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A technical discussion of VDSL and MVnet

Wm Magill - September 11, 2018

Under Construction sign

Background

  • Keep in mind, despite the technical jargon, this is a 20,000 foot, simplified, explanation of things!
  • Note that there are two technically different implementations of MVnet: in Masonic Village buildings and in the Cottages.

Here at the Masonic Village, we effectively have our own Local Exchange Carrier (LEC) or Local Telephone Company -- it is the Masonic Village's privately-owned Private Business Exchange (PBX). All on-campus telecommunications takes place through this PBX. It is what allows 5-digit dialing from one resident to another. It also provides Caller-ID, Voice Mail and Audix services. Note that all this refers to "Land-Lines" only! The Masonic Village does not provide any Cellular telephone service. The PBX device itself was manufactured by Lucent Technologies.

Lucent Technologies, Inc., was an American multinational telecommunications equipment company headquartered in Murray Hill, New Jersey. It was established on September 30, 1996, through the divestiture of the former AT&T Technologies business unit of AT&T Corporation, which included Western Electric and Bell Labs.

Lucent was merged with Alcatel SA of France in a merger of equals on December 1, 2006, forming Alcatel-Lucent. Alcatel-Lucent was absorbed by Nokia in January 2016.

This PBX plays an important role on campus. In addition to providing basic telephone service, it's infrastructure, i.e. the physical, copper-wiring plant, provides the support for the Pull-Cord Emergency System, Fire Alarms, and other similar emergency monitoring and communication services on campus. More importantly, from the MVnet point of view, the PBX wiring plant connects to every cottage, apartment and building on Campus!

Parallel to this is the Cable wiring plant, which provides Xfinity Television and Internet service. It too connects to every cottage, apartment and building on campus, but it is not under control of the Masonic Village in Elizabethtown, it is owned and controlled by Xfinity (Comcast).

The Masonic Village at Elizabethtown is a bulk reseller of certain portions of the Xfinity television product line.
MVnet itself uses Xfinity Business Internet service to connect the MVnet backbone to the Internet.

MVnet in Masonic Village buildings
The MVnet Backbone

All residential buildings in the Village Green, including the two administrative buildings, Goodyear and Berks; the Health Care Center; the Village apartments, Sycamore North and South, the Eisenlohr, Smith and Brown buildings and the James Buchanan building, are connected via Fiber-optic based Ethernet connections to their respective building switch-hubs. Each of these switch-hubs in turn is connected to the multiple WiFi Access Points (AP) in the building via Ethernet wiring.

Digital communication speeds in these facilities all enjoy the same high-speed and maximum throughput potential of MVnet.

This Fibre-optic backbone connection provides, potentially, extremely high-speed connectivity for MVnet well into the future. That is to say, the capacity of the Fibre-optic backbone is significantly higher than what can be provided via copper-based Ethernet today. It's capacity (speed) is strictly limited by the constantly improving capabilities of electro-optical technology.

Note that the 72 newest cottages on campus, the Commandrey Cottages, were built with Fibre-to-the-home and enjoy this same potential.

This Fibre-optic cabling represents the backbone of MVnet. Nominally, Gigabit speed is possible with this today.

MVnet at the Cottages

In contrast, MVnet at the cottages is provided using Very-high-bit-rate digital subscriber line (VDSL) technology.

Many Masonic Village residents are familiar with the Windstream DSL product as the low-cost alternative to Xfinity (Comcast) cable-based Internet. Historically, DSL was an acceptable alternative to a dial-up connection to the Internet, especially if one was only interested in reading electronic mail, or visiting static web pages.

However, DSL is extremely slow-speed and incapable of supporting today's web pages with embedded, streamed videos and the desire for live-streaming of programming over the Internet, such as: gaming, movies and sporting events. Devices such as the Amazon Fire-stick, Apple-TV, Roku and other similar Internet based streaming-TV devices simply cannot perform at even close to their best on DSL.

That said, some sort of WiFi Internet access in each cottage is needed for the Masonic Village plan to implement K4 monitoring in every Cottage, as is planned for other residential units in 2019. The K4 Box requires a WiFi connection to the Internet to operate.
See: K4-13 - Installation of K4 boxes campus-wide

The technological solution currently available, which would not require digging up the entire campus to install new Fibre-optic cabling to each and every cottage, is VDSL. This VDSL connection extends the MVnet Backbone into each individual cottage.

Residential Gateway

In communications networking, a residential gateway is a device that allows a local area network (LAN) in the home to connect to a wide area network (WAN) via a modem.
The WAN in our case is simply a larger computer network, MVnet.
The LAN may be one device directly connected to the modem, or multiple devices accessing a WiFi network provided by a Wireless Access Point (AP).

The MVnet Residential Gateway is typically comprised of two devices.

  • The first is the VDSL Modem - A SMART/RG 501 Modem/Router.
    This box performs dual duty as a modem and a Router.
  • The second is the WiFi Access Point (AP) - a Cisco Aiphone.

The Smart/RG 501 Modem/Router

Smart