Para que Zypper y Yast bajen primero los archivos y luego los instalen edité el archivo /etc/zypp/zypp.conf de la siguiente manera
paris@linux-m7f2:~> sudo vi /etc/zypp/zypp.conf
root's password:
##
## Commit download policy to use as default.
##
## DownloadOnly, Just download all packages to the local cache.
## Do not install. Implies a dry-run.
##
## DownloadInAdvance, First download all packages to the local cache.
## Then start to install.
##
## DownloadInHeaps, Similar to DownloadInAdvance, but try to split
## the transaction into heaps, where at the end of
## each heap a consistent system state is reached.
##
## DownloadAsNeeded Alternating download and install. Packages are
## cached just to avid CD/DVD hopping. This is the
## traditional behaviour.
##
## If a value is not set, empty or unknown, we pick
## some sane default.
##
commit.downloadMode = DownloadInAdvance