The DNS server finds the hostname set corresponding to a domain
name and sends the hostname set to the client to implement load sharing
among nodes.

The DNS server supports IPv4 SRV record query, helping the client select an optimal node based on the load sharing principle.

Figure 1


http://localhost:7904/pages/31185199/02/31185199/02/resources/figure/cn_10_01_1430017_fig1.png

1. DNS Server-1 receives a request message from the DNS client. The
   request type is SRV. Based on the NAME field carried in the request
   message, DNS Server-1 obtains SRV record list, which includes the
   information about the server, such as the domain
   name, priority, weight and port number of the server.
2. DNS
   Server-1 includes the SRV record list in RDATA in the response message
   which it returns to the DNS client. If the IP address corresponding to
   the domain name is available on DNS Server-1, then DNS Server-1 includes
   the IP address in the additional
   section field returned to the DNS client.
3. Based on the priority
   and weight in the returned SRV record list, the DNS client selects a SRV
   record, then initiates a request for obtaining A records to DNS
   Server-2.
4. DNS Server-2 includes the IP address in RDATA in the response message which it returns to the DNS client.
5. If
   the IP address corresponding to the DNS client field is not available
   on DNS Server-2, DNS Server-2 returns a response message in which RDATA
   is empty.

This document is very well done

Yes it support IPv6.Thanks..........

Huawei DNS also Support IPv6 SRV Record Query................