CN102647333B - Communication means under distributed base station system between baseband processing equipment and device - Google Patents

Abstract

The invention provides a communication method and device between baseband processing devices in a distributed base station system. Wherein, the method includes: when each intermediate device between the source BBU and the destination BBU receives the data flow sent by the source BBU, according to the identification of the destination BBU carried by the data flow, it determines the next step for sending the data flow. One hop, if the determined number of next hops N is greater than 1, then use the characteristic parameters of the data stream to select a next hop for sending the data stream from the determined N next hops, through which The selected next hop sends the data flow, and if N is equal to 1, the data flow is directly sent through the determined next hop. By adopting the invention, the communication between the baseband processing devices under the distributed base station system can be realized.

Description

Communication method and device between baseband processing devices in a distributed base station system

technical field

The present invention relates to network communication technology, in particular to a communication method and device between baseband processing equipment (BBU: BaseBandUnit) in a distributed base station system.

Background technique

The core concept of the distributed base station system is to separate the baseband processing equipment from the radio frequency processing equipment (RRU: RemoteRadioUnit), and connect the two through optical fibers. For details, please refer to the structure diagram of the distributed base station system shown in Figure 1. In the distributed base station system shown in Figure 1, the BBU, core network, and wireless network control equipment are concentrated in the equipment room, and are connected to the RRU through optical fibers to complete network coverage.

Among them, the optical fiber connection between BBU and RRU complies with the standard interface protocol, which supports network topologies such as star connection, chain connection and ring connection, so that BBU+RRU can be more flexible in networking.

Compared with the traditional macro base station network construction method, the distributed base station system can provide flexible and simple installation methods and more effective network coverage. However, in a distributed base station system, BBUs complete baseband signal processing internally. In other words, there is no coordination and interaction between BBUs, which leads to unbalanced traffic and insufficient utilization of BBU resources. Referring to FIG. 2, FIG. 2 shows a schematic diagram of traffic imbalance. In Figure 2, there are two BBUs, namely BBU-A and BBU-B, where BBU-A is connected to RRU-A, which is mainly distributed in residential areas, and BBU-B is connected to RRU-B, and the RRU -B is mainly distributed in commercial areas. The RRU-B and BBU-B distributed in the commercial area will be busy during working hours, such as Monday to Friday from 9:00 am to 6:00 pm, and relatively idle during non-working hours; while the RRU-A located in the residential area And BBU-A is just the opposite, it will be relatively free during working hours and busy during non-working hours. In this way, BBU-B may be overloaded during working hours, but processing resources cannot be supplemented during non-working hours; similarly, BBU-A may be overloaded during non-working hours, but in Processing resources during working hours are not replenished.

In summary, it can be seen that in order to achieve traffic balance and make full use of BBU resources, the communication method between BBUs in a distributed base station system is a technical problem that needs to be solved urgently. However, there is no method in the prior art to implement communication between BBUs in a distributed base station system.

Contents of the invention

The invention provides a communication method and device between baseband processing devices in a distributed base station system, so as to realize communication between baseband processing devices in a distributed base station system.

The technical solutions provided by the invention include:

A communication method between baseband processing devices in a distributed base station system, the method is applied in a topology structure including multi-layer switching, in the topology structure, a source BBU and a destination BBU are connected through a plurality of intermediate devices, And, there is at least one route for communication between the source BBU and the destination BBU; the method includes:

When each intermediate device between the source BBU and the destination BBU receives the data stream sent by the source BBU, it determines the next hop for sending the data stream according to the identifier of the destination BBU carried in the data stream, if determined The number N of next hops is greater than 1, then use the characteristic parameters of the data flow to select a next hop for sending the data flow from the determined N next hops, and send the data flow through the selected next hop For the data flow, if N is equal to 1, the data flow is directly sent through the determined next hop.

