Address resolution method, apparatus, and system
An address resolution method uniformly processing ARP broadcast packets by an address server to avoid broadcasting in the network, so that the occupied bandwidth is reduced. The method also includes storing by a network device and terminal address correspondence information of local and remote terminals in communication with one another, which reduces the size of the MAC table in the data center network, reduces the load of the network device, and improves the processing capabilities of the network device, so that it is possible to deploy a large layer-2 network to thereby solve real-time relocation problems of a virtual machine.
1. An address resolution method, comprising:
receiving, by an address resolution server, an address request packet from a first terminal, wherein encapsulation information of the address request packet comprises an identifier of the address resolution server and a first device identifier of a first edge switch to which the first terminal is connected; and the address request packet comprises an Address Resolution Protocol (ARP) request packet in IPv4 or a neighbor solicitation (NS) packet in IPv6;
querying an address correspondence table in the address resolution server according to a destination IP address in the address request packet, wherein the address correspondence table comprises address correspondence information, wherein the address correspondence information comprises correspondence between an IP address of a terminal, a MAC address of the terminal, and a device identifier of a edge switch to which the terminal is connected; and
when the destination IP address is the same as an IP address in second existing address correspondence information in the address correspondence table:
sending, by the address resolution server, the second existing address correspondence information to the first edge switch, so that the first edge switch updates its MAC table according to the second existing address correspondence information;
sending, by the address resolution server, a first MAC address of the first terminal and the first device identifier of the first network edge switch to a second edge switch corresponding to a second device identifier in the second existing address correspondence information, so that the second edge switch updates its MAC table by using the first MAC address of the first terminal and the first device identifier of the first edge switch; and
sending, by the address resolution server, the address request packet to the second edge switch, to forward the address request packet to a second terminal corresponding to the IP address and MAC address in the second existing address correspondence information, so that the second terminal returns an address reply to the first terminal.
2. The method according to claim 1 , wherein before receiving the address request packet from the first terminal, the method further comprises:
receiving an address advertisement packet from the first terminal, wherein encapsulation information of the address advertisement packet comprises the first device identifier of the first edge switch; the address advertisement packet comprises: any one of free ARP packet, ARP reply packet, and RARP reply packet in IPv4; or an unsolicited neighbor advertisement (NA) packet in IPv6;
obtaining first address correspondence information according to the address advertisement packet, wherein the first address correspondence information comprises correspondence between a first IP address of the first terminal, the first MAC address of the first terminal, and the first device identifier of the first edge switch; and
updating the address correspondence table according to the first address correspondence information.
3. The method according to claim 2 , wherein updating the address correspondence table according to the first address correspondence information comprises:
when the first IP address of the first terminal is different from any IP address in the address correspondence table, adding the first address correspondence information to the address correspondence information table; and
when the first IP addresses of the first terminal is the same as an IP addresses in first existing address correspondence information in the address correspondence table and the first MAC addresses of the first terminal is the same as a MAC addresses in the first existing address correspondence information, and the first device identifier of the first edge switch is different from a device identifier in the first existing address correspondence information, using the first address correspondence information to update the first existing address correspondence information, and sending the first address correspondence information to a third edge switch, so that the third edge switch update its MAC table according to the first address correspondence information.
4. An address resolution system, comprising:
a first terminal;
a first edge switch; and
an address resolution server, wherein the first terminal connects to the first edge switch, the address resolution server is configured to:
receive an address request packet from the first terminal, wherein encapsulation information of the address request packet comprises an identifier of the address resolution server and a first device identifier of the first edge switch; and the address request packet comprises an Address Resolution Protocol (ARP) request packet in IPv4 or a neighbor solicitation (NS) packet in IPv6;
query an address correspondence table in the address resolution server according to a destination IP address in the address request packet, wherein the address correspondence table comprises address correspondence information, wherein the address correspondence information comprises IP addresses of terminals, MAC addresses of the terminals, and device identifiers of edge switches to which the terminals are connected; and
when the destination IP address is the same as an IP address in second existing address correspondence information in the address correspondence table,
send the second existing address correspondence information to the first edge switch, so that the first edge switch updates its MAC table according to the second existing address correspondence information,
send a first MAC address of the first terminal and the first device identifier of the first edge switch to a second edge switch corresponding to a second device identifier in the second existing address correspondence information, so that the second edge switch updates its MAC table by using the first MAC address of the first terminal and the first device identifier of the first edge switch; and
send the address request packet to the second edge switch, to forward the address request packet to a second terminal corresponding to the IP address and MAC address in the second existing address correspondence information, so that the second terminal returns an address reply to the first terminal.
