Ping in Ethercard Library

Hi, I am using Arduino Uno connect with ENC28J60 and Ethercard Library to run a local Server and it's working well.
But sometimes the request from web browser can not come to the Uno (seem like the Encj60 lost connection) eventhought the Uno still work fine.

How can the Uno know that the connection between ENCJ60 and Router still working fine or not?
Any one tell me a function in Ethercad Library can take a ping to gateway?
or how to send a packet in loop-back?

solved. i found it in sample of ethercard lib. thank you for no answer.