A device applied to communication between baseband processing equipment in a distributed base station system, the device is applied in a topology structure including multi-layer switching, in the topology structure, the source BBU and the destination BBU are connected through multiple described The device is connected, and there is at least one route for communication between the source BBU and the destination BBU, and the device includes:

The receiving unit is used to receive the data stream sent by the source BBU,

a next hop determining unit, configured to determine a next hop for sending the data stream according to the identifier of the destination BBU carried by the data stream;

a sending unit, configured to select a next hop for sending the data stream from the determined N next hops by using the characteristic parameters of the data stream when the determined number N of the next hops is greater than 1, The data flow is sent through the selected next hop, and when N is equal to 1, the data flow is directly sent through the determined next hop.

As can be seen from the above technical solutions, in the present invention, the source BBU transmits data streams to the destination BBU through a plurality of intermediate devices, realizing the communication between the source BBU and the destination BBU;

Further, in the present invention, when each intermediate device determines that the number N of next hops used to send the data flow is greater than 1 according to the identifier of the destination BBU carried by the data flow, use the The feature parameter selects a next hop for sending the data flow from the determined N next hops, and sends the data flow through the selected next hop, which realizes the communication between the source BBU and the destination BBU. Communication, which realizes that different data streams sent by the source BBU may reach the destination BBU through different routes to achieve routing load balancing.

Description of drawings

FIG. 1 is a structural diagram of a distributed base station system;

FIG. 2 is a schematic diagram of existing unbalanced traffic;

FIG. 3 is a specific schematic diagram of the topology structure applied to the process provided by the embodiment of the present invention;

Fig. 4 is the basic flowchart provided by the embodiment of the present invention;

FIG. 5 is an interactive flowchart of a resource reservation request message and a response message provided by an embodiment of the present invention;

Fig. 6 is a schematic diagram of a specific embodiment provided by an embodiment of the present invention;

FIG. 7 is a structural diagram of a device provided by an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The embodiment of the present invention provides a communication method between BBUs in a distributed base station system. It should be noted that the BBU in the embodiment of the present invention can be called a calculation unit, which can independently complete the processing of baseband signals. According to different situations, It can be regarded as a BBU entity, or a baseband processing board entity, which is not specifically limited in this embodiment of the present invention.

The method provided by the embodiment of the present invention is applied to a topology structure including multi-layer switching. In the topology structure, a source BBU and a destination BBU are connected through multiple intermediate devices, where the intermediate device is specifically a switching device. Moreover, the topology structure in the embodiment of the present invention requires that the number of routes required for communication between any two BBUs be greater than or equal to one.

Preferably, the topology structure may be a fat tree (FatTree) topology structure in a specific implementation. FIG. 3 shows a schematic diagram of a fat tree topology. The topology shown in Figure 3 provides continuous bandwidth between switching layers and constitutes a non-blocking and scalable switching system. The topology structure can be specifically divided into the following three layers shown in FIG. 3 : boundary layer, convergence layer and core layer. In Figure 3, the boundary layer includes a plurality of BBUs, and the convergence layer and the core layer include intermediate devices between BBUs (the intermediate devices are specifically the switching devices shown in Figure 3, and the following are examples of intermediate devices as switching devices to describe). As can be seen from Figure 3, there are multiple switching devices between any two BBUs in the aggregation layer, and by introducing multiple switching devices, large-scale BBU interconnection can be provided, and the present invention does not require the switching devices to have a higher Backplane switching capability, that is, the present invention does not have high requirements on switching equipment, which can realize low-cost large-scale BBU interconnection. In practical applications, the fat tree topology requires switching devices at different layers to have the same characteristics, such as the number of ports is equal, so, assuming that the total number of ports of the switching device shown in Figure 3 is k, then the fat tree topology requires 5K ² /4 switch devices to support k ³ /4 BBUs.

It should be noted that before implementing the communication between BBUs under the distributed base station system provided by the embodiment of the present invention, the route learning process provided by the embodiment of the present invention needs to be executed first. The route learning process is mainly carried out according to the OSPF protocol, specifically: each switching device under the fat tree topology learns the route according to the OSPF protocol, and records the learned route into the routing table. Learning routes through the OSPF protocol can meet the routing protocol requirements of the shortest path, that is, the communication between any two BBUs will choose the path with the shortest hops. Based on the characteristics of the fat tree topology shown in Figure 3, there will be multiple paths with the same number of hops in the communication between any two BBUs, that is, the number of optimal routes required for communication between any two BBUs greater than or equal to 1.

