Transcoding on SBCs and its capacity cost

See also

Sources

1. 1
   Active transcoding sessions on an AudioCodes Mediant Software SBC can be viewed with the CLI command show voip calls statistics sbc media.

   Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, monitoring note · Checked 2026-10-14
2. 2
   By default an AudioCodes Mediant Software SBC transcodes only when necessary, so calls whose legs share a coder are not transcoded.

   Transcoding Mode - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Transcoding Mode, first paragraph · Checked 2026-10-14
3. 3
   For coder transcoding, an AudioCodes Mediant Software SBC must have available DSP resources for both the inbound and the outbound leg.

   Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, prerequisites list · Checked 2026-10-14
4. 4
   AudioCodes Mediant Software SBC extension coders are appended below the original coders in the outbound SDP offer, raising the chance that media flows without transcoding.

   Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, Extension Coders paragraph · Checked 2026-10-14
5. 5
   On AudioCodes Mediant Software SBC, if one SIP entity's IP Profile forces transcoding, the device also forces transcoding toward the SIP entity it communicates with, regardless of that entity's IP Profile.

   Transcoding Mode - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Transcoding Mode, note on IP Profile Mediation Mode · Checked 2026-10-14
6. 6
   On AudioCodes Mediant Software SBC, the License Key's Transcoding Sessions value sets the maximum number of transcoding sessions.

   Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, prerequisites list · Checked 2026-10-14
7. 7
   An AudioCodes Media Transcoding Cluster can include up to eight hardware Media Components (MC).

   Overview of Media Transcoding Cluster - Mediant 9000 Series SBC User's Manual Version 7.6 · Overview of Media Transcoding Cluster · Checked 2026-10-14
8. 8
   AudioCodes Media Transcoding Cluster, which offloads transcoding to an external pool of DSP Media Components, is supported only on the Mediant 9080 SBC.

   Overview of Media Transcoding Cluster - Mediant 9000 Series SBC User's Manual Version 7.6 · Overview of Media Transcoding Cluster · Checked 2026-10-14
9. 9
   When Media Transcoding Cluster is enabled, the AudioCodes Mediant 9080 uses none of its internal DSP resources, and reaching the licensed transcoding capacity requires deploying enough Media Components.

   Overview of Media Transcoding Cluster - Mediant 9000 Series SBC User's Manual Version 7.6 · Overview of Media Transcoding Cluster · Checked 2026-10-14
10. 10
    During an HA switchover of an AudioCodes Mediant 9080 using Media Transcoding Cluster, existing transcoding sessions on the Media Components are maintained.

    Overview of Media Transcoding Cluster - Mediant 9000 Series SBC User's Manual Version 7.6 · Overview of Media Transcoding Cluster, high-availability paragraph · Checked 2026-10-14
11. 11
    If no incoming or outbound coder is permitted by the Allowed Audio Coders Group, the AudioCodes Mediant Software SBC rejects the call with SIP 488.

    Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, Allowed Audio Coders paragraph · Checked 2026-10-14
12. 12
    An AudioCodes Mediant Software SBC can transcode between different settings of the same coder, for example G.729 at 20 ms to G.729 at 30 ms.

    Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, opening paragraphs · Checked 2026-10-14
13. 13
    For transcoding on AudioCodes Mediant VE, the SBC Performance Profile must be set to Optimized for Transcoding.

    Coder Transcoding - Mediant Software (VE, CE and SE) SBC User's Manual Version 7.6 · Coder Transcoding, prerequisites list · Checked 2026-10-14
14. 14
    Cisco's PVDM data sheet lists low-to-low complexity transcoding performance of 6672 for the Catalyst C8300-2N2S-4T2X and 3336 for the C8300-1N1S-6T.

    Cisco Packet Voice Digital Signal Processor Modules (PVDMs) for Cisco Unified Communications Solutions Data Sheet · Table 6. Platform Performance for Transcoding, rows C8300-2N2S-4T2X and C8300-1N1S-6T · Checked 2026-10-14
15. 15
    On Cisco IOS XE, a dspfarm transcode profile requires dsp services dspfarm to be configured under the voice-card, and Cisco recommends a physical router with a DSP card.

    DSPFARM Profile Configurations - IOS-XE VoIP - Cisco DevNet · DSPFARM Profile Configurations, prerequisites and recommendation notes · Checked 2026-10-14
16. 16
    Cisco's PVDM data sheet lists low-to-low complexity transcoding performance of 768 for the ISR 4321, 1024 for the ISR 4331, 3336 for the ISR 4451 and 6160 for the ISR 4461.

    Cisco Packet Voice Digital Signal Processor Modules (PVDMs) for Cisco Unified Communications Solutions Data Sheet · Table 6. Platform Performance for Transcoding, rows 4321, 4331, 4451, 4461 · Checked 2026-10-14
17. 17
    Cisco's PVDM data sheet classes G.711 as a low-complexity codec for DSP sizing.

