Patent Publication Number: US-10791167-B2

Title: User migration

Description:
BACKGROUND 
     Network Functions Virtualisation (NFV) application networking may include a virtual Broadband Remote Access Server (vBRAS) and a NFV Manager. 
     The vBRAS is a physical service function node and may perform verification for access users as a gateway of the access users. The NFV Manager may be included in a cloud management platform, and is used to manage each vBRAS, and assign vBRASs for users to access so that different users may access different vBRASs for being provided with process services. The NFV Manager may be also used to monitor a running state of each vBRAS in real time, start a new vBRAS to share subsequent traffic when discovering vBRAS service loads are too heavy, and close a certain vBRAS for saving resources when the service load of the certain vBRAS is too low. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart illustrating a user migration method according to an example of the present disclosure. 
         FIG. 2  is a diagram illustrating a network according to an example of the present disclosure. 
         FIGS. 3A and 3B  are diagrams illustrating a NFV Manager shown in  FIG. 2  making a sub vBRAS of access users migrate according to an example of the present disclosure. 
         FIG. 4  is a diagram illustrating a user migration apparatus according to an example of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the term “includes” means includes but not limited to, the term “including” means including but not limited to. The term “based on” means based at least in part on. In addition, the terms “a” and “an” are intended to denote at least one of a particular element. 
       FIG. 1  is a flowchart illustrating a user migration method  100  according to an example of the present disclosure. The method  100  may be performed by a NFC Manager to make a sub vBRAS of access users migrate between vBRASs. The method may start from process  101 . 
     At process  101 , the NFV Manager may receive user traffic notified by each sub vBRAS of each vBRAS. 
     At process  102 , the NFV Manager may calculate user traffic of each vBRAS. 
     At process  103 , the NFV Manager may select a source vBRAS and a target vBRAS from all of the vBRASs and select a migration sub vBRAS needing to migrate from the source vBRAS to the target vBRAS. 
     At process  104 , the NFV Manager may notify the source vBRAS to send data relevant to the migration sub vBRAS to the target vBRAS. The data relevant to the migration sub vBRAS at least include: a MAC address of the migration sub vBRAS which is used as identification information of the migration sub vBRAS, the number of users accessing the migration sub vBRAS, traffic of the users accessing the migration sub vBRAS, and etc. 
     The NFV Manager may make the sub vBRAS accessed by the users migrate between the vBRASs by taking the sub vBRAS as a unit according to the method shown in  FIG. 1 . Hence, the users may migrate between different vBRASs, and thus network resilience of the NFV network is improved. 
       FIG. 2  is a diagram illustrating a network according to an example of the present disclosure. MAC addresses of three vBRASs, i.e. vBRAS 21 , vBRAS 22  and vBRAS 23  are MAC 1 , MAC 2  and MAC 3  respectively. A NFV Manager  25  running on a cloud management platform  24  manages the vBRAS 21 , vBRAS 22  and vBRAS 23 . 
     The vBRAS 21  is configured with three sub vBRASs, i.e. sub vBRAS 21 _ 1 , sub vBRAS 21 _ 2  and sub vBRAS 21 _ 3 , through virtualization software. The three sub vBRASs  21 _ 1  to  21 _ 3  are used as virtual gateways, and MAC addresses of the sub vBRAS 21 _ 1 , sub vBRAS 21 _ 2  and sub vBRAS 21 _ 3  are MAC 21 _ 1 , MAC 21 _ 2  and MAC 21 _ 3  respectively. 
     The vBRAS 22  is configured with three sub vBRASs, i.e. sub vBRAS 22 _ 1 , sub vBRAS 22 _ 2  and sub vBRAS 22 _ 3 , through virtualization software. The three sub vBRASs  22 _ 1  to  22 _ 3  are used as virtual gateways, and MAC addresses of the sub vBRAS 22 _ 1 , sub vBRAS 22 _ 2  and sub vBRAS 22 _ 3  are MAC 22 _ 1 , MAC 22 _ 2  and MAC 22 _ 3  respectively. 
     The vBRAS 23  is configured with three sub vBRASs, i.e. sub vBRAS 23 _ 1 , sub vBRAS 23 _ 2  and sub vBRAS 23 _ 3 , through virtualization software. The three sub vBRASs  23 _ 1  to  23 _ 3  are used as virtual gateways, MAC addresses of the sub vBRAS 23 _ 1 , sub vBRAS 23 _ 2  and sub vBRAS 23 _ 3  are MAC 23 _ 1 , MAC 23 _ 2  and MAC 23 _ 3  respectively. 
     The sub vBRAS 21 _ 1  starts and sends a register request packet carrying the MAC 21 _ 1  and information of the vBRAS 21  to which the sub vBRAS 21 _ 1  belongs to the NFV Manager  25 . The sub vBRAS 21 _ 1  also sends a Reverse Address Resolution Protocol (RARP) request packet, in which a source MAC address is MAC 21 _ 1 . 
     The NFV Manager  25  receives the register request packet from the sub vBRAS 21 _ 1 , records the MAC address of MAC 21 _ 1  requested to be registered by the sub vBRAS 21 _ 1  and the information of the vBRAS 21  to which the sub vBRAS 21 _ 1  belongs. 
