DOS/spam attack

[hugeblack]

So what will happen if i want to make Dos attack against Bitcoin network  By making many transactions fast and sequence till make network Down . because one of the Weaknesses of bitcoin network is block size is limited and lower than computing resources So is this possible

[BayAreaCoins]

Already actively happening.

https://blockchain.info/unconfirmed-transactions

[TheRomanLegion_]

Already actively happening.

https://blockchain.info/unconfirmed-transactions

How does this effect the network? Surely, all of the transactions must be legitimate. Pointless transactions (spam etc.) will just get pushed to the bottom of the pile and basically discarded because of the minimal Tx fee so a spam attack would either have to be extremely expensive or just won't work... right?

[btctousd81]

you know there are other ways to attack the bitcoin network., instead of spending money on each transaction.