AudioCodes Mediant 1000B - Page 450

User's Manual 450 Document #: LTRT-27055
Mediant 1000B Gateway & E-SBC
Parameter Description
erence]
SDP to offer groups of network addresses (IPv4 and IPv6) and the IP
address version preference to establish the media stream. The IP
address is indicated in the "c=" field (Connection) of the SDP.
 [0] Only IPv4 = (Default) SDP offer includes only IPv4 media IP
addresses.
 [1] Only IPv6 = SDP offer includes only IPv6 media IP addresses.
 [2] Prefer IPv4 = SDP offer includes IPv4 and IPv6 media IP
addresses, but the first (preferred) media is IPv4.
 [3] Prefer IPv6 = SDP offer includes IPv4 and IPv6 media IP
addresses, but the first (preferred) media is IPv6.
To indicate ANAT support, the device uses the SIP Allow header or
to enforce ANAT it uses the Require header:
Require: sdp-anat
In the outgoing SDP, each 'm=' field is associated with an ANAT
group. This is done using the 'a=mid:' and 'a=group:ANAT' fields.
Each 'm=' field appears under a unique 'a=mid:' number, for
example:
a=mid:1
m=audio 63288 RTP/AVP 0 8 18 101
c=IN IP6 3000::290:8fff:fe40:3e21
The 'a=group:ANAT' field shows the 'm=' fields belonging to it, using
the number of the 'a=mid:' field. In addition, the ANAT group with the
preferred 'm=' fields appears first. For example, the preferred group
includes 'm=' fields under 'a=mid:1' and 'a=mid3':
a=group:ANAT 1 3
a=group:ANAT 2 4
If you configure the parameter to a "prefer" option, the outgoing SDP
offer contains two medias which are the same except for the "c="
field. The first media is the preferred address type (and this type is
also on the session level "c=" field), while the second media has its
"c=" field with the other address type. Both medias are grouped by
ANAT. For example, if the incoming SDP contains two medias, one
secured and the other non-secured, the device sends the outgoing
SDP with four medias:
 Two secured medias grouped in the first ANAT group, one with
IPv4 and the other with IPv6. The first is the preferred type.
 Two non-secured medias grouped in the second ANAT group,
one with IPv4 and the other with IPv6. The first is the preferred
type.
Note:
 The parameter is applicable only when the device offers an SDP.
 The IP addressing version is determined according to the first
SDP "m=" field.
 The feature is applicable to any type of media (e.g., audio and
video) that has an IP address.
 The parameter is applicable to both Gateway and SBC calls.
 The corresponding global parameter is
MediaIPVersionPreference.
RTP Redundancy Depth
rtp-redundancy-depth
Enables the device to generate RFC 2198 redundant packets. This
can be used for packet loss where the missing information (audio)
can be reconstructed at the receiver's end from the redundant data