     An aggregation switch  26  receives the RARP request packet from the sub vBRAS 21 _ 1  and learns a MAC address entry based on a port receiving the RARP request packet and the source MAC address. 
     The processing of sending the register request packet to the NFV Manager  25  and the processing of sending the RARP request packet which are performed by the sub vBRAS 21 _ 2  and sub vBRAS 21 _ 3 , sub vBRAS 22 _ 1  to sub vBRAS 22 _ 3  and sub vBRAS 23 _ 1  to sub vBRAS 23 _ 3  are similar with the above processing. 
     Each sub vBRAS may send the register request to the NFV Manager  25  based on a private interaction protocol so as to carry the identification information of the sub vBRAS and information of the vBRAS to which the sub vBRAS belongs. In the example, the MAC address of each sub vBRAS is used as the identification information of the sub vBRAS. 
     The aggregation switch  26  receives the RARP request packets sent by the sub vBRAS 21 _ 1  to sub vBRAS 21 _ 3 , sub vBRAS 22 _ 1  to sub vBRAS 22 _ 3 , and sub vBRAS 23 _ 1  to sub vBRAS 23 _ 3 , and learns MAC address entries based on a port receiving each RARP packet and the source MAC address of each RARP packet. The aggregation switch  26  may forward each RARP request packet or discard the received RARP request packet. 
     A user  281  sends a broadcast protocol packet carrying user identification information. The broadcast protocol packet may be a Dynamic Host Configuration Protocol (DHCP) discover packet or a Point to Point Protocol over Ethernet (PPPoE) request packet and etc., which is not limited in the present disclosure. Herein, a source MAC address of the broadcast protocol packet sent by the user  281  is MAC 281  which is the user identification information. The DHCP discover packet is taken as an example, the aggregation switch  26  receives the DHCP discover packet, and sends the DHCP discover packet to the NFV Manager  25  based on packet redirection or an ACL entry. The NFV Manager  25  receives the DHCP discover packet and assigns sub vBRAS 21 _ 1  for the user  281  by taking the source MAC address of the DHCP discover packet, i.e. MAC_ 281  as the user identification information. 
     The NFV Manager  25  may randomly select one sub vBRAS from registered sub vBRASs and assign the user  281  to the selected sub vBRAS. Or, the NFV Manager  25  may select one sub vBRAS based on the number of users or traffic assigned to each sub vBRAS, and assign the user  281  to the selected sub vBRAS, thereby implementing load balancing between the sub vBRAS. 
     The NFV Manager  25  sends the DHCP discover packet to the sub vBRAS 21 _ 1  and notifies that the user  281  is assigned to the sub vBRAS 21 _ 1 . For example, NFV Manager  25  may modify a destination MAC address of the DHCP discover packet as MAC 21 _ 1  which is the MAC address of the selected sub vBRAS 21 _ 1 , and send the DHCP discover packet having the modified destination MAC address based on a MAC address entry matching with the modified destination MAC address. Or, the NFV Manager  25  may send the DHCP discover packet having the modified destination MAC address of MAC 21 _ 1  to the aggregation switch  26  based on redirection or an ACL entry. The aggregation switch  26  receives the DHCP discover packet having the destination MAC address of MAC 21 _ 1 , searches a MAC table based on the destination MAC address of MAC 21 _ 1 , finds a matched MAC address entry, and sends the DHCP discover packet via an interface of the matched MAC address entry. Thus, the DHCP discover packet having the destination MAC address of MAC 21 _ 1  is sent to the vBRAS 21 . 
     The vBRAS 21  receives the DHCP discover packet having the destination MAC address of MAC 21 _ 1 , and sends the DHCP discover packet to the sub vBRAS 21 _ 1 . The sub vBRAS 21 _ 1  receives the DHCP discover packet, identifies that the destination MAC address of DHCP discover packet is the virtual gateway MAC address of the sub vBRAS 21 _ 1 , and determines the assigned user  281  based on the source MAC address of MAC 281 . The sub vBRAS 21 _ 1  may send a DHCP response packet and assign an IP address for the user  281 . If another broadcast protocol packet, e.g. the PPPoE packet is used, the sub vBRAS 21 _ 1  may perform subsequent processing based on corresponding protocol, which is not limited herein. 
     In  FIG. 2 , the processing of the NFV Manager  25  assigning users from a user  282  to a user N to corresponding vvBRASs is the same as the above processing of assigning the user  281  to the sub vBRAS 21 _ 1 . The processing of the NFV Manager  25  notifying each sub vBRAS of each vBRAS of the assigned user is the same as the processing of notifying the .sub vBRAS 21 _ 1  of the assigned user  281 . 
     As shown in table 1, in the example, the NFV Manager  25  records each sub vBRAS of each vBRAS, and also records the number of users assigned to each sub vBRAS. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Sub vBRAS 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
               
