U.S. patent application number 13/406700 was filed with the patent office on 2013-03-07 for method and devices for transferring data.
The applicant listed for this patent is Markus Balb, Dieter Gleis. Invention is credited to Markus Balb, Dieter Gleis.
Application Number | 20130058261 13/406700 |
Document ID | / |
Family ID | 35847473 |
Filed Date | 2013-03-07 |
United States Patent
Application |
20130058261 |
Kind Code |
A1 |
Balb; Markus ; et
al. |
March 7, 2013 |
METHOD AND DEVICES FOR TRANSFERRING DATA
Abstract
The invention relates to a method, to a first and a second
device (1, 2) and to a system (10) comprising the first and second
device (1, 2) for transferring data, said system and devices
matching the user data transfer rate during the data transfer
between the first and the second device (1, 2). The first device
(1) comprises in particular a medium access controller and operates
in the second layer according to the OSI reference model, whilst
the second device (2) transmits and receives user data in the first
layer according to the OSI reference model and comprises an
interface unit (24) for a DSL connection. The transfer rate match
is achieved in particular by PAUSE frames according to the IEEE
802.3-2004 standard and the second device also operates in the
second layer according to the OSI reference model to transmit and
receive the PAUSE frames.
Inventors: |
Balb; Markus; (Unterhaching,
DE) ; Gleis; Dieter; (Grosskarolinenfeld,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Balb; Markus
Gleis; Dieter |
Unterhaching
Grosskarolinenfeld |
|
DE
DE |
|
|
Family ID: |
35847473 |
Appl. No.: |
13/406700 |
Filed: |
February 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11814478 |
Jun 19, 2008 |
8125924 |
|
|
PCT/EP05/13787 |
Dec 21, 2005 |
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13406700 |
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Current U.S.
Class: |
370/276 ;
370/241; 370/412 |
Current CPC
Class: |
H04L 47/266 20130101;
H04L 29/06 20130101; H04L 69/32 20130101 |
Class at
Publication: |
370/276 ;
370/412; 370/241 |
International
Class: |
H04L 12/26 20060101
H04L012/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2005 |
DE |
10 2005 003 016.5 |
Claims
1-32. (canceled)
33. A method for transmitting data, the method comprising:
transmitting data in packets between a first device and a second
device, wherein the data are transmitted from the second device to
the first device with a first transmission rate and wherein the
data are transmitted from the first device to the second device
with a second transmission rate; adjusting the first transmission
rate to a first processing rate of the first device or adjusting
the second transmission rate to a second processing rate of the
second device; sending a first signal from the first device to the
second device, on receipt of which the second device does not send
any more data to the first device, if a first condition is
satisfied, the first condition being selected from the group
consisting of: (i) memory elements of the first device are filled
beyond a predetermined first threshold value with data from the
second device that could not yet be sent further from the first
device, and (ii) the memory elements of the first device do not
offer any more space to store at least a maximum size data stream
from the second device which streams for a time interval whereby
the time interval is the time that elapses from a time-point at
which the first device decides to send the first signal to the
second device until a time-point at which because of the first
signal that has been sent no more data from the second device are
received by the first device; or sending a second signal from the
first device to the second device, upon receipt of which the second
device sends data that are to be sent to the first device if a
second condition is satisfied, the second condition being selected
from the group consisting of: (i) the memory elements of the first
device are filled below a predetermined second threshold value, and
(ii) the memo elements of the first device offering at least
sufficient space to store the maximum size data stream from the
second device that streams for the time interval.
34. The method according to claim 1, wherein transmitting data
between the first device and the second device is run in full
duplex mode.
35. The method according to claim 1, wherein transmitting data
between the first device and the second device comprises selecting
an interface, the interface comprising a Medium Independent
Interface (MID, a Reduced Medium Independent Interface (RMII), a
Serial Medium Independent Interface (SMII) or a Source Synchronous
Serial Medium Independent Interface (SSSMII) interface.
36. The method according to claim 1, wherein transmitting data
between the first device and the second device comprises using a
10-Base-T or 100-Base-T Ethernet protocol.
37. The method according to claim 1, wherein the first device
operates only in a second layer according to an Open Systems
Interconnection (OSI) layer model and/or in that the second device
processes its user data only in a first layer according to the Open
Systems Interconnection (OSI) layer model.
38. The method according to claim 1, wherein the first device and
the second device are disposed together on a circuit board and/or
the first device and the second device are together integrated in a
semiconductor circuit.
39. The method according to claim 1, wherein adjusting the first
transmission rate to the first processing rate comprises sending
user data to the first device only at a transmission rate at which
the first device can forward the user data and wherein adjusting
the second transmission rate to the second processing rate
comprises sending user data to the second device only at a
transmission rate at which the second device can forward the user
data.
