June 1, 2020
VIA ELECTRONIC DELIVERY
Marlene H. Dortch, Secretary
Federal Communications Commission
445 12th Street, SW
Washington, DC 20554
Competitive Bidding Procedures and Certain Program Requirements for the Rural Digital Opportunity Fund Auction, AU Docket No. 20-34
Rural Digital Opportunity Fund, WC Docket No. 19-126
Connect America Fund, WC Docket No. 10-90
Dear Ms. Dortch:
On May 29, 2020, GeoLinks CEO Skyler Ditchfield, President and COO Ryan Adams and General Counsel and V.P. of Government Affairs and Education Melissa Slawson attended a telephone call Chairman Ajit Pai and Advisor Preston Wise.
During this call, GeoLinks expressed the importance of the Rural Digital Opportunity Fund (“RDOF”) auction and discussed the Company’s concerns regarding certain of the proposed rules set forth in the Draft Procedures Public Notice that, in the Company’s opinion, could lead to failures to perform or defaults if service providers are not adequately vetted. Specifically, GeoLinks expressed concern regarding allowing service providers with no operational history of providing Gigabit speeds to bid at the Gigabit Tier in the auction. GeoLinks explained that while some companies, like GeoLinks, have been successful at offering and delivering Gigabit+ speeds to customers throughout their service territory, this is the result of stringent equipment vetting and detailed network design, particularly in rural and remote areas.
As GeoLinks explained, without real-world operating experience providing Gigabit services to customers, GeoLinks is concerned that some companies may rely blindly on manufacturers’ specifications and data sheets when designing a proposed RDOF network plan (and when developing an RDOF bidding strategy). The possible result is companies defaulting on their RDOF obligations when RDOF funds end up not being sufficient to properly engineer and deploy the network necessary to offer Gigabit services.
GeoLinks explained that specific performance of individual equipment types is dependent on many factors including available spectrum, weather, topography, topology, the number of customers being served, oxygen absorption and, most importantly, engineering. GeoLinks emphasized that it is prepared for scenarios that can affect throughput and has extensive, successful experience engineering a Gigabit+ network across numerous types of terrain (spanning some of California’s most challenging topographies and topologies) utilizing various equipment types and accounting for potential equipment shortfalls. GeoLinks has also worked to develop relationships with equipment manufacturers to develop proprietary equipment offerings that offer higher throughputs and reduce the effects of various environmental conditions. However, GeoLinks fears that this is likely not the case for inexperienced providers hoping to provide Gigabit+ speeds to unserved rural areas.
To avoid network operators without experience offering Gigabit services from potentially “biting off more than they can chew” during the Auction, GeoLinks proposed that the Commission return to its original proposal to prohibit certain service providers who have not previously offered Gigabit services to customers (and have not reported doing so via their Form 477s) from being able to bid the Gigabit Tier during RDOF. In the alternative, GeoLinks strongly urged the Commission to ensure that the short-form vetting process is rigorous and relies on more than equipment manufacturers’ claims.
During the call, GeoLinks shared the question it received during its call with from the Rural Broadband Auction Task Force (“RBATF”) staff on May 27, 2020 regarding certain manufacturers’ claims that equipment may support Gigabit speeds under certain conditions. Specifically, RBATF staff asked GeoLinks to comment on the information set forth in Footnote 238 of the Public Notice. GeoLinks explained to Chairman Pai and Mr. Wise that while the claims made regarding throughput are technically attainable, in GeoLinks’ experience, real world throughput, even in a very clean environment, never comes close to as-advertised over-the-air (“OTA”) link rates. In fact, GeoLinks finds that, in general, the equipment it procures obtains about 1/3 to 1/2 the capacity of the manufacturer’s OTA rate in real world deployments with a 10% reduction for each additional client added. It is simply not realistic to expect full modulation on every link, especially with point-to-multipoint (“P2MP”) deployments or as additional customer connections are added to the same equipment.
