Method for forwarding multicast data and NAT equipment

Abstract

The invention discloses a method for transmitting multicast data and NAT equipment. The method comprises: the NAT equipment receives an MSDP protocol message sent by a private network side RP; according to the MSDP protocol message, a private network address of a multicast source and a multicast set address are obtained; according to the address conversion relation, the NAT equipment obtains a public network address of the multicast source and establishes a mapping relation among the public network address, the private network address and the multicast set address of the multicast source; theNAT equipment sends a registration message to a public network side RP from an interface of the public network side and triggers the public network side RP to establish a corresponding multicast set table item; and according to the mapping relation, the NAT equipment transmits the received multicast protocol message and the multicast data. Through the method, the NAT equipment surrogates the multicast source of the private network and sends the registration message to the public network, transmits the multicast protocol message and the multicast data according to the mapping relation locally configured, realizes that the multicast flow of the private network can traverse the NAT equipment and reach the public network in the network with the NAT equipment and improves the network applicability.

Description

technical field [0001] The invention relates to the field of network technology, in particular to a method for multicast data to reach a public network through NAT equipment and the corresponding NAT equipment. Background technique [0002] NAT (Network Address Translation, Network Address Translation) is a process of converting the IP address in the header of an IP (Internet Protocol, Internet Protocol) data packet into another IP address. In practical applications, NAT is mainly used to enable private networks to access public networks. This approach of using a small number of public IP addresses to represent a large number of private IP addresses will help slow the depletion of available IP address space. NAT is especially prevalent in the current unicast access process. [0003] Since the private network address is invisible to the public network, when the multicast source is located in the private network, the NAT device will shield the address of the multicast source...

AI Technical Summary

Problems solved by technology

[0003] Since the private network address is invisible to the public network, when the multicast source is located in the private network, the NAT device will shield the address of the multicast source in the private network. The device cannot know the address of the multicast source located in the private network

Therefore, for a network that uses the PIM-SM (Protocol Independent Multicast-Sparse Mode, Protocol Independent Multicast-Sparse Mode) protocol, the "pull" mechanism is used to transmit multicast data, and only the network segment with receivers will receive the group data. broadcast data flow, which cannot be applied in a NAT networking environment, resulting in private network multicast traffic not being able to pass through the NAT device

Therefore, when the multicast source is inside the private network, the orderers on the public network cannot order the multicast stream of the private network

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