Reply comments on FCC non-IP call authentication inquiry

An interesting variety of reply comments were filed on the FCC’s non-IP call authentication inquiry. This article reviews these filings and recurring themes.

Recurring themes

  • Seven participants, including a joint filing, urged the Commission to phase out the non-IP extension and require providers that rely on non-IP to either transition to IP or deploy one or more of the non-IP SHAKEN methods.
    • They argue that the non-IP methods are fully standardized and reasonably available.
    • Out-of-Band has been used successfully in production networks by many providers.
    • Exchanging traffic over the public internet raises security and quality of service concerns.
  • Six participants are opposed to the standardized non-IP methods. Instead, they ask the Commission to encourage the IP transition.
    • Some also argued that the SIP Interconnection WG Report describes an option to exchange traffic over the public internet, which they argue may be suitable for some small providers.
  • Five participants called out large ILECs (Verizon, AT&T, Lumen, and Frontier) using large networks of non-IP TDM access tandem switches.
    • These commenters contend that these large ILECs have no apparent interest in transitioning to IP and will not do so until forced by regulatory changes.
    • This observation was raised by commenters on both sides of the non-IP standards issue.

Notable remarks

There were a few remarks that raised points not found in many other reply comments. We thought they are worth notice.

  • GCI Communications provided interesting comments from their perspective as a service provider in Alaska. They oppose a mandate for non-IP methods, especially if it requires deployment in 2023. (Some commenters had suggested this deadline in the first round of comments.)
  • NCTA and Aureon made an interesting suggestion that the Commission mandate that providers must exchange traffic in IP if the downstream provider uses IP.
    • NCTA suggested this mandate might apply to larger intermediates first, not small rural voice service providers.


There were 150 pages of reply comments in 14 submissions representing 19 entities (one submission was a joint filing).

Some of the following summaries are long! We decided to err on the side of completeness rather than leaving out important points that shouldn’t be missed.

If you’d like more information, you can click the filer’s name above each summary to read that organization’s filing.

We also summarized the first round of comments here.

ABA et al, the Associations

  • This is a joint filing by the American Bankers Association, ACA International, Credit Union National Association, Mortgage Bankers Association, National Association of Federally-Insured Credit Unions, and Student Loan Servicing Alliance.
  • Because of the availability of call authentication solutions for non-IP networks, the Associations respectfully request that the Commission terminate the STIR/SHAKEN exemption for non-IP networks by a date certain.
  • The presence of non-IP networks significantly contributes to the problem of illegal call spoofing by hindering the full deployment of STIR/SHAKEN.
  • As Chairwoman Rosenworcel said, the Commission should not just wait for this non-IP infrastructure to be updated and eligible for STIR/SHAKEN.
  • Requiring implementation of an alternative [non-IP SHAKEN] solution may incentivize providers to upgrade their networks to IP to avoid having to implement an alternative.

Alliance for Telecommunications Industry Solutions

  • The ATIS NIPCA and IP-NNI task forces addressed technical issues associated with call authentication. These groups identify but do not resolve business and policy issues.
  • NIPCA is developing a new technical report examining the viability of operationalizing these standards.
  • The IP-NNI is working on VoIP interconnection over the public internet.

Cloud Communications Alliance

  • The record provides substantial support for the Commission to terminate the non-IP network exemption and set a deadline for non-IP network operators to either convert to IP or implement an alternative solution.
  • Several smaller providers submitted comments explaining that they invested in STIR/SHAKEN but continue to receive unsigned calls or call authentication on their outgoing calls is lost due to TDM networks. This has competitive consequences.
    • Unsigned calls are less likely to be answered and more likely to be blocked or mislabeled.
  • The Commission should phase out the non-IP exemption and require non-IP providers to either upgrade their networks to IP or adopt one of the commercially available solutions.


  • The Commission should carefully consider security risks in non-IP call authentication methods.
  • Out-of-Band could allow bad actors to present fraudulent calls as legitimate calls.
  • Out-of-Band may not provide adequate protection for customer proprietary network information (CNPI), including time of calls and frequency.
  • Non-IP In-Band requires providers to remove call-identifying information, which could have a detrimental impact on service and customer understanding of caller ID information.
  • The proposed non-IP solutions do not meet the TRACED Act and Commission requirements.
  • Instead, the Commission should continue to promote the transition to IP networks.

GCI Communications Corp.

  • GCI runs wireline and wireless networks, and IP and non-IP networks in Alaska. It serves as an ILEC, CLEC, and IXC in various locations. It is transitioning its networks to IP.
  • There aren’t many switching engineers in Alaska trained to work on TDM networks. Adding the work required to implement a non-IP call authentication method would strain this limited resource.
  • The Commission should encourage the move to all-IP networks rather than place new requirements on non-IP network operators.
  • The proposed non-IP standards would require extraordinary measures by Alaska providers and a 2023 deadline is unrealistic.


