CN110417592A - A Qos rate limiting method, device, routing device and storage medium - Google Patents

Abstract

The embodiment of the invention discloses a Qos rate limiting method, device, routing equipment and storage medium. The method includes: providing the application layer with a first program for clearing the connection tracking table of the kernel; receiving the first instruction for Qos speed limit of the target terminal sent by the requesting terminal; calling the first instruction of the application layer according to the first instruction. The program clears the connection tracking table; performs flow control on the target terminal based on the speed limit information of the first instruction. In the technical solution of the embodiment of the present invention, by clearing the connection tracking table of the kernel and without restarting the routing device/gateway device, the Qos speed limit will take effect within 2 seconds without affecting the Internet behavior of other user terminals, which can greatly improve user experience.

Description

A Qos rate limiting method, device, routing device and storage medium

technical field

The embodiment of the present invention relates to Qos technology, in particular to a Qos rate limiting method, device, routing device and storage medium.

Background technique

Qos (Quality of Service) uses various basic technologies to provide better service capabilities for designated network communications. It is a security mechanism for the network and a technology used to solve problems such as network delay and congestion.

The most common and effective Qos mechanism in routing devices/gateway devices is to limit the speed of designated user terminals. When some users in the network are performing P2P (Peer to Peer, peer-to-peer network) downloads (such as Thunder downloads) and other operations that occupy a large network bandwidth, in order to avoid affecting the normal network services of other network members, generally choose to use Users with large bandwidth are limited by Qos, only allowing them to occupy the network resources with the specified bandwidth at most, so as to ensure the reasonable allocation of the entire network resources and improve the online experience.

The method of Qos speed limit is generally through WEB UI (Website User Interface, network product interface design) or APP (Application, application program) to issue Qos speed limit to the designated terminal device, set the network bandwidth range that you want to limit, and the routing device /Gateway device performs flow control on specified IP (Internet Protocol, network protocol)/MAC (Media Access Control, media access control) according to user configuration, and sets tc (TrafficControl) flow control rules and iptables firewall rules, but if the user terminal It is a wired terminal and is doing Thunder download, network disk download, BT download, etc. Since the connection tracking table has been successfully established, usually, it is necessary to restart the network or restart the routing device/gateway device, Qos-related tc flow control and iptables firewall rules to take effect.

In order to make the Qos speed limit take effect immediately, restart the network or restart the routing device/gateway, the network will generally be interrupted for more than 15 seconds to recover, that is, the connected user terminal is interrupted for more than 15 seconds, and the user experience is very bad.

Contents of the invention

Embodiments of the present invention provide a Qos rate limiting method, device, routing device, and storage medium. Without restarting the routing device/gateway device, the Qos rate limit takes effect immediately within 2 seconds without interrupting the network services of other users, greatly improving Improve user experience.

In the first aspect, the embodiment of the present invention provides a Qos rate limiting method, including:

Provide the application layer with a first program for clearing the connection tracking table of the kernel;

receiving the first instruction of Qos speed limit for the target terminal sent by the requesting terminal;

calling the first program of the application layer according to the first instruction to clear the connection tracking table;

Perform flow control on the target terminal based on the speed limit information of the first instruction.

Optionally, before calling the first program of the application layer according to the first instruction to clear the connection tracking table, the method includes:

Set tc flow control rules and iptables firewall rules.

Optionally, the first instruction of receiving the Qos speed limit for the target terminal sent by the requesting terminal includes:

The first instruction of Qos rate limit for the target terminal sent by the requesting terminal through the WEB UI or APP is received.

Optionally, the first program for providing the application layer with clearing the connection tracking table of the kernel includes:

A model that pushes preset cleanup functions to the application layer.

Optionally, calling the first program of the application layer according to the first instruction to clear the connection tracking table includes:

Instructing the application layer to execute the model to write specified characters to the specified file in the preset directory to clear the connection tracking table.

In the second aspect, the embodiment of the present invention also provides a Qos rate limiting device, including:

providing a unit for providing the application layer with a first program for clearing the connection tracking table of the kernel;

A receiving unit, configured to receive a first instruction for Qos speed limit of the target terminal sent by the requesting terminal;

A clearing unit, configured to call the first program of the application layer according to the first instruction to clear the connection tracking table;

A control unit, configured to control the flow of the target terminal based on the speed limit information of the first instruction.

Optionally, the device also includes:

The setting unit is used to set tc flow control rules and iptables firewall rules.

Optionally, the receiving unit includes:

The first receiving subunit is configured to receive the first instruction of the Qos rate limit for the target terminal sent by the requesting terminal through the WEB UI or the APP.

