IBM Tivoli Monitoring > Version 6.3 Fix Pack 2 > Installation Guides > Installation Guide > Configure IBM Tivoli Monitoring components > Control port number assignments
IBM Tivoli Monitoring, Version 6.3 Fix Pack 2
Configure port number assignments for monitoring agents
If multiple Tivoli Monitoring agents are installed on the same system, they cannot share the same port number for IP.PIPE and IP6.PIPE, or IP.SPIPE and IP6.SPIPE communications. An automatic mechanism has been developed to allocate additional ports for communications to the monitoring server. IBM Tivoli Monitoring uses the following algorithm to allocate port numbers for monitoring agents to reach the monitoring server: reserved port = well-known port + (N*4096)
where:
- well-known port is the port number assigned to the monitoring server, for example, 1918.
- N indicates the position of the monitoring agent in the startup sequence for agents.
For example, if there are two monitoring agents on a system, and the monitoring server uses port 1918, the first monitoring agent in the startup sequence is assigned port 6014 (1918 + 1*4096), and the second agent to start is assigned port 10110 (1918 + 2*4096). These port assignments occur automatically to avoid conflicts between multiple monitoring agents.
For "piped" protocols such as IP.PIPE, IP6.PIPE, IP.SPIPE, and IP6.SPIPE (but not IP, IP6, or SNA), you also have the ability to control how port numbers are assigned to a monitoring agent using the SKIP and COUNT parameters on the KDE_TRANSPORT environment variable. These two parameters are described in more detail below, but here is an example of how you might use them when configuring a monitoring agent:
KDE_TRANSPORT=IP.PIPE PORT:1918 COUNT:1 SKIP:2 IP use:n SNA use:n IP.SPIPE use:nSee also the following information about using the IP.PIPE, IP6.PIPE, IP.SPIPE, and IP6.SPIPE protocols and parameters:
- The PORT parameter specifies the well-known port for the monitoring server.
- The piped protocols allocate one, and only one, physical port per process.
- There can be at most 16 IP.PIPE/IP6.PIPE/IP.SPIPE/IP6.SPIPE processes per host.
- If you need to run more than 16 processes on a host, you can choose one of the following options:
- Use IP.UDP (User Datagram Protocol) or IP6.UDP for connections except to and from the Tivoli Enterprise Portal Server. The use of UDP is not recommended for the portal server.
- Add EPHEMERAL:Y as an optional KDE_TRANSPORT setting, for example:
KDE_TRANSPORT=IP.PIPE PORT:1918 EPHEMERAL:Y IP use:n SNA use:n
Marking an agent as ephemeral means that it will not try to open its own listening port. Instead, it will only initiate one-way, outbound communication to the monitoring server.
The COUNT:N parameter is the mechanism for reserving IP.PIPE/IP6.PIPE ports for components that connect to the monitoring server. N is the number of IP.PIPE/IP6.PIPE ports to reserve on a host in addition to the well-known port for the monitoring server. Use the COUNT parameter to reserve ports for components that must be accessible from outside a firewall. Accessibility from outside the firewall requires IP.PIPE/IP6.PIPE ports and because these ports must be permitted at the firewall, the ports must be predictable. For example, if the well-known port is 1918, COUNT:3 starts the search at port 6014 (1918 + 1*4096). If the agent process cannot bind to port 6014, the algorithm tries port 10110 (1918 + 2*4096). If port 10110 is not available, the search goes to port 14206 (1918 + 3*4096).
The agent is assigned to the first available port encountered in the search. The process fails to start if the search reaches the highest port without a successful binding (port 14206 in this example).
The SKIP:N parameter specifies the number of ports to skip when starting the search for an available port using the port assignment algorithm. Use the SKIP parameter for components that do not need access across a firewall. For example, if the well-known port is 1918, SKIP:2 specifies to start the search at port 10110 (1918 + 2*4096), skipping ports 1918 and 6014 (1918 + 1*4096). The algorithm continues searching until it finds an available port.
The USE parameter enables or disables a protocol. To disable a protocol, specify use:n. To enable a protocol, specify use:y. This parameter has no default.
Tivoli Monitoring agents allocate ports 1920 and 3661 as HTTP and HTTPS listener ports.
In environments behind firewalls it is critical that the Warehouse Proxy Agent listens on the same port each time it is started. To ensure a consistent IP.PIPE/IP6.PIPE listening port, regardless of the sequence in which other monitoring agents on the system are started, the Warehouse Proxy Agent by default uses the high-numbered port 63358. This is accomplished by leveraging the COUNT and SKIP parameters. The Warehouse Proxy Agent internally sets COUNT:1 and SKIP:15 in order to obtain 63358 as its listening port (63358 = 1918 + (15 * 4096)). You do not need to add these parameters when configuring the Warehouse Proxy Agent. All other monitoring agents that archive their historical data should then configure 63358 as the well-known listening port of the Warehouse Proxy Agent.
You are not required to use port 63358 for the Warehouse Proxy Agent, but this is the most commonly used port. If you decide to use a different listening port, then you will need to add your own custom COUNT and SKIP values when configuring the agent.
Example
The example in Table 1 shows the coding to use on a system that contains the components shown:
Using COUNT and SKIP variables to assign port numbers
Component Coding Tivoli Enterprise Monitoring Server The monitoring server uses port 1918. Warehouse Proxy Agent
- Requires firewall access
This coding reserves port 63358 (1918 + 15*4096) for the Warehouse Proxy Agent.
Windows OS agent
- Does not require firewall access
This coding reserves port 10110 (1918 + 2*4096) for the Windows OS agent. If the agent fails to open port 10110, it tries port 14206 and so on, until it finds an available port or exhausts all possibilities.
- Add the KDE_TRANSPORT environment variable
The KDE_TRANSPORT environment variable must be added to the appropriate file (*ENV file on Windows).
Parent topic:
Control port number assignments