GeoLinks shared the following information with Chairman Pai and Mr. Wise regarding the claims cited in Footnote 238 of the Public Notice:
According to the specifications sheet GeoLinks was able to locate, the equipment referenced in Footnote 238 does not have a sector capacity of 1.6 Gbps but instead 1.2 Gbps. While GeoLinks is unclear whether this is a typo or outdated information, this is sector capacity and not applicable to end user speed. To fully understand the capabilities of the Cambium cnMedusa (“450m”), one must look at the manufacturers’ specifications more closely. Cambium states that the 450m has a maximum data rate of 172 Mbps, and can utilize Multi User Multiple in Multiple Out (“MU-MIMO”) to stream data to up to seven client radios simultaneously for a total sector capacity of 1200 Mbps (172mbps x 7 clients). This means the maximum capacity per client is limited to 172mbps aggregate in perfect conditions. However, not all connected clients will meet “perfect conditions.”
According to Siklu’s specifications sheet for its MultiHaul P2MP product, maximum data rates, as advertised, are 2300 Mbps OTA and 1000 Mbps aggregate with a footnote stating that “actual throughput varies with traffic patterns.” An aggregate throughput of 1000 Mbps is not sufficient to meet the Commission’s 1000 Mbps/ 500 Mbps service tier.
In its Ex Parte filing from May 15, 2020, the Wireless Internet Service Providers Association (“WISPA”) states that JAB Wireless, Inc. is using equipment manufactured by IgniteNet that operates in the 57-71GHZ bands. GeoLinks has extensive experience working with IgniteNet and its executive team. Specifically, the Company worked with IgniteNet for over 3 years trying to get spectrum utilization in the upper 60 GHz and lower 70 GHz bands. In GeoLinks’ experience, and based on their own documentation, their equipment only supports use to 65 GHz, thus vastly limiting the broadcast distance. While IgniteNet claims 2.4 Gbps of sector capacity, its use of an 802.11ac based chipset makes it subject to differential in its OTA and TCP/IP throughput rates. In GeoLinks own internal testing, IgniteNet devices obtained a capacity of about 1/3 the layer 1 OTA link rate. The best GeoLinks was able to achieve was approximately 650 Mbps aggregate.
In GeoLinks’ experience, Ericsson’s data rates of 4.3 Gbps in a single one-way session is accurate with 800mhz of available spectrum. However, to the best of GeoLinks’ knowledge, Ericsson does not make this equipment commercially available today. Moreover, Footnote 238 notes that the speeds cited were achieved in a trial – not a real-world deployment scenario.
As noted in Footnote 238, Starry’s equipment uses an 802.11ac chipset. As discussed in detail below, 802.11ac chipsets only achieve actual end user speeds of about 1/3 of their OTA link rate capacity. Therefore, GeoLinks estimates actual capacity at a full 160 MHz channel is closer 566 Mbps. Thus, the claim of 6.9 Gpbs of sector capacity, while technically accurate, is not relevant to end user speed.
As exemplified by the above, there is a distinct difference between what certain equipment manufacturers claim to be capable of (and may be in laboratory-type settings) vs. what they are more likely capably of in real-world settings. GeoLinks asserts that the above information shows clearly why the Commission cannot rely on information provided by service providers wishing to bid the Gigabit tier what simply parrot the information provided from the manufacturer(s) whose equipment they plan to utilize, and which is also not applicable to end user speed (as discussed below). Instead, as emphasized during the call, if the Commission is to allow service providers with no experience providing Gigabit services to bid in the Gigabit tier, it must hold them to strict scrutiny regarding their network engineering plans.
During the call, Mr. Wise asked GeoLinks what information the Company suggested the Commission look to when undertaking its short-form review process to ensure it is robust. Similar to GeoLinks’ response to the same question posed by RBATF staff, GeoLinks emphasized the need for strong vetting procedures. In furtherance of the information offered during the call with Chairman Pai and Mr. Wise, GeoLinks asserts that the Commission consider the claimed capacities of client premises equipment (“CPEs”) offered by various equipment manufacturers in addition to actual aggregate TCP/IP capacity. Notably, CPE capacity is not discussed in Footnote 238, however GeoLinks believes that information regarding the speeds that can be supported by various manufacturers’ CPEs is a vital component to determining whether Gigabit+ services can be supported by a proposed network engineering plan.