               
                   
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
               
               
                 vBRAS 
                 21_1 
                 21_2 
                 21_3 
                 22_1 
                 22_2 
                 22_3 
                 23_1 
                 23_2 
                 23_3 
               
               
                   
               
               
                 vBRAS21 
                 the  
                 the  
                 the  
                   
                   
                   
                   
                   
                   
               
               
                   
                 number 
                 number 
                 number 
                   
                   
                   
                   
                   
                   
               
               
                   
                 of users 
                 of users 
                 of users 
                   
                   
                   
                   
                   
                   
               
               
                   
                 5000 
                 3000 
                 3000 
                   
                   
                   
                   
                   
                   
               
               
                 vBRAS22 
                   
                   
                   
                 the  
                 the  
                 the  
                   
                   
                   
               
               
                   
                   
                   
                   
                 number 
                 number 
                 number 
                   
                   
                   
               
               
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
                   
                   
                   
               
               
                   
                   
                   
                   
                 4000 
                 4000 
                 3000 
                   
                   
                   
               
               
                 vBRAS23 
                   
                   
                   
                   
                   
                   
                 the  
                 the  
                 the  
               
               
                   
                   
                   
                   
                   
                   
                   
                 number 
                 number 
                 number 
               
               
                   
                   
                   
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
               
               
                   
                   
                   
                   
                   
                   
                   
                 5000 
                 3000 
                 1000 
               
               
                   
               
            
           
         
       
     
     The NFV Manager  25  may assign access users for the sub vBRASs based on the number of users assigned for each sub vBRAS, so as to make the number of access users assigned for each sub vBRAS balanced. 
     When different users perform different services and generate different traffic, traffic loads of the sub vBRAS may be not balanced. 
     According to an example of the present disclosure, the NFV Manager  25  assigns access users for each sub vBRAS, and each sub vBRAS monitors the total traffic of the access users and sends running state information of the sub vBRAS to the NFV Manager  25  in real time or regularly. The running state information of each sub vBRAS at least includes the number of access users, traffic of the access users and etc. In the example, each sub vBRAS may send the running state information to the NFV Manager  25  based on the private interaction protocol, and the T-L-V field of the private interaction protocol may be used to carry the running state information. 
     The NFV Manager  25  receives and stores the running state information of each sub vBRAS, so as to monitor the running state information of each sub vBRAS. 
     The NFV Manager  25  updates the running state information of each sub vBRAS recorded in table 1 based on the monitored running state information of each sub vBRAS, and the updated running state information is shown in table 2. 
     
       
         
           
               
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                   
                 Sub vBRAS 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
               
               
                   
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
               
               
                 vBRAS 
                 21_1 
                 21_2 
                 21_3 
                 22_1 
                 22_2 
                 22_3 
                 23_1 
                 23_2 
                 23_3 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 vBRAS21 
                 the  
                 the  
                 the  
                   
                   
                   
                   
                   
                   
               
               
                   
                 number 
                 number 
                 number 
                   
                   
                   
                   
                   
                   
               
               
                   
                 of users 
                 of users 
                 of users 
                   
                   
                   
                   
                   
                   
               
               
                   
                 5000, 
                 3000, 
                 3000, 
                   
                   
                   
                   
                   
                   
               
               
                   
                 user  
                 user  
                 user  
                   
                   
                   
                   
                   
                   
               
               
                   
                 traffic  
                 traffic 
                 traffic 
                   
                   
                   
                   
                   
                   
               
               
                   
