300-820 Question #218: Real Exam Question with Answer & Explanation

Question

Employees at company A must call employees at company B in an extension range of [email protected]. Both companies have a Cisco collaboration infrastructure. All required zones are configured in Cisco Expressways at company A. What must be configured on the Expressway at company A to enable outbound B2B calls?

Options

• Asearch rule with a regex pattern of [4]\d{3}@companyB\.com that targets the DNS zone
• Bsearch rule with a suffix pattern of *[email protected] that targets the neighbor zone
• Ccall policy rule from the DNS zone to allow a destination pattern of 4[1-9]@companyB.com
• Dcall policy rule from the neighbor zone to allow a destination pattern of 4[1-9]@companyB.com

Explanation

To enable outbound B2B calls from Company A to Company B using SIP URIs like [email protected], you must configure a search rule on Expressway-C at Company A. The search rule needs to match the SIP URI pattern being dialed. The correct regex to match 4-digit extensions starting with 4 is: [4]\d{3}@companyB.com. This rule must target the DNS zone, which is responsible for resolving external B2B domains like companyB.com. Call policy rules are used to allow or block traffic after routing decisions. In this case, the first requirement is to route the call correctly, so a search rule is required.

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