Based on the above description, the following describes the communication method between BBUs in the distributed base station system:

Referring to FIG. 4, FIG. 4 is a flowchart provided by an embodiment of the present invention. As shown in Figure 4, the process may include the following steps:

Step 401, when each switching device between the source BBU and the destination BBU receives the data flow sent by the source BBU, step 402 is executed.

Step 402: Determine the next hop for sending the data flow according to the identifier of the destination BBU carried by the data flow. If the number N of the determined next hops is greater than 1, use the characteristic parameters of the data flow to determine Select one of the N next hops for sending the data flow, and send the data flow through the selected next hop. If N is equal to 1, send it directly through the determined next hop the data stream.

The determination in step 402 is specifically: according to the identifier of the destination BBU carried by the data flow (the identifier of the destination BBU may be the address of the destination BBU), look up the next hop for sending the data flow in the routing table.

In this step 402, a next hop for sending the data stream is selected from the determined N next hops by using the characteristic parameters of the data stream, specifically:

Step 1: Divide the value space corresponding to the set hash function used to select the next hop into N areas, and assign the N areas to the N next hops, that is, one area and one next hop A hop is a one-to-one correspondence.

Step 2, using the hash function to perform a hash operation on the characteristic parameters carried by the data stream to obtain a first hash value;

Step 3: Determine the area where the first hash value is located from the N areas, and determine the next hop corresponding to the area where the first hash value is located as the next step for sending the data stream Jump.

In the above description, the characteristic parameters carried by the data stream may be specifically implemented as: the identifier of the data stream, the identifier of the source BBU, and the identifier of the destination BBU.

Wherein, the identifier of the data stream may be the serial number (id) of the data stream, which is unique, the identifier of the source BBU may be the address of the source BBU (src), and the identifier of the destination BBU may be the address of the destination BBU (dst). The following takes id, src, and dst as examples to describe the operations of steps 1 to 3 above:

If it is determined that the three next hops, that is, the next hop 1 to the next hop 3 are all used to send the data stream, then the value space corresponding to the set hash function is divided into three areas, for example, set The size of the value space corresponding to the given hash function is n bits, then the value space is: 0 to 2 ⁿ , so, the value space 0 to 2 ⁿ is divided into 3 areas, which are respectively area 1 to area 3; and the three areas are allocated to three next hops respectively, for example, area 1 is allocated to next hop 1, area 2 is allocated to next hop 2, and area 3 is allocated to next hop 3.

Afterwards, perform a hash operation on src, dst, and id to obtain the first hash value k=hash(src, dst, id); and select a specific next-hop address by judging which area k falls in. For example, if k falls in area 2, the next hop 2 is selected to send the data flow.

So far, the operation of selecting a next hop for sending the data flow from the determined N next hops by using the characteristic parameters carried by the data flow can be realized.

It should be noted that the above-mentioned division of the value space corresponding to the set hash function into N regions may include: dividing the value space corresponding to the set hash function into N regions evenly according to the principle of uniform distribution area; or, configure a weighted value for each of the N next hops, and divide the value space corresponding to the set hash function into N areas according to the configured weighted value;

Wherein, when the value space corresponding to the set hash function is divided into N areas according to the configured weight value, the corresponding assignment of the N areas to the N next hops includes: according to the weight of the next hop The value assigns N areas to N next hops correspondingly, that is, assigns the area to the next hop configured with the weight value on which the area is based.

So far, the process shown in FIG. 4 is completed. It can be seen from the process shown in FIG. 4 that different data streams sent from the source BBU to the destination BBU will reach the destination BBU through different routes, which realizes routing load balancing.

