netstat output

Hi,

Could someone help me understand the meaning of link#x entries under
Gateway in this netstat -nr output ?
(i am running Mac OS X 10.5)

--
netstat -nr
Routing tables

Internet:
Destination Gateway Flags Refs Use Netif
Expire
default 10.25.253.1 UGSc 5 43 en1
10.25.253/24 link#6 UCS 2 0 en1
10.25.253.1 0:8:da:72:28:54 UHLW 5 18 en1
1170
10.25.253.159 127.0.0.1 UHS 0 0 lo0
10.25.253.255 ff:ff:ff:ff:ff:ff UHLWb 0 6 en1
127 127.0.0.1 UCS 0 0 lo0
127.0.0.1 127.0.0.1 UH 3 10520 lo0
169.254 link#6 UCS 0 0 en1
172.16.141/24 link#7 UC 1 0 vmnet8
172.16.141.255 ff:ff:ff:ff:ff:ff UHLWb 0 6 vmnet8
172.16.247/24 link#8 UC 1 0 vmnet1
172.16.247.255 ff:ff:ff:ff:ff:ff UHLWb 0 6 vmnet1

Internet6:
Destination
Gateway Flags Netif Expire
::1
link#1 UHL lo0
fe80::%lo0/64
fe80::1%lo0 Uc lo0
fe80::1%lo0
link#1 UHL lo0
ff01::/32 ::
1 U lo0
ff02::/32
fe80::1%lo0 UC lo0

--

I understand IP addresses and interfaces, but what is a link ?

thanks,

regards,
Puneet.