Comcast Business SIP trunking

See also

Sources

1. 1
   Each Service Location can support up to 10,000 telephone numbers.

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, telephone numbers paragraph · Checked 2026-10-14
2. 2
   The marketed 800-session ceiling is reachable only on fiber access. A coax-delivered site is capped at 46 concurrent sessions under the PSA, so a capacity design above 46 should assume fiber.inferred

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, SIP Trunk Service capacity paragraph · Checked 2026-10-14
3. 3
   The optional Bursting feature raises the CCS by up to 20% during periods of high calling volume, for an additional monthly fee.

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, SIP Trunk Service optional features (Bursting) · Checked 2026-10-14
4. 4
   For SIP Trunk Service, Comcast provides the connection to its network over either a cable modem or a fiber connection.

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1 (Service Description and Technical Specifications), SIP Trunk Service description · Checked 2026-10-14
5. 5
   Call Forward Not Reachable (CFNR) routes calls to a specific phone number that the customer supplies during the technical interview.

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, features (Call Forward Not Reachable) · Checked 2026-10-14
6. 6
   To use the SIP Trunk Service, the customer must use a Comcast-issued modem and a Comcast-issued Enterprise SIP Gateway (ESG).

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 9.1(b) · Checked 2026-10-14
7. 7
   The trunk Services are intended for commercial, non-residential use only.

   Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 7.2 · Checked 2026-10-14
8. 8
   In Cisco's July 2016 Comcast note, the primary CUBE in HA redundancy mode did not take back the active role after a reboot or network outage.

   Comcast SIP Trunking: Cisco Unified Communications Manager 10.5.2 with Cisco Unified Border Element (CUBE 11.5.0) on ISR4321/K9 using SIP · p. 8 (caveats) · Checked 2026-10-14
9. 9
   The Comcast interop CUBE configurations set 'asserted-id pai' and 'privacy pstn' under voice service voip.

   Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 9 (global configuration) · Checked 2026-10-14
10. 10
    In Cisco's Comcast interop configurations, CUBE presents the full ten-digit DID to CUCM for inbound PSTN calls, and CUCM uses the last four digits as significant digits.

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 12 (inbound dial-peer description); p. 38 (CUCM trunk significant digits) · Checked 2026-10-14
11. 11
    The Comcast interop CUCM SIP profile set the OPTIONS ping interval to 60 seconds for in-service trunks and 120 seconds for out-of-service trunks.

    Comcast SIP Trunking: Cisco Unified Communications Manager 10.5.2 with Cisco Unified Border Element (CUBE 11.5.0) on ISR4321/K9 using SIP · p. 36 (SIP profile, OPTIONS ping settings) · Checked 2026-10-14
12. 12
    A customer-owned SBC such as CUBE sits on the LAN side of the Comcast ESG as the customer's own demarcation point. It does not replace the Comcast edge device.inferred

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 5 (CUBE demarcation role) and p. 7 (Comcast(Adtran) ESG provided and managed by Comcast) · Checked 2026-10-14
13. 13
    Comcast markets SIP Trunks with a dedicated 100 Mbps port and voice bandwidth, plus managed QoS.

    SIP Trunks | Comcast Business · Section 'SIP essentials you need' · Checked 2026-10-14
14. 14
    For the SIP service, Comcast stores site addresses for 911 purposes for up to 3,000 telephone numbers. The PRI limit is 1,000.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, 911 site address paragraph · Checked 2026-10-14
15. 15
    The customer alone is responsible for configuring its multi-line telephone system so that each number and extension sends the correct location information for 911.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 8.2 · Checked 2026-10-14
16. 16
    The customer must contact Comcast at least 36 hours before moving the Service so the 911 location can be updated.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 8.2 · Checked 2026-10-14
17. 17
    The customer may optionally designate up to 1,000 locations for E911 identification. Comcast sends email notifications when a 911 call is made unless the customer opts out.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 8.9 (including 8.9(d)) · Checked 2026-10-14
18. 18
    Comcast's enterprise SIP Trunks page names no certified IP-PBX models and no edge device model.

