Refer to the exhibit. 

Which option describes the method used by Cisco IOS gateways to tunnel QSIG signaling messages in H.323 protocol? 

Answer options:

A. H.323 Annex M1
B. H.323 Annex M2
C. H.323 Annex A
D. ISDN Generic Transparency Descriptor
E. H.450.1

D

H.323 is an umbrella recommendation that encompasses various ITU-T recommendations, primarily recommendations H.225.0 and H.245 (basic communication capabilities) and recommendation H.450.1 (generic functional protocol for the support of supplementary services). Tunneling QSIG over H.323 is specified in H.323 Annex-M1. However, Cisco IOSSoftware H.323 QSIG tunneling does not implement Annex-M1 (as the Cisco Unified Communications Manager H.323 implementation does). Instead it uses the ISDN Generic Transparency Descriptor (GTD) to transport QSIG messages in the corresponding H.225 message to another Cisco gateway device on the other side of the network. References: http://www.cisco.com/c/en/us/solutions/collateral/enterprise-networks/empowered-branch-solution/white_paper_c11_459092.html