Description

The following messages are logged to a MX-series router, even though no prefix limits are configured:

RPD_RT_PREFIX_LIMIT_REACHED

Symptoms

A MX-series router is logging the following messages to the /var/log/messages system file:

RPD_RT_PREFIX_LIMIT_REACHED: Number of prefixes (32768) in table inet.0 reached configured maximum (32768)
RPD_RT_PREFIX_LIMIT_REACHED: Number of prefixes (32768) in table inet.0 still exceeds or equals configured maximum (32768)

There are no prefix limits configured on the node.

Solution

MX-series routers can be configured to run in IP or Ethernet Services Mode. In this particular scenario, RPD_RT_PREFIX_LIMIT_REACHED messages are logged because the router is configured to run in Ethernet Services Mode. Ethernet Services Mode is limited to Layer 2.5 functions, and can only support up-to 32768 routes in the main routing table. To obtain full functionality, the node must be configured to run in IP Services Mode.

To confirm what mode your router is configured in, you can check under the chassis hierarchy in config mode:

lab@router# show
chassis {
    network-services ethernet;
}

or


lab@router# show
    chassis { network-services ip;
}

The output will show ethernet (layer 2) or IP (layer 3). If you need more than 32,768 routes for your MX and it is configured for ethernet, you will need to change this to IP mode. Changing this will require a reboot of the router to take effect, and is recommended to be performed in a planned maintenance window. Also be aware that some DPC's only power up when the chassis is in ethernet mode. See the MX DPC guide for more details.

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