please answer correctly

Assume that two companies, A and B, have deployed Kerberos-based systems to secure internal communications inside their respective boundaries (e.g., each company maintains its independent Kerberos realm). Let KDCA and KDCB be the central Key Distribution Centers for A and B, respectively. Now assume that A and B decide to collaborate on a new product and wish to link their two Kerberos networks together so that a Client CA in company A can get Kerberos tickets to a Server SB in company B. Similarly, a client CB in company B can get Kerberos tickets to talk to a Server SA in company A. (You may assume that A and B have linked their computer networks so that every client in either A or B has access to the KDC, TGS, and Servers of both companies.) Note that only KDCA (respectively KDCB ) can authenticate company A (respectively, B) Clients. Assume that the two companies have exchanged a shared secret key KAB beforehand and that this key is known only to each company's KDC. Describe how you would enhance or modify the Kerberos scheme presented in class to support cross-realm trust