Unfortunately there is not much that you can do on your own on improving your network connection in order to reduce lag in minecraft.
Minecraft lag spikes. Lag spikes can suddenly make the game you re playing feel much slower as a result of a serious drop in frame rats. Lag spikes are a huge problem in every video game including minecraft. I do use optifine and it does help with regular lag more on that later but i can t seem to figure out this issue in particular. If you have not been able to resolve minecraft lag problems using the fixes provided above the problem lies in your network connection.
This can be a very big problem and can be costly especially if you re playing a multiplayer game. This means that this lag is caused by your computer running the minecraft game. Anyway i use a 64x64 texture pack normally when the spikes appear. If i turn it off then the spikes disappear.