AudioCodes Media Pack MP-11x, User Manual

Page: 507 / 650

Version 6.6 507 MP-11x & MP-124
User's Manual 44. Configuration Parameters Reference
Parameter Description

If this parameter is set to Preferable [3] and two 'm=' lines are
received in the SDP offer, the device prefers the SAVP
(secure audio video profile) regardless of the order in the SDP.

Option [2] Disable is applicable only to IP Profiles.

This parameter can also be configured per IP Profile, using the
IPProfile parameter (see 'Configuring IP Profiles' on page
225 ).
Web: Master Key Identifier (MKI)
Size
EMS: Packet MKI Size
[SRTPTxPacketMKISize]
Defines the size (in bytes) of the Master Key Identifier (MKI) in
SRTP Tx packets.
The range is 0 to 4. The default is 0 (i.e., new keys are generated
without MKI).
Notes:

The device only initiates the MKI size.

You can also configure MKI size in an IP Profile.
Web: Symmetric MKI
Negotiation
EMS: Enable Symmetric MKI
[EnableSymmetricMKI]
Enables symmetric MKI negotiation.

[0] Disable = (Default) The device includes the MKI in its 200
OK response according to the SRTPTxPacketMKISize
parameter (if set to 0, then it is not included; if set to any other
value, it is included with this value).

[1] Enable = The answer crypto line contains (or excludes) an
MKI value according to the selected crypto line in the offer. For
example, assume that the device receives an INVITE
containing the following two crypto lines in SDP:
a=crypto:2 AES_CM_128_HMAC_SHA1_80
inline:TAaxNnQt8/qLQMnDuG4vxYfWl6K7eBK/ufk04pR
4|2^31|1:1
a=crypto:3 AES_CM_128_HMAC_SHA1_80
inline:bnuYZnMxSfUiGitviWJZmzr7OF3AiRO0l5Vnh0k
H|2^31
The first crypto line includes the MKI parameter "1:1". In the
200 OK response, the device selects one of the crypto lines
(i.e., '2' or '3'). Typically, it selects the first line that supports
the crypto suite. If the device selects crypto line '2', it includes
the MKI parameter in its answer SDP, for example:
a=crypto:2 AES_CM_128_HMAC_SHA1_80
inline:R1VyA1xV/qwBjkEklu4kSJyl3wCtYeZLq1/QFux
w|2^31|1:1
If the device selects a crypto line that does not contain the MKI
parameter, then the MKI parameter is not included in the
crypto line in the SDP answer (even if the
SRTPTxPacketMKISize parameter is set to any value other
than 0).
Notes:

To enable symmetric MKI, the SRTPTxPacketMKISize
parameter must be set to any value other than 0.

You can also enable MKI negotiation per IP Profile.
Web/EMS: SRTP offered Suites
[SRTPofferedSuites]
Defines the offered crypto suites (cipher encryption algorithms)
for SRTP.

[0] = (Default) All available crypto suites.

[1] CIPHER SUITES AES CM 128 HMAC SHA1 80 = device
uses AES-CM encryption with a 128-bit key and HMAC-SHA1