CN1411210A - Method of acting address analytic protocol Ethernet Switch in application - Google Patents

Abstract

The invention relates to a method for proxy address resolution protocol (ARP) in a broadband access server (BAS), which is an ARP protocol conversion form, that is, an intermediate device sends an ARP reply message to a source end sending a request on behalf of a destination end. For a valid ARP request message from a user with a legal source IP address, the BAS first checks whether there is a destination user IP address requesting resolution in the access information table (ARP CACHE), if it does not exist, it will not respond; if it exists, it will further compare the source IP Whether the virtual local area network marks of the address user and the destination IP address user are consistent; when they are inconsistent, the BAS uses the physical address (MAC) of its access unit to send an ARP response message to the source IP address user, and then searches the source IP address user for the source IP address. The IP datagram is sent to the user with the destination IP address. If the IP addresses of the source end and the destination end are in the same interface unit of the BAS, the BAS also uses the MAC address of its access unit to send an ARP response message to the source user.

Description

Method of Proxy Address Resolution Protocol in Ethernet Access Application

technical field

The present invention relates to the technical field of broadband access, and more precisely relates to a processing method of proxy address resolution protocol (Proxy ARP) in a virtual local area network (VLAN) Ethernet broadband access media gateway, which can be applied to Ethernet access into business.

Background technique

Typically, network interfaces can only communicate with each other based on the user's Layer 2 address, which is derived from the Layer 3 address through the Address Resolution Protocol (ARP). If interface A wants to send data to interface B on the same network segment, and A only knows B's IP address, it must first look up B's physical address based on B's IP address. It sends an ARP broadcast containing B's IP address, requesting B's physical address, and B responds to A with its physical address after receiving the broadcast. When A and B are not on the same network segment, A only sends an ARP request to the next-hop router instead of directly to B.

Referring to Fig. 1, it is a kind of virtual local area network (VLAN) Ethernet broadband access network structure, shows broadband access server (BAS), local area network switchboard LSW (LAN SWITCH) and user host computer (as A, B) among the figure connection relationship.

In Ethernet access applications, the Broadband Access Server (BAS), as an access aggregation device, needs to provide users with service distribution and aggregation functions, as well as user management, security management, authentication and billing functions. In order to support the isolation of business traffic between users, the user access layer often adopts the method of dividing VLANs on the 2-layer switch LSW, and divides the physical network connected by the LAN switch LSW and the user host into multiple logical subnets, that is, one LSW ( The user port A and user port B of LAN SWITCH) can be respectively located in different VLANs, as shown in the dotted circle among the figure, VLAN1 supports user host A, and VLAN2 supports user host B.

Because the broadcast data packet sent by the station in a VLAN will only be forwarded to the station belonging to the same VLAN, the broadcast packet from port A will not reach user port B at this time. However, when the IP address assigned by user host A connected to port A and the IP address assigned by user host B of port B are located in the same network segment and need to communicate based on TCP/IP, according to the ARP protocol, when user A needs to send an IP packet When sending to user B, an ARP request message should be sent first to query the physical (MAC) address of user B, but due to VLAN isolation, user B cannot receive the ARP message, and at this time the BAS must respond to the ARP request Packets, that is, the BAS needs to support the proxy ARP function. The Address Resolution Protocol (ARP) is used to map network layer (layer 3) addresses to data link layer (layer 2) addresses.

BAS supports proxy ARP and needs to consider the situation of supporting multiple user hosts under one VLAN port, because multiple users under one VLAN port can communicate with each other. In this case, even if the BAS receives the ARP request message, it cannot No acknowledgment is required, but an ARP acknowledgment should be made directly by the user.

To sum up, currently in Ethernet broadband access, there is no method that can not only ensure the isolation of service traffic between users, but also support the proxy address resolution protocol during normal communication between access users.

Contents of the invention

The purpose of the present invention is to design a method for proxy address resolution protocol in Ethernet access applications, this kind of proxy ARP processing method in VLAN Ethernet broadband access media gateway, not only supports the situation of a VLANID accessing a user, Moreover, it supports the situation that one VLAN ID has multiple users, so that user hosts in different VLAN sub-virtual networks can communicate with each other. In Ethernet broadband access, it can not only ensure the isolation of business traffic between users, but also support the normal communication between access users.