                 500 G 
                 150 G 
                 100 G 
                   
                   
                   
                   
                   
                   
               
               
                 vBRAS22 
                   
                   
                   
                 the  
                 the  
                 the  
                   
                   
                   
               
               
                   
                   
                   
                   
                 number 
                 number 
                 number 
                   
                   
                   
               
               
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
                   
                   
                   
               
               
                   
                   
                   
                   
                 4000, 
                 4000, 
                 3000, 
                   
                   
                   
               
               
                   
                   
                   
                   
                 user  
                 user  
                 user  
                   
                   
                   
               
               
                   
                   
                   
                   
                 traffic  
                 traffic  
                 traffic 
                   
                   
                   
               
               
                   
                   
                   
                   
                 100 G 
                 100 G 
                 300 G 
                   
                   
                   
               
               
                 vBRAS23 
                   
                   
                   
                   
                   
                   
                 the  
                 the  
                 the  
               
               
                   
                   
                   
                   
                   
                   
                   
                 number 
                 number 
                 number 
               
               
                   
                   
                   
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
               
               
                   
                   
                   
                   
                   
                   
                   
                 5000, 
                 3000, 
                 1000, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 user  
                 user  
                 user  
               
               
                   
                   
                   
                   
                   
                   
                   
                 traffic  
                 traffic  
                 traffic 
               
               
                   
                   
                   
                   
                   
                   
                   
                 400 G 
                 100 G 
                 100 G 
               
               
                   
               
            
           
         
       
     
     In table 2, the total number of the access users for the sub vBRAS 21 _ 1  to the sub vBRAS 21 _ 3  on the vBRAS 21  is identical with the total number of the access users for the sub vBRAS 22 _ 1  to the sub vBRAS 22 _ 3  on the vBRAS 22 , but the sum of traffic of the access users for the sub vBRAS 21 _ 1  to the sub vBRAS 21 _ 3  on the vBRAS 21  is larger than the sum of traffic of the access users for the sub vBRAS 22 _ 1  to the sub vBRAS 22 _ 3  on the vBRAS 22 . The total number of the access users for the sub vBRAS 22 _ 1  to the sub vBRAS 22 _ 3  on the vBRAS 22  is larger than the total number of the access users for the sub vBRAS 23 _ 1  to the sub vBRAS 23 _ 3  on the vBRAS 23 , but the sum of traffic of the access users for the sub vBRAS 23 _ 1  to the sub vBRAS 23 _ 3  on the vBRAS 23  is larger than the sum of traffic of the access users for the sub vBRAS 22 _ 1  to the sub vBRAS 22 _ 3  on the vBRAS 22 . 
     The NFV Manager  25  calculates the traffic of the vBRAS 21  based on the traffic of the sub vBRAS 21 _ 1  to the sub vBRAS 21 _ 3  and obtains a result of 750 G; calculates the traffic of the vBRAS 22  based on the traffic of the sub vBRAS 22 _ 1  to the sub vBRAS 22 _ 3  and obtains a result of 500 G and calculates the traffic of the vBRAS 23  based on the traffic of the sub vBRAS 23 _ 1  to the sub vBRAS 23 _ 3  and obtains a result of 600 G. 
     According to an example of the present disclosure, a maximum traffic threshold is configured as 650 G The NFV Manager  25  determines the vBRAS 21  having the traffic higher than the maximum traffic threshold as a source vBRAS, and determines, from two vBRASs having the traffic lower than the maximum traffic threshold, the vBRAS 22  having a lowest traffic as a target vBRAS. The NFV Manager  25  determines that the traffic of the access users for the sub vBRAS 21 _ 3  is most close to a traffic value obtained by subtracting the maximum traffic threshold from the traffic of the vBRAS 21 , and thus determines the sub vBRAS 21 _ 3  as a migration sub vBRAS. The NFV Manager  25  determines that the traffic of the vBRAS 22  is lower than the maximum traffic threshold after the sub vBRAS 21 _ 3  is migrated to the vBRAS 22 . 
     According to another example of the present disclosure, the NFV Manager  25  determines the vBRAS 21  having the highest traffic as a source vBRAS, determines the vBRAS 23  having the lowest traffic as a target vBRAS, and calculates an average traffic based on the traffic of the vBRAS 21 , vBRAS 22  and vBRAS 23 . The NFV Manager  25  selects from the vBRAS 21  a sub vBRAS having the traffic of the access users most closed to a traffic value obtained by subtracting the average traffic from the traffic of the vBRAS 21 . 
     The NFV Manager  25  assigns a first Transmission Control Protocol (TCP) port number for the vBRAS 21 , and assigns a second TCP port number for the vBRAS 22 . The vBRAS 21  and vBRAS 22  are notified of the first TCP port number and the second TCP port number respectively. The NFV Manager  25  notifies the vBRAS 21  of that the sub vBRAS 21 _ 3  is migrated to the vBRAS 22 . 
     The vBRAS 21  and vBRAS 22  establishes a TCP connection based on the first TCP port number and the second TCP port number. The vBRAS 21  sends the data relevant to the sub vBRAS 21 _ 3  to the vBRAS 22  via the TCP connection. 
     In the example of the present disclosure, each sub vBRAS starts a user mode process, and address space of the user mode process records data relevant to the sub vBRAS. The address space of the user mode process of each sub vBRAS is separate from each other. The vBRAS 21  may send data recorded in the address space of the user mode process of the sub vBRAS 21 _ 3  to the vBRAS 22 . 
     The vBRAS 22  receives the data relevant to the sub vBRAS 21 _ 3 , and starts a new user mode process. The address space of the new user mode process may reuse original address space of the user mode process of the sub vBRAS 21 _ 3 . The data relevant to the sub vBRAS 21 _ 3  are stored in the address space of the new user mode process. As shown in  FIG. 3A , the sub vBRAS 21 _ 3  is migrated to the vBRAS 22 . 
     The NFV Manager  25  updates the table 2 and obtains table 3. 
     
