On the ping command the numeric value defines the datagram size, not the packet size.
So with the default MTU of 1500, the maximum non-framented value that can be used with the ping command is 1472 (1500 - 38 overhead). 1500 is the proper MTU for your cable connection.
In order to get the larger packets to succeed you would need to disable MTU discovery (PMTUD). (Decidedly not advised except as an experiment).
PMTUD is implemented by having an IP sender set the "Don't Fragment" (DF) flag in the IP header. If an IP packet with this flag set reaches a router whose next-hop link has too small an MTU to send the packet without fragmentation, that router discards that packet and sends an ICMP "Fragmentation needed but DF set" error to the IP sender. When the IP sender receives this Internet Control Message Protocol (ICMP) message, it should learn to use a smaller IP MTU for packets sent to this destination, and subsequent packets should be able to get through.
Various problems can cause the PMTUD algorithm to fail, so that the IP sender will never learn the smaller path MTU but will continue unsuccessfully to retransmit the too-large packet, until the retransmissions time out. Some problems include the following:
i. The router with the too-small next hop path fails to generate the necessary ICMP error message.
ii. Some router in the reverse path between the small-MTU router and the IP sender discards the ICMP error message before it can reach the IP sender.
iii. Confusion in the IP sender's stack in which it ignores the received ICMP error messages.
With the above problems, a workaround is to configure the IP sender to disable PMTUD. This causes the IP sender to send their datagrams with the DF flag clear. When the large packets reach the small-MTU router, that router fragments the packets into multiple smaller ones. The smaller, fragmented data reaches the destination where it is reassembled into the original large packet.
Sometimes a router will have a link with a large (1500 byte) MTU, but the router is unable to deliver a datagram of that size over that link. That router will not return a "Fragmentation needed but DF set" ICMP error to the sender, because the link does not actually have a small MTU. However, large datagrams will be unable to pass through the link. Therefore, PMTUD will not help, and all large-packet transmission attempts through this link will fail
Disable PMTUD:
PMTU discovery is enabled by default, but can be controlled by adding the following value to the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\EnablePMTUDiscovery
PMTU Discovery: 0 or 1 (Default = 1)
Data Type: DWORD
A "1" enables discovery while a "0" disables it. When PMTU discovery is disabled, a MTU of 1500 bytes is used for all non-local destination IP addresses. The TCP MSS=1460.
Setting this parameter to 1 (True) causes TCP to attempt to discover the Maximum Transmission Unit (MTU or largest packet size) over the path to a remote host. By discovering the Path MTU and limiting TCP segments to this size, TCP can eliminate fragmentation at routers along the path that connect networks with different MTUs. Fragmentation adversely affects TCP throughput and network congestion.
