Assuming you are running the NW server on linux, if you run "nsr_shutdown -l", would list the running processes from NW. It will show the correlation of which process is under control of which process (and their process ID's).

The nsrdisp processes are directly linked to making Vmware based image level backups. Only a backup server that actually makes vproxy based backups, actually shows more than only the nsrdispd process.

If those nsrdisp_dd or other nsrdisp processes should be running is not clear, as besides nsrdispd and nsrdisp_nwbg they are not explained (and even those rather limited). A KB article about a memory leak of nsrdisp_nwbg states it as "NetWorker dispatcher process".

In a NW19.3 server running since march, connecting to 2 VC's:
...
+--o nsrd (13358)
+--o ansrd (6210)
+--o nsrworkflow (6864)
+--o ansrd (7195)
+--o ansrd (8616)
+--o ansrd (9362)
+--o ansrd (10264)
+--o ansrd (10898)
+--o ansrd (12704)
+--o ansrd (13498)
+--o java (13560)
+--o nsrmmdbd (13825)
+--o nsrindexd (13860)
+--o nsrdispd (13905)
+--o nsrdisp_dd (2363)
+--o nsrdisp_dd (4337)
+--o nsrdisp_nwbg (6079)
+--o nsrdisp_vcenter (6244)
+--o nsrdisp_nwbg (6404)
+--o nsrdisp_dd (7467)
+--o nsrdisp_dd (8098)
+--o nsrdisp_nwbg (8501)
+--o nsrdisp_vcenter (8660)
+--o nsrdisp_dd (8899)
+--o nsrdisp_dd (9237)
+--o nsrdisp_dd (9284)
+--o nsrdisp_nwbg (9340)
+--o nsrdisp_vcenter (9395)
+--o nsrdisp_nwbg (10177)
+--o nsrdisp_dd (10194)
+--o nsrdisp_vcenter (10300)
+--o nsrdisp_nwbg (10868)
+--o nsrdisp_dd (10919)
+--o nsrdisp_vcenter (10932)
+--o nsrdisp_dd (11506)
+--o nsrdisp_nwbg (12614)
+--o nsrdisp_vcenter (12737)
+--o nsrdisp_nwbg (13475)
+--o nsrdisp_vcenter (13558)
+--o nsrdisp_dd (14226)
+--o nsrdisp_nwbg (14911)
+--o nsrdisp_dd (16076)
+--o nsrdisp_nwbg (16362)
+--o nsrdisp_vproxy (16620)
+--o nsrdisp_dd (16810)
+--o nsrdisp_nwbg (18529)
+--o nsrdisp_dd (18653)
+--o nsrdisp_dd (20125)
+--o nsrdisp_dd (21195)
+--o nsrdisp_dd (22030)
+--o nsrdisp_dd (23805)
+--o nsrdisp_dd (25194)
+--o nsrdisp_dd (26157)
+--o nsrdisp_dd (28717)
+--o nsrdisp_dd (29055)
+--o nsrdisp_dd (29397)
+--o nsrdisp_nwbg (31434)
+--o nsrdisp_dd (31839)
+--o nsrdisp_dd (31840)
+--o nsrjobd (14224)
+--o nsrvmwsd (15045)
+--o nsrvisd (13425)
...

Another NW server running NW19.4 connecting to only one VC:
...
+--o nsrd (25544)
+--o nsrlmc (25679)
+--o java (25923)
+--o nsrmmdbd (26884)
+--o nsrindexd (27047)
+--o nsrdispd (27276)
+--o nsrdisp_dd (11348)
+--o nsrdisp_dd (13346)
+--o nsrdisp_dd (14241)
+--o nsrdisp_dd (15183)
+--o nsrdisp_dd (20541)
+--o nsrdisp_dd (28184)
+--o nsrdisp_nwbg (29553)
+--o nsrjobd (27513)
+--o nsrvisd (25760)
...