       
         
           
               
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                   
                 Sub vBRAS 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
               
               
                   
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
               
               
                 vBRAS 
                 21_1 
                 21_2 
                 21_3 
                 22_1 
                 22_2 
                 22_3 
                 23_1 
                 23_2 
                 23_3 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 vBRAS21 
                 the  
                 the  
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 number 
                 number 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 of users 
                 of users 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 5000, 
                 3000, 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 user  
                 user  
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 traffic 
                 traffic 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 500 G 
                 150 G 
                   
                   
                   
                   
                   
                   
                   
               
               
                 vBRAS22 
                   
                   
                 the  
                 the  
                 the  
                 the  
                   
                   
                   
               
               
                   
                   
                   
                 number 
                 number 
                 number 
                 number 
                   
                   
                   
               
               
                   
                   
                   
                 of users 
                 of users 
                 of users 
                 of users 
                   
                   
                   
               
               
                   
                   
                   
                 3000, 
                 4000, 
                 4000, 
                 3000, 
                   
                   
                   
               
               
                   
                   
                   
                 user  
                 user  
                 user  
                 user  
                   
                   
                   
               
               
                   
                   
                   
                 traffic  
                 traffic  
                 traffic 
                 traffic 
                   
                   
                   
               
               
                   
                   
                   
                 100 G 
                 100 G 
                 100 G 
                 300 G 
                   
                   
                   
               
               
                 vBRAS23 
                   
                   
                   
                   
                   
                   
                 the  
                 the  
                 the  
               
               
                   
                   
                   
                   
                   
                   
                   
                 number 
                 number 
                 number 
               
               
                   
                   
                   
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
               
               
                   
                   
                   
                   
                   
                   
                   
                 5000, 
                 3000, 
                 1000, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 user  
                 user  
                 user  
               
               
                   
                   
                   
                   
                   
                   
                   
                 traffic  
                 traffic  
                 traffic 
               
               
                   
                   
                   
                   
                   
                   
                   
                 400 G 
                 100 G 
                 100 G 
               
               
                   
               
            
           
         
       
     
     The vBRAS 22  receives the data relevant to the sub vBRAS 21 _ 3  from the vBRAS 21  and closes the TCP connection between the vBRAS 21  and the vBRAS 22 . 
     The sub vBRAS 21 _ 3  sends a RARP response packet after the sub vBRAS 21 _ 3  is migrated to the vBRAS 22 . In the RARP response packet, a source MAC address is MAC 21 _ 3  and a destination MAC address is a MAC address of an interface actually sending the RARP response packet by the sub vBRAS 21 _ 3 . Hence, the RARP response packet sent by the sub vBRAS 21 _ 3  will not be broadcast in the vlan nor sent to other vBRAS. The aggregation switch  26  receives the RARP response packet sent by the sub vBRAS 21 _ 3 , finds a MAC address entry matching with the source MAC address, i.e. MAC 21 _ 3  from the MAC table, and updates an port in the matched MAC address entry as an port receiving the RARP response packet. The aggregation switch  26  may send the RARP response packet to the vBRAS 21  according the destination address of the RARP response packet. Protocol packets and data packets sent from users assigned to the sub vBRAS 21 _ 3  to the sub vBRAS 21 _ 3  which is the virtual network gateway will be sent to the sub vBRAS 22  based on the updated MAC address entry. Hence, the users accessing the sub vBRAS 21 _ 3  are migrated to the vBRAS 22 . 
     In the above examples, the migration of the users between different vBRASs is implemented via the migration of the sub vBRAS between different vBRASs. The data relevant to the migration sub vBRAS are migrated to the target vBRAS, thus original service access of the users accessing the migration sub vBRAS is not affected. On the premise that the user is online, the user may migrate between different vBRASs, expansion and contraction of NFV network nodes are optimized, and network resilience of the NFV network is further improved. 
     According to an example of the present disclosure, it is supposed that, after a certain period of time, the NFV Manager  25  updates the table 3 and obtains a table 4 based on the user traffic notified by each sub vBRAS. 
     
