I did sh arp on router
Protocol Address Age (min) Hardware Addr Type Interface
Internet 96.51.x.x - 000f.8f6d.7e60 ARPA FastEthernet0/0
Internet 192.168.1.40 95 000b.be59.cc60 ARPA FastEthernet1/0
Internet 192.168.1.11 199 0015.e9cf.190b ARPA FastEthernet1/0
Internet 192.168.1.10 224 000b.bece.bbc0 ARPA FastEthernet1/0
Internet 192.168.1.1 - 000f.8f6d.7e70 ARPA FastEthernet1/0
Internet 192.168.1.3 8 0026.c64a.b844 ARPA FastEthernet1/0
Internet 188.8.131.52 38 0013.46d2.fb11 ARPA FastEthernet0/0
Internet 184.108.40.206 0 0011.20a8.04a7 ARPA FastEthernet0/0
Here 96.51.x.x is ip of fa0/0 interface of my router and it directly connects to cable modem
220.127.116.11 is my next hop route.
my question is why i see - under age for fa0/0 interface ip of my router and 0 for next hop ip 18.104.22.168 ?
They do not change remail same - and 0 under age field.
The age time in the output is the amount of time the entry has been cached without being renewed. Because there is constant traffic from your router to the next-hop the cache will forever be being renewed so that is why you see it as 0 most of the time.