Patent Application
20150281174
The present invention relates to an Advanced Domain Name System for implementing method of data transfer between TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) in transport layer for IP protocols in application layer of the Communications Protocol, and more particularly to a method of providing a relay server between a PC (personal computer) and a server for transmitting data.
Domain Name System (DNS) is an existing system for converting a domain name into an IP address. As shown in
Dynamic Domain Name System (DDNS) is also an existing system for converting a domain name into a dynamic IP address. As shown in
But if both PC 1 and server 2 are installed with NAT (Network Address Translator) firewall, PC 1 cannot connect with server 2 even if PC 1 acquires the newest IP address of UB of server 2 from DDNS 14.
Communication Protocols have five layers, i.e. physical layer, data link layer, network layer, transport layer and application layer. The present invention relates to transport layer and application layer. In application layer there are HTTP (HyperText Transfer Protocol), RTSP (Real Time Streaming Protocol), SIP (Session Initiation Protocol), etc. In transport layer there are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), etc. TCP is a reliable channel transmission, while UDP is an unreliable channel transmission. IP protocols like HTTP and RTSP which need reliable channel transmission generally transmit data on TCP. If HTTP and RTSP wants to be transmitted on UDP, a reliable transmitting method must be implemented on UDP.
Referring to
Referring to
The object of the present invention is to provide an Advanced Domain Name System for processing data transfer between TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) in transport layer for IP protocols in application layer of the Communications Protocol, and and more particularly to a method of providing a relay server between a PC (personal computer) and a server for transmitting data.
The system of the present invention comprises:
a PC;
a server;
an ADNS server is installed between the PC and the server;
a first NAT firewall is installed between the PC and the ADNS server;
a second NAT firewall is installed between the ADNS server and the server;
a first ADNS module is installed between the PC and the first NAT firewall;
a second ADNS module is installed between the second NAT firewall and the server;
a relay sever is installed between the first NAT firewall and the second NAT firewall;
channels among the first ADNS module, the first NAT firewall, the ADNS server, the relay server, the second NAT firewall and the second ADNS module are UDP channels;
a channel between the PC and the first ADNS module and a channel between the second ADNS module and the server are TCP channels or UDP channels;
The method of the present invention comprises steps of:
a. the PC first sends a Setup message to the first ADNS module to express beginning of data transmitting with the server;
b. thereafter the first ADNS module sends a plurality of Register message to the ADNS server through the first NAT firewall for conducting a plurality of registration;
c. the server provides N communication service ports, and sends a SetServicePort message to the second ADNS module to express a service can be provided; and then the server sends a Setup message to the second ADNS module to express beginning of data transmitting with the PC;
d. thereafter the second ADNS module sends a plurality of Register message to the ADNS server through the second NAT firewall for conducting a plurality of registration;
e. the PC sends a GetInfo message to the first ADNS module to express an intention to get an IP address of a domain name of the server;
f. the first ADNS module sends an Invite message to the ADNS server, the ADNS server returns a Relay IP (IP of the relay server) messge to the first ADNS module to express that an IP of the relay server substitutes for an IP address of domain name of the server;
g. the ADNS server sends Invite message and Relay IP message to the second ADNS module to express to the server that IP of the relay server substitutes for an IP address of domain name of the PC;
h. each of the first ADNS module and the second ADNS module sends a Peer message to the relay server to express achieving the first NAT firewall and the second NAT firewall traversing;
i. the relay server sends Peer OK message to both the first ADNS module and the second ADNS module to express that the relay server can transmit data for the PC and the server;
j. the first ADNS module sends a Get message to the relay server, the relay server sends the Get message to the second ADNS module in order to get N communication service ports of the server;
k. the second ADNS module provides N communication service ports of the server to the relay server, and then to the first ADNS module by the relay server so that the first ADNS module will also open N communication service ports correspondingly;
l. the first ADNS module sends a Give Local IP message to the PC to pretend that the IP of domain name of the server is a local IP;
m. the PC conducts a three-way-handshaking with the first ADNS module, then the first ADNS module sends a Notify connect message to the relay server, and then to the second ADNS module by the relay server to enable the second ADNS module and the server to perform a three-way-handshaking;
n. the second ADNS module sends a Notify FINE message to the relay server, and then to the first ADNS module by the relay server to express that everything is ready for accepting packets;
o. the PC sends an IP GET packet to the first ADNS module for being hold by the first ADNS module;
p. the first ADNS module sends the IP GET packet to the relay server, the relay server sends the IP GET packet to the second ADNS module;
q. the second ADNS module sends the IP GET packet to the server;
r. the server returns an IP 200 OK packet to the second ADNS module;
s. the second ADNS module sends the IP 200 OK packet to the relay server, the relay server sends the IP 200 OK packet to the first ADNS module;
t. the first ADNS module sends the IP 200 OK packet to the PC to express that the IP packet is delivered.
