The Expressway supports two protocols for traversing media across a firewall: H.460.18/19 and Assent. Both protocols use a TCP/TLS connection established from the client to the server for signaling, and UDP ports for media.  The difference is that H.460.18/19 is a standard protocol for H.323 firewall traversal, while Assent is a Cisco proprietary protocol for SIP firewall traversal 1 2 3

H.460.18/19 is an extension of the H.323 protocol that allows endpoints to communicate with each other through a firewall or a NAT device. H.460.18 defines the signaling procedures for establishing a TCP/TLS connection between the endpoint and the Expressway-E, which acts as the traversal server. H.460.19 defines the media procedures for sending and receiving RTP/RTCP packets through the same TCP/TLS connection or through UDP ports.  The Expressway-E uses media demultiplexing to route the media packets to the correct destination 1 2 4

Assent is a protocol that is similar to H.460.18/19, but it is used for SIP firewall traversal of media. The signaling is traversed through a TCP/TLS connection established from the client to the server. The media is traversed through UDP ports that are negotiated using the SDP offer/answer exchange.  The Expressway-E uses media demultiplexing to route the media packets to the correct destination 1 2 3

References  :=  1 Cisco Expressway Administrator Guide (X14.0) - Firewall Traversal   2 Cisco Expressway IP Port Usage for Firewall Traversal   3 Firewall Traversal and NAT Traversal On Cisco Expressway Explained With Wireshark   4 Firewall Traversal Mechanisms > CCIE Collaboration Quick Reference

= The Calendar Connector is a Hybrid Services connector that provides integration between on-premises calendaring applications and Cisco Collaboration Cloud. It enables users to schedule and join Webex meetings from their calendar clients, such as Microsoft Outlook or Google Calendar, and also provides One Button to Push (OBTP) functionality for cloud-registered room and desk devices and Webex Boards.  The Calendar Connector supports Microsoft Exchange, Office 365, and Google Calendar as on-premises calendaring applications 1 2 3 .  References  :=  1 2

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cloudCollaboration/spark/hybridservices/calendarservice/cmgt_b_deploy-spark-hybrid-calendar-service/cmgt_b_deploy-spark-hybrid-calendar-service_chapter_0111.html

https://help.webex.com/en-us/article/7dmbcr/Deployment-Guides-for-Webex-Hybrid-Services

TMS stands for TelePresence Management Suite, which is a software application that provides centralized management, scheduling, and monitoring of video conferencing endpoints and infrastructure 1 .

TMS uses two primary protocols to communicate with endpoints and infrastructure: SIP and SNMP 2 3 .

SIP stands for Session Initiation Protocol, which is a signaling protocol that is used to establish, modify, and terminate multimedia sessions, such as voice and video calls.  TMS uses SIP to communicate with endpoints and infrastructure that support SIP, such as Cisco Unified Communications Manager, Cisco Expressway, Cisco Meeting Server, and Cisco TelePresence endpoints 2 3 .

SNMP stands for Simple Network Management Protocol, which is a protocol that is used to monitor and manage network devices, such as routers, switches, servers, and endpoints.  TMS uses SNMP to communicate with endpoints and infrastructure that support SNMP, such as Cisco TelePresence System MXP series, Cisco TelePresence Server, and Cisco TelePresence Conductor 2 3 .

TMS also uses other protocols, such as HTTP/HTTPS, XML, and SOAP, to communicate with endpoints and infrastructure, depending on the type and version of the system 2 3 .

References  :=  1 :  Cisco TelePresence Management Suite - Cisco   2 :  Cisco TelePresence Management Suite Administrator Guide (15.13) - How Cisco TMS Communicates with Managed Systems   3 :  Cisco TelePresence Management Suite Administrator Guide (15.13) - Required Ports for Cisco TMS Communication  : [Session Initiation Protocol - Wikipedia] : [Simple Network Management Protocol - Wikipedia]

 = The Cisco event log on the Telepresence Server shows key events that have occurred on the server, such as call events, login events, and alarms. The event log can be accessed through the web interface or the command-line interface (CLI) of the server. The event log allows the administrator to view and sort through conferencing events, such as conference creation, deletion, joining, leaving, and media negotiation. The event log also indicates the status and outcome of each event, such as success, failure, or error.  The event log can be useful for troubleshooting and monitoring purposes 1 2 3   References  :=  1 Cisco TelePresence Server Administration and User Guide (4.4) - Event log   2 Cisco TelePresence Server Command Reference Guide (4.4) - file view log   3 Cisco TelePresence System Message Overview

According to the Cisco documentation 1 , the Expressway stores the username and password of the local database users in its local database. These users can be used for authentication and authorization purposes when accessing the Expressway web interface or API.  The other elements, such as user authority, CA authority, and crypto hash key, are not stored in the local database of the Expressway, but are either derived from other sources or generated dynamically.  References :  1 : Cisco Expressway Basic Configuration Deployment Guide, Chapter 3: Configuring Local Database Users, https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-11/Cisco-Expressway-Basic-Configuration-Deployment-Guide-X8-11.pdf

Authentication credentials can be stored in the local database of the Expressway.  This is true because the Expressway can use its local authentication database to verify the credentials of incoming requests from devices or external systems 1 .  Alternatively, the Expressway can also use external authentication methods, such as LDAP, SAML, or OAuth 1 .

