A subnet is an IPv4 network range that is calculated by the client using the IP Gateway and Subnet information from the network interface used to access the source data.
The correct adapter and path to use are calculated using the Windows API’s. StifleR is able to identify which gateway is the best one to use in order to access the data. StifleR is then able to calculate the subnet based on the first IP address configured on the adapter which is in the same network segment as the gateway that the client is configured to use. The reason for this complexity is that Issues arise as a NIC can have multiple IP addresses on different subnets. Confused? The following may help:
Consider a client machine that has both a Wireless 3G Card and a Cable plugged into a physical Ethernet Port. StifleR provides Windows with the IP address of the source host, and Windows returns the best interface to access the data. An inquiry is then made on that interface which is the best route (gateway) to the source. The best gateway that should be used to access the source data is then returned,. We then iterate through all the available IP Addresses on that interface and identify the first one that has the gateway set to the same as that previously identified. This is then used to calculate the network ID using the IP address and the subnet information. This is the network segment ID that is then send up to the StifleR Server. This should be the correct network ID to use, unless the network segment is broken and clients have switched over to 3G connections or other data networks.
A Location in StifleR management and configuration terms is a physical site that consists of two or more subnets that should be managed as a single entity for the purpose of bandwidth control. These subnets can be defined in many different ways, as VLAN tagging or just a different subnet network IDs. The concept of a Location is then used to group together those subnets into a single management unit. Typical use case would be a remote Location that has several network segments that are logically best managed together due to the fact that they share the same WAN connectivity back to the main Location where the source servers are located.
Creating a Location is as simple as linking together two or more network segments (subnets). This creates a Parent-Child relationship where the Parent subnet string is the identifying item for the Location.
A Location can be used as an administrative container to set a bandwidth limit for an entire remote site. Rather than having to set limits per subnet you can set a limit for all segments that share the same network infrastructure and WAN connection. These settings are configured via the ParentLocation class in WMI. StifleR will calculate the portion of bandwidth for each active Red Leader to use at any time according to the number of active Red Leaders in each Location. For example, if you have 3 network segments at a location but only 2 are actively downloading, the total allowed bandwidth for the Location will be split 50/50 between the two active segments. If another segment becomes active then each would receive 1/3 of the configured bandwidth for that location.
Without Locations configured the Server effectively treats each subnet as a Location which leads to each separate Red Leader trying to use the full link bandwidth.
In StifleR Enterprise each subnet not only has a Red leader assigned for each subnet, but StifleR also assigns a Blue Leader for each subnet. The Blue Leaders are able to facilitate BranchCache data to be shared across segment boundaries which further greatly reduces WAN traffic.
DO groups are set up through WMI by grouping clients together using the DO Group ID. You can set this using a generated GUID (PowerShell can do this for you) or you could use the Location IDs that you are already using in StifleR (these will be unique in your environment). StifleR will check to see if the client is DO capable (Windows Build 14393/Version 1607 and above), DO enabled (Download mode is not set to ”0”) and then check if a DO Group ID is present in the LocationData.xml file. Once StifleR has all of this information DO group membership can be ascertained and the DO group is then managed in the same manner as a location. Note that as the DO group is meant to be well connected and used specifically for P2P file sharing there is no Blue Leader functionality as all members should be local.
As mentioned in the Location segment above, several subnets can be bundled together into a single Location. This creates a many to one relationship between the Child subnet(s) and the Parent subnet. A Parent Location cannot (currently) be set to be a Child of another Location, which logically means that a Child cannot be made Parent for another Location. The “Parent” is simply used for management identification purposes. The Parent subnet is treated equally in all respects to any Child subnets at the Location.
It is suggested for logical tracking purposes that the lowest network ID be set as the Parent network ID. For instance: 10.1.1.0 should be configured as the Parent for 10.1.2.0 and 10.1.3.0.
As an example, we have three network segments, each a standard C class network with a 24 bit subnet mask:
Subnet A: 192.168.1.0/24
Subnet B: 192.168.2.0/24
Subnet C: 192.168.3.0/24
Once you configure Network A to be the Parent of Network B and C the following Location structure would be created:
Parent: Subnet A – 192.168.1.0
Child: Subnet B – 192.168.2.0
Child: Subnet C – 192.168.3.0
Typically, most configuration is still performed on a per subnet basis, and only a few changes are performed on the Location level, primarily the Target Bandwidth setting for the location. In the example above you would set a Target Bandwidth limit of 4096Kbits/s for the Location by setting the a limit on Subnet A (the Parent Subnet and therefore the Location Identifier for management purposes) StifleR will then dynamically apportion the bandwidth for each active Red Leader. If there is an active download current in each Subnet the StifleR Server service would automatically calculate and set a Target Bandwidth of 1365 (4096 / 3) for each of the Red Leaders at that location.