BELD Broadband provides Internet access to its cable subscribers via cable modems interconnected to a CMTS (cable modem termination system) via a HFC (hybrid fiber coaxial) network. The CMTS transfers Internet to subscribers via interconnections with core routers which in turn peer to multiple top-tier Internet providers.
Cable Modem Limitations
The upstream and downstream bandwidth limitations are set in configuration files that are transferred to the cable modems when they are provisioned. There are no restrictions in these files regarding the nature of the traffic passed in either direction between customer equipment and the Internet. The only limitation is on instantaneous speeds, and this limitation is set according to the Internet package to which the subscriber has subscribed.
Subscriber connections are provided with real, fully routable IP addresses. The cable modems have a limit to the number of devices that can be connected directly to them, but there is no limit to how many devices can be attached using a router and NAT (Network Address Translation).
There are limitations on traffic to and from the cable modem itself. These limitations are to protect the cable modem from being hacked or hijacked without the subscriber’s knowledge or consent. Limitations include the fact that cable modems are assigned non-routable addresses, and can only be contacted via SNMP (Simple Network Management Protocol) from our own network.
Cable modems that are configured as EMTAs in order to also provide phone service set a QOS (Quality of Service) priority on phone calls with a certain amount of guaranteed bandwidth allocated to that purpose when the telephone is in use. This is to accommodate the possibility of an emergency phone call being made while a large download is also going on. When the telephone is not in use, all bandwidth is available for downloads and uploads, but when the phone is in use its traffic is prioritized over other Internet usage and a set amount of bandwidth is dedicated to the telephone.
It is only voice service offered through our cable modems that is prioritized in this way. Other voice services are treated like ordinary Internet traffic.
The CMTS (Cable Modem Termination System) establishes baseband privacy with connected cable modems in order to prevent eavesdropping on Internet traffic between subscribers. This is transparent to subscribers.
Our HFC (Hybrid Fiber Coaxial) network is divided into geographically defined nodes. This allows us to control how many subscribers use a given set of channels in order to prevent congestion. Each node has a certain number of downstream and upstream channels allocated, and the total bandwidth of each channel is determined by the modulation methods and other physical parameters employed. These channels are shared between all subscribers using a form of multiplexing. Load balancing is employed to minimize congestion.
No traffic is blocked or slowed down on the basis of its sources, destination, nature or content within the CMTS. The only traffic prioritized within the CMTS is voice traffic to or from cable modems configured to provide phone service. In practice, this prioritization would only be evident during times of congestion.
We employ ACLs (Access Control Lists) within our core routers to avert IP address scans or direct access from uncontrolled networks to our network infrastructure. In practice, the only thing subscribers would notice is an inability to “ping” many of our addresses from outside of our network. This is the ONLY thing we block.
We peer with top-tier fiber backbones and also our voice provider via our core routers. We employ EBGP (External Border Gateway Protocol) to distribute traffic to the backbone with the best performance for any given destination. Although we will occasionally employ a prepend in order to redistribute traffic between our peers if a particular connection is being over-utilized, we do not redistribute or prioritize in any other way.
We do not block, slow down, transparently inhibit or otherwise interfere with Internet traffic in either direction.
Monitoring and Surveillance
We are required by law to have the ability to implement transparent surveillance of any of our subscriber’s Internet or voice traffic at any time when given notice by various law enforcement agencies. We are further required NOT to inform the targets of such surveillance when it is in progress. In certain circumstances, this does NOT require a warrant. Also, we are required to keep logs of email, IP address use and other data that we will provide to law enforcement authorities when presented with a subpoena or warrant.
From time to time when we troubleshoot or repair problems in response to a subscriber complaint, we will need to examine or monitor customer email or Internet traffic. This information is used ONLY for purposes of troubleshooting and repair and is kept confidential, is not disclosed, and is shared only with those who need access to the information for purposes of troubleshooting and repair.
Under no circumstances is any subscriber data or information used or shared for any sort of commercial purpose.
We consider any packet loss at all beyond loss of the first packet to constitute a service issue, and we dispatch technicians to repair until 0% packet loss is achieved. 0% packet loss does not correlate to a customer having access to full advertised throughput, but packet loss greater than that almost always correlates to receiving less than advertised throughput.
We likewise monitor channel usage in the CMTS to detect bottlenecks in any of our nodes (nodes correspond to geographic areas), and shift loads where necessary to alleviate them. Channels are monitored daily with one-minute granularity. If bottlenecks cannot be solved by shifting loads, we install more powerful equipment or allocate more channels. Considered across all subscribers in all locations 24 hours a day over the past month, subscribers have had access to full advertised speeds 96.875% of the time.