Optionally, the providing unit includes:

The push subunit is used to push the model of the preset clearing function to the application layer.

Optionally, the cleaning unit includes:

The executing subunit is used to instruct the application layer to execute the model to write specified characters to the specified file in the preset directory to clear the connection tracking table.

In the third aspect, the embodiment of the present invention also provides a routing device, including a memory, a processor, and a computer program stored in the memory and operable on the processor, and the above implementation is realized when the processor executes the computer program. The Qos rate limiting method described in any of the examples.

In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the Qos speed limiting method described in any one of the above-mentioned embodiments is implemented.

In the embodiment of the present invention, by clearing the connection tracking table of the kernel, without restarting the routing device/gateway device, the Qos speed limit will take effect within 2 seconds, without affecting the online behavior of other user terminals, and the user experience can be greatly improved.

Description of drawings

Fig. 1 is a system structure diagram of a method for implementing Qos rate limiting provided by an embodiment of the present invention;

Fig. 2 is a schematic flow chart of a Qos rate limiting method in Embodiment 1 of the present invention;

FIG. 3 is a schematic structural diagram of a Qos speed limiting device in Embodiment 2 of the present invention;

FIG. 4 is a schematic structural diagram of a routing device in Embodiment 3 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.

Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the steps as sequential processing, many of the steps may be performed in parallel, concurrently, or simultaneously. Additionally, the order of steps may be rearranged. The process may be terminated when its operations are complete, but may also have additional steps not included in the figure. The processing may correspond to a method, function, procedure, subroutine, subroutine, or the like.

In addition, the terms "first", "second", etc. may be used herein to describe various directions, actions, steps or elements, etc., but these directions, actions, steps or elements are not limited by these terms. These terms are only used to distinguish a first direction, action, step or element from another direction, action, step or element. For example, a first speed difference could be termed a second speed difference, and, similarly, a second speed difference could be termed a first speed difference, without departing from the scope of the present application. Both the first speed difference and the second speed difference are speed differences, but they are not the same speed difference. The terms "first", "second", etc. should not be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

FIG. 1 is a system structural diagram of a method for implementing Qos rate limiting provided by an embodiment of the present invention. As shown in FIG. 1 , the system of the embodiment of the present invention includes a routing device 110 , an upper-level network 120 and a user terminal 130 . Wherein, the user terminal 130 includes a first terminal 131, a second terminal 132... an Nth terminal 13N, where N is a positive integer. Wherein, the routing device 110 may also be replaced by a gateway device or other devices with similar functions.

The system provided in the embodiment of the present invention is used to implement the Qos rate limiting method provided in the embodiment of the present invention. The Qos rate limiting method provided in the embodiment of the present invention will be described in detail below.

Embodiment one

FIG. 2 is a schematic flow chart of the Qos rate limiting method provided by Embodiment 1 of the present invention. The embodiment of the present invention is applicable to the case of Qos rate limiting. The method in the embodiment of the present invention can be executed by the Qos rate limiting device, which can be realized by software and/or hardware, and can generally be integrated into a routing device. Wherein, the routing device may also be replaced by a gateway device or other devices with similar functions. With reference to Fig. 2, the Qos speed limiting method of the embodiment of the present invention specifically comprises the following steps:

Step 210, providing the first program for clearing the connection tracking table of the kernel to the application layer.

Specifically, the application layer directly interfaces with the application program and provides common network application services. It is the highest layer of the system and directly provides services for the application process. Its function is to complete a series of services while realizing the communication between multiple system application processes. Process required services. In this embodiment, the application layer is used to receive an instruction from the requesting terminal, and send an instruction to the target terminal to perform Qos speed limit. Linux generates a new connection entry for each packet passing through the network stack. Thereafter, all packets belonging to this connection are uniquely assigned to this connection and identify the state of the connection. Connection tracking is the basis of stateful inspection of the firewall module, and it is also the premise of implementing SNAT and DNAT in address translation. For each piece of data, there are "source" and "destination" hosts. The host that initiates the connection is called the "source", and the host that responds to the request of the "source" is the destination. Termination for tracking records, the table generated by all record items is called the connection tracking table. In this embodiment, the connection tracking table is a hash table for recording connection information of all data packets, and is a bidirectional circular linked list array composed of hash values of data packets.

In the routing mode, nat modifies the source/destination address of the IP packet according to the forwarding rules, and the returned data packets can be routed to the requesting machine only by the records of the connection tracking table, and the connection tracking table enables the WAN side packets to be routed to the requesting machine Machines, such as mobile phones/PCs on the LAN side.