    Enterprise SIP Trunks | Comcast Business · Whole page (absence observed across both renderings) · Checked 2026-10-14
19. 19
    Comcast's enterprise SIP Trunks page markets the service as scalable to 800 concurrent call sessions.

    Enterprise SIP Trunks | Comcast Business · Product overview · Checked 2026-10-14
20. 20
    Comcast's SIP Trunks page says equipment, taxes and fees are extra and subject to change, and a minimum term agreement is required.

    SIP Trunks | Comcast Business · Footer disclaimer · Checked 2026-10-14
21. 21
    In Cisco's 2016 and 2018 Comcast interop tests, the Comcast-side edge device was a Comcast (Adtran) ESG running firmware R11.4.3.V, provided and managed by Comcast.

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 7 (tested components table) · Checked 2026-10-14
22. 22
    The ESG is Comcast Equipment: Comcast keeps ownership and management responsibility for it, and it may be used only to deliver the Service.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 9.1 and Schedule A-1 (Comcast Equipment paragraph) · Checked 2026-10-14
23. 23
    Under the Fail-Over feature, a call is routed to another trunk group when one trunk group is busy.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, SIP Trunk Service features (Fail-Over) · Checked 2026-10-14
24. 24
    Cisco's 2016 Comcast interop note lists G.711 fax pass-through as a supported feature over the Comcast SIP trunk.disputed

    Comcast SIP Trunking: Cisco Unified Communications Manager 11.0.1 with Cisco Unified Border Element (CUBE 11.5.0) on ISR 4321 · p. 7 (features supported); p. 8 (fax protocol pass-through g711ulaw) · Checked 2026-10-14
25. 25
    Cisco's 2018 Comcast interop note states that Comcast does not support fax with its SIP service.disputed

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 7 (features / caveats) · Checked 2026-10-14
26. 26
    Field pattern: in a 2024 community thread, a FreePBX customer who had an 'EDI' installed ahead of SIP trunk delivery asked for preconfiguration settings. Comcast staff sent them to a phone line to reach 'Orion' support and posted no technical settings publicly.field report

    SIP Preconfiguration question · Original post (btwaukegan) and reply by Comcast_Sara · Checked 2026-10-14
27. 27
    In Cisco's Comcast interop tests, G.711 mu-law was the preferred and tested codec, with G.729 configured as the second preference.

    Comcast SIP Trunking: Cisco Unified Communications Manager 10.5.2 with Cisco Unified Border Element (CUBE 11.5.0) on ISR4321/K9 using SIP · p. 11 (voice class codec) · Checked 2026-10-14
28. 28
    Cisco tested its Comcast interop configurations against Comcast's generic SIP trunking test methodology. The scope covered basic calls, DTMF, MOH, transfers, call forward, conferences and Unity Connection interop.

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 5 (introduction / testing scope) · Checked 2026-10-14
29. 29
    The service is available only within Comcast's footprint, and installation is limited to the host Service Location. No technician is dispatched to satellite locations.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, installation paragraph · Checked 2026-10-14
30. 30
    Cisco's July 2016 Comcast interop note tested CUCM 10.5.2 with CUBE 11.5.0 on an ISR4321/K9 running IOS-XE 3.17.1 (15.6(1)S1).

    Comcast SIP Trunking: Cisco Unified Communications Manager 10.5.2 with Cisco Unified Border Element (CUBE 11.5.0) on ISR4321/K9 using SIP · Cover and pp. 1-2; p. 7 (tested components) · Checked 2026-10-14
31. 31
    Cisco's May 4, 2016 Comcast interop note tested CUCM 11.0.1 with CUBE 11.5.0 on an ISR 4321 running IOS-XE 3.17.0 (15.6(1)S).

