TCP/IP Communications (Velocity)
[This topic is pre-release documentation and is subject to change in future releases. Blank topics are included as placeholders.]
All Microsoft project code named "Velocity" cache hosts use TCP/IP to communicate with each other and support the cache cluster. To enable this communication, firewall exceptions may be required on the cache hosts. Cache clients use TCP/IP for cache operations, but do not require firewall exceptions to communicate with the cluster.
"Velocity" is a high-performance application designed to run within the perimeter of the corporate firewall. To optimize performance, data is not encrypted and is therefore susceptible to network "sniffing" and "replay" attacks.
TCP/IP Port Configuration
To function correctly, each cache server needs firewall exceptions to be configured for the cache host service. Three separate ports are used: the cluster port, the arbitration port, and the cache port.
The port numbers specified for these ports can be different for each cache host and cache client. The cache cluster keeps track of the ports for all cache hosts in the cluster configuration settings so that cache hosts can maintain communications with each other.
Note
Firewall exceptions for these ports can be automatically configured by the installation program during the installation.
These three ports are summarized in the following table:
| Port Name | Default Value | Application Configuration File Attribute | Cluster Configuration File Attribute |
|---|---|---|---|
cache port |
22233 |
|
|
cluster port |
22234 |
Not applicable |
|
arbitration port |
22235 (Cluster Port + 1) |
Not applicable |
Always the |
Note
You can change these values post-installation by using the Set-CacheConfig PowerShell command. For more information, see Cache Administration with PowerShell (Velocity).
Cache Ports
The cache port is used for transmitting data between the cache hosts and your cache-enabled application. You may select any port number for the cache port; the default at installation is 22233.
Cluster Ports
The cache hosts use the cluster port to communicate availability to each of their neighbors in the cluster. You may select any port number for the cluster port; the installation default is 22234.
Arbitration Ports
If a cache host fails, the arbitration port is used to make certain that the cache host is unavailable. The arbitration port number is based on the cluster port. This number is always equal to the cluster port number plus one. Because the cluster port default is 22234, the arbitration port default is 22235.
Security Considerations
Firewall exceptions for these ports are automatically configured by the installation program during the installation process. After uninstalling the cache host service, we recommend that you manually reconfigure these ports based on corporate policy and the needs of other applications on the server. In some cases, that may mean closing these ports in the firewall.
See Also
Concepts
Physical Model (Velocity)
Logical Model (Velocity)
Programming Model (Velocity)
Configuration Model (Velocity)