SIP endpoints always need authentication credentials.  This is false because the Expressway’s authentication policy can be configured separately for each zone, and it can be set to “Do not check credentials” or “Treat as authenticated” for SIP messages from local or non-local domains 1 . This means that some SIP endpoints may not need authentication credentials to communicate with the Expressway, depending on the zone configuration.

The endpoint and Expressway must be configured and synchronized with an NTP server delivering an identical time stamp.  This is false because the Expressway and the endpoint do not need to be synchronized with identical NTP timestamps for authentication purposes 2 .  However, it is recommended to synchronize the Expressway and the endpoint with the same NTP server for other reasons, such as logging, troubleshooting, and certificate validation 3 .

Expressways and endpoints do not need to be synchronized with identical NTP timestamps.  This is true because the Expressway and the endpoint do not need to be synchronized with identical NTP timestamps for authentication purposes 2 .  However, it is recommended to synchronize the Expressway and the endpoint with the same NTP server for other reasons, such as logging, troubleshooting, and certificate validation 3 .

When a subzone is set for “Treat as Authenticated”, the endpoint must have the correct authentications configured.  This is false because the “Treat as Authenticated” option means that the Expressway will not verify the credentials and will allow the message to be processed as if it has been authenticated 1 .  This option can be used to cater for endpoints from third-party suppliers that do not support authentication within their registration mechanism 1 .

References  :=  1 :  Cisco Expressway Administrator Guide (X14.0) - Device Authentication   2 :  Cisco Expressway Administrator Guide (X14.0) - NTP Configuration   3 :  Cisco Expressway Administrator Guide (X14.0) - Time and Date

= Transforms are a way of modifying the destination alias or address of a call before it is routed to the appropriate zone or service. Transforms can be applied at different stages of the call routing process, such as pre-search, search rules, or call policy. The Cisco recommended method to add a domain to a numeric E.164 alias dialed by an H.323 endpoint is to use a pre-search transform. A pre-search transform is applied to the destination alias before any searches are sent to external zones. This allows the Expressway to standardize the destination aliases originating from both H.323 and SIP devices. For example, if the called address is an H.323 E.164 alias “01234”, the Expressway can automatically append the configured domain name (in this case example.com) to the called address (that is, 01234@example.com making it into a URI), before attempting to set up the call. This way, the Expressway can route the call to the correct destination zone or service based on the full URI.  References  :=  Cisco Expressway-E and Expressway-C Basic Configuration Deployment Guide (X14.0) - Routing Configuration Cisco Expressway Administrator Guide (X14.0) - Dial Plan and Call Processing

 The H.323 standard defines the protocols to provide audio-visual communication sessions on any packet network 1  The H.323 standard uses a number of protocols to establish and control multimedia sessions, such as voice and video calls. Two of the protocols used in the H.323 standard are H.245 and Q.931.

H.245 is a protocol that is used for media control and logical channel signaling 2  H.245 allows the endpoints to negotiate the media capabilities, such as the codec, the bit rate, and the format, and to open and close the logical channels for media transmission. H.245 also provides functions for conference control, such as floor control, chair control, and multipoint mode. H.245 messages are exchanged between the endpoints using TCP or UDP.

Q.931 is a protocol that is used for call signaling and connection control 3  Q.931 is based on the ISDN protocol and is adapted for packet networks. Q.931 allows the endpoints to set up, maintain, and terminate the calls, and to exchange information such as the call identity, the call type, the call state, and the reason for call release. Q.931 messages are exchanged between the endpoints using TCP.

The other options are not protocols used in the H.323 standard. SDP is a protocol that is used to describe the media session parameters, such as the media type, the codec, the port number, and the encryption method. SDP is used in conjunction with SIP, but not with H.323. SIP is another protocol that is used to establish and control multimedia sessions on packet networks, but it is not part of the H.323 standard. SIP is an alternative to H.323 and has a different architecture, syntax, and functionality. 802.1 is a standard that defines the LAN protocols, such as the MAC address, the VLAN, the spanning tree, and the link aggregation. 802.1 is not related to the H.323 standard, which operates at the application layer.  References :  H.323 - Wikipedia ,  H.245 - Wikipedia ,  Q.931 - Wikipedia