    Comcast SIP Trunking: Cisco Unified Communications Manager 11.0.1 with Cisco Unified Border Element (CUBE 11.5.0) on ISR 4321 · pp. 1-2 (title and date); p. 6 (tested components) · Checked 2026-10-14
32. 32
    Cisco's 2018 Comcast interop note (dated July 26, 2018) tested CUCM 12.0.1 and Unity Connection 12.0.1 with CUBE 12.0 on an ISR 4321/K9 running IOS-XE 16.06.02.

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 2 (date); p. 5 and p. 7 (tested components) · Checked 2026-10-14
33. 33
    To prevent fraud, Comcast does not offer direct dialing to a listed set of countries, such as Algeria, Morocco, Papua New Guinea, Senegal and Zimbabwe. Operator-assisted calls to them may be available for an extra fee.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 7.3 · Checked 2026-10-14
34. 34
    In the Cisco interop configurations the CUBE-to-ESG trunk is addressed by fixed IP with a non-secure CUCM trunk profile and no digest credentials. This suggests IP-based peering toward the ESG in those tests.inferred

    Comcast SIP Trunking: Cisco Unified Communications Manager 10.5.2 with Cisco Unified Border Element (CUBE 11.5.0) on ISR4321/K9 using SIP · p. 32 (security profile 'Non Secure SIP Trunk Profile'); p. 22 (sip-server and keepalive target) · Checked 2026-10-14
35. 35
    In Cisco's Comcast interop tests, 911 calls were routed internally in the Comcast lab, so the notes do not show end-to-end E911 delivery to a PSAP.

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 7 (notes) · Checked 2026-10-14
36. 36
    The trunk SLA's maintenance window is Monday to Friday, 8:00 pm to 6:00 am Eastern, and scheduled maintenance is excluded from credits.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-2, exclusions and maintenance · Checked 2026-10-14
37. 37
    Comcast's SIP Trunks product page markets capacity as 6 to 800 trunks.

    SIP Trunks | Comcast Business · Comparison table and 'Flexibility' section · Checked 2026-10-14
38. 38
    On a coax cable connection, the SIP Trunking Service supports up to 46 concurrent call sessions.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, SIP Trunk Service capacity paragraph · Checked 2026-10-14
39. 39
    On a fiber connection, the SIP Trunking Service supports up to 800 concurrent call sessions.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, SIP Trunk Service capacity paragraph · Checked 2026-10-14
40. 40
    The SIP Trunking Service requires a minimum of 6 concurrent call sessions (CCS).

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, SIP Trunk Service capacity paragraph · Checked 2026-10-14
41. 41
    Comcast does not provide battery backup for the trunk equipment. If power to the ESG, PBX or handsets fails without backup, calling, including 911, may fail.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Sec. 8.10 ('Recommended Battery Back-Up is NOT Included') · Checked 2026-10-14
42. 42
    The customer may bring or port phone numbers from another carrier to Comcast, or Comcast can provide new numbers.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, telephone numbers and porting paragraph · Checked 2026-10-14
43. 43
    The customer is solely responsible for the PBX and for any customer-provided equipment connected to the ESG, including providing, configuring and maintaining working PBX equipment and handsets.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1 (SIP Trunk Service, ESG paragraph); Sec. 9.3 · Checked 2026-10-14
44. 44
    Comcast's SIP Trunks page warns that calling, including calls to 911, may be unavailable during a power outage or network issue.

    SIP Trunks | Comcast Business · Footer disclaimer · Checked 2026-10-14
45. 45
    The PSA prohibits using the Services for auto-dialing, robocalling, continuous call forwarding, telemarketing (including charitable and political) and fax or voicemail blasting. It also forbids misleading caller ID.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Secs. 6.1, 6.2 and 6.3 · Checked 2026-10-14
46. 46
    Comcast's Trunk Services Product-Specific Attachment defines its Services as PRI Trunk Services and SIP Trunk Services, so a single contract attachment governs both trunk types.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Article 1 (Definitions), definition of 'Service(s)' · Checked 2026-10-14
47. 47
    The Trunk Services PSA in Comcast's 2026 enterprise terms library is Version 1.7. Its text carries no effective date.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Document footer 'Ver. 1.7'; URL path '2026 Terms Conditions Ent' · Checked 2026-10-14
48. 48
    Cisco's Comcast interop tests used and passed RFC 2833 DTMF relay (rtp-nte) in both directions, with telephony-event payload type 101 on CUCM.