40. The method according to claim 1, wherein transmitting data in
packets between the first device and the second device comprises
transmitting data between the second device and the first device
via a first communication connection and transmitting data between
the first device and the second device via a second communication
connection.
41. The method according to claim 1, further comprising
transmitting the data between the second device and a third
device.
42. A system for transmitting data, the system comprising: a first
device comprising a first interface unit that is configured such
that data can be exchanged in packets via the first interface unit
using a transmission rate; and a second interface unit that is
configured such that data can be exchanged via the second interface
unit; and a second device, wherein the device is configured to
adjust the transmission rate to a processing rate of the first
device when transmitting data via the first interface unit to the
first device, wherein a first signal is sent from the first device
to the second device, on receipt of which the second device does
not send any more data to the first device, if a first condition is
satisfied, the first condition being selected from the group
consisting of: (i) memory elements of the first device are filled
beyond a predetermined first threshold value with data from the
second device that could not yet be sent further from the first
device, and (ii) the memory elements of the first device do not
offer any more space to store at least a maximum size data stream
from the second device which streams for a time interval whereby
the time interval is the time that elapses from a time-point at
which the first device decides to send the first signal to the
second device until a time-point at which because of the first
signal that has been sent no more data from the second device are
received by the first device, and wherein the second signal is sent
from the first device to the second device, upon receipt of which
the second device sends data that are to be sent to the first
device if a second condition is satisfied, the second condition
being selected from the group consisting of: (i) the memory
elements of the first device are filled below a predetermined
second threshold value, and (ii) the memory elements of the first
device offering at least sufficient space to store the maximum size
data stream from the second device that streams for the time
interval.
43. The system according to claim 10, wherein the first device is
configured such that it processes its user data only in a first
layer according to an Open Systems Interconnection (OSI) layer
model.
44. The device according to claim 10, wherein the first device is
configured to adjust the transmission rate to the processing rate
of the second device comprises the device is configured to send
user data to the second device only at a transmission rate at which
the second device can forward the user data.
45. The system according to claim 10, further comprising a
communication connection between the device and the second device,
wherein the communication connection is configured to transport
data from the second device to the first device.
46. A system for transmitting data, the system comprising a first
device and a second device, the first device comprising an
interface unit, the first device being configured to transmit data
in packets to the second device via the interface unit using a
transmission rate, the second device being configured such that
data can be exchanged in packets via a first interface unit of the
second device with the first device and that data can be exchanged
via a second interface unit of the second device, wherein the first
device is configured to adjust the transmission rate to a
processing rate of the second device when transmitting data via the
interface unit, wherein a first signal is sent from the second
device to the first device, on receipt of which the first device
does not send any more data to the second device, if a first
condition is satisfied, the first condition being selected from the
group consisting of: (i) memory elements of the second device are
filled beyond a predetermined first threshold value with data from
the first device that could not yet be sent further from the second
device, and (ii) the memory elements of the second device do not
offer any more space to store at least a maximum size data stream
from the first device which streams for a time interval whereby the
time interval is the time that elapses from a time-point at which
the second device decides to send the first signal to the first
device until a time-point at which because of the first signal that
has been sent no more data from the first device are received by
the second device, and wherein the second signal is sent from the
second device to the first device, upon receipt of which the first
device sends data that are to be sent to the second device if a
second condition is satisfied, the second condition being selected
from the group consisting of: (i) the memory elements of the second
device are filled below a predetermined second threshold value, and
(ii) the memory elements of the second device offering at least
sufficient space to store the maximum size data stream from the
first device that streams for the time interval.
47. The system according to claim 14, wherein the first device is
configured for medium access control and is additionally configured
such that it operates only in a second layer according to an Open
Systems Interconnection (OSI) layer model.
48. The device according to claim 14, wherein the first device is
configured to adjust the transmission rate to the processing rate
of the second device comprises the first device is configured to
send user data to the second device only at a transmission rate at
which the second device can forward the user data.
49. The system according to claim 14, further comprising a
communication connection between the first device and the second
device, wherein the communication connection is configured to
transport data from the first device to the second device.