  • Traffic exchange between TDM and IP is not simply a result of smaller providers that have not upgraded their networks but is in some cases a business decision by some of the largest LECs not to exchange traffic in IP.
  • Major voice service providers presumably have the resources to expedite IP transition on their networks and should be encouraged to do so.
  • Requiring smaller non-IP providers to adopt a non-IP call authentication solution would discourage their transition to IP and divert resources that could be used to upgrade their networks.
  • The Commission should monitor the industry’s progress on IP interconnection and insist that the SIP Interconnection WG facilitate interconnection agreements per solutions and expectations in the WG report.

Iowa Network Services, Inc. d/b/a Aureon Network Services

  • The FCC should mandate IP interconnection with smaller carriers.
  • The Commission should ensure that small carriers are not saddled with costs to transport traffic to distant points of interconnection to implement STIR/SHAKEN.
  • Aureon supports Out-of-Band.
    • IP transition is dependent on the cooperation of LECs and IXCs and may not be completed as soon as hoped.
    • Effective Out-of-Band solutions implementing finalized industry standards are readily available and currently deployed by many different carriers.
  • Aureon will have to exchange traffic with IXCs over TDM until these IXCs establish IP interconnections. Therefore, Aureon will use Out-of-Band as an interim solution.
  • It is impossible to know how long the IP transition will take. Thus, there must be a solution option outside of IP networks.
    • The current availability, effectiveness, and viability of Out-of-Band provide a further reason not to delay.
  • The Commission should:
    • Require large IXCs and ILECs to send calls to rural carriers using IP,
    • Ensure timely implementation of an interim Out-of-Band solution in non-IP networks,
    • Adopt NTCA’s proposed rule for IP interconnections at current POIs rather than distant POIs to prevent digital deployment discrimination.

NCTA—The Internet & Television Association

  • The Commission should not require providers to implement non-IP call authentication solutions and should instead prioritize the IP transition.
  • Non-IP STIR/SHAKEN methods are not fully completed, deployable or viable.
  • Requiring non-IP solutions would delay the IP transition.
  • One of the major barriers to the IP transition is the continued refusal by the largest ILECs to exchange traffic in IP.
    • These large ILECs are unlikely to transition to IP in the absence of regulatory action.
  • The Commission should require large ILECs to exchange traffic in IP when the next network in the call path is IP-based.
    • The Commission should consider whether to limit this mandate to interconnections between major providers before separately considering solutions for traffic that originates or terminates on rural providers’ networks.
  • The Commission should not adopt NTCA’s network edge proposal, which would lock in the TDM interconnection regime and apply it to IP voice traffic.
    • Instead, the Commission should consider proposals raised in the SIP Interconnection WG report.

NTCA—The Rural Broadband Association

  • The non-IP gap in the STIR/SHAKEN ecosystem is considerable. Millions of consumers subscribe to an IP-enabled voice service provider that can implement STIR/SHAKEN but is prevented STIR/SHAKEN information end to end due to non-IP facilities in the call path owned by other operators.
  • The Commission can mandate that those with non-IP facilities use two developed and reasonably available solutions or further the IP transition. The latter would negate the need for the former.
  • Complaints about the costs of non-IP methods are specious and belied by the facts. The Commission should not fall for these obvious stalling tactics.
  • Non-IP call authentication methods have fully developed standards and are reasonably available.
  • The Commission should not accept a tradeoff in which larger national and regional operators foist the cost of exchanging calls onto small rural customer bases.
    • A network edge rule would establish a simple default apportionment of costs among operators: Any party exchanging traffic with an RLEC would be financially responsible to interconnect with an RLEC in IP at the currently established interconnection point.


  • STIR/SHAKEN is an essential part of combating illegal scam calls.
    • For it to be effective, calls should be signed by an originating service provider with a direct, authenticated relationship with the caller and a verified association with the calling number. This enables full attestation. This call authentication must survive transit intact to the terminating service provider. It cannot be lost at a non-IP barrier.
  • Despite a steady increase in SHAKEN authorized providers who are signing their calls, the percentage of signed calls received at termination remains stuck at around 24%. This is because of non-IP tandem switches scattered throughout the PSTN.
  • Out-of-Band is highly scalable and secure. It can be used at any point along the call path where needed. Out-of-Band components are available today.
  • Actual IP transition examples are available in the public record today.
    • Aureon has been working on an IP transition since 2015.
    • Verizon filed a petition that noted that a “rip-and-replace” IP transition for their international gateway network would take multiple years and cost in the eight-figure range.
    • Both Aureon and Verizon noted that IP conversion is dependent on exchange partners agreeing to convert also and exchange traffic in IP.
  • Exchanging traffic across the public internet raises concerns about security, reliability, and quality of service.
    • We have heard from small providers who are concerned about using public internet and the risk of delivering an inferior service. They view this as unfair and anti-competitive.