       
         
           
               
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                   
                 Sub vBRAS 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
               
               
                   
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
               
               
                 vBRAS 
                 21_1 
                 21_2 
                 21_3 
                 22_1 
                 22_2 
                 22_3 
                 23_1 
                 23_2 
                 23_3 
               
               
                   
               
               
                 vBRAS21 
                 the  
                 the  
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 number 
                 number 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 of users 
                 of users 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 5000, 
                 3000, 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 user  
                 user  
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 traffic  
                 traffic 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 400 G 
                 100 G 
                   
                   
                   
                   
                   
                   
                   
               
               
                 vBRAS22 
                   
                   
                 the  
                 the  
                 the  
                 the  
                   
                   
                   
               
               
                   
                   
                   
                 number 
                 number 
                 number 
                 number 
                   
                   
                   
               
               
                   
                   
                   
                 of users 
                 of users 
                 of users 
                 of users 
                   
                   
                   
               
               
                   
                   
                   
                 3000, 
                 4000, 
                 4000, 
                 3000, 
                   
                   
                   
               
               
                   
                   
                   
                 user  
                 user  
                 user  
                 user  
                   
                   
                   
               
               
                   
                   
                   
                 traffic 
                 traffic 
                 traffic 
                 traffic 
                   
                   
                   
               
               
                   
                   
                   
                 100 G 
                 100 G 
                 100 G 
                 300 G 
                   
                   
                   
               
               
                 vBRAS23 
                   
                   
                   
                   
                   
                   
                 the  
                 the  
                 the  
               
               
                   
                   
                   
                   
                   
                   
                   
                 number 
                 number 
                 number 
               
               
                   
                   
                   
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
               
               
                   
                   
                   
                   
                   
                   
                   
                 5000, 
                 3000, 
                 1000, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 user  
                 user  
                 user  
               
               
                   
                   
                   
                   
                   
                   
                   
                 traffic  
                 traffic  
                 traffic 
               
               
                   
                   
                   
                   
                   
                   
                   
                 50 G 
                 30 G 
                 20 G 
               
               
                   
               
            
           
         
       
     