50. A system for transmitting data, the system comprising: a first
device; a second device wherein the system is configured to
transmit data in packets between the first device and the second
device, wherein during the data transmission between the first
device and the second device the system is configured to adjust
transmission rates, wherein the second device is further configured
to transmit data from itself to a third device, wherein the first
device comprises an interface unit and is configured to transmit
data in packets to the second device via the interface unit, the
first device being configured to adjust a first transmission rate
to a data second processing rate of the second device when
transmitting data via the interface unit; wherein the second device
comprises a first interface unit that is configured such that data
can be exchanged in packets with the first device via the first
interface unit, and wherein the second device comprises a second
interface unit that is configured such that data can be exchanged
via the second interface unit, the second device being configured
to adjust a second transmission rate to a data first processing
rate of the first device when transmitting data via the first
interface unit; wherein a first signal is sent from the first
device to the second device, on receipt of which the second device
does not send any more data to the first device, if a first
condition is satisfied, the first condition being selected from the
group consisting of: (i) memory elements of the first device are
filled beyond a predetermined first threshold value with data from
the second device that could not yet be sent further from the first
device, and (ii) the memory elements of the first device do not
offer any more space to store at least a maximum size data stream
from the second device which streams for a time interval whereby
the time interval is the time that elapses from a time-point at
which the first device decides to send the first signal to the
second device until a time-point at which because of the first
signal that has been sent no more data from the second device are
received by the first device, and wherein the second signal is sent
from the first device to the second device, upon receipt of which
the second device sends data that are to be sent to the first
device if a second condition is satisfied, the second condition
being selected from the group consisting of: (i) the memory
elements of the first device are filled below a predetermined
second threshold value, and (ii) the memory elements of the first
device offering at least sufficient space to store the maximum size
data stream from the second device that streams for the time
interval.
51. The system according to claim 18, wherein the system is
configured on a circuit board as an assembly.
52. The system according to claim 18, wherein the system is
configured as a single-chip, integrated circuit.
53. The system according to claim 18, wherein the first device is
configured for medium access control and is additionally configured
such that it operates only in a second layer according to an Open
Systems Interconnection (OSI) layer model.
54. The system according to claim 18, wherein the second device is
configured such that it processes its user data only in a first
layer according to an Open Systems Interconnection (OSI) layer
model.
55. The system according to claim 18, wherein the first device is
configured to adjust the first transmission rate to the second data
processing rate of the second device comprises the first device is
configured to send user data to the second device only at a
transmission rate at which the second device can forward the user
data and wherein the second device is configured to adjust the
second transmission rate to the first data processing rate of the
first device comprises the second device is configured to send user
data to the first device only at a transmission rate at which the
first device can forward the user data.
56. The system according to claim 18, further comprising a first
communication connection between the first device and the second
device, wherein the first communication connection is configured to
transport data from the first device to the second device, and
second communication connection between the second device and the
first device, wherein the second communication connection is
configured to transport data form the second device to the first
device.
57. A method for transmitting data, the method comprising:
transmitting data in packets between a first device and a second
device, wherein the data are transmitted from the second device to
the first device with a first transmission rate and wherein the
data are transmitted from the first device to the second device
with a second transmission rate; adjusting the first transmission
rate to a first processing rate of the first device or adjusting
the second transmission rate to a second processing rate of the
second device; and transmitting the data between the second device
and a third device, wherein a first signal is sent from the first
device to the second device, on receipt of which the second device
does not send any more data to the first device, if a first
condition is satisfied, the first condition being selected from the
group consisting of: (i) memory elements of the first device are
filled beyond a predetermined first threshold value with data from
the second device that could not yet be sent further from the first
device, and (ii) the memory elements of the first device do not
offer any more space to store at least a maximum size data stream
from the second device which streams for a time interval whereby
the time interval is the time that elapses from a time-point at
which the first device decides to send the first signal to the
second device until a time-point at which because of the first
signal that has been sent no more data from the second device are
received by the first device, and wherein the second signal is sent
from the first device to the second device, upon receipt of which
the second device sends data that are to be sent to the first
device if a second condition is satisfied, the second condition
being selected from the group consisting of: (i) the memory
elements of the first device are filled below a predetermined
second threshold value, and (ii) the memory elements of the first
device offering at least sufficient space to store the maximum size
data stream from the second device that streams for the time
interval.
58. The method according to claim 25, wherein a third signal is
sent from the second device to the first device, upon receipt of
which the first device does not send any more data to the second
device, if a third condition is satisfied, the third condition
being selected from the group consisting of: (i) memory elements of
the second device are filled beyond a predetermined third threshold
value with data from the first device that could not yet be sent
further from the second device, and (ii) the memory elements of the
second device do not offer any more space to store at least a
maximum size data stream from the first device which streams for a
further time interval whereby the further time interval is the time
that elapses from a time-point at which the second device decides
to send the third signal to the first device until a time-point at
which because of the signal that has been sent no more data from
the first device are received by the second device.
59. The method according to claim 26, wherein the fourth signal is
sent from the second device to the first device, upon receipt of
which the first device sends data that are to be sent to the second
device if a fourth condition is satisfied, the fourth condition
being selected from the group consisting of: (i) the memory
elements of the second device are filled below a predetermined
fourth threshold value, and (ii) the memory elements of the second
device offering at least sufficient space to store the maximum size
data stream from the first device that streams for the time
interval.
