Deployment Scenarios - Cisco 8800 Series Administration Manual

Phone Feature Configuration
• Cisco Preferred Architecture for Enterprise Collaboration, Design Overview
• Cisco Preferred Architecture for Enterprise Collaboration, CVD
• Unified Communications Mobile and Remote Access via Cisco VCS Deployment Guide
• Cisco TelePresence Video Communication Server (VCS), Configuration Guides
During the phone registration process, the phone synchronizes the displayed date and time with the Network
Time Protocol (NTP) server. With Mobile and Remote Access Through Expressway, the DHCP option 42
tag is used to locate the IP addresses of the NTP servers designated for time and date synchronization. But if
the DHCP option 42 tag is not found in the configuration information, the phone looks for the
0.tandberg.pool.ntp.org tag to identify the NTP servers.
After registration, the phone uses information from the SIP message to synchronize the displayed date and
time unless there is an NTP server configured in the Cisco Unified Communications Manager phone
configuration.
If the phone security profile for any of your phones have TFTP Encrypted Config checked, you cannot
Note
use the phone with Mobile and Remote Access. This limitation is because the MRA solution does not
support devices interacting with CAPF (Certificate Authority Proxy Function).

Deployment Scenarios

The following table shows various deployment scenarios for Mobile and Remote Access Through Expressway.
Scenario
On-premises user logs into the enterprise network,
after deploying Mobile and Remote Access
Through Expressway.
Off-premises user logs into the enterprise network
with Mobile and Remote Access Through
Expressway.
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Actions
The enterprise network is detected, and the phone
registers with Cisco Unified Communications Manager
as it would normally.
The phone detects that it is in off-premises mode, the
Mobile and Remote Access Through Expressway
Sign-In window appears, and the user connects to the
corporate network.
Users must have a valid service domain, username, and
password to connect to the network.
Users must also reset the service mode to clear the
Alternate TFTP setting before they can access the
company network. This clears the Alternate TFTP Server
setting so the phone detects the off-premises network
and it stops the phone from making a VPN connection.
If a phone is being deployed out of the box, users may
skip the reset the service mode requirement.
If users have the DHCP option 150 or option 66 enabled
on their network router, they may not be able to log in
to the corporate network. Users should reset their service
mode to enter MRA mode.