IP Address Translation for ALS Equipment Managers
If ALS is used together with FOXMAN-UN the same problem with IP address translation of Equipment Managers applies as for native FOXMAN-UN Element Agents. Some Equipment Managers offered by ALS listen for SNMP alarm traps on specific IP addresses and ports. The corresponding parameters can be specified per Manager in the ALS Configurator on the respective Manager's SNMP tab. The parameters are named as follows:
• Manager SNMP Trap Reception IP
• Manager SNMP Trap Reception Port
These two parameters are stored in the ALS database which is part of any database dump taken on the Main Server. After transfer of the dump to the Standby Server there is no mechanism in place that replaces a defined Manager SNMP Trap Reception IP valid for the Main Server with the corresponding one on the Standby Server. That means, after import of the database dump on the Standby Server, ALS would not be able to start the corresponding Manager's trap handler (listener) due to an incorrect IP address in the ALS database.
In order to solve this issue, the ALS on the Standby Server must make use of a specific file where a mapping between trap reception IPs of the Main Server and trap reception IPs of the Standby Server can be defined. The file does not exist and must be created by the user on the Standby Server as follows:
/var/lib/ABB/FOXMAN/ALS28/config/TrapIpTranslation.properties
On the Main Server the file is not needed and thus does not need to be created.
After creation of the file on the Standby Server, entries in the form IP1=IP2 can be added, e.g. “172.20.162.223=192.168.32.148”.
Every line in the file signifies that on the Standby Server ALS starts all trap handlers (listeners) on IP2 whose parameter “Manager SNMP Trap Reception IP” equals to IP1 on the Main Server. Additional entries can be appended to the file in order to consider additional SNMP Trap Reception IPs. For instance, if there is an Equipment Manager in ALS that listens for traps on IP 172.20.162.112 on the Main Server and shall listen for traps on IP 192.168.32.112 on the Standby Server, the following entry must be appended to the file:
172.20.162.112=192.168.32.112
The entire file then would read as follows:
172.20.162.223=192.168.32.148
172.20.162.112=192.168.32.112
Please note:
It is also possible to specify 0.0.0.0 as SNMP Trap Reception IP for an ALS Equipment Manager signifying that the corresponding trap receiver listens on all available Ethernet Interfaces (IP addresses) of the system for incoming traps. This address of course does not need an entry in the file TrapIpTranslation.properties as 0.0.0.0=0.0.0.0 becomes superfluous. The problem with specifying 0.0.0.0 as trap reception IP is that it cannot be used for automatic trap subscription through ALS as every equipment needs configuration of a specific Trap Reception IP in order to know where to send its traps to1.
1 ALS offers automatic SNMP Trap Subscription for some of its Equipment Mangers. This means that it registers the corresponding Equipment Manager's SNMP Trap Reception IP and SNMP Trap Reception Port on every respective equipment that it supervises.