Usually, in order to meet the real-time requirements of baseband signal processing, there is no data confirmation mechanism between BBUs. In this way, once the resources of a switching device on the path, such as bandwidth, do not meet the resource requirements of the data flow, data loss will result, which will reduce end-to-end transmission. reliability. Based on this, the embodiment of the present invention proposes a resource reservation method, that is, each intermediate device between the source BBU and the destination BBU is required to reserve the resources required by the data flow for the data flow in advance, so as to realize end-to-end real-time reliable transmission . Wherein, the resource may be bandwidth or other resources used to transmit data streams during specific implementation, which is not specifically limited here.

The above method for reserving resources takes place before the source BBU sends data streams to the destination BBU, and is based on an end-to-end resource reservation protocol (RSVP). Among them, RSVP is a one-way protocol. Each protocol interaction process only serves one data flow. Different data flows need to reserve resources separately. In addition, this protocol is encapsulated in the routing protocol and does not determine the routing behavior of the data flow.

Based on this, each switching device between the source BBU and the destination BBU reserves resources for the data flow through the following steps:

Step a, when each switching device between the source BBU and the destination BBU receives the resource reservation request message (Req) sent by the source node to the destination BBU before sending the data flow, confirm whether the current requirements are satisfied. The resource requirement for the data flow carried by the Req, if yes, determine the next hop for sending the Req according to the identity of the destination BBU carried by the Req, if the determined number of next hops M is greater than 1, Then use the characteristic parameters of the data stream carried by the Req, and select a next hop for sending the data stream from the determined M next hops according to the above-described operation of selecting a next hop from the N next hops Select a next hop for sending the Req from the hops, send the Req through the selected next hop, if M is equal to 1, send the Req directly through the determined next hop until the destination is reached BBU, if not, send a resource reservation failure response message to the upper hop, so that when the previous hop receives the resource reservation failure response message, update the next hop that sends the data flow to the destination BBU, and select a new The next hop to send the Req until reaching the destination BBU;

Step b, when each intermediate device between the source BBU and the target BBU receives the acknowledgment resource reception message sent by the target BBU to the source BBU according to the path passed by the Req after receiving the Req, reserve the resources required by the data flow described above.

Wherein, both the confirmation resource reception message and the resource reservation failure response message are Req response messages, but the two correspond to different identifiers.

Preferably, in order to make the above step a and step b clearer, the embodiment of the present invention uses FIG. 5 to show the interaction process of the resource reservation request message and the response message in step a and step b. Wherein, Resp(1) in FIG. 5 represents a resource reservation failure response message, and Resp(0) represents a resource reception confirmation message.

In addition, in order to ensure that the destination BBU sends a resource reception confirmation message to the source BBU according to the path passed by the resource reservation request message, the path along which the resource reservation request message passes can be recorded in the resource reservation request message.

It should be noted that, in the embodiment of the present invention, when reserving the resources required by the data flow, it may further include: starting a timer corresponding to the data flow; If the data flow is detected, the resource reservation for the data flow is revoked. This ensures full utilization of resources.

It should also be noted that in step a, when the previous hop receives the resource reservation failure response message, updating the next hop to send the data stream to the destination BBU includes: setting the previous hop to send the resource reservation The intermediate device of the failure response message is not the next hop for sending the data flow to the destination BBU. In this way, when the previous hop subsequently receives the data flow sent by the source BBU and determines the next hop for sending the data flow, it will directly send the intermediate device that sends the resource reservation failure response message Excluded. Based on this, in step a, selecting a new next hop to send the resource reservation request message includes: selecting an unconfigured next hop from the next hop used to send the resource reservation request message, if the If the number of unconfigured next hops is greater than 1, use the characteristic parameters of the data stream carried in the resource reservation request message, and select one of the N next hops as described above for sending The operation of the next hop of the data flow selects a next hop for sending the resource reservation request message from unset next hops, if the number of unset next hops is equal to 1, the resource reservation request message is directly sent through the unconfigured next hop. This can ensure that the path of the data flow is consistent with the path of the resource reservation request message.

So far, the operation of each intermediate device between the source BBU and the destination BBU to reserve resources for the data flow is completed.

The method provided by the embodiment of the present invention has been completely described above. The present invention will be described in detail below using a specific embodiment.