60. The method according to claim 27, wherein, after receiving the
first or third signal and before receiving the second or fourth
signal, the first device and/or the second device send only the
first or third signal, or the second or fourth signal to the other
device, respectively.
61. The method according to claim 27, wherein, after being
evaluated, the first or third signal and/or the second or fourth
signal is/are rejected immediately.
62. The method according to claim 27, wherein the first or third
signal and/or the second or fourth signal is/are produced by a
specific frame.
63. The method according to claim 30, wherein the specific frame is
an Ethernet frame.
64. The method according to claim 31, wherein the first or third
signal is produced by a STOP-Ethernet frame and/or the second or
fourth signal is produced by a GO-Ethernet frame, wherein after
receiving the STOP-Ethernet frame, a receiver of the STOP-Ethernet
frame does not send any more user data to a sender of the
STOP-Ethernet frame until the receiver receives the GO-Ethernet
frame from the sender.
65. The method according to claim 31, wherein the first or third
signal and/or the second or fourth signal is/are produced by a
PAUSE-Ethernet frame.
66. The method according to claim 31, wherein the second device
uses as a Medium Access Control (MAC) sender address of the
Ethernet frame a MAC sender address from a data packet which the
second device receives from the third device.
67. The method according to claim 25, wherein when checking whether
the memory elements offer sufficient space to accept the maximum
size data stream, a predetermined quantity of data is taken into
account as a safety buffer.
68. A system for transmitting data comprising: a first device
comprising a first interface unit that is configured such that data
can be exchanged in packets via the first interface unit using a
transmission rate; a second interface unit that is configured such
that data can be exchanged via the second interface unit; and a
second device, wherein the second device is configured to adjust
the transmission rate to a processing rate of the first device when
transmitting data via the first interface unit to the first device,
wherein the first device further comprises memory elements, wherein
data is stored that the first device receives via the first
interface unit but has not yet processed further, wherein the first
device is configured to send a first signal via the first interface
unit if the first device registers that a specific capacity of the
memory elements has been filled beyond a predetermined first
threshold value, or if the first device registers that the memory
elements no longer offer space to store at least a maximum size
data stream that is received via the first interface unit which
streams for a time interval, wherein the time interval is the tune
that elapses from a time-point at which the first device decides to
send the first signal until a time-point at which due to the first
signal that has been sent no more data is received by the first
device via the first interface unit, wherein the first device is
configured to send a second signal via the first interface unit if
the first device registers that the memory elements are filled
below a predetermined second threshold value, or if the first
device registers that the memory elements offer at least sufficient
space to store the maximum size data stream from the first
interface unit that streams for the time interval, and wherein the
second device is configured such that the second device, if the
second device receives the first signal, does not send any more
data via the first interface unit, except for the first and second
signal.
69. A first device comprising: a first interface unit that is
configured such that data can be exchanged in packets via the first
interface unit using a transmission rate; a second interface unit
that is configured such that data can be exchanged via the second
interface unit; and a processor configured to receive data via the
first interface from a second device, wherein the second device is
configured to adjust the transmission rate to a processing rate of
the first device when transmitting data, wherein the first device
is configured to send a first signal to the second device, on
receipt of which the second device does not send any more data to
the first device, if a first condition is satisfied, the first
condition being selected from the group consisting of: (i) memory
elements of the first device are filled beyond a predetermined
first threshold value with data from the second device that could
not yet be sent further from the first device, and (ii) the memory
elements of the first device do not offer any more space to store
at least a maximum size data stream from the second device which
streams for a time interval whereby the time interval is the time
that elapses from a time-point at which the first device decides to
send the first signal to the second device until a time-point at
which because of the first signal that has been sent no more data
from the second device are received by the first device, and
wherein the second signal is sent from the first device to the
second device, upon receipt of which the second device sends data
that are to be sent to the first device if a second condition is
satisfied, the second condition being selected from the group
consisting of: (i) the memory elements of the first device are
filled below a predetermined second threshold value, and (ii) the
memory elements of the first device offering at least sufficient
space to store the maximum size data stream from the second device
that streams for the time interval.
70. The first device according to claim 37, wherein the first
interface comprises a Medium Independent Interface (MII), a Reduced
Medium Independent Interface (RMII), a Serial Medium Independent
Interface (SMII) or a Source Synchronous Serial Medium Independent
Interface (SSSMII) interface.
71. The first device according to claim 37, wherein the first
device operates only in a second layer according to an Open Systems
Interconnection (OSI) layer model and/or in that the second device
processes its user data only in a first layer according to the Open
Systems Interconnection (OSI) layer model.
72. The first device according to claim 37, wherein the first
device and the second device are disposed together on a circuit
board and/or the first device and the second device are together
integrated in a semiconductor circuit.
