Product Documentation

Deployment Worksheet

Aug 09, 2017

On the following worksheet, you can calculate the number of appliances needed for your installation and the recommended mask field size. The recommended mask size is 1-2 bits larger than the minimum mask size for your installation.

Parameter Value Notes
Appliance Model Used  
Supported XenApp and XenDesktop Users Per Appliance Uspec = From data sheet
XenApp and XenDesktop Users on WAN Link Uwan =
User overload Factor Uoverload = Uwan/Uspec =
Supported BW Per Appliance BWspec = From data sheet
WAN Link BW BWwan =
BW Overload Factor BWoverload = BWwan/BWspec =
Number of appliances required N = max(Uoverload, BWoverload) +1 = Includes one spare
Min number of buckets Bmin = N, rounded up a power of 2 =
If SD-WAN 4000 or 5000, Bmin = 2*N, rounded up to a power of 2 =
Recommended value B = 4 * Bmin if Bmin <= 16, else 2 * Bmin =
Number of “one” bits in address mask M = log2(B) If B=16, M=4.

Mask value: The mask value is a 32-bit address mask with a number of “one” bits equal to M in the above worksheet. Often these bits can be the least-significant bits in the WAN subnet mask used by your remote sites. If the masks at your remote sites vary, use the median mask. (Example: With /24 subnets, the least significant bits of the subnet are 0x00 00 nn 00. The number of bits to set to one is log2(mask size): if mask size is 16, set four bits to one. So with a mask size of 16 and a /24 subnet, set the mask value to 0x00 00 0f 00.): ______

The above guidelines work only if the selected subnet field is evenly distributed in your traffic, that is, that each address bit selected by the mask is a one for half the remote hosts, and a zero for the other half. Otherwise, load-balancing is impaired. This even distribution might be true for only a small number of bits in the network field (perhaps only two or three bits). If this is the case with your network, instead of masking bits in the offending area of the subnet field, displace those bits to a portion of the host address field that has the 50/50 property. For example, if only three subnet bits in a /24 subnet have the 50/50 property, and you are using four mask bits, a mask of 0x00 00 07 10 avoids the offending bit at 0x00 00 0800 and displaces it to 0x00 00 00 10, a portion of the address field that is likely to have the 50/50 property if your remote subnets generally use at least 32 IP addresses each.

Parameter Value Notes
Final Mask Value  
Accelerated Bridge   Usually apA
WAN Service Group   A service group not already in use on your router (51-255)
LAN Service Group   Another unused service group
Router IP address   IP address of router interface on port facing the appliance
WCCP Protocol (usually “Auto”)  
DC Algorithm   Use “Deterministic” if you have only two appliances or are using dynamic load balancing like HSRP or GSLB. Otherwise, use “Least Disruptive.”