AudioCodes Mediant 4000 SBC User Manual page 422

Parameter
Reset SRTP Upon Re-key
reset-srtp-upon-re-key
[IpProfile_ResetSRTPStateU
ponRekey]
Generate SRTP Keys Mode
generate-srtp-keys
[IpProfile_GenerateSRTPK
eys]
SBC Remove Crypto
Lifetime in SDP
sbc-sdp-remove-crypto-
lifetime
[IpProfile_SBCRemoveCrypt
oLifetimeInSDP]
SBC Early Media
Remote Early Media
sbc-rmt-early-media-supp
[IpProfile_SBCRemoteEarly
MediaSupport]
Remote Multiple 18x
sbc-rmt-mltple-18x-supp
[IpProfile_SBCRemoteMultip
le18xSupport]
User's Manual
for encrypting media channels for SRTP key exchange, the support
is important for deployments implementing WebRTC. For more
information on WebRTC, see WebRTC on page 566.
Enables synchronization of the SRTP state between the device and a
server when a new SRTP key is generated upon a SIP session expire.
This feature ensures that the roll-over counter (ROC), one of the
parameters used in the SRTP encryption/decryption process of the
SRTP packets is synchronized on both sides for transmit and receive
packets.

[0] Disable = (Default) ROC is not reset on the device side.

[1] Enable = If the session expires causing a session refresh
through a re-INVITE, the device or server generates a new key and
the device resets the ROC index (and other SRTP fields) as done
by the server, resulting in a synchronized SRTP.
Note:

If this feature is disabled and the server resets the ROC upon a re-
key generation, one-way voice may occur.

The corresponding global parameter is
ResetSRTPStateUponRekey.
Enables the device to generate a new SRTP key upon receipt of a re-
INVITE with the SIP entity associated with the IP Profile.

[0] Only If Required= (Default) The device generates an SRTP key
only if necessary.

[1] Always = The device always generates a new SRTP key.
Defines the handling of the lifetime field in the 'a=crypto' attribute of
the SDP for the SIP entity associated with the IP Profile. The SDP field
defines the lifetime of the master key as measured in maximum
number of SRTP or SRTCP packets using the master key.

[0] No = (Default) The device retains the lifetime field (if present) in
the SDP.

[1] Yes = The device removes the lifetime field from the 'a=crypto'
attribute.
Note: If you configure the parameter to Yes, the following IP Profile
parameters must be configured as follows:

IpProfile_EnableSymmetricMKI configured to Enable [1].

IpProfile_MKISize configured to 0.

IpProfile_SBCEnforceMKISize configured to Enforce [1].
Defines whether the remote side can accept early media or not.

[0] Not Supported = Early media is not supported.

[1] Supported = (Default) Early media is supported.
Defines whether multiple 18x responses including 180 Ringing, 181
Call is Being Forwarded, 182 Call Queued, and 183 Session Progress
are forwarded to the caller, for the SIP entity associated with the IP
Profile.

[0] Not Supported = Only the first 18x response is forwarded to the
caller.

[1] Supported = (Default) Multiple 18x responses are forwarded to
422
Mediant 4000 SBC
Description
Document #: LTRT-40203