The aforementioned step o and step r have to conduct a conversion as stated below:
Data transferred from TCP channel (such as IP GET packet, IP 200 OK packet) are sent to a first numbering header for assigning an identifying number header to the data, and then sent to a UDT Library, the UDT Library will add a UDT header to the data transferred from TCP channel, and let the data transfer through UDP channel by a reliable mechanism of UDT;
data transferred from UDP channel are sent to a second numbering header for assigning an identifying number header to the data, and then sent to UDP channel directly.
The aforementioned step q and step t have to conduct a conversion as stated below:
Data transferred from UDP channel (such as IP GET packet, IP 200 OK packet) are determined if it is a UDT packet, If the data has a UDT header, then it is a UDT packet, so the packet is sent to the UDT Library to delete the UDT header, and sent to the first numbering header to delete the identifying number header, then sent through a corresponding TCP channel according to the identifying number;
if the data has no UDT header, then it is a UDP packet, so the packet is sent to the second numbering header to delete the identifying number header, and then sent to a corresponding UDP channel according to the identifying number.
The aforementioned UDT Library can be downloaded from http://udt.sourceforge.net/software.html.
Referring to
Referring to
In
Referring to
Concurrently, server 2 provides three communication service ports i, ii, iii, and sends a SetServicePort (i, iii) message to ADNS module 7 to express a service can be provided. Server 2 will then sends a Setup message to ADNS module 7 to express beginning of transmitting data with PC1, thereafter ADNS module 7 sends a Register UB message to ADNS server 5 through NAT firewall 4, then ADNS server 5 returns a Register UB OK message to ADNS module 7 throughNAT firewall 4. The registrations are conducted for several times (step 2 in
Thereafter PC 1 sends a GetInfo (UB) message to ADNS module 6 to express the intention to get the IP address of UB of server 2. ADNS module 6 sends Invite UB message to ADNS server 5 through NAT firewall 3. ADNS server 5 returns a Relay IP message to ADNS module 6 (step 3 in
ADNS server 5 sends Invite UB message and Relay IP message to ADNS module 7, expresses to server 2 that the IP of relay server 15 is used to substitute the IP of UA of PC 1.
Both ADNS module 6 and ADNS module 7 send Peer message to relay server 15 expressing that traversing NAT firewall 3 and NAT firewall 4 can be achieved. Relay server 15 will then sends Peer OK message to both ADNS module 6 and ADNS module 7, expressing that data transmitting can be done for PC 1 and server 2.
ADNS module 6 sends a Get message to relay server 15 to express the intention to get communication service ports of server 2, relay server 15 send Get message to ADNS module 7. ADNS module 7 will then provides three communication service ports i, iii of the server 2 to relay server 15, and then to ADNS module 6 by relay server 15, so that ADNS module 6 will also open three communication service ports i, ii, iii correspondingly. ADNS module 6 sends a Give Local IP message to PC 1 to pretend that the IP address of UB of server 2 is a local IP.
