Linux machine, Symlink is allowed. All but cache, tmp, logs under slave site are symlinked.
Slave sub.domain.com has been configured under master domain.com.
sub.domain.com successfully resolves to its path but sub.domain.com/administrator redirects to domain.com/administrator.
If the directory is not symlinked it works fine.
What is missing here?

If you are redirected to the master website, this probably mean that you have not correctly enter the same domain or URL as the one you have defined in JMS.

The most frequent error is that you have not defined both URL with and without the WWW
Perhaps also you are using http and https - if this is the case, you also have to define slave domain with http and https.

for example
www.domain.com
domain.com
www.domain.com
domain.com

You can NOT use redirection as this destroy the URL information.
If you are using cPanel, you can only use subdomain, domain or parked domain and NEVER REDIRECTION.
Redirection change the URL with the new one and therefore Jms Multisites will receive the new redirected URL information.

I am not the one redirecting. I have created a slave site with the following values. With this configuration I can see sub.domain.com but sub.domain.com/administrator sends me to domain.com/administrator

CONFIGURATION VALUES AT domain.com BACKEND
Deployed directory: /home/domain/public_html/sub
List of domain names:
www.sub.domain.com
sub.domain.com

Perhaps you have put manually a "live_site" value in the slave "configuration.php" file that contain the URL of the master. or you have setup your HTTP Server (not JMS) to redirect the subdomain to the main not.

I remember you that you can NOT use redirect when you configure a subdomain in your HTTP Server (cPanel, plesk, or whatever) administration tool.

I have removed the value of the parameter live_site but still no change.
Please notice that I don't know why but ONLY slave site administration (sub.domain.com/administrator) redirects to domain.com/administrator.
That is slave site can be viewed without any problems.
I have done no modifications in cPanel configuration.

This time I have leaved the parameter live_site EMPTY for both slave and master.
Slave site administration opened slave.master.com/administration. That is it has not been redirected to master.com/administration but it started seeing the configuration.php of the master site.
This means slave site administration opens as if it is master site administration.