5. The system according to claim 4 , wherein the address resolution server is further configured to:
receive an address advertisement packet from the first terminal, wherein according to the second existing address correspondence information the address advertisement packet comprises the first device identifier of the first edge switch; the address advertisement packet comprises: any one of free ARP packet, ARP reply packet, and RARP reply packet in IPv4; or an unsolicited neighbor advertisement (NA) packet in IPv6;
obtain first address correspondence information according to the address advertisement packet, wherein the first address correspondence information comprises correspondence between a first IP address of the first terminal, the first MAC address of the first terminal, and the first device identifier of the first edge switch; and
update the address correspondence table according to the first address correspondence information.
6. The system according to claim 5 , wherein the address resolution server is specifically configured to:
when the first IP address of the first terminal is different from any IP address in the address correspondence table, add the first address correspondence information to the address correspondence information table; and
when the first IP addresses of the first terminal is the same as an IP addresses in first existing address correspondence information in the address correspondence table and the first MAC addresses of the first terminal is the same as a MAC addresses in the first existing address correspondence information, and the first device identifier of the first edge switch is different from a device identifier in the first existing address correspondence information, use the first address correspondence information to update the first existing address correspondence information, and send the first address correspondence information to a third edge switch, so that the third edge switch updates its MAC table according to the first address correspondence information.
7. An address resolution server, comprising a processor executing program stored on a computer-readable storage medium to perform:
receiving an address request packet from a first terminal, wherein encapsulation information of the address request packet comprises an identifier of the address resolution server and a first device identifier of a first edge switch to which the first terminal is connected; and the address request packet comprises an Address Resolution Protocol (ARP) request packet in IPv4 or a neighbor solicitation (NS) packet in IPv6;
querying an address correspondence table in the address resolution server according to a destination IP address in the address request packet, wherein the address correspondence table comprises address correspondence information, wherein the address correspondence information comprises correspondence between an IP address of a terminal, a MAC address of the terminal, and a device identifier of a edge switch to which the terminal is connected; and
when the destination IP address is the same as an IP address in second existing address correspondence information in the address correspondence table:
sending the second existing address correspondence information to the first edge switch, so that the first edge switch updates its MAC table according to the second existing address correspondence information;
sending a first MAC address of the first terminal and the first device identifier of the first edge switch to a second edge switch corresponding to a second device identifier in the second existing address correspondence information, so that the second edge switch updates its MAC table by using the first MAC address of the first terminal and the first device identifier of the first edge switch; and
sending the address request packet to the second edge switch, to forward the address request packet to a second terminal corresponding to the IP address and MAC address in the second existing address correspondence information, so that the second terminal returns an address reply to the first terminal.
8. The address resolution server according to claim 7 , wherein before receiving the address request packet from the first terminal, the processor further performs:
receiving an address advertisement packet from the first terminal, wherein encapsulation information of the address advertisement packet comprises the first device identifier of the first edge switch; the address advertisement packet comprises: any one of free ARP packet, ARP reply packet, and RARP reply packet in IPv4; or an unsolicited neighbor advertisement (NA) packet in IPv6;
obtaining first address correspondence information according to the address advertisement packet, wherein the first address correspondence information comprises correspondence between a first IP address of the first terminal, the first MAC address of the first terminal, and the first device identifier of the first edge switch; and
updating the address correspondence table according to the first address correspondence information.
9. The address resolution server according to claim 8 , wherein updating the address correspondence table according to the first address correspondence information comprises:
when the first IP address of the first terminal is different from any IP address in the address correspondence table, adding the first address correspondence information to the address correspondence information table; and
when the first IP addresses of the first terminal is the same as an IP addresses in first existing address correspondence information in the address correspondence table and the first MAC addresses of the first terminal is the same as a MAC addresses in the first existing address correspondence information, and the first device identifier of the first edge switch is different from a device identifier in the first existing address correspondence information, using the first address correspondence information to update the first existing address correspondence information, and sending the first address correspondence information to a third edge switch, so that the third edge switch updates its MAC table according to the first address correspondence information.