At this time, the UDP channel between ADNS module 6 and ADNS module 7 has been getting through by relay server 15. The channel between PC 1 and ADNS module 6 as well as the channel between ADNS module 7 and server 2 are TCP channels.
Continuously referring to
Thereafter i port of ADNS module 6 sends Notify TCP connect message to relay server 15, relay server 15 sends Notify TCP connect message to ADNS module 7 to enable ADNS module 7 and i port of server 2 to perform three-way-handshaking.
ADNS module 7 first sends SYN message to i port of server 2, then i port of server 2 returns SYN-ACK message to ADNS module 7, finally ADNS module 7 sends ACK message to i port of server 2 for achieving three-way-handshaking.
After ADNS module 7 and server 2 finish three-way-handshaking, ADNS module 7 sends Notify FINE message to relay server 15, relay server 15 sends Notify FINE message to i port of ADNS module 6 to express that everything is ready for accepting packets.
PC 1 sends HTTP GET packet to i port of ADNS module 6 for being hold by i port of ADNS module 6.
Thereafter i port of ADNS module 6 sends HTTP GET packet to relay server 15, relay 15 sends HTTP GET packet to ADNS module 7, and then ADNS module 7 sends HTTP GET packet to i port of server 2.
The i port Server 2 returns HTTP 200 OK packet to ADNS module 7, and then ADNS module 7 sends HTTP 200 OK packet to relay server 15, relay server 15 send HTTP 200 OK packet to i port of ADNS module 6, thereafter ADNS module 6 sends HTTP 200 OK packet to PC 1 to express that HTTP packet is delivered.
The three communication service ports i, ii, iii of server 2 is for example only, actually it is not limited to three ports. The aforementioned HTTP is also for example only, other IP protocols like RTSP, SIP can also be used, and HTTP GET changes into IP GET, HTTP 200 OK changes into IP 200 OK.
If the channel between PC1 and ADNS module 6, the channel between ADNS module 6, relay server 15 and ADNS module 7, and the channel between ADNS module 7 and server 2 are all UDP channels (for example SIP protocol), then as shown in
HTTP GET packet from PC 1 to i port of ADNS module 6 is by way of TCP channel, but HTTP GET packet from ADNS module 6 to relay server 15 is by way of UDP channel, so a conversion has to be conducted in ADNS module 6. Similarly, HTTP 200 OK packet from i port of server 2 to ADNS module 7 is by way of TCP channel, but HTTP 200 OK packet from ADNS module 7 to relay server 15 is by way of UDP channel, so a conversion has to be conducted in ADNS module 7.
Referring to TCP converter 8 and UDP converter 9 in
Data transferred from TCP channel are sent to numbering header 10 for assigning an identifying number header n to the data, and then sent to UDT Library 11. UDT means “UDP-based Data Transfer Protocol”, which is an algorithm for implementing reliable data transfer on UDP channel. UDT Library 11 will add UDT header to the data transferred from TCP channel, and let the data transfer through UDP channel by a reliable mechanism of UDT, as shown by “UDP Send”. UDT Library 11 can be downloaded from http://udt.sourceforge.net/software.html.
Data transferred from UDP channel are sent to numbering header 12 for assigning an identifying number header n to the data, and then sent to UDP channel directly, as shown by “UDP Send”.
The aforementioned HTTP GET packet from i port of ADNS module 6 to relay server 15 and then to ADNS module 7 is by way of UDP channel, but HTTP GET packet from ADNS module 7 to i port of server 2 is by way of TCP channel, a conversion has to be conducted. Similarly, HTTP 200 OK packet from ADNS module 7 to relay server 15 and then to i port of ADNS module 6 is by way of UDP channel, but HTTP 200 OK packet from ADNS module 6 to PC 1 is by way of TCP channel, a conversion has also to be conducted.
Referring to TCP converter 8 and UDP converter 9 in
The jobs in
The scope of the present invention depends upon the following claims, and is not limited by the above embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103111387 | Mar 2014 | TW | national |
