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H323 Telephone Installation
Page 84
Issue 23e (Friday, February 15, 2019)
IP Office™ Platform 11.0
Comments on this document? [email protected]
6. SRTP Support
For IP Office Release 9.1, SRTP is supported.
·
Support IP Office Modes:
SRTP is supported in all IP Office modes.
·
Supported Phones:
It can be applied to SIP and H323 extensions. However, there may be restrictions for some specific models of IP
telephone.
·
Supported for H323 on 9608, 9611, 9621 and 9641 Series telephones.
·
Supported for SIP on Avaya and 3rd-party telephones.
·
Supported Trunks:
It can be applied to all types of IP lines (SIP, SM and IP Office (SCN)) except external H323 trunks.
·
Licensing and Capacity:
The use of SRTP does not require any licenses. However, the use of SRTP impacts on the call capacity of the IP
Office system.
·
For IP500 V2 systems with IP500 VCM cards, those cards are used to support SRTP and reduce the impact on
the system call capacity. This does not apply to combination cards.
6.1 Enabling System SRTP
By default, all IP extensions and lines are configured to automatically match the top-level system settings for SRTP,
whether disabled or enabled. This simplifies enabling SRTP by ensuring that all devices are using the same SRTP settings.
Using this approach, once SRTP is enabled, the only device level configuration required is to disable SRTP on those lines or
devices for which it is not required.
The exception to the above is SIP lines for which SRTP is disabled by default. This is due to the low number of SIP line
providers who currently support SRTP. However, SIP lines can be configured to also match the system level settings if
required.
To enabled system level SRTP:
1. Receive the configuration from the system.
2. Click
System
and select the
VoIP Security
tab.
3. For
Media Security
, select the level of STRP operation required:
·
Disabled
STRP is not used for connections.
·
Best Effort
Support both RTP and SRTP. Use SRTP if matching SRTP settings can be negotiated with the remote end. This
requires the remote end to support srtp rfc5939 (capability negotiation for SRTP). Otherwise use RTP. Note
that E129 phones does not support
Best Effort
.
·
Enforce
Use SRTP only. The call is not allowed if the remote leg does not support matching SRTP.
·
Advanced Settings
After selecting either
Best Effort
or
Enforce
as the STRP method, it is recommended that all other SRTP
settings are left at their defaults. The default SRTP flags and crypto suite settings were chosen so that they
work with all Avaya H323 and SIP devices. For example, the majority of Avaya implementations don’t support
RTCP encryption and Avaya H323 phones only support the SHA_80 crypto suite.
4. Click
OK
.
To disable SRTP on an extension or line:
1. Click on
Extension
or
Line
and select the required extension or line.
2. Select the
VoIP
tab.
3. Change the
Media Security
setting to
Disabled
.
4. Click
OK
.
5. Repeat for any other extension or line for which SRTP should not be used.