Referring to FIG. 6 , FIG. 6 is a schematic diagram of a specific embodiment provided by an embodiment of the present invention. In Figure 6, the source BBU (src is 192.168.0.1) needs to send data stream 1 and data stream 2 to the destination BBU (dst is 192.168.2.3), and before sending the data stream 1 and data stream 2, the source BBU first Send resource reservation request messages (req) 1 and req2 to the target BBU, where req1 corresponds to data flow 1, and req2 corresponds to data flow 2.

When two reqs arrive at any intermediate device between the source BBU and the destination BBU, the intermediate device judges whether it meets the resource requirements carried by req1 and req2. If the requirements are met, it finds the next node for forwarding the request from the routing table. It can be seen from the routing table that there are two next hops that can send req1 and req2 to the destination BBU. Based on this, by inputting the characteristic parameters carried in req1 and req2 such as (src, dst, id) triplet to The set hash function performs hash operation to obtain two different hash values. Since there are two next hops, the value space corresponding to the hash function is divided into two parts. Here it is easy to see that the data flow id is different, so the two reqs correspond to different next hops. For example, req1 is routed from port0 to the next One hop, req1 is routed from port1 to the next hop, and then req1 and req2 will be gradually forwarded to the destination BBU;

If the requirements are not met, send a resource reservation failure response message to the upper hop, so that when the previous hop receives the resource reservation failure response message, update the next hop that sends the data flow to the destination BBU, and select a new The next hop sends req1 and req2 until reaching the destination BBU.

When the destination BBU receives req1 and req2, it replies to resp1 and resp2, and each intermediate device reserves resources for data streams 1 and 2 when receiving resp1 and resp2.

When the source BBU sends data stream 1 and data stream 2 to the destination BBU, data stream 1 and data stream 2 are transmitted according to the process shown in FIG. 4 . Since the resource reservation request message and the data flow are routed in the same way, the data flow can be guaranteed to be transmitted according to the reserved resources, which ensures that the data flow can reach the destination in an orderly manner without congestion through the existing routing protocol BBU.

So far, the flow description of the method provided by the embodiment of the present invention is completed.

The device provided by the embodiment of the present invention is described below:

Referring to FIG. 7, FIG. 7 is a structural diagram of a device provided by an embodiment of the present invention. The device is applied to a topology including multi-layer switching such as a fat tree topology. In the topology, the source BBU and the destination BBU are connected through multiple devices, and the source BBU and the destination BBU There is at least one route for communication between them, and the device may specifically be a switching device between the source BBU and the destination BBU, as shown in Figure 7, the device includes:

The receiving unit is used to receive the data stream sent by the source BBU,

a next hop determining unit, configured to determine a next hop for sending the data stream according to the identifier of the destination BBU carried by the data stream;

a sending unit, configured to select a next hop for sending the data stream from the determined N next hops by using the characteristic parameters of the data stream when the determined number N of the next hops is greater than 1, The data flow is sent through the selected next hop, and when N is equal to 1, the data flow is directly sent through the determined next hop.

Preferably, as shown in Figure 7, the device further includes:

a resource reserving unit, configured to reserve resources for the data flow; based on this, the sending unit uses the determined or selected next hop to send the data flow. Wherein, the resource at least includes bandwidth.

Wherein, the resource reservation unit reserves resources for the data flow through the following subunits:

The first receiving subunit is configured to receive a resource reservation request message sent by the source node to the destination BBU before sending the data stream;

A confirmation subunit, configured to confirm whether the device currently meets the resource requirements required by the data flow carried in the resource reservation request message;

The routing subunit is configured to determine the next hop for sending the resource reservation request message according to the identifier of the destination BBU carried in the resource reservation request message when the confirmation result of the confirmation subunit is yes, if The determined number M of next hops is greater than 1, using the characteristic parameters of the data flow carried in the resource reservation request message, and selecting one of the N next hops for sending the data flow Select a next hop for sending the resource reservation request message from the determined M next hops, and send the resource reservation request message through the selected next hop , if M is equal to 1, then directly send the resource reservation request message through the determined next hop until reaching the destination BBU;

