The terminal PC underlying R2501 cannot access the exterior devices, and the PC cannot communicate its own gateway.
Networking diagram: PC---L2----(gateway)R2501------exterior network
R2501 has the following Alarming Info：
malloc error 32 byte puu is used up ，ARP-rp request malloc failed
1. after enabling ospf and doing routing filter，make R2501 release OSPF routes only，not receive OSPF routes，reduce R2501 routing entries. After saving the configuration, reboot the router.
2. after rebooting, R2501 can forward data normally, and not prompt such information any longer. Till now we can judge because the routing table of OSPF is so large that it occupies the memory, so the ARP entries cannot be saved.
1. from the Alarming Info of R2501，we can know the ARP entries of the router not being established may relate with memory occupation.
2. R2501 enables OSPF protocol，check the routing table and detect the routing table of OSPF is too large，so the memory is occupied fully, and arp entries cannot be established.
3. after undoing OSPF，reboot R2501，PC can communicate with its own gateway and no Alarming Info
“malloc error 32 byte puu is used up，ARP-rp request malloc failed”occurs.