This passage does not refer to local deacons. These deacons traveled with the traveling elders (apostles) and they traveled at the direction of the traveling elders. They were apostolic deacons just like Timothy and Titus were.  Traveling deacons have been restored to the church, although most Christians aren't even aware of it.  I remember asking my pastor about it after the Lord revealed this order to me from Scripture.  My pastor assured me that a good portion of Scripture went defunct after what he termed the "apostolic age."  Later, I found that the pastor just wasn't aware.

Acts 6:1-2 "And in those days, when the number of the disciples was multiplied, there arose a murmuring of the Grecians against the Hebrews, because their widows were neglected in the daily ministration. Then the twelve called the multitude of the disciples to them, and said, It is not reason that we should leave the word of God, and serve tables."  

Acts 6:3-6 "Wherefore, brethren, look ye out among you seven men of honest report, full of the Holy Ghost and wisdom, whom we may appoint over this business.  But we will give ourselves continually to prayer, and to the ministry of the word. And the saying pleased the whole multitude: and they chose Stephen, a man full of faith and of the Holy Ghost, and Philip, and Prochorus, and Nicanor, and Timon, and Parmenas, and Nicolas a proselyte of Antioch: Whom they set before the apostles: and when they had prayed, they laid their hands on them."

 Acts 6:7 "And the word of God increased; and the number of the disciples multiplied in Jerusalem greatly; and a great company of the priests were obedient to the faith."

Let God be true and every man a liar.

Apostles are given the responsibility of protecting the entire flock of God from the attack of the enemy, but with so many voices in the world, each one claiming to be the one that should be listened to, how can you know?  You are responsible to be close enough to God so that you can tell the difference between false apostles and real apostles.

Read the complete definition of "Apostle."