Example: Scaling NLB Solutions

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

An organization provides VPN remote access to the organization’s users through the Internet. The design includes Network Load Balancing to eliminate any application outages and to improve performance. The VPN remote access servers, which run Routing and Remote Access and Windows Server 2003, reside in the organization’s perimeter network, which is located between the Internet and the organization’s private network.

Pilot testing of the VPN remote access solution indicates the need for an increase in remote access client performance. Figure 8.15 illustrates the Routing and Remote Access VPN design to be tested.

Figure 8.15   VPN Solution Pilot Test Environment

VPN Solution Pilot Test Environment

Table 8.23 lists the results of the pilot test for each portion of the design that is illustrated in Figure 8.15.

Table 8.23   Results of VPN Pilot Test

Design Portion Tested Results

Network infrastructure
  • Router-01 was saturated with client traffic.

  • Switch-01 was saturated with client traffic.

  • The network segment between Switch-01 and Router-01 was saturated.

  • The connection to the Internet was saturated.

Cluster hosts hardware
  • Individual cluster hosts lacked sufficient memory to handle the required number of simultaneous users.

  • The total number of cluster hosts was insufficient to handle total number of simultaneous users.

After the pilot test, the organization modifies the VPN remote access design. Figure 8.16 illustrates the modified version of the VPN design.

Figure 8.16   Revised VPN Remote Access Design

Revised VPN Remote Access Design

The organization made the following design decisions to improve scalability for the cluster:

  • Add Firewall-02 and Router-02 to provide additional network bandwidth to the Internet and to solve the saturation problem on Router-01.

  • Add Switch-02 to provide additional network bandwidth to the Internet and to solve the saturation problem on Switch-01.

  • Add memory for all cluster hosts to ensure sufficient system resources for the hosts.

  • Add VPN-07 and VPN-08 to support the maximum number of simultaneous users.