The IS-IS (Intermediate System to Intermediate System) link-state database is full and no additional memory can be allocated for it.
The problem related to this syslog message is described in the following sections:
The RPD_ISIS_OVERLOAD message is logged when the IS-IS database has run out of memory to perform an update.
The error message reported looks similar to the following:
RPD_ISIS_OVERLOAD: IS-IS database overload
This error may be seen if there is legitimately no additional memory available for storing the IS-IS link-state information.
It may also be seen if the device’s own LSP (Link State PDU (Protocol Data Unit)) requires more than 256 fragments to contain all of the locally-reachable destinations. The IS-IS protocol can hold a maximum 256 of 1492 byte fragments.
It may also result from a software error that affects memory or the routing protocol daemon (rpd), such as a memory leak.
Check for unusually high memory usage by the IS-IS task or rpd (with the commands show system processes extensive and show task memory detail).
Also check the messages log (show log messages) for events occurring around the same time as the message.
Check for any core-dumps (show system core-dumps) that were generated at or near the time of the message. These can be analyzed to determine if there is a memory leak.
Check the number of fragments with the command show isis database. A large number of fragments may indicate a problem.
Deactivate or delete features that use large amounts of memory, such as trace-options, or any unnecessary logging.
If IS-IS export policies are configured, make sure they are correct. Mis-configuration of an export policy can result in a large number of other routes, such as the entire BGP route table being redistributed into IS-IS, which will inflate the link-state database into overload.
If there are any core-dumps or suspicious log messages, consult with your technical support representative to rule out the possibility of a memory leak or other software error.
If the lack of memory is not due to mis-configuration or software error, then your options are to add more memory (your Juniper account team can advise on any possible hardware upgrades) or redesign the network to carry fewer IS-IS routes.