Which two configurations provide the best SIP trunk redundancy with Cisco Unified Communications Manager? (Choose two.)
A.
Configure all SIP trunks with DNS SRV
B.
Configure all SIP trunks with Cisco Unified Border Element
C.
Configure all SIP trunks to point to a SIP gateway
D.
Configure SIP trunks to be members of route groups and route lists
E.
Configure all SIP trunks to allow TCP ports 5060
F.
Configure all SIP trunks to point to a gatekeeper through SIP to H.323 gateway
Explanation:
Incorrect answer: BCEF
For SIP trunks, Cisco Unified Communications Manager supports up to 16 IP addresses for each DNS SRV and up to 10 IP addresses for each DNS host name. The order of the IP addresses depends on the DNS response and may be identical in each DNS query. The OPTIONS request may go to a different set of remote destinations each time if a DNS SRV record (configured on the SIP trunk) resolves to more than 16 IP addresses, or if a host name (configured on the SIP trunk) resolves to more than 10 IP addresses. Thus, the status of a SIP trunk may change because of a change in the way a DNS query gets resolved, not because of any change in the status of any of the remote destinations.
Link:http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/8_6_1/ccmsys/a08sip.html