\setuppagenumbering
    [alternative=doublesided,location=]

\setupheadertexts
    [{\getmarking[sectionnumber]\enskip\getmarking[section]}]
    [{\getmarking[chapternumber]\enskip\getmarking[chapter]}]

\setupfootertexts
    [{(\fetchallmarks[sectionnumber])\enskip(\fetchallmarks[section])}]

\starttext
    \chapter[title={T},marking={T}] \dorecurse{14}{\input tufte}
    \section[title={A},marking={A}] \dorecurse{14}{\input tufte}
    \section[title={B},marking={B}] \dorecurse{14}{\input tufte}
\stoptext