Description
[0001] The present invention relates to a method, devices and a
system for transmitting data in packets, whereby a loss of data is
almost impossible and in particular a transmission rate is
increased.
[0002] Due to the increasing number of internet users and due to
the increasing amounts of data that are moved uplink or downlink by
a user of the Internet, DSL technologies for transmitting data are
becoming increasingly popular particularly on the so-called last or
first mile (EFM=Ethernet in the First Mile) on the connection path
to the internet user. Therefore transmitting data on this
connection path should be as secure as possible, i.e. not tolerate
any loss of data packets, and should have a transmission rate that
is as high as possible. The EFM standard IEEE 802.3-2004, which
standardises the transmitting of data on the so-called last mile,
does not however always prevent a loss of data. If for example the
data are received via a DSL connection from a device interacting in
the first layer according to the OSI layer model and forwarded with
a specific transmission rate to a device which has a medium access
control (MAC), a loss of data can occur if the specific
transmission rate is higher than a transmission rate at which the
device which has the medium access control can forward this
data.
[0003] The object of the present invention is therefore to improve
the transmitting of data between a device that interacts mainly in
the first layer according to the OSI layer model, which receives
and/or sends data via a DSL connection, and a device which has a
medium access control (MAC).
[0004] According to the invention, this task is solved by a method
for transmitting data according to claim 1, a device for
transmitting data according to claim 19 or 25 and a system
according to claim 31. The dependent claims define preferred and
advantageous embodiments of the invention.
[0005] According to the invention, a method for transmitting data
is provided whereby data are transmitted in packets between a first
device and a second device. In particular, the first device has a
medium access control and interacts only in the second layer
according to the OSI layer model, while the second device processes
its user data only in the first layer according to the OSI layer
model. With this, packets transmitted between the first and the
second device when data are transmitted between the first and the
second device are analysed only for the purposes of regenerating
the data transmitted in the packets. Furthermore, the second device
is configured for transmitting data to a third device using DSL
technology. The transmitting of data between the first device and
the second device, in particular in both directions, is controlled
by comparing transmission rates.
[0006] Since in particular when transmitting data from the first to
the second device and also when transmitting data from the second
to the first device the transmission rates are compared,
advantageously no loss of data can occur when transmitting data
bidirectionally between the first and second device, which can be
the case according to the prior art, see the EFM standard
802.3-2004. Transmission rate comparison, or rather user data
transmission rate comparison, is understood as meaning that the
first (second) device sends user data to the second (first) device
only at a transmission rate at which the second (first) device can
then also process this user data. This prevents a loss of data from
occurring as the first (second) device sends user data to the
second (first) device at a transmission rate whereby this
transmission rate exceeds a processing rate of the second (first)
device. User data is understood to mean data that contain
information that does not serve to control the first and second
device and is transmitted unchanged from the first and second
device.
[0007] According to the invention, the transmission rate comparison
can be achieved by means of two signals, a first and a second
signal. If the first (second) device receives the first signal, it
does not send any further data to the second (first) device until
it receives the second signal or until a time interval has elapsed
that is defined by the first signal. The first (second) device can
then send the first signal to the second (first) device if the
first (second) device registers that a specific capacity of the
memory elements of the first (second) device has been exceeded
beyond a predetermined threshold value. In this, the memory
elements store data that have been sent from the second (first)
device but that could not yet be sent further or processed by the
first (second) device. Another condition on the occurrence of which
the first (second) device sends the first signal to the second
(first) device may also be present if the memory elements of the
first (second) device no longer offer any space to store more than
or at least a maximum size data stream from the second (first)
device beyond a specific time interval. In this, the time interval
is determined by the time that elapses between a first and a second
time-point. In this, the first (second) device decides to send the
first signal to the second (first) device at the first time-point,
whereby the second time-point is present if the first (second)
device no longer receives any data from the second (first) device,
as the first (second) device has sent the first signal to the
second (first) device. In other words, the first (second) device
then sends the first signal to the second (first) device if the
first (second) device registers that it cannot accept any more data
from the second (first) device in its memory elements than those
that are still being sent to it from the second (first) device
until the data stream from the second (first) device is interrupted
due to the first signal being received.
[0008] Conversely, the second signal is then sent from the first
(second) device to the second (first) device if the memory elements
of the first (second) device again have sufficient space, e.g.
because the first (second) device has processed or passed on the
data present in the memory elements.
[0009] With this procedure according to the invention it is almost
impossible for there to be a loss of data, in that the first
(second) device sends data to the second (first) device which the
second (first) device must not accept in its memory elements and
must therefore reject.