The response subunit is configured to send a resource reservation failure response message to the upper hop when the confirmation result of the confirmation subunit is No, so that when the previous hop receives the resource reservation failure response message, it updates the destination BBU Send the next hop of the data flow, and select a new next hop to send the resource reservation request message until reaching the destination BBU;

The reservation subunit is configured to reserve the resource reservation message when the destination BBU receives the resource reservation request message and sends the confirmation resource reception message to the source BBU according to the path through which the resource reservation request message passes. resources required by the data stream;

The second receiving subunit is configured to receive a resource reservation failure response message sent by the next hop of the data flow, update the next hop of sending the data flow to the destination BBU, and select a new next hop Send the resource reservation request message.

In this embodiment, the reserving subunit further starts a timer corresponding to the data flow when reserving the resources required by the data flow, and if the resource is not received within the time allowed by the timer data flow, the resource reservation for the data flow is revoked.

In the embodiment of the present invention, the second receiving subunit updating the next hop of sending the data flow to the target BBU includes: setting the intermediate device used to send the resource reservation failure response message to not be used to send the resource reservation failure response message to the target BBU the next hop of the data flow;

The selecting a new next hop to send the resource reservation request message includes: selecting an unconfigured next hop from the next hop used to send the resource reservation request message, if the unset next hop The number of one hop is greater than 1, then use the characteristic parameters of the data flow carried in the resource reservation request message, and select a next hop for sending the data flow from N next hops The operation selects a next hop for sending the resource reservation request message from the next hops that have not been set, and if the number of the next hops that are not set is equal to 1, then directly pass the unconfigured next hop The configured next hop sends the resource reservation request message.

In this embodiment, the sending unit selects a next hop for sending the data stream from the determined N next hops through the following subunits:

The allocation subunit is used to divide the value space corresponding to the set hash function for selecting the next hop into N areas, and allocate the N areas to the N next hops. Preferably, said dividing the value space corresponding to the set hash function into N regions includes: evenly dividing the value space corresponding to the set hash function into N regions according to the principle of uniform distribution; Alternatively, a weighted value is configured for each of the N next hops, and the value space corresponding to the set hash function is divided into N regions according to the configured weighted value. Wherein, when the value space corresponding to the set hash function is divided into N areas according to the configured weight value, the corresponding assignment of the N areas to the N next hops includes: according to the weight of the next hop The value assigns N regions to N next hops.

The operation subunit is configured to use the hash function to perform a hash operation on the characteristic parameters carried by the data stream to obtain a first hash value. Preferably, the characteristic parameters carried by the data stream include at least: an identifier of the data stream, an identifier of the source BBU, and an identifier of the destination BBU.

A determining subunit, configured to determine the area where the first hash value is located from the N areas, and determine the next hop corresponding to the area where the first hash value is located to be used for sending the data stream next hop.

The device provided by the embodiment of the present invention is described above.

As can be seen from the above technical solutions, in the present invention, the source BBU transmits data streams to the destination BBU through a plurality of intermediate devices, realizing the communication between the source BBU and the destination BBU;

Further, in the present invention, when each intermediate device determines that the number N of next hops used to send the data flow is greater than 1 according to the identifier of the destination BBU carried by the data flow, use the The feature parameter selects a next hop for sending the data flow from the determined N next hops, and sends the data flow through the selected next hop, which realizes the communication between the source BBU and the destination BBU. Communication, which realizes that different data streams sent by the source BBU may reach the destination BBU through different routes to achieve routing load balancing.

Furthermore, the present invention can ensure that the data flow arrives at the destination BBU in an orderly manner without congestion through the method of reserving resources, thereby improving the reliability of communication between the source BBU and the destination BBU.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (16)