    Cisco Packet Voice Digital Signal Processor Modules (PVDMs) for Cisco Unified Communications Solutions Data Sheet · Table 2. Voice, Fax, and Modem Codec Support on PVDMs, row G.711 · Checked 2026-10-14
18. 18
    Cisco's PVDM data sheet classes G.729a and G.722 as medium-complexity codecs, and G.729 (non-annex A) and iLBC as high-complexity codecs.

    Cisco Packet Voice Digital Signal Processor Modules (PVDMs) for Cisco Unified Communications Solutions Data Sheet · Table 2. Voice, Fax, and Modem Codec Support on PVDMs, rows G.729a, G.722, G.729, iLBC · Checked 2026-10-14
19. 19
    Cisco PVDM DSP modules support universal transcoding, meaning conversion from any supported codec to any other supported codec.

    Cisco Packet Voice Digital Signal Processor Modules (PVDMs) for Cisco Unified Communications Solutions Data Sheet · Features and benefits, Universal transcoding bullet · Checked 2026-10-14
20. 20
    Cisco's PVDM channel-density table lists the PVDM4-256 with the values 256, 192 and 128, falling as codec complexity rises.

    Cisco Packet Voice Digital Signal Processor Modules (PVDMs) for Cisco Unified Communications Solutions Data Sheet · Table 3. Channel Densities of PVDM4, NIM-PVDM-X and SM-X-PVDM Modules, row PVDM4-256 · Checked 2026-10-14
21. 21
    The Acme Packet 1100 supports a maximum of one DSP transcoding module.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources, maximum DSP modules per platform list · Checked 2026-10-14
22. 22
    The Acme Packet 3900 supports a maximum of 5 DSP transcoding modules.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources, maximum DSP modules per platform list · Checked 2026-10-14
23. 23
    The Acme Packet 4600 supports a maximum of 12 DSP transcoding modules.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources, maximum DSP modules per platform list · Checked 2026-10-14
24. 24
    The Acme Packet 4900 supports a maximum of 8 DSP transcoding modules.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources, maximum DSP modules per platform list (Acme Packet 3950/4900 line) · Checked 2026-10-14
25. 25
    The Acme Packet 6300 and 6350 platforms support a maximum of 48 DSP modules per system, with one or two transcoding units (TCUs) of 24 DSPs each.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources, maximum DSP modules per platform list · Checked 2026-10-14
26. 26
    On Oracle Enterprise SBC, setting the transcoding capacity value to 0 makes the SBC treat transcoding capacity as unlimited, while a value greater than zero is treated as the maximum licensed capacity.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Transcoding Resources, licensing and capacity settings paragraph · Checked 2026-10-14
27. 27
    Changes to Oracle Enterprise SBC vSBC core allocation, including transcoding cores, take effect only after a reboot.

    Configuring The Oracle Enterprise Session Border Controller as a Virtual Machine (VM) (ECZ8.1.0 Configuration Guide) · Configuring The Oracle Enterprise Session Border Controller as a Virtual Machine, core configuration paragraph · Checked 2026-10-14
28. 28
    Oracle Enterprise SBC verify-config checks that forwarding plus DoS plus transcoding cores do not exceed the number of physical cores.

    Configuring The Oracle Enterprise Session Border Controller as a Virtual Machine (VM) (ECZ8.1.0 Configuration Guide) · Configuring The Oracle Enterprise Session Border Controller as a Virtual Machine, core configuration paragraph · Checked 2026-10-14
29. 29
    In Oracle Enterprise SBC release E-CZ7.4.0, G.729 transcoding required a licence (for royalty reasons) installed in groups of 25 sessions.

    Software-based transcoding (Oracle Enterprise Session Border Controller ECZ7.4.0 Configuration Guide) · Software-based transcoding, G.729 licensing paragraph · Checked 2026-10-14
30. 30
    In Oracle Enterprise SBC release E-CZ7.4.0, software-based transcoding capacity was limited to 100 sessions.

    Software-based transcoding (Oracle Enterprise Session Border Controller ECZ7.4.0 Configuration Guide) · Software-based transcoding · Checked 2026-10-14
31. 31
    In Oracle Enterprise SBC release E-CZ7.4.0, software-only transcoding did not support T.38 fax interworking, in-band DTMF detection or generation, QoS marking, or IPv4-IPv6 interworking for transcoded calls.

