Content distribution system, cache server, and content distribution method
First Claim
1. A content distribution system, comprising:
- a distribution server that distributes content;
a packet forwarding apparatus that forwards a packet to be sent and received between the distribution server and a user terminal; and
a cache server connected to the packet forwarding apparatus,wherein the cache server comprises;
a content temporary storage unit that temporarily stores at least some of the content;
a bit rate calculator that calculates a bit rate when the content is sent, based on a TCP (Transmission Control Protocol) response signal received from the user terminal;
an acquisition unit that searches for a file or stream of the content requested in a content request message received from the user terminal, a corresponding bit rate of the file or stream not being greater than the bit rate, from the content temporary storage unit or the distribution server, stores the file or the stream in a packet of a prescribed protocol, and sends the packet; and
a transmission unit that reads the packet from the acquisition unit and sends the packet to the packet forwarding apparatus,the bit rate calculator measures a packet response time as difference between time at which a prescribed packet is transmitted from the transmission unit and time at which a TCP response signal to the prescribed packet is received from the user terminal, and calculates the bit rate based on the packet response time,the bit rate is B,the bit rate calculator calculates the bit rate B according to;
B=(1−
α
)×
Bc+α
×
β
×
(Ta−
T), andthe packet response time is T, a prescribed target response time is Ta, a prescribed convergence factor is α
, a prescribed conversion factor by which time change is converted to bit rate is β
, and a previous packet transmission bit rate is Bc.
3 Assignments
0 Petitions
Accused Products
Abstract
A cache server, connected to a packet forwarding apparatus that forwards a packet to be sent and received between a user terminal and a distribution server that distributes content over the Internet, temporarily stores at least some of the content in a content temporary storage unit of the cache server, calculates a bit rate when sending content based on a TCP response signal or an ECN (Explicit Congestion Notification) signal received from the terminal, and reads a file or stream of content requested in a content request message received from the terminal, whose bit rate is not greater than the bit rate, from the content temporary storage unit or the distribution server, stores the read file or stream in a packet of a prescribed protocol, and sends the packet.
22 Citations
11 Claims
-
1. A content distribution system, comprising:
-
a distribution server that distributes content; a packet forwarding apparatus that forwards a packet to be sent and received between the distribution server and a user terminal; and a cache server connected to the packet forwarding apparatus, wherein the cache server comprises; a content temporary storage unit that temporarily stores at least some of the content; a bit rate calculator that calculates a bit rate when the content is sent, based on a TCP (Transmission Control Protocol) response signal received from the user terminal; an acquisition unit that searches for a file or stream of the content requested in a content request message received from the user terminal, a corresponding bit rate of the file or stream not being greater than the bit rate, from the content temporary storage unit or the distribution server, stores the file or the stream in a packet of a prescribed protocol, and sends the packet; and a transmission unit that reads the packet from the acquisition unit and sends the packet to the packet forwarding apparatus, the bit rate calculator measures a packet response time as difference between time at which a prescribed packet is transmitted from the transmission unit and time at which a TCP response signal to the prescribed packet is received from the user terminal, and calculates the bit rate based on the packet response time, the bit rate is B, the bit rate calculator calculates the bit rate B according to;
B=(1−
α
)×
Bc+α
×
β
×
(Ta−
T), andthe packet response time is T, a prescribed target response time is Ta, a prescribed convergence factor is α
, a prescribed conversion factor by which time change is converted to bit rate is β
, and a previous packet transmission bit rate is Bc. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A cache server connected to a packet forwarding apparatus that forwards a packet to be sent and received between a user terminal and a distribution server that distributes content, the cache server comprising:
-
a content temporary storage unit that temporarily stores at least some of the content; a bit rate calculator that calculates a bit rate when the content is sent, based on a TCP (Transmission Control Protocol) response signal received from the user terminal; an acquisition unit that searches for a file or stream of the content requested in a content request message received from the user terminal, a corresponding bit rate of the file or stream not being greater than the bit rate, from the content temporary storage unit or the distribution server, stores the file or stream in a packet of a prescribed protocol, and sends the packet; and a transmission unit that reads the packet from the acquisition unit and sends the packet to the packet forwarding apparatus; wherein the bit rate calculator measures a packet response time as difference between time at which a prescribed packet is transmitted from the transmission unit and time at which a TCP response signal to the prescribed packet is received from the user terminal, and calculates the bit rate based on the packet response time, the bit rate is B, the bit rate calculator calculates the bit rate B according to;
B=(1−
α
)×
Bc+α
×
β
×
(Ta−
T), andthe packet response time is T, a prescribed target response time is Ta, a prescribed convergence factor is α
, a prescribed conversion factor by which time change is converted to bit rate is β
, and a previous packet transmission bit rate is Bc.
-
-
8. A content distribution method, comprising:
-
by a cache server connected to a packet forwarding apparatus that forwards a packet to be sent and received between a user terminal and a distribution server that distributes content, temporarily storing at least some of the content in a content temporary storage unit of the cache server; calculating a bit rate when sending the content based on a TCP (Transmission Control Protocol) response signal received from the user terminal; searching for a file or stream of the content requested in a content request message received from the user terminal, a corresponding bit rate of the file or stream not being greater than the bit rate, from the content temporary storage unit or the distribution server, storing the file or stream in a packet of a prescribed protocol, and sending the packet, wherein the cache server measures a packet response time as difference between time at which a prescribed packet is transmitted from a transmission unit and time at which a TCP response signal to the prescribed packet is received from the user terminal, and calculates the bit rate based on the packet response time, wherein the bit rate is B, the bit rate B is calculated according to;
B=(1−
α
)×
β
+a×
β
×
(Ta−
T), andthe packet response time is T, a prescribed target response time is Ta, a prescribed convergence factor is α
, a prescribed conversion factor by which time change is converted to bit rate is β and
a previous packet transmission bit rate is Bc. - View Dependent Claims (9, 10, 11)
-
Specification