Route-based Forwarding Fails Because the Number of FIB Entries limit
Network Topology
Figure 1-1 Route-based Forwarding Fails
Fault Description
The ping from the NE40 router to the customer service network segment 2400:A980:30FA::1 fails. In the tracert process, traffic is interrupted on the switch. The routing table on the switch is checked, and it is found that a static route is used.
Troubleshooting Procedure
1. The route to the destination address is checked, and statistics about all routes on the switch are queried.
[6720-diagnose] display ipv6 routing-table statistics
Summary Prefixes : 55355
Protocol route active added deleted freed
DIRECT 24 24 42 18 18
STATIC 16 15 26 10 10
RIPng 0 0 0 0 0
OSPFv3 0 0 0 0 0
IS-IS 0 0 0 0 0
BGP 55319 55317 910774 855455 855455
UNR 0 0 0 0 0
2. There are a large number of routes. Therefore, run the following command to check whether the number of routes exceeds the upper limit.
[6720-diagnose] display ipv6 fib overload state slot 0
Overload mode:
Overload forward mode.
Overload state:
Overload forward state.
Root Cause
1. When the number of routes exceeds the upper limit, new Layer 3 forwarding entries cannot be delivered.
2. If routing entries fail to be delivered, data arriving at the device cannot be forwarded.
