session target ipv4:192.0.2.1:5080
The 'session target' command specifies the destination IP address and optionally the port. However, for SIP dial-peers, the port is specified using the 'session target ipv4:<ip>:<port>' syntax, but this is only valid if the port is specified as part of the session target. Actually, this is correct if the port is included. However, the more common and flexible method is to use a voice class uri with the port. But session target ipv4:192.0.2.1:5080 is valid and would send SIP messages to port 5080. Wait, let's verify: In Cisco IOS, 'session target ipv4:192.0.2.1:5080' is indeed valid for SIP dial-peers. So this option is correct. But the question asks for the required configuration; there might be multiple ways. However, the other options may be invalid. Let's check: The correct answer is A. But to ensure one unambiguous answer, we need to see if other options are definitively wrong. Option B: 'voice-class sip url sip:192.0.2.1:5080' is not a valid command. Option C: 'destination-pattern 5080' is for matching, not for setting the port. Option D: 'voice-class sip outbound-proxy ipv4:192.0.2.1:5080' is for outbound proxy, not for session target. So A is correct. However, the explanation for A should state it is correct. But the question asks 'Which configuration is required', and A is correct. But I need to ensure that the port is indeed specified this way. In Cisco IOS, for SIP dial-peers, you can specify the port in the session target. So A is correct. But I have to write explanations for all options. For A, explain it's correct. For B, explain it's not a valid command. For C, explain it's for matching, not port. For D, explain outbound-proxy is for a different purpose. However, note that outbound proxy can also direct signaling to a specific IP and port, but it's not the session target. The scenario says 'send outbound INVITEs to this provider on port 5080', which is typically done via session target. So A is correct. But I must be careful: some documentation says to use 'session target ipv4:<ip>:<port>' for SIP. Yes, that's correct. So I'll set A as correct. But the instructions say to vary correct answers; I'll put correct as A here, but I need to ensure it's not always A. I'll set correct as A for this one. But let's double-check: Is there a command 'voice-class sip outbound-proxy ipv4:192.0.2.1:5080'? Yes, outbound-proxy can specify a port. But the question says 'to send outbound INVITEs to this provider on port 5080', which could also be achieved with outbound-proxy. However, outbound-proxy is typically used when the provider requires all signaling to go through a proxy. The scenario does not mention a proxy; it just says the provider uses a non-standard port. So session target with port is the direct method. Therefore, A is correct.