USTelecom—The Broadband Association

  • Non-IP call authentication methods are not ready. They pose security risks that may not be overcome. Out-of-Band would require the development of a governance structure and several industry databases.
  • New IP-based solutions, described in the SIP Interconnection WG Report, show promise. Concerns about the quality of service are misguided.
  • IP transition mandates are not necessary.
  • The Commission should reduce or eliminate the technology transition service discontinuance rules to ease the IP transition.
  • The Commission may use TRACED Act Section 4 authority to regulate originating and terminating voice service providers but not interconnection providers.


  • Given the increased momentum toward an IP-based voice ecosystem, it would be premature, unnecessary, and wasteful to require non-IP call authentication methods. Instead, the Commission should implement policies that encourage and accelerate the IP transition.
  • Non-IP methods present major security, governance, and other challenges.
  • The Commission should not and cannot mandate IP interconnection.
  • The Commission should promote the IP transition by relieving ILECs of outdated legacy service obligations and by streamlining service discontinuance rules and processes.
  • The SIP Interconnection WG Report includes an option to exchange traffic over an encrypted connection on an existing internet transit service. The options were published by ATIS last month.
    • Each provider must select the most economical and appropriate solution based on its circumstances.

Wabash Communications

  • Wabash was one of TransNexus’s first live-production recipients of TDM SHAKEN three years ago and has proudly been authenticating and verifying PSTN TDM calls free from trouble or issue since inception.
  • The industry can debate SHAKEN security issues forever. Security issues will be ongoing for as long as bad actors exist and the ecosystem is performing security. IP-SHAKEN has already set a precedent for this and is proof that further development of SHAKEN while in live production is highly effective.
  • The FCC should not be persuaded that a new governance authority must be created.
    • Additional SHAKEN administrative issues should not stand in the way of removing existing extension deadlines.
    • Wabash has served on the STI-GA board since its founding and can attest that the STI-GA has consistently taken on additional responsibilities related to SHAKEN.
  • If IP-SEC is so good why aren’t large carriers using it themselves?
    • We’ve heard large carrier representatives say they tried it but it didn’t work very well.
  • Wabash strongly supports phasing out the non-IP STIR/SHAKEN implementation extension and recommends the FCC require all providers to either convert to IP or use one or more of the standardized non-IP SHAKEN methods to enable the originating service provider’s call authentication information to survive transit to the terminating service provider.

WTA—Advocates for Rural Broadband

  • WTA supports the termination of the continuing extension for STIR/SHAKEN compliance by non-IP networks because the Out-of-Band and Non-IP In-Band standards have been fully developed and finalized and the underlying equipment and software are reasonably available on the commercial market.
  • The best approach is to accelerate the IP transition. However, if an all-IP network is not possible at this time, WTA believes that the Out-of-Band standard is a feasible and effective alternative.
    • The Out-of-Band standard was published over 15 months ago, has not been revised or otherwise changed since that time, and there does not appear to be any proceeding opened to consider potential revisions.
    • Out-of-Band is fully developed, finalized, and in actual use.
  • The ATIS NIPCA task force addressed and resolved potential security issues.
    • The document Verizon uses as evidence of security concerns comes very late in the process, dated November 30, 2022—over 15 months after publication of the Out-of-Band standard and over a month after the release of the Commission’s Notice of Inquiry.
  • Out-of-Band does not make it likely for bad actors to hijack legitimate STIR/SHAKEN credentials.
    • Any entity accessing the STI-CPS must be an authorized service provider and have a valid STI certificate.
    • CPS requests must provide both the calling and called number.
    • PASSporTs are held in the STI-CPS for a brief period, 5-15 seconds, which means a bad actor does not have time to overwhelm the network with multiple attempts to guess the calling and called number before being discovered and locked out.
    • Because CPS requests must be signed with a valid STI certificate, the bad actor would be identified.
  • PASSporTs in the CPS contain no sensitive information other than the calling and called numbers that are essential for STIR/SHAKEN verification. These numbers are used for a specific and lawful robocall deterrence reason and not for any activities subject to CNPI protections and restrictions.
  • The STI Interconnection WG Report is an eleventh-hour attempt to enable Verizon, AT&T, Lumen, and Frontier to evade the problems created by their TDM access tandem switches.
    • This report is not a consensus agreement. It is opposed by many providers of small volumes of voice traffic.
    • Its primary impact will be to delay STIR/SHAKEN implementation.
    • The solutions in the report have been available for several years while the ATIS non-IP standards were being developed, but are only now being raised at the last minute to avoid addressing the problems caused by TDM access tandems.
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