1. a communication method between baseband processing equipment (BBU) under a distributed base station system, it is characterized in that, the method is applied in the topological structure that comprises multi-layer exchange, and in described topological structure, source BBU and destination BBU are connected through multiple intermediate devices, and there is at least one route for communication between the source BBU and the destination BBU, the method includes: When each intermediate device receives the data stream sent by the source BBU, it determines the next hop for sending the data stream according to the identifier of the destination BBU carried by the data stream, if the number N of the determined next hops is greater than 1, Then use the characteristic parameters of the data flow to select a next hop for sending the data flow from the determined N next hops, and send the data flow through the selected next hop, if N is equal to 1 , then directly send the data flow through the determined next hop. 2. The method according to claim 1, wherein before each intermediate device receives the data stream, it further comprises: reserving resources required by the data stream for the data stream, and the resources at least include bandwidth; Sending the data flow through the next hop includes: sending the data flow through the next hop and using reserved resources for sending the data flow. 3. The method according to claim 2, wherein each intermediate device reserves resources for the data flow through the following steps: When each intermediate device receives the resource reservation request message sent by the source node to the destination BBU before sending the data stream, confirms whether it meets the requirements of the data stream carried in the resource reservation request message. Resource requirements, if yes, determine the next hop for sending the resource reservation request message according to the identifier of the destination BBU carried in the resource reservation request message, if the determined number of next hops M is greater than 1, use The characteristic parameters of the data flow carried in the resource reservation request message, and select a next hop for sending the data flow from the determined M next hops according to the operation of selecting a next hop from the N next hops Select a next hop for sending the resource reservation request message from the hops, and send the resource reservation request message through the selected next hop, if M is equal to 1, then directly pass the determined next hop One hop sends the resource reservation request message until it reaches the destination BBU; if not, then send a resource reservation failure response message to the upper hop, so that when the last hop receives the resource reservation failure response message, update the The destination BBU sends the next hop of the data flow, and selects a new next hop to send the resource reservation request message until reaching the destination BBU; When each intermediate device receives the confirmation resource reception message sent by the destination BBU to the source BBU according to the path through which the resource reservation request message passes after receiving the resource reservation request message, reserve the data resources required by the stream. 4. The method according to claim 3, wherein updating the next hop for sending the data stream to the destination BBU when the previous hop receives the resource reservation failure response message comprises: setting the previous hop for sending The intermediate device of the resource reservation failure response message is not the next hop for sending the data flow to the destination BBU; The selecting a new next hop to send the resource reservation request message includes: selecting an unconfigured next hop from the next hop used to send the resource reservation request message, if the unset next hop The number of one hop is greater than 1, then use the characteristic parameters of the data flow carried in the resource reservation request message, and select a next hop for sending the data flow from N next hops The operation selects a next hop for sending the resource reservation request message from the next hops that have not been set, and if the number of the next hops that are not set is equal to 1, then directly pass the unconfigured next hop The configured next hop sends the resource reservation request message. 5. The method according to claim 3, wherein when reserving the resources required by the data flow, the method further comprises: Start a timer corresponding to the data flow; If the data flow is not received within the time allowed by the timer, the resource reservation for the data flow is revoked. 6. The method according to any one of claims 1 to 5, wherein the characteristic parameters carried by the data stream are used to select a next hop for sending the data stream from the determined N next hops. Jumps include: Divide the value space corresponding to the hash function that has been set for selecting the next hop into N areas, and assign the N areas to the N next hops; performing a hash operation on the characteristic parameters carried by the data stream by using the hash function to obtain a first hash value; Determine the area where the first hash value is located from the N areas, and determine the next hop corresponding to the area where the first hash value is located as the next hop for sending the data flow. 7. The method according to claim 6, wherein the characteristic parameters carried by the data flow at least include: an identifier of the data flow, an identifier of the source BBU, and an identifier of the destination BBU. 8. The method according to claim 6, wherein dividing the value space corresponding to the set hash function into N regions comprises: dividing the value space corresponding to the set hash function into N regions according to the principle of uniform distribution The value space is evenly divided into N areas; or, a weighted value is configured for each of the N next hops, and the value space corresponding to the set hash function is divided into N according to the configured weighted value regions; Wherein, when the value space corresponding to the set hash function is divided into N areas according to the configured weight value, the corresponding assignment of the N areas to the N next hops includes: according to the weight of the next hop The value assigns N regions to N next hops. 9. The method according to claim 1, wherein the topology of the multi-layer switch is a fat tree topology. 