The technical scheme that realizes the object of the present invention is such: a kind of method of agent address resolution protocol in Ethernet access application, it is characterized in that comprising following processing steps:

A. Broadband access server receives the effective Address Resolution Protocol (ARP) request message from source IP address user, contains the IP address of destination user in this message;

B. Whether there is the IP address of the purpose user who requests address resolution in the broadband access server inspection access information table (ARP CACHE);

C. When the IP address of the destination user requesting address resolution exists in the access information table (ARP CACHE), further compare the consistency between the virtual local area network mark (VLAN ID) of the source IP address user and the destination IP address user;

D. When the virtual local area network tag (VLAN ID) of the source IP address user and the destination IP address user is inconsistent, the address resolution protocol (ARP) response message is sent to the source IP address user by the broadband access server with the physical address of its access unit ;

E. The source IP address user sends the IP data packet to the broadband access server after receiving the Address Resolution Protocol (ARP) response message, and the broadband access server searches for a route and sends the IP data packet to the destination IP address user ;

F. When the IP address of the destination user requesting address resolution does not exist in the access information table (ARP CACHE), or there is an IP address of the destination user requesting address resolution in the access information table (ARP CACHE), but in When the VLAN IDs of the source IP address user and the destination IP address user are inconsistent, the broadband access server does not send an Address Resolution Protocol (ARP) response message to the source IP address user, and when the source IP address user receives the destination IP address user After sending the Address Resolution Protocol (ARP) response message, the IP data packet is sent to the destination IP address user.

In the described step A, also comprise by broadband access server inquiry described access information table (ARP CACHE), address resolution protocol (ARP) to the source IP address user existing in the access information table (ARP CACHE) ) The request message is judged as a valid message.

In the described step A, it also includes judging whether the source IP address user and the destination IP address user are in the same interface of the broadband access server by the broadband access server, and using the physical interface of the access unit of the broadband access server when they are the same interface The address sends an Address Resolution Protocol (ARP) response message to the source IP address user, and the source IP address user sends an IP data packet to the destination IP address user after receiving the Address Resolution Protocol (ARP) response message.

The access information table (ARP CACHE) is a comparison table of the relationship between the user IP address and its physical address (MAC) established in the broadband access server in the user authentication process.

Proxy Address Resolution Protocol (Proxy ARP) of the present invention is a kind of transformed form of ARP agreement, and under this form, the host computer that sends request is sent an ARP response by the intermediate device of router class on behalf of destination.

The method of proxy address resolution protocol of the present invention, that is, the method of realizing ARP proxy in the Ethernet access gateway, cooperates with the existing VLAN technology of the user access layer, and can ensure that the user The business traffic between them is completely isolated, and it can support normal communication between access users. The method is effective and concise.

Description of drawings

Fig. 1 is a kind of virtual local area network (VLAN) Ethernet broadband access network structural representation;

Fig. 2 is a block diagram of a method for proxying an address resolution protocol in an Ethernet access application according to the present invention.

Detailed ways

Referring to Fig. 2 and referring to Fig. 1 in conjunction with, proxy Address Resolution Protocol (ARP) in the Broadband Access Server (BAS), that is, the method that the Broadband Access Server (BAS) receives the ARP request packet, comprises the following processing steps:

Step 21, the access unit of BAS receives the valid ARP request message of user A (source user), which contains an IP address of user B (destination user), which is a non-gateway IP address, and first checks user A by BAS Whether it has been verified and assigned a legal IP address, that is, check whether the user A corresponding to the source IP address is a legal user. The legal user is an authenticated user, and the IP address is established in the access information table (ARP CACHE table) (3 layers of address) and the user of the mapping relation between physical address (MAC), if illegal user then return, if legal user then further execute step 22;

Step 22, then the BAS judges whether user B is a user on the same interface as user A according to the IP address of user B analyzed by the request, if yes, execute step 23, if not, execute step 24;