     According to an example of the present disclosure, a minimum traffic threshold is configured as 150 G. The NFV Manager  25  determines the vBRAS 23  having the traffic lower than the minimum traffic threshold as a source vBRAS, and determines the vBRAS 21  having the traffic lower than the maximum traffic threshold as a target vBRAS. The NFV Manager  25  determines all sub vBRASs on the vBRAS 23 , i.e. the sub vBRAS 23 _ 1  to sub vBRAS 23 _ 3  as migration sub vBRASs. If there are at least two vBRASs having the traffic lower than the maximum traffic threshold, the vBRAS having the lowest traffic may be determined as the target vBRAS. 
     The NFV Manager  25  assigns TCP port numbers for the vBRAS 21  and vBRAS 23  respectively. For example, the NFV Manager  25  assigns a third TCP port number for the vBRAS 21 , and assigns a fourth TCP port number for the vBRAS 23 . The vBRAS 21  and vBRAS 23  are notified of the third TCP port number and the fourth TCP port number respectively. The NFV Manager  25  notifies the vBRAS 23  that the sub vBRAS 23 _ 1 , the sub vBRAS 23 _ 2  and the sub vBRAS 23 _ 3  are migrated to the vBRAS 21 . The NFV Manager  25  determines all of sub vBRASs of the vBRAS 23  are migrated, and sends a packet having a close identifier to the vBRAS 23  based on the private interaction protocol to notify the vBRAS 23  to close. 
     The vBRAS 21  and vBRAS 23  establishes a TCP connection between the vBRAS 21  and vBRAS 23  based on the notified third TCP port number and the fourth TCP port number. 
     The vBRAS 23  sends data in address space of the user mode process for the sub vBRAS 23 _ 1 , data in address space of the user mode process for the sub vBRAS 23 _ 2  and data in address space of the user mode process for the sub vBRAS 23 _ 3  to the vBRAS 21  via the TCP connection. 
     The vBRAS 21  receives the data in the address space of the user mode process for the sub vBRAS 23 _ 1 , and starts a new user mode process. The address space of the new user mode process may reuse the original address space of the user mode process for the sub vBRAS 23 _ 1  to store the data relevant to the sub vBRAS 23 _ 1 . The vBRAS 21  receives the data in the address space of the user mode process for the sub vBRAS 23 _ 2 , and starts a new user mode process. The address space of the new user mode process may reuse the original address space of the user mode process for the sub vBRAS 23 _ 2  to store the data relevant to the sub vBRAS 23 _ 2 . The vBRAS 21  receives the data in the address space of the user mode process for the sub vBRAS 23 _ 3 , and starts a new user mode process. The address space of the new user mode process may reuse the original address space of the user mode process for the sub vBRAS 23 _ 3  to store the data relevant to the sub vBRAS 23 _ 3 . 
     After receiving the data relevant to the sub vBRAS 23 _ 1 , the data relevant to the sub vBRAS 23 _ 2  and the data relevant to the sub vBRAS 23 _ 3 , the vBRAS 21  closes the TCP connection between the vBRAS 21  and the vBRAS 23 . As shown in  FIG. 3B , the sub vBRAS 23 _ 1 , the sub vBRAS 23 _ 2  and the sub vBRAS 23 _ 3  are migrated to the vBRAS 21 . 
     After sending the data relevant to the sub vBRAS 23 _ 1 , the data relevant to the sub vBRAS 23 _ 2  and the data relevant to the sub vBRAS 23 _ 3 , the vBRAS 23  closes the TCP connection between the vBRAS 23  and the vBRAS 21 . The vBRAS 23  may perform a close operation based on a close notification received from the NFV Manager  25 . 
     The NFV Manager  25  updates the table 4 and obtains a table 5. 
     
       
         
           
               
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                   
                 Sub vBRAS 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
                 Sub  
               
               
                   
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
                 vBRAS 
               
               
                 vBRAS 
                 21_1 
                 21_2 
                 21_3 
                 22_1 
                 22_2 
                 22_3 
                 23_1 
                 23_2 
                 23_3 
               
               
                   
               
               
                 vBRAS21 
                 the  
                 the  
                   
                   
                   
                   
                 the  
                 the  
                 the  
               
               
                   
                 number 
                 number 
                   
                   
                   
                   
                 number 
                 number 
                 number 
               
               
                   
                 of users 
                 of users 
                   
                   
                   
                   
                 of users 
                 of users 
                 of users 
               
               
                   
                 5000, 
                 3000, 
                   
                   
                   
                   
                 5000, 
                 3000, 
                 1000, 
               
               
                   
                 user  
                 user  
                   
                   
                   
                   
                 user  
                 user  
                 user  
               
               
                   
                 traffic  
                 traffic 
                   
                   
                   
                   
                 traffic  
                 traffic  
                 traffic 
               
               
                   
                 400 G 
                 100 G 
                   
                   
                   
                   
                 50 G 
                 30 G 
                 20 G 
               
               
                 vBRAS22 
                   
                   
                 the  
                 the  
                 the  
                 the  
                   
                   
                   
               
               
                   
                   
                   
                 number 
                 number 
                 number 
                 number 
                   
                   
                   
               
               
                   
                   
                   
                 of users 
                 of users 
                 of users 
                 of users 
                   
                   
                   
               
               
                   
                   
                   
                 3000, 
                 4000, 
                 4000, 
                 3000, 
                   
                   
                   
               
               
                   
                   
                   
                 user  
                 user  
                 user  
                 user  
                   
                   
                   
               
               
                   
                   
                   
                 traffic  
                 traffic 
                 traffic  
                 traffic 
                   
                   
                   
               
               
                   
                   
                   
                 100 G 
                 100 G 
                 100 G 
                 300 G 
                   
                   
                   
               
               
                 vBRAS23 
               
               
                   
               
            
           
         
       
     