10. The method according to claim 1, characterized in that, the route for the communication between the source BBU and the destination BBU is learned by each intermediate device using the OSPF protocol. 11. A device applied to communication between baseband processing equipment (BBU) in a distributed base station system, characterized in that the device is applied in a topology comprising multi-layer switching, in the topology, the source BBU and The destination BBUs are connected through multiple devices, and there is at least one route for communication between the source BBU and the destination BBU, and the devices include: The receiving unit is used to receive the data stream sent by the source BBU, a next hop determining unit, configured to determine a next hop for sending the data stream according to the identifier of the destination BBU carried by the data stream; a sending unit, configured to select a next hop for sending the data stream from the determined N next hops by using the characteristic parameters of the data stream when the determined number N of the next hops is greater than 1, The data flow is sent through the selected next hop, and when N is equal to 1, the data flow is directly sent through the determined next hop. 12. The device according to claim 11, wherein the device further comprises: a resource reservation unit, configured to reserve resources for the data flow; The sending unit sends the data stream by using the determined or selected next hop and utilizing the reserved resource for sending the data stream. 13. The device according to claim 12, wherein the resource reservation unit reserves resources for the data stream through the following subunits: The first receiving subunit is configured to receive a resource reservation request message sent by the source node to the destination BBU before sending the data stream; A confirmation subunit, configured to confirm whether the device meets the resource requirements required by the data flow carried in the resource reservation request message; The routing subunit is configured to determine the next hop for sending the resource reservation request message according to the identifier of the destination BBU carried in the resource reservation request message when the confirmation result of the confirmation subunit is yes, if The determined number M of next hops is greater than 1, using the characteristic parameters of the data flow carried in the resource reservation request message, and selecting one of the N next hops for sending the data flow Select a next hop for sending the resource reservation request message from the determined M next hops, and send the resource reservation request message through the selected next hop , if M is equal to 1, then directly send the resource reservation request message through the determined next hop until reaching the destination BBU; The response subunit is configured to send a resource reservation failure response message to the upper hop when the confirmation result of the confirmation subunit is No, so that when the previous hop receives the resource reservation failure response message, it updates the destination BBU Send the next hop of the data flow, and select a new next hop to send the resource reservation request message until reaching the destination BBU; The reservation subunit is configured to reserve the resource reservation message when the destination BBU receives the resource reservation request message and sends the confirmation resource reception message to the source BBU according to the path through which the resource reservation request message passes. resources required by the data stream; The second receiving subunit is configured to receive a resource reservation failure response message sent by the next hop of the data flow, update the next hop of sending the data flow to the destination BBU, and select a new next hop Send the resource reservation request message. 14. The device according to claim 13, wherein the reservation subunit further starts a timer corresponding to the data flow when reserving the resources required by the data flow, and if If the device does not receive the data flow within the allowed time, the resource reservation for the data flow is revoked. 15. The device according to claim 13, wherein the second receiving subunit updating the next hop for sending the data flow to the destination BBU comprises: setting an intermediate link for sending the resource reservation failure response message The device is not the next hop for sending the data flow to the destination BBU; The selecting a new next hop to send the resource reservation request message includes: selecting an unconfigured next hop from the next hop used to send the resource reservation request message, if the unset next hop The number of one hop is greater than 1, then use the characteristic parameters of the data flow carried in the resource reservation request message, and select a next hop for sending the data flow from N next hops The operation selects a next hop for sending the resource reservation request message from the unconfigured next hops. If the number of the unconfigured next hops is equal to 1, then directly pass the unconfigured next hop The configured next hop sends the resource reservation request message. 16. The device according to any one of claims 11 to 15, wherein the sending unit comprises: The allocation subunit is used to divide the value space corresponding to the set hash function for selecting the next hop into N areas, and allocate the N areas to the N next hops; An operator unit, configured to use the hash function to perform a hash operation on the characteristic parameters carried by the data stream to obtain a first hash value; A determining subunit, configured to determine the area where the first hash value is located from the N areas, and determine the next hop corresponding to the area where the first hash value is located to be used for sending the data stream next hop.