Message Routing issue

Dear TI,

I have observed a messsage routing issue for which I need your help.

I am using ZStack-CC2530-2.5.1a with ZIGBEEPRO and Z-SECURE enabled.

Following is my setup



PCDesktop(connected with router thru USB)Router1 <-----> Coordinator<-----> Router2 <-----> Router3 <-----> Router4


At the beginning all the routers get binded with the Coordinator. Also address of Router1 (as USB Gateway) is forwarded by Coordinator to the rest of the routers.

Command Message is getting sent to all the routers from a PC as the messages from Router1 are addressed to Coordinator and Coordinator after authorizing forwards the messages to the desired routers.

Upon receiving the command Message each router is supposed to Respond to the Router 1. Messages from Router 2 and Router 3 are always being received by Router 1., however message from Router 4 is not always getting received on Router1.

Please clarify whether we need to have some sort of binding between routers with router 1 as well or there is some tuning required in my setup.

Thanks
Anubhav