Display ipv4/ipv6 connection, protocol, protocol type code, timeout time (it will be consumed regularly until more packets of this connection are received), [current state (can be used to match firewall filter rules)], source address , destination address, source port and destination port, [UNREPLIED (the connection has not received a response, delete the connection first when the connection tracking table is full)], the information of the response packet you want to receive, the address and port are opposite to the previous ones. An example connection tracking table query is as follows:

Specifically in FIG. 1 , the routing device 110 provides the application layer with a first program of clearing the connection tracking table of the kernel. The first program is a program provided by the kernel to the application layer and capable of clearing the connection tracking table of the kernel.

Optionally, provide the application layer with the first program for clearing the connection tracking table of the kernel; including:

A program model that pushes the preset clearing function to the application layer.

For example, the model supports the application layer for the kernel to perform functions equivalent to the kernel nf_ct_iterate_cleanup function.

Step 220, receiving a first instruction of Qos rate limit for the target terminal sent by the requesting terminal.

Specifically in FIG. 1, the requesting terminal 13i (1≤i≤N, i is a positive integer) sends to the routing device 110 the first instruction of Qos speed limit for the target terminal 13j (1≤j≤N, j is a positive integer) , requesting Qos speed limit for the target terminal 13j.

The routing device 110 receives the first instruction of the Qos rate limit for the target terminal 13j sent by the requesting terminal 13i.

Optionally, receiving the first instruction of Qos speed limit for the target terminal sent by the requesting terminal includes:

The first instruction of Qos rate limit for the target terminal sent by the requesting terminal through the WEB UI or APP is received. For example, Qos speed limit is applied to the terminals with specified MAC/IP, so that the occupied network bandwidth cannot exceed the upper limit.

Step 230: Call the first program of the application layer according to the first instruction to clear the connection tracking table.

Optionally, calling the first program of the application layer according to the first instruction to clear the connection tracking table includes:

Instructing the application layer to execute the model to write specified characters to the specified file in the preset directory to clear the connection tracking table.

For example, the application layer clears the connection tracking table by writing specified characters to the specified file under /proc/.

Because general routers have hardware acceleration function, that is, hwnat is enabled by default, when performing high-speed download operations such as Thunder download and network disk download through a wired connection, it is almost no more than the CPU, and it is directly forwarded from the switch to improve network performance. Therefore, in the case of a wired connection, after the connection tracking table is established, due to hardware acceleration, large-capacity downloads can not be controlled by the CPU, resulting in the Qos speed limit not taking effect. At this time, the connection tracking table needs to be cleared, and the rules are marked when the connection tracking table is re-established, so that the Qos rate limit takes effect.

Specifically, in FIG. 1 , the routing device 110 calls the first program of the application layer according to the first instruction to clear the connection tracking table.

Optionally, before calling the first program of the application layer according to the first instruction to clear the connection tracking table, the method includes:

Set tc flow control rules and iptables firewall rules.

Specifically, operate the mangle table through iptables rules, mark the specified terminal (mac or ip, etc.), and then use the tc flow control command to configure flow control. The linux kernel can mark the upstream and downstream network packets of the terminal and perform traffic statistics and control.

Specifically in FIG. 1 , the routing device 110 sets tc flow control rules and iptables firewall rules.

Step 240: Perform flow control on the target terminal based on the speed limit information of the first instruction.

Since the connection tracking table has been cleared, the flow control of the target terminal can make the Qos speed limit take effect immediately.

Specifically in FIG. 1 , the routing device 110 performs flow control on the target terminal 13j based on the speed limit information of the first instruction. Wherein, the speed limit information may include information such as speed limit speed, speed limit time period, and speed limit object.

The following describes the Qos rate limiting method in combination with the system provided by the embodiment of the present invention. The system in this embodiment of the present invention includes a routing device 110 , an upper-level network 120 and a user terminal 130 . Wherein, the user terminal 130 includes a first terminal 131, a second terminal 132... an Nth terminal 13N, where N is a positive integer. In implementing the Qos speed-limiting method of the present invention, any i-th terminal 13i (1≤i≤N, i is a positive integer) sends a request to the routing device 110 as a requesting terminal 13i, requesting another j-th terminal 13j ( 1≤j≤N, j is a positive integer), that is, the target terminal 13j performs Qos speed limit. Specific steps are as follows:

The routing device 110 provides the first program for clearing the connection tracking table of the kernel to the application layer;

The requesting terminal 13i sends to the routing device 110 a first instruction for the Qos speed limit of the target terminal 13j, requesting that the target terminal 13j be subjected to Qos speed limit;

The routing device 110 receives the first instruction of Qos speed limit for the target terminal 13j sent by the requesting terminal 13i;

Routing device 110 sets tc flow control rules and iptables firewall rules;

The routing device 110 invokes the first program of the application layer according to the first instruction to clear the connection tracking table;

The routing device 110 performs flow control on the target terminal 13j based on the speed limit information of the first instruction.

