The NetBIOS name calling idea can be implemented also in a Internet environment, using a WINS server: NetBIOS clients can be configured to use a WINS server to resolve names. PCs using the same WINS server will be able to make direct calling between them.
A (WINS Server is S) − − − − I − − − − B (WINS Server is S)
N
T
E − − − − − S (WINS Server)
C (WINS Server is S) − − − − R
Simple communication: IP to IP 13 N
E − − − − D (WINS Server is S)
T
Internet communication
A, B, C and D are in different subnets, but they can call each other in a NetBIOS name calling fashion. The needed is that all are using S as WINS Server.
Note: WINS server hasn't very high performance cause it use NetBIOS feature and should only be used for joining few subnets.
ILS server
ILS is a kind of server which allows you to solve your name during an H323 calling: when you start VoIP application you first register to ILS server using a name, then everyone will be able to see you using that name (if he uses same Server ILS!).
A big problem: the masquering.
A problem of few IPs is commonly solved using the so called masquering (also NAT, network address translation): there is only 1 IP public address (that Internet can directly "see"), the others machines are "masqueraded" using all this IP.
A − − −
B − − − Router with NAT − − − Internet
C − − −
This doesn't work
In the example A,B and C can navigate, pinging, using mail and news services with Internet people, but they CANNOT make a VoIP call. This because H323 protocol send IP address at application level, so the answer will never arrive to source (that is using a private IP address).
.jpg "Pankaj Bhagchandani")