ploying any centralized policy server, you need to answer the following questions before selecting the right SBC for you: Chapter 9: Questions to Ask of a Service Provider Offering and an SBC Vendor Does the product support Media Policing? Does the product support Signaling Policing? Does the product support Domain-level and User-level blacklists? Does the product support granular call admission control policies? Does the product support policy-based call routing? Does the product support digit and header manipulation? Does the product provide support for full E.164 addressing (including the +)? Does the product categorize and police traffic based on originating network? Does the product categorize and police traffic based on SIP domain? Does the product categorize and police traffic based on originating user? Does the product categorize and police traffic based on originating user groups? Does the product categorize and police traffic based on originating device? Does the product categorize and police traffic based on time of day? Access Control Controlling the access of your network is another security measure. You need to authen- ticate the user before accessing any resources and then authorize that user to use the resources at different levels. Check with your SBC vendors about the following questions about access control mechanism: Does the product support Secure Sockets Layer (SSL)/TLS X.509 root certificate mutual authentication? Does the product support RFC-3280 public key infrastructure? Does the product support SIP digest authentication? Does the product support granular CAC policies? Does the product support clientless RSA (Rivest, Shamir, and Adleman first publicly described it) two-factor authentication? Operations and Management After you deploy the network with an SBC, you need to run and manage it every day. You will be using some methods, procedures, and tools that pertain to the operation, administration, maintenance, and provisioning of the systems. Data for network manage- ment is collected th