provisioned instances are added into &PRODUCT; automatically
              – no manual configuration by the administrator is required. Once a VPX instance is
              added into &PRODUCT;, it is treated the same as a VPX on an ESXi host.</para></entry>
        </row>
      </tbody>
    </tgroup>
  </informaltable>
</section>