The technical scheme of the embodiment of the present invention adds the function of supporting the clearing of the application layer connection tracking table in the kernel. When doing Qos speed limit, in addition to setting the tc flow control rule and the iptables firewall rule, the connection tracking table of the kernel is cleared at the same time, without restarting On the premise of routing equipment/gateway equipment, the Qos speed limit will take effect within 2 seconds, without affecting the online behavior of other user terminals, which can greatly improve user experience.

Embodiment two

The Qos speed limiting device 300 provided in the embodiment of the present invention can execute the Qos speed limiting method provided in any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method. The device 300 can be composed of software and/or hardware ( integrated circuit) and can generally be integrated into routing equipment. Wherein, the routing device may also be replaced by a gateway device or other devices with similar functions. FIG. 3 is a schematic structural diagram of a Qos rate limiting device 300 in Embodiment 2 of the present invention. Referring to Fig. 3, the Qos speed limiting device 300 of the embodiment of the present invention may specifically include:

A providing unit 310, configured to provide the application layer with a first program for clearing the connection tracking table of the kernel;

The receiving unit 320 is configured to receive a first instruction for Qos speed limit of the target terminal sent by the requesting terminal;

A clearing unit 330, configured to call the first program of the application layer according to the first instruction to clear the connection tracking table;

The control unit 340 is configured to control the flow of the target terminal based on the speed limit information of the first instruction.

Optionally, the device 300 also includes:

The setting unit is used to set tc flow control rules and iptables firewall rules.

Optionally, the receiving unit 320 includes:

The first receiving subunit is configured to receive the first instruction of the Qos rate limit for the target terminal sent by the requesting terminal through the WEB UI or the APP.

Optionally, the providing unit 310 includes:

The push subunit is used to push the model of the preset clearing function to the application layer.

Optionally, the clearing unit 330 includes:

The executing subunit is used to instruct the application layer to execute the model to write specified characters to the specified file in the preset directory to clear the connection tracking table.

In the technical solution of the embodiment of the present invention, by clearing the connection tracking table of the kernel and without restarting the routing device/gateway device, the Qos speed limit will take effect within 2 seconds without affecting the Internet behavior of other user terminals, which can greatly improve user experience.

Embodiment Three

FIG. 4 is a schematic structural diagram of a routing device provided in Embodiment 4 of the present invention, as shown in FIG. 4 , wherein the routing device can also be replaced by a gateway device or other devices with similar functions. The routing device includes a processor 410, a memory 420, an input device 430 and an output device 440; the number of processors 410 in the routing device can be one or more, and one processor 410 is taken as an example in Fig. 4; the processing in the routing device The controller 410, the memory 420, the input device 430, and the output device 440 may be connected via a bus or in other ways. In FIG. 4, connection via a bus is taken as an example.

The memory 420, as a computer-readable storage medium, can be used to store software programs, computer executable programs and modules, such as program instructions/modules corresponding to the Qos speed limiting method in the embodiment of the present invention (for example, the Qos speed limiting device in the Qos speed limiting device) providing unit 310, receiving unit 320, clearing unit 330 and control unit 340). The processor 410 executes various functional applications and data processing of the routing device by running software programs, instructions and modules stored in the memory 420, that is, implements the above-mentioned Qos rate limiting method.

That is:

Provide the application layer with a first program for clearing the connection tracking table of the kernel;

receiving the first instruction of Qos speed limit for the target terminal sent by the requesting terminal;

calling the first program of the application layer according to the first instruction to clear the connection tracking table;

Perform flow control on the target terminal based on the speed limit information of the first instruction.

Of course, the processor of the routing device provided in the embodiments of the present invention is not limited to performing the operations of the method described above, and may also perform related operations in the Qos rate limiting method provided in any embodiment of the present invention.

The memory 420 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application program required by at least one function; the data storage area may store data created according to the use of the terminal, and the like. In addition, the memory 420 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage devices. In some examples, the memory 420 may further include memory located remotely relative to the processor 410, and these remote memories may be connected to the routing device through a network. Examples of the aforementioned networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The input device 430 can be used to receive input numbers or character information, and generate key signal input related to user settings and function control of the routing device. The output device 440 may include a display device such as a display screen.