[0010] Advantageously, the first (second) device can also send the
first signal or the second signal to the second (first) device in a
time interval between receiving the first signal and before
receiving the second signal. Only the sending of other data is
forbidden in this period. Furthermore, after evaluating this
signal, the first and/or the second signal is immediately rejected
in particular by the first (second) device.
[0011] This ensures that for its part the first (second) device can
interrupt or re-establish the data stream from the second (first)
device also in a situation in which because it is receiving the
first signal the first (second) device can send no more data to the
second (first) device, in that it is sending the first or the
second signal to the second (first) device. By rejecting the first
or the second signal after an evaluation it is furthermore ensured
that the first or second signal does not use up any further
resources, e.g. the memory elements, of the first (second)
device.
[0012] A further possibility is that the first or second signal is
produced by a specific Ethernet frame; for example, the first
signal can be produced by a STOP-Ethernet frame or a PAUSE-frame
and the second signal can be produced by a GO-Ethernet frame or a
PAUSE-frame.
[0013] Since PAUSE-frames are used to compare transmission rates,
advantageously, any device with a medium access control
standardised in accordance with the Ethernet standard may be used
as the first device.
[0014] It is also emphasised explicitly that the method according
to the invention applies also if transfer rates are compared, in
particular using PAUSE-frames, only in one direction, namely only
when transmitting data from the first to the second device or only
when transmitting data from the second to the first device.
[0015] According to the invention, the second device can extract a
MAC sender address from a data packet that the second device
receives from the third device via the DSL connection and use it as
the MAC sender address of the specific Ethernet frame generated by
the second device.
[0016] Since the second device extracts the MAC sender address from
a data packet sent from a third device, advantageously, a MAC
address does not have to be assigned to the second device,
therefore the second device can then use this assigned MAC address
to construct a correct Ethernet frame. As a result, advantageously,
a standard device with medium access control may be used as the
first device, since it is ensured that the Ethernet frames sent as
the first or the second signal are also constructed by the second
device with a correct MAC sender address. A standard device with
medium access control is namely usually only able to evaluate
Ethernet frames that have a correct MAC sender address.
[0017] Furthermore, data transmission between the first and the
second device can be run in full duplex mode.
[0018] Since, according to the EFM standard IEEE 802.3-2004,
transmission between the first and the second device is run only in
half duplex mode, this means on the one hand a doubling of the
possible transmission rate for transmitting data between the first
and second device. On the other hand, the use of standard devices
with medium access control as the first device is made easier,
since standard devices with medium access control usually work only
in full duplex mode.
[0019] The interface for transmitting data between the first and
the second device may be selected from the following interfaces:
[0020] MII (Medium Independent Interface) [0021] RMII (Reduced
Medium Independent Interface) [0022] SMII (Serial Medium
Independent Interface) [0023] SSSMII (Source Synchronous Serial
Medium Independent Interface)
[0024] Moreover, according to the invention, when transmitting data
between the first and the second device the Ethernet protocols
10Base-T (transmission rate of 10 Mbps) and 100Base-T (transmission
rate of 100 Mbps) may be used.
[0025] According to the invention, a device, which in particular
processes its user data only in the first layer according to the
OSI layer model, is also provided which comprises a first and a
second interface unit. The first interface unit is configured to
transmit data in packets and the second interface unit is
configured to transmit data using DSL technology. During data
transmission via the first interface unit the device is configured
to compare transmission rates.
[0026] Additionally, according to the present invention a further
device, which is configured in particular for medium access
control, is provided which comprises an interface unit and is
configured to transmit data in packets via the interface unit with
the device. The further device is configured such that during data
transmission via the interface unit it performs a transmission rate
comparison.
[0027] Finally, the present invention discloses a system for
transmitting data that comprises a first and a second device. The
first device, which is configured in particular for medium access
control, and the second device, which processes its user data in
particular in the first layer according to the OSI layer model, is
configured to transmit data in packets between the first and second
device. The second device is furthermore configured to transmit
data between itself and a third device using DSL technology.
Furthermore, the first and the second device are configured such
that during data transmission between the first and the second
device the transmission rates are compared.
[0028] If this system is integrated in a semiconductor circuit, the
design of the interface between the first and second device is
relatively open, because the interface is not accessible from
outside the semiconductor circuit. In this case therefore the first
and second signal are not usually produced by Ethernet frames, so
the extracting of a MAC sender address from an Ethernet frame
received from the second device does not occur.
[0029] The present invention is suited preferably for use in
communication networks in which transmission to an end-node of the
communication network is carried out with DSL technology.
Naturally, the invention is however not limited to this preferred
area of application, but can for example also be used in a detached
communication node that exchanges data using DSL technology.
[0030] The present invention is explained further below with
reference to the attached drawing on the basis of preferred
embodiments.