    Software-based transcoding (Oracle Enterprise Session Border Controller ECZ7.4.0 Configuration Guide) · Software-based transcoding, list of unsupported features · Checked 2026-10-14
32. 32
    The Oracle Enterprise SBC G.729 transcoding utilization alarm is raised when utilization rises above 95% of licensed capacity and clears when it falls below 80%.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Software-based transcoding alarms and traps · Checked 2026-10-14
33. 33
    In a redundant Oracle Enterprise SBC vSBC pair using PCIe transcoding cards, both systems must have the same population of PCIe cards and installed DSPs.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · PCIe Transcoding Accelerator Cards · Checked 2026-10-14
34. 34
    On Oracle Enterprise SBC hardware platforms, transcoding capacity depends on the codecs in use and the number of transcoding (DSP) modules installed, and scales linearly with each added module.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources, opening paragraph · Checked 2026-10-14
35. 35
    An Oracle Enterprise SBC deployment may use only one of the three transcoding resource types per system.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Transcoding Resources (opening section) · Checked 2026-10-14
36. 36
    If a PCIe transcoding accelerator card fails after an Oracle Enterprise SBC vSBC starts, the system raises an alarm and reboots.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · PCIe Transcoding Accelerator Cards · Checked 2026-10-14
37. 37
    On an Oracle Enterprise SBC vSBC, provisioning any transcoding cores for software-based transcoding is incompatible with using a PCIe transcoding accelerator card.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · PCIe Transcoding Accelerator Cards · Checked 2026-10-14
38. 38
    Software-based transcoding on Oracle Enterprise SBC virtual platforms is supported only on Intel CPU infrastructure.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Software-based transcoding, opening paragraph · Checked 2026-10-14
39. 39
    Oracle Enterprise SBC invokes software-based transcoding when codec policies are configured but no transcoding hardware is recognized in the system.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Software-based transcoding, opening paragraph · Checked 2026-10-14
40. 40
    Oracle Enterprise SBC transcoding resources come in three forms: hardware-based transcoding on physical platforms, software-based transcoding on vSBC platforms, and Artesyn PCIe card-based transcoding on vSBC platforms.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Transcoding Resources (opening section), numbered list of resource forms · Checked 2026-10-14
41. 41
    Oracle Enterprise SBC also raises transcoding capacity traps at 95% (clearing at 80%) for AMR, AMR-WB, EVRC and EVRCB licensed-capacity usage.

    Transcoding Capacity Traps (Oracle Enterprise Session Border Controller Configuration Guide, release 9.2.0) · Transcoding Capacity Traps, trap table rows apSysXCodeAMRCapacity, apSysXCodeAMRWBCapacity, apSysXCodeEVRCCapacity, apSysXCodeEVRCBCapacity · Checked 2026-10-14
42. 42
    Oracle Enterprise SBC sends apSysMgmtGroupTrap when total DSP usage (apSysXCodeCapacity) exceeds 95%, and sends apSysMgmtGroupClearTrap when usage falls back to 80%.

    Transcoding Capacity Traps (Oracle Enterprise Session Border Controller Configuration Guide, release 9.2.0) · Transcoding Capacity Traps, trap table row apSysXCodeCapacity (OID 1.3.6.1.4.1.9148.3.2.1.1.34) · Checked 2026-10-14
43. 43
    Oracle Enterprise SBC vSBCs can transcode only a subset of the codecs transcodable on physical platforms, and the release notes list which ones.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources > Transcodable Codecs · Checked 2026-10-14
44. 44
    The maximum supported packetization time (ptime) for transcoding on the Oracle Enterprise SBC vSBC is 60 ms; longer ptimes apply only on physical platforms.

    Transcoding Resources (Oracle Enterprise Session Border Controller Configuration Guide, release 9.3.0) · Hardware-based Transcoding Resources > Transcodable Codecs, note preceding the codec table · Checked 2026-10-14
45. 45
    On an Oracle Enterprise SBC virtual machine, the system-config parameter transcoding-cores sets how many cores are allocated to transcoding and defaults to 0.

    Configuring The Oracle Enterprise Session Border Controller as a Virtual Machine (VM) (ECZ8.1.0 Configuration Guide) · Configuring The Oracle Enterprise Session Border Controller as a Virtual Machine, system-config parameter transcoding-cores · Checked 2026-10-14
46. 46
    RFC 5369 advises that an offerer avoid invoking a transcoder until it confirms the answerer lacks the needed capabilities, to avoid inserting two transcoders unnecessarily.

    RFC 5369: Framework for Transcoding with the Session Initiation Protocol (SIP) · Section 2 (Discovery of the Need for Transcoding Services) · Checked 2026-10-14
47. 47
    RFC 5369, an Informational RFC, describes two models for invoking a SIP transcoder: third-party call control and a two-party conference bridge.

    RFC 5369: Framework for Transcoding with the Session Initiation Protocol (SIP) · Sections 3.1 and 3.2 · Checked 2026-10-14
48. 48
    Microsoft Teams Direct Routing supports SILK, G.711, G.722, G.729 and AMR-WB (AMR-WB in non-bypass calls only) between Teams and the SBC.

    Plan Direct Routing · Plan Direct Routing, section Supported codecs (ms.date 2026-09-10) · Checked 2026-10-14
49. 49
    An SBC connecting Teams Direct Routing to a trunk or PBX leg that offers no codec from the Teams list (SILK, G.711, G.722, G.729, AMR-WB) must transcode those calls and so consume transcoding capacity.inferred

    Plan Direct Routing · Plan Direct Routing, section Supported codecs · Checked 2026-10-14

Documents

Cite this page

WarmTransfer. (2026, October 14). Transcoding on SBCs and its capacity cost. WarmTransfer. https://warmtransfer.net/knowledge/transcoding-on-sbcs

@misc{warmtransfer-transcoding-on-sbcs,
  title  = {Transcoding on SBCs and its capacity cost},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/transcoding-on-sbcs},
  note   = {Verified 2026-10-14}
}