In the technical solution of the embodiment of the present invention, by clearing the connection tracking table of the kernel and without restarting the routing device/gateway device, the Qos speed limit will take effect within 2 seconds without affecting the Internet behavior of other user terminals, which can greatly improve user experience.

Embodiment Four

Embodiment 4 of the present invention also provides a storage medium containing computer-executable instructions, the computer-executable instructions are used to execute a Qos rate limiting method when executed by a computer processor, the method comprising:

Provide the application layer with a first program for clearing the connection tracking table of the kernel;

receiving the first instruction of Qos speed limit for the target terminal sent by the requesting terminal;

calling the first program of the application layer according to the first instruction to clear the connection tracking table;

Perform flow control on the target terminal based on the speed limit information of the first instruction.

Of course, in the storage medium containing computer-executable instructions provided in the embodiments of the present invention, the computer-executable instructions are not limited to the above-mentioned method operations, and can also execute the Qos rate limiting method provided in any embodiment of the present invention. related operations.

The computer-readable storage medium in the embodiments of the present invention may use any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (non-exhaustive list) of computer readable storage media include: electrical connections with one or more leads, portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), Erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a data signal carrying computer readable program code in baseband or as part of a carrier wave. Such propagated data signals may take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. .

Program code contained on a storage medium may be transmitted using any appropriate medium, including - but not limited to wireless, wires, optical cables, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out the operations of the present invention may be written in one or more programming languages, or combinations thereof, including object-oriented programming languages—such as Java, Smalltalk, C++, and conventional Procedural Programming Language - such as "C" or a similar programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or terminal. In cases involving a remote computer, the remote computer can be connected to the user computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (such as through an Internet service provider). Internet connection).

In the technical solution of the embodiment of the present invention, by clearing the connection tracking table of the kernel and without restarting the routing device/gateway device, the Qos speed limit will take effect within 2 seconds without affecting the Internet behavior of other user terminals, which can greatly improve user experience.

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention, and the present invention The scope is determined by the scope of the appended claims.

Claims (10)

1. A Qos speed-limiting method is characterized in that, comprising: Provide the application layer with a first program for clearing the connection tracking table of the kernel; receiving the first instruction of Qos speed limit for the target terminal sent by the requesting terminal; calling the first program of the application layer according to the first instruction to clear the connection tracking table; Perform flow control on the target terminal based on the speed limit information of the first instruction. 2. The Qos speed-limiting method according to claim 1, wherein, before the first program calling the application layer according to the first instruction to clear the connection tracking table, includes: Set tc flow control rules and iptables firewall rules. 3. The Qos speed limit method according to claim 1, wherein the first instruction for the Qos speed limit of the target terminal sent by the receiving request terminal includes: The first instruction of Qos rate limit for the target terminal sent by the requesting terminal through the WEB UI or APP is received. 4. the Qos speed-limiting method according to claim 1, is characterized in that, the first program that the described connection tracking table of clearing kernel is provided to application layer, comprises: A model that pushes preset cleanup functions to the application layer. 5. The Qos speed-limiting method according to claim 4, wherein said calling the first program of the application layer according to the first instruction to clear the connection tracking table includes: Instructing the application layer to execute the model to write specified characters to the specified file in the preset directory to clear the connection tracking table. 6. A Qos speed limiting device, characterized in that, comprising: providing a unit for providing the application layer with a first program for clearing the connection tracking table of the kernel; A receiving unit, configured to receive a first instruction for Qos speed limit of the target terminal sent by the requesting terminal; A clearing unit, configured to call the first program of the application layer according to the first instruction to clear the connection tracking table; A control unit, configured to control the flow of the target terminal based on the speed limit information of the first instruction. 7. Qos speed limiting device according to claim 6, is characterized in that, described device also comprises: The setting unit is used to set tc flow control rules and iptables firewall rules. 8. The Qos speed limiting device according to claim 6, wherein the receiving unit comprises: The first receiving subunit is configured to receive the first instruction of the Qos rate limit for the target terminal sent by the requesting terminal through the WEB UI or the APP. 9. A routing device, comprising a memory, a processor, and a computer program stored on the memory and operable on the processor, characterized in that, when the processor executes the computer program, the computer program according to claims 1-5 is implemented. Any of the Qos rate limiting methods described above. 10. A computer-readable storage medium, on which a computer program is stored, wherein, when the computer program is executed by a processor, the Qos speed limiting method according to any one of claims 1-5 is implemented.