GeoLinks asserts that client radio capacity needs to be a minimum of 1000 Mbps/ 500 Mbps true TCP/IP throughput in order to effectively ensure delivery of Gigabit service speeds. This is how all standardized and Commission testing is done. However, as discussed above, many manufacturers, such as Starry, utilize 802.11ac Chipsets. With adequate spectrum (160 MHz), 802.11ac chipsets are capable of OTA link rates of up to 1700 Mbps per client radio (layer 1 OTA rate) and can utilize MU-MIMO to stream data to up to four client radios simultaneously for a total sector capacity of 6800 Mbps. (1700 Mbps to each of four clients). However, this doesn’t mean a sector has 6800 Mbps of TCP/IP throughput (actual customer throughput) nor does the 1700 Mbps OTA rate translate to a TCP/IP capacity of 1700 Mbps. These are layer 1 OTA link rates and are typically used for marketing and are not applicable for TCP/IP throughput. In GeoLinks’ experience, in real-world observed applications, 802.11ac-based devices typically have a layer 2 (customer) capacity of about 1/3 of their layer 1 OTA link rate. In other words, the links rates claimed by 802.11ac-based devices do not translate to the speeds an end-user actually receives. To further corroborate the above, according to support information available on Netgear’s website, “user activities like file transfer and web content browsing happen at the application layer. The rate obtained at the application layer will be much lower than the physical layer rate. In fact, [an OTA] link rate of ‘300 Mbps’ usually corresponds to 50 to 90 Mbps speed on the TCP/UDP layer.” Notably, none of the discussion cited in Footnote 238 mentioned end user capacity.
It is GeoLinks’ strong suggestion, based on the forgoing, that the Commission implement the following to ensure stringent short-form review during the RDOF process. First, the Commission should only allow for equipment that has a capacity of at least 1500 Mbps aggregate on the client device, so that full 1000 Mbps/500 Mbps data rates can be achieved in all real-world applications. A higher threshold of 1750 Mbps aggregate to ensure adequate headroom for varying link conditions would be ideal. Second, the Commission should require all applications to make a showing that throughput capacity of their intended end user equipment meets or exceed the above standards in TCP/IP testing.
Pursuant to Section 1.1206(b) of the Commission’s rules, I am filing this letter electronically in the above referenced dockets. Please contact me directly with any questions.
/s/ Skyler Ditchfield
Chief Executive Officer
Chairman Ajit Pai
 Public Notice, Rural Digital Opportunity Fund Phase I Auction Scheduled for October 29, 2020; Notice and Filing Requirements and Other Procedures for Auction 904, AU Docket No. 20-34 and WC Docket Nos. 19-126 and 10-90, FCC CIRC2006-01 (May 19, 2020) (“Draft Procedures Public Notice”).
 Public Notice at para. 103.
 Available at: https://cdn.cambiumnetworks.com/wp-content/uploads/2016/06/Spec_PMP_450m_cam-10046_000v016.pdf
 Available at: https://www.balticnetworks.com/docs/MultiHaul-Point-to-Multipoint-V2.pdf
 Comments of the Wireless Internet Service Providers Association, AU Docket No. 20-34 (filed. March 27, 2020), at 13.
Available at: https://www.ignitenet.com/downloads/datasheets/MetroLinq-2.5G-60-BF-Sector-Datasheet.pdf., citing channel 4.5 support its highest frequency (65 GHz)
 See Id.
 For instance, assuming good wireless conditions and the 1700 Mbps link rate is achieved, actual TCP/IP capacity will be somewhere around 566 Mbps, not the 1500 Mbps aggregate required for 1000 Mbps/ 500 Mbps levels of service needed for RDOF “Gigabit Tier” service.