SIP Interoperability and Integration 3

Question 1

Which SIP extension allows a UA to learn the capabilities of a remote UA without establishing a call?

Accepted Answer

OPTIONS method

Answer

SUBSCRIBE method

Answer

INFO method

Answer

MESSAGE method

Question 2

In SIP federation between two service providers, ENUM (RFC 3761) is primarily used to:

Accepted Answer

Map telephone numbers to SIP URIs via DNS

Answer

Encrypt SIP messages between domains

Answer

Compress SDP bodies

Answer

Authenticate SIP registrations

Question 3

A SIP proxy receives a request with a Max-Forwards value of 0. What must the proxy do?

Accepted Answer

Return a 483 Too Many Hops response

Answer

Forward the request and reset the value to 70

Answer

Drop the request silently

Answer

Forward to the next hop and decrement to -1

Question 4

Which header enables a SIP UA behind NAT to advertise an externally reachable contact address learned from a STUN server?

Accepted Answer

Contact

Answer

P-Asserted-Identity

Answer

Via received/rport parameters

Answer

P-Preferred-Identity

Question 5

When integrating SIP with Microsoft Teams Direct Routing, the Session Border Controller must support which audio codec mandatorily?

Accepted Answer

G.711 (PCMU/PCMA)

Answer

G.729

Answer

Opus

Answer

G.722

Question 6

In SIP interworking with XMPP (Jingle), which RFC defines the mapping between SIP and XMPP for instant messaging?

Accepted Answer

RFC 7247

Answer

RFC 3428

Answer

RFC 4960

Answer

RFC 5626

Question 7

A call center deploys SIP and needs to fork an incoming call to multiple agents simultaneously. Which SIP feature supports this?

Accepted Answer

Parallel forking by a proxy

Answer

Sequential forking via 301 redirect

Answer

SIP REFER with Replaces

Answer

SIP PRACK