Step 23, if user B and user A are in the same interface, construct an ARP response message with the physical address (MAC) of the interface and send it, then return;

Step 24, if user B and user A are not in the same interface, then further judge whether the IP address of user B requesting resolution exists in the access information table (ARP CACHE table), that is, whether user B is in the access information table ( ARP CACHE table) establishes the corresponding relationship between the IP address and the MAC address, returns if the corresponding relationship is not established in the table, and then further executes step 25 if the corresponding relationship has been established in the table;

Step 25, judge whether two users belong to the same virtual local area network (VLAN) according to the virtual local area network identification (VLAN ID) of user A and user B by BAS, if belong to the same virtual local area network (VLAN), then return, namely BAS needn't send ARP reply message to user A, and sends ARP reply message by broadcast mode by user B, if A and B do not belong to same virtual local area network (VLAN), then further execute step 26;

Step 26, if the virtual local area network identity (VLAN ID) of user A and user B is not the same, then the ARP reply message of requesting to resolve B user IP address is sent by BAS with the physical address (MAC) of BAS access unit.

User A sends the IP packet to user B after receiving the ARP response packet from user B; or user A sends the IP packet to the access unit of the BAS after receiving the ARP response packet from the BAS, and the The BAS is responsible for finding the route and sending the IP message to user B, thus successfully realizing the communication problem between users in the Ethernet access.

The above-mentioned effective and concise implementation method of the present invention cooperates with the VLAN technology of the user access layer. In Ethernet broadband access, it can not only ensure that the service flow between users is completely isolated, but also support the communication between access users. Normal communication.

The realization method of the present invention is proved to have very good practicability and reliability after being used in EXPERT media gateway equipment.

Claims (4)

1. A method for agent address resolution protocol in Ethernet access application, characterized in that it comprises the following processing steps: A. Broadband access server receives the effective Address Resolution Protocol (ARP) request message from source IP address user, contains the IP address of destination user in this message; B. Whether there is the IP address of the purpose user who requests address resolution in the broadband access server inspection access information table (ARP CACHE); C. When the IP address of the destination user requesting address resolution exists in the access information table (ARP CACHE), further compare the consistency between the virtual local area network mark (VLAN ID) of the source IP address user and the destination IP address user; D. When the virtual local area network tag (VLAN ID) of the source IP address user and the destination IP address user is inconsistent, the address resolution protocol (ARP) response message is sent to the source IP address user by the broadband access server with the physical address of its access unit ; E. The source IP address user sends the IP data packet to the broadband access server after receiving the Address Resolution Protocol (ARP) response message, and the broadband access server searches for a route and sends the IP data packet to the destination IP address user ; F. When the IP address of the destination user requesting address resolution does not exist in the access information table (ARP CACHE), or there is an IP address of the destination user requesting address resolution in the access information table (ARP CACHE), but in When the VLAN IDs of the source IP address user and the destination IP address user are inconsistent, the broadband access server does not send an Address Resolution Protocol (ARP) response message to the source IP address user, and when the source IP address user receives the destination IP address user After sending the Address Resolution Protocol (ARP) response message, the IP data packet is sent to the destination IP address user. 2. the method for agent address resolution protocol in a kind of Ethernet access application according to claim 1, is characterized in that: in the described step A, also comprises querying described access information table by broadband access server (ARP CACHE), for those existing in the access information table (ARP CACHE) 3. the method for agent address resolution protocol in a kind of Ethernet access application according to claim 1, is characterized in that: in the described step A, also comprises judging source IP address user and destination IP by broadband access server Whether the address user is in the same interface of the broadband access server, when being the same interface, send an Address Resolution Protocol (ARP) response message to the source IP address user with the physical address of this access unit of the broadband access server, and the source IP address user receives After the Address Resolution Protocol (ARP) responds to the message, it sends an IP data message to the user with the destination IP address. 4. the method for agent address resolution protocol in a kind of Ethernet access application according to claim 1, is characterized in that: described access information table (ARP CACHE) is set up in broadband access in user authentication process A comparison table of the relationship between the user's IP address and its physical address (MAC) in the server.

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