[0031] The sole FIGURE shows a system according to the invention
with two devices according to the invention, which brings about the
transmitting of data in packets.
[0032] In the sole FIGURE a system 10 consisting of a first device
1 and a second device 2 and a third device 3 are shown which
communicate via connections 33, 34 by means of DSL technology with
Ethernet data (Ethernet protocol). The first device 1 is a
communication device that via a first interface unit 13 has access
to the internet through a connection 35. Furthermore, the first
device 1 has a second interface unit 14 through which by
packet-oriented data transmission 31, 32 it communicates with the
second device 2. The first device 1 also comprises a first memory
element 11 and a second memory element 12. In the first memory
element 11 the first device 1 stores data that it has received via
the first interface unit 13 but has not yet forwarded to the second
device 2 via the second interface unit 14. Similarly, the first
device stores in the second memory element 12 data that it has
received from the second device 2 via the second interface unit 14
but has not yet forwarded via the first interface unit 13.
[0033] The second device 2 comprises a first interface unit 23 to
communicate data with the first device 1 and a second interface
unit 24 to communicate data with the third device 3 using DSL
technology and also a first memory element 21 and a second memory
element 22. In the first memory element 21 the second device 2
stores data that it has received via its first interface unit 23
but has not yet forwarded via its second interface unit 24. In the
same way, the second device 2 stores, in the second memory element
22, data that it has received via the second interface unit 24 but
has not yet forwarded via the first interface unit 23 to the first
device 1.
[0034] The system 10 is integrated in a semiconductor circuit,
which means that the connections 31, 32 between the first and
second device 1, 2 are connections within this semiconductor
circuit. The first and second device 1, 2 communicate with each
other via a Medium Independent Interface (MII).
[0035] To simplify further description, below, the first device 1
is called MAC and the second device 2 is called EFM PHY. PHY stands
for physical layer, as the EFM PHY 2 receives and sends its user
data in this physical layer, the first layer according to the OSI
layer model. The system 10 can belong to a customer premises
equipment (CPE) or to a central office termination (COT).
[0036] The MAC 1 operates in the second layer according to the OSI
layer model and is configured for medium access control (MAC), i.e.
the first device 1 is able to work in accordance with a medium
access control protocol. The medium access control protocol defines
a method that determines a sequence in which certain devices
temporarily have access to a transmission medium, to which the MAC
1 is also connected. On the other hand, the EFM PHY 2, as already
indicated above, operates both in the first and also the second
layer of the OSI layer model. With this, through the MII the EFM
PHY 2 sends or receives its user data via the first layer to or
from the MAC 1, while the EFM PHY 2 sends any PAUSE-frames via the
second layer to the MAC 1 or receives them from the MAC. On the
other hand, the MAC 1 sends or receives both user data and also any
PAUSE-frames via the second layer to or from the EFM PHY 2. In
doing so a characteristic of the MII is used to move data shown in
the first layer to the second layer, and/or to move data shown in
the second layer to the first layer, as a result of which the MAC 1
and the EFM PHY 2 can exchange user data via the MII, even though
the MAC 1 sends and receives the user data via the second layer,
while the EFM PHY 2 sends and receives the user data via the first
layer.
[0037] It is explained below how data is communicated from the
Internet via the first interface unit 13 of the MAC 1 to the third
device 3 and parallel to that data is communicated from the third
device 3 to the internet.
[0038] Via its first interface unit 13 the MAC 1 receives data
through the connection 35 that are intended to be forwarded to the
EFM PHY 2. The MAC 1 collects this data in its first memory element
11, which is assigned to a connection between the MAC 1 and the EFM
PHY 2, before it forwards it via its second interface unit 14 and
the connection 31 to the EFM PHY 2. Similarly, the EFM PHY 2
collects data, which it receives via its first interface unit 23
from the MAC 1, in its first memory element 21, before forwarding
it via its second interface unit 24 through the connection 33 to
the third device 3.
[0039] Let it be assumed that the EFM PHY 2 is not able to forward
to the third device 3 the data received from the MAC 1 at the same
or a higher transmission rate at which the EFM PHY 2 receives this
data from the MAC 1, as a result of which the first memory element
21 of the EFM PHY 2 slowly fills up. As soon as the EFM PHY 2
recognises that a specific memory capacity of its first memory
element 21 has been exceeded (e.g. more than 90%), the EFM PHY 2
sends a PAUSE-Ethernet frame (PAUSE-frame) to the MAC 1, with which
it signals to the MAC 1 that for the time being the MAC 1 should
not send any more data to the EFM PHY 2. To construct the
PAUSE-frame correctly, the EFM PHY 2 has previously stored a MAC
sender address from an Ethernet frame sent to it through the DSL
connection 34, which the EFM PHY 2 now uses as the MAC sender
address of the PAUSE-frame. Generally, through a parameter within
the PAUSE-frame the EFM PHY 2 transmits a time interval in which
the receiver of the PAUSE-frame, in this case the MAC 1, should not
send data to the sender of the PAUSE-frame, in this case the EFM
PHY 2. The MAC 1 analyses the PAUSE-frame and rejects it, i.e. it
does not at any time store it in its second memory element 12 and
neither does it forward it via its first interface unit 13. While
the MAC 1 does not send any more data to the EFM PHY 2, the EFM PHY
2 sends the data in its first memory element 21 via its second
interface unit 24 to the third device 3. There are now two
possibilities for the MAC 1 to send data again to the EFM PHY 2.
