The Seventy Interpreters noted.

There was, indeed, a Migdal Eder near Beth-lehem, and this was near Jerusalem; and perhaps there were more places of that name in the land of Israel. For as that word denotes the Tower of a Flock, so those towers seem to have been built for the keeping of flocks; that shepherds might be there ready also a-nights; and that they might have weapons in a readiness to defend their flocks, not only from wild beasts, but from robbers also. And to this sense we suppose that expression, 'the Tower of the Keepers,' is to be taken in that saying, "From the Tower of the Keepers to the strong city," 2 Kings 17:9, 18:8.

Hence the Targumist Jonathan, to distinguish Migdal Eder of Beth-lehem from all others, thus paraphraseth Moses' words: "And Israel went forward and pitched his tabernacle beyond Migdal Eder, the place whence the Messias is to be revealed in the end of days." Which very well agree with the history, Luke 2:8. Whether Micah, chapter 4:8, speak of the same, inquire.