O seu ISP pode estar usando um servidor de cache. Tente mudar o seu servidor DNS para o servidor DNS do Google. Isso impedirá que a rota do pacote seja manipulada pelo ISP. Certos ISPs usam um servidor de cache para reduzir os custos de largura de banda, mas os servidores não conseguem lidar com o problema descrito acima (tive os mesmos problemas).
Você pode seguir as instruções em esta página do Google.
Citado:
Windows
DNS settings are specified in the TCP/IP Properties window for the selected network connection.
Example: Changing DNS server settings on Windows 7
Go to the Control Panel.
Click Network and Internet > Network and Sharing Center > Change adapter settings.
Select the connection for which you want to configure Google Public DNS. For example:
- To change the settings for an Ethernet connection, right-click Local Area Connection > Properties.
To change the settings for a wireless connection, right-click Wireless Network Connection > Properties.
If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Select the Networking tab. Under This connection uses the following items, select Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6) and then click Properties.
Click Advanced and select the DNS tab. If there are any DNS server IP addresses listed there, write them down for future reference, and remove them from this window.
Click OK.
Select Use the following DNS server addresses. If there are any IP addresses listed in the Preferred DNS server or Alternate DNS server, write them down for future reference.
Replace those addresses with the IP addresses of the Google DNS servers:
- For IPv4: 8.8.8.8 and/or 8.8.4.4.
- For IPv6: 2001:4860:4860::8888 and/or 2001:4860:4860::8844.
Restart the connection you selected in step 3.
Test that your setup is working correctly; see Test your new settings below.
Repeat the procedure for additional network connections you want to change.
As instruções para Mac e Linux estão disponíveis no link fornecido acima .
Isto é dependente do ISP.
Há evidências das táticas da Virgin Media pesquisando Virgin Media Youtube Caching
(estou em uma rede de trabalho, portanto não posso vincular a fóruns infelizmente)