     After being migrated to the vBRAS 21 , the sub vBRAS 23 _ 1 , the sub vBRAS 23 _ 2  and sub vBRAS 23 _ 3  send a RARP response packet respectively. 
     The aggregation switch  26  receives the RARP response packets sent by the sub vBRAS 23 _ 1 , the sub vBRAS 23 _ 2  and sub vBRAS 23 _ 3 , finds MAC address entries matching with the source MAC addresses of the RARP response packets, and updates the matched MAC address entries based on ports receiving the RARP response packets. Hence, the users accessing the sub vBRAS 23 _ 1 , the sub vBRAS 23 _ 2  and sub vBRAS 23 _ 3  are migrated to the vBRAS 21 . 
     According to the above examples of the present disclosure, when load of a certain vBRAS is lower than a preconfigured minimum load, all of the sub vBRASs on the vBRAS having the load lower than the preconfigured minimum load are migrated to another vBRAS, and the vBRAS having the load lower than the preconfigured minimum load is closed. Hence, even if the vBRAS is closed, the users originally accessing each sub vBRAS of the closed vBRAS may be migrated to another vBRAS on the premise that the users are online, and it is unnecessary for the users to log online again by accessing to a vBRAS reassigned by the NFV Manager  25 . Therefore, expansion and contraction of NFV network nodes are optimized, and network resilience of the NFV network is further improved. 
       FIG. 4  is a diagram illustrating a user migration apparatus based on an example of the present disclosure. The user migration apparatus  400  may be applied to a NFV Manager. As shown in  FIG. 4 , the user migration apparatus  400  at least includes multiple ports  410  to receive and send packets, a processor  420  and storage  430 . The storage  430  may store multiple machine-readable instruction modules executed by the processor  420 . The machine-readable instruction modules may include a receiving module  431 , a recording module  432 , an assigning module  433  and a migrating module  434 . 
     The receiving module  431  is to receive user traffic notified by each sub vBRAS of each vBRAS. The migrating module  434  is to calculate user traffic of each vBRAS, select a source vBRAS and a target vBRAS from all of the vBRASs and select a migration sub vBRAS needing to migrate from the source vBRAS to the target vBRAS, and notify the source vBRAS to send data relevant to the migration sub vBRAS to the target vBRAS. 
     In an example, the migrating module  434  is to monitor traffic of each vBRAS by calculating the traffic of each vBRAS. The migrating module  434  may determine a vBRAS having traffic higher than a maximum traffic threshold as a source vBRAS, determine from vBRASs having traffic lower than the maximum traffic threshold a vBRAS having a lowest traffic as a target vBRAS, and determine from multiple sub vBRASs of the source vBRAS a sub vBRAS having user traffic most close to a traffic value obtained by subtracting the maximum traffic threshold from the traffic of source vBRAS. 
     In an example, the migrating module  434  may determine a vBRAS having highest traffic as a source vBRAS, determine a vBRAS having lowest traffic as a target vBRAS, calculate an average traffic based on the traffic of each vBRAS, and determine from multiple sub vBRASs of the source vBRAS a sub vBRAS having user traffic most close to a traffic value obtained by subtracting the average traffic from the traffic of source vBRAS. 
     In an example, the migrating module  434  may determine a vBRAS having traffic lower than a minimum traffic threshold as a source vBRAS, determines a vBRAS having traffic lower than the maximum traffic threshold as a target vBRAS, and determine all sub vBRASs on the source vBRAS as migration sub vBRASs. 
     In an example, the migrating module  434  is further to assign TCP port numbers for the source vBRAS and the target vBRAS respectively, and to notify the source vBRAS and the target vBRAS of the assigned TCP port numbers. 
     In an example, the receiving module  431  is to receive multiple register request packets and multiple user broadcast protocol packets. The recording module  432  is to record each vBRAS and each sub vBRAS of each vBRAS based on identification information of a sub vBRAS and vBRAS information included in each register request packet. The assigning module  433  is to assign a user to each sub vBRAS of each vBRAS based on user identification information of each user broadcast protocol packet. 
     In an example, the migrating module  434  is to determine that all sub vBRASs of the source vBRAS are migrated and notify the source vBRAS to close. 
     The NFV Manager having the user migration apparatus  400  may make the sub vBRAS having accessed users migrate between the vBRASs by taking the sub vBRAS as a unit. Hence, users may migrate between different vBRASs, and thus network resilience of the NFV network is improved. 
     The foregoing are some examples of the present disclosure and are not used to limit the protection scope of the present disclosure. Any modification, equivalent substitution and improvement without departing from the spirit and principle of the present disclosure are within the protection scope of the present disclosure.