A remote worker using the Avaya Communicator on the smart mobile phone obtains a private IP address delivered from the corporate network over WiFi when in range of the wireless hot-spot. When the…

Question

Options

• ANetwork Address Translation (NAT)
• BAvaya Session Border Controller for Enterprise (SBCE) public IP-address
• CSplit Horizon DNS with FQDN
• DVirtual Private Network (VPN)

• B
  10% (2)
• C
  85% (17)
• D
  5% (1)

Explanation

Split Horizon DNS allows the smartphone to always use a single FQDN (e.g., sip.company.com) as the SIP proxy address - DNS then resolves that name to the internal private IP when queried from the corporate network, and to the public IP (typically the SBCE's external interface) when queried from the internet. Because the configured address never changes (it's always the same FQDN), the user roams transparently without touching any settings.

Why the distractors fail:

• A (NAT): NAT translates addresses at the network edge but does nothing to help the client locate its SIP proxy across two different networks - it's a server/gateway function, not a client addressing strategy.
• B (SBCE public IP): Hardcoding the SBCE's public IP works from the internet but forces internal traffic to hairpin out to a public address when on the corporate LAN - it's not a roaming solution, and it breaks the "no reconfiguration" requirement.
• D (VPN): A VPN could unify the address space, but it requires the VPN to be active and stable across the roaming event; a VPN drop or handoff gap disrupts the call. It also adds complexity and isn't the architecturally intended Avaya solution here.

Memory tip: Think of Split Horizon DNS as a "two-faced GPS" - same destination name, but it gives you the back-door address when you're inside and the front-door address when you're outside. One name, two answers, zero manual changes.

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