    Comcast SIP Trunking: Cisco Unified Communications Manager 10.5.2 with Cisco Unified Border Element (CUBE 11.5.0) on ISR4321/K9 using SIP · p. 7 (supported features); p. 11 (dial-peers); p. 35 (SIP profile) · Checked 2026-10-14
49. 49
    Comcast's SIP Trunks product page lists a 'SIP gateway with Session Border Control' among the included capabilities, described as regulating and helping protect IP communications.

    SIP Trunks | Comcast Business · Section 'SIP essentials you need' / 'Enhanced capabilities' · Checked 2026-10-14
50. 50
    The customer must request an SLA credit within 30 days of the start of the Service Interruption. Credits under $1.00 are not issued unless the law requires it.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-2 · Checked 2026-10-14
51. 51
    SLA credits in a month cannot exceed 50% of the monthly recurring charge for the affected service, and credits are the customer's sole remedy for Service Interruptions.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-2 · Checked 2026-10-14
52. 52
    Under the trunk SLA, outages under 30 minutes earn no credit. Credits then scale from 1/8 of a day's charge for 30 minutes to under 3 hours up to one full day for 15 to 24 hours.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-2 (Service Level Agreement), credit table · Checked 2026-10-14
53. 53
    The Comcast PDF named 'SMB Trunk Service Level Agreement' is titled the PRI Trunk Service Level Agreement, covers PRI Trunk Services only and does not mention SIP.

    Comcast Business PRI Trunk Service Level Agreement · Title and introductory paragraph · Checked 2026-10-14
54. 54
    Cisco's 2016 Comcast interop notes record that T.38 fax is not supported by the service provider.

    Comcast SIP Trunking: Cisco Unified Communications Manager 11.0.1 with Cisco Unified Border Element (CUBE 11.5.0) on ISR 4321 · p. 7 (features not supported) · Checked 2026-10-14
55. 55
    Before delivery, Comcast holds one or more technical interviews with the customer, and number porting and CFNR targets are settled in them.

    Comcast Enterprise Services Product-Specific Attachment: Trunk Services (Ver. 1.7) · Schedule A-1, technical interview and porting paragraphs · Checked 2026-10-14
56. 56
    Cisco's Comcast interop notes record that caller ID is not updated on the PSTN side after attended or unattended transfer. This is attributed to CUBE modifying PAI/PPI headers (Cisco bug CSCuv04539).

    Comcast SIP Trunking: Cisco Unified Communications Manager 11.0.1 with Cisco Unified Border Element (CUBE 11.5.0) on ISR 4321 · p. 7 (caveats) · Checked 2026-10-14
57. 57
    Cisco's Comcast interop notes state that SIP trunks to the Comcast SBC should use UDP as the SIP transport.

    Comcast SIP Trunking (Cisco UCM 12.0.1 with Cisco UBE on ISR 4321/K9, IOS-XE 16.06.02) · p. 30 (CUCM SIP trunk security profile section) · Checked 2026-10-14
58. 58
    Comcast markets an Unreachable Destination continuity feature that reroutes calls to a designated 10-digit number at another site.

    SIP Trunks | Comcast Business · Section 'Continuity features to keep the phone lines open' · Checked 2026-10-14

Documents

Cite this page

WarmTransfer. (2026, October 14). Comcast Business SIP trunking. WarmTransfer. https://warmtransfer.net/knowledge/comcast-business-sip-trunking

@misc{warmtransfer-comcast-business-sip-trunking,
  title  = {Comcast Business SIP trunking},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/comcast-business-sip-trunking},
  note   = {Verified 2026-10-14}
}