I'm trying to understand which of these OpenSSH package options I should use with the CORE_IMAGE_EXTRA_INSTALL option:

    openssh
    openssh-sshd
    openssh-sftp
    openssh-sftp-server

I want OpenSSH server functionality that supports both the scp and sftp protocols. I first tried just 'openssh' and found that it provides scp but not sftp.
So then I tried the latter 3 options and I got sftp, but not scp. Do I really need all 4 of these to get scp and sftp?

I checked this recipe guide and found it lists yet another package named 'packagegroup-core-ssh-openssh' but it says nothing about sftp.
    http://recipes.yoctoproject.org/rrs/recipes/2.1/M2/

I would appreciate some advise.

Thanks, Clay Montgomery