This topic provides answers to some frequently asked questions about IPv6 Gateway.

Why do I fail to receive an echo reply packet from an IPv6 network after I ping the network with an echo request packet that exceeds 1,500 bytes in size?

In data transmission, the size of each packet is limited. The largest packet size is called the maximum transmission unit (MTU). For example, the Ethernet MTU is 1,500 bytes. If a packet that exceeds the MTU requires transmission at the network layer, the packet is divided into fragments to ensure that the size of each fragment is equal to or smaller than the MTU. This is called fragmentation. Frequent fragmentation reduces the efficiency of data transmission.

In IPv6 networks, IPv6 routers do not fragment packets. Fragmentation is performed only at the network layer on the source host. This improves the efficiency of packet processing. If a packet exceeds the MTU, the IPv6 router drops the packet and returns a message to the source host that indicates that the packet is too large. The source host fragments the packet at the network layer and retransmits the fragments. When you ping an IPv6 network with an echo request packet that exceeds 1,500 bytes (MTU), you cannot receive an echo reply packet. We recommend that you use a smaller packet to test the network connectivity.

How does a backend server that uses an IPv4 address provide services to IPv6 clients?

You can use Global Accelerator (GA) to enable IPv6 clients to access IPv4 backend services. For more information, see Access IPv4 services from IPv6 clients by using GA.

Can I change the metering method of IPv6 Internet bandwidth?

No.

However, you can delete the pay-by-bandwidth Internet bandwidth, and then purchase pay-by-data-transfer bandwidth. This does not change the IPv6 address.