System Landscape settings for EP connecting to SAP Webdisp to ess/mss

Question

We have external facing portal . for reverse proxy we are using sap webdispatcher.
sapwebdispatcher->ep->sapwebdispatcher--->HCM(ess/mss)
EP connects to HCM(ess/mss) via sap webdispatcher.
What should be my system landscape defination in Portal and JCo destinations for webdynpro where ep and webdynpro is connecting to backend(ess/mss) via sap webdispatcher.
My guess is instead of message server I should point to sap webdispatcher url then what should be my port for connectors,ITS settings and WebAS settings in system landscape.
Thanks very much in advance for your help.

Answer 1

Something like that, with Firewalls and additional web dispatcher for external access to HCM:
FW                   FW
FW sapwebdispatcher1-FW-->ep--->sapwebdispatcher3--->HCM(ess/mss)
FW                   FW            ^
FW                   FW            |
FW sapwebdispatcher2-FW----------->|
FW                   FW
The reason is that EP iview with ITS content requires browser to have direct visibility of ITS backend. You can see it if you trace HTTP requests.
Regarding system definition in PCD:
Michael is correct about Connector part - you can do direct HCM.
The more important issue is what you will put in "ITS Connection" (and SAP Web AS Connection). It is important to put public hotname/URL of sapwebdispatcher2, otherwise external web browser will have issues.
Another thing: no protocol mix for external URLs. If your EP is accessed via HTTPS, you will have to put HTTPS in ITS connector definition. Otherwise users will see browser warnings. You can do SSL termination on web dispatchers if you want and use HTTP from DMZ web dispatchers, but definition of external URLs should be protocol consistent.
Regards,
Slava