EarthLink and Level 3, two service providers that are building out sizeable fiber networks but still have to rent ILEC facilities, say that the Ethernet over hybrid fiber coax (EoHFC) facilities provided by cable operators aren't suitable substitutes to fulfill business service requests.
In a joint FCC filing, the two companies said availability is only one issue that is a concern. The two companies point out that EoHFC pose three other fundamental challenges: high jitter, smaller maximum transmission units (MTUs), and overall slower speeds.
Given the larger size of business customer that Level 3 serves, the service provider said that the jitter levels associated with EoHFC are too high to satisfy customers that want dedicated services.
Unlike Ethernet over Fiber (EoFiber) and Ethernet over Copper (EoC) or EoTDM, EoHFC does not offer the same kind of service level agreements (SLAs) where a service provider will agree to have jitter levels that are low enough to not affect the delivery of real-time video and voice applications. In the event that a provider does not deliver on its promised SLA parameters, they have to pay penalties to their customer.
"In contrast, Ethernet-over-HFC is not typically offered subject to SLAs with performance commitments for jitter," EarthLink and Level 3 said. "Instead, Ethernet-over-HFC is typically offered with service level objectives for jitter that do not require the cable company to pay customers a penalty if they fail to meet these objectives. Even the jitter objectives for Ethernet-over-HFC are set at levels that are significantly higher (i.e., at lower performance levels) than the commitments typically made by Ethernet providers under SLAs and at levels that are too high to reliably support real-time applications."
Level 3 said it found the jitter levels in Ethernet-over-HFC offerings it tested from a number of cable companies are far higher than the jitter levels observed in Ethernet-over-fiber or Ethernet-over-legacy facilities.
Another issue is the size of the MTU, which has a large impact on the rate and efficiency of a circuit's throughput. According to Level 3's estimates, "Ethernet-over-HFC delivers an MTU of 1518 bytes (1522 bytes with a single virtual LAN tag)," which is "significantly below the MTU that can be supported by Ethernet-over-fiber and Ethernet-over-legacy loop networks."
Finally, EarthLink and Level 3 cite how EoHFC does not provide the speed that business customers want for their locations.
"Many parties, including the incumbent LECs, have discussed the fact that Ethernet-over-HFC typically delivers no more than 10 Mbps," EarthLink and Level 3 said. "As Sprint recently explained, this means that customers that need more than 10 Mbps are unlikely to view Ethernet-over-HFC as a substitute for the many dedicated services that do deliver more than 10 Mbps."
EarthLink and Level 3's argument is counter to a view touted previously by CenturyLink (NYSE: CTL), which claimed that it successfully uses EoHFC to satisfy business service requests outside of its wireline network footprint where it operates as a CLEC.
CenturyLink said in an FCC filing that since it launched, "the number of buildings with non-ILEC Ethernet access available has increased exponentially," adding that "we project growth in 2016 and beyond."
The telco noted that it has a number of options for last mile access, including EoHFC and EoCopper from a growing host of cable operators and CLECs.
- see this FCC filing (PDF)
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