The first possibility is that the time interval set by the
PAUSE-frame in the MAC 1 has expired, so the MAC 1 resumes the
sending of data to the EFM PHY 2. The second possibility is that
the EFM PHY 2 recognises that its first memory element 21 has only
been filled to a second specific degree or less (e.g. less than
10%), which is why the EFM PHY 2 sends a further PAUSE-frame,
whereby the MAC CONTROL parameter of the PAUSE-frame is set at 0,
as a result of which it is signalled to the MAC 1 that it can again
send data to the EFM PHY 2, even if the time interval set by the
PAUSE-frame sent before has not yet elapsed.
[0040] As the system 10 consisting of the first and second device
operates in full duplex mode, parallel to receiving data from the
MAC 1, for its part the EFM PHY 2 sends data that it receives via
its second interface unit 24 from the third device 3 using DSL
technology and in the meantime buffers in its second memory element
22, to the MAC 1. The MAC 1 stores this data, which the MAC 1
receives via its second interface unit 14 through the connection
32, in its second memory element 12 and then forwards it via its
first interface unit 13 through the connection 35. If the MAC 1 is
not able to forward the data received from the EFM PHY 2 quickly
enough via its first interface unit 13, e.g. because the
transmission rate at which the EFM PHY 2 sends its data to the MAC
1 is greater than the transmission rate at which the MAC 1 for its
part forwards the data, the second memory element 12 of the MAC 1
fills up. As soon as the MAC 1 recognises that its second memory
element 12 has become full beyond a first certain degree, the MAC 1
sends a PAUSE-frame to the EFM PHY 2 to signal to the EFM PHY 2 not
to send any more data to the MAC 1. The EFM PHY 2 analyses the
PAUSE-frame it has received, rejects it, without storing it in its
first memory element and without forwarding it to the third device,
and does not send any more user data to the MAC 1. As soon as
either the time interval set by the PAUSE-frame that has been sent
has elapsed in the EFM PHY 2 or as soon as the EFM PHY 2 receives a
PAUSE-frame from the MAC 1, in which the MAC CONTROL PARAMETER=0,
the EFM PHY 2 resumes sending user data to the MAC 1.
[0041] Let it be noted that the MAC 1 can or may also send
PAUSE-frames to the EFM PHY 2 if the MAC 1 has previously been
prevented by the EFM PHY 2 by means of a PAUSE-frame from sending
further data to the EFM PHY 2. This is useful for two reasons.
Firstly, pause frames are not stored, so they do not increase the
degree to which the corresponding memory element is full, because
after evaluation they are immediately rejected by the receiver of
the pause frame. Also, it must be possible for the MAC 1 or the EFM
PHY 2 to signal to the EFM PHY 2 or the MAC 1 at any time not to
send any more user data, as particularly in full duplex mode the
EFM PHY 2 and the MAC 1 sends data to the MAC 1 or the EFM PHY 2
even if itself it is not receiving data from the MAC 1 or the EFM
PHY 2, because the EFM PHY 2 or the MAC 1 have prevented this by
means of a PAUSE-frame sent previously. Note also that the
PAUSE-frames sent from the MAC 1 or the EFM PHY 2 correspond to the
PAUSE-frames standardised in IEEE 802.3 Chapter 31.
[0042] With the exemplary method described above it is ensured that
with the system 10, no loss of data can occur during the
transmission of data between the MAC 1 and the EFM PHY 2 by the
sender sending user data to the receiver at a higher transmission
rate than the receiver can process or forward this data.
[0043] Instead of the PAUSE-frame, the system 10 shown in the
FIGURE can also use STOP-Ethernet frames and GO-Ethernet frames. In
this, the MAC 1 or the EFM PHY 2 sends a STOP-frame in order to
prevent the further sending of user data from the EFM PHY 2 or the
MAC 1. Because a time interval cannot be set with the STOP-frame
and the GO-frame, the MAC 1 or the EFM PHY 2 must in any event send
a GO-frame in order to signal to the EFM PHY 2 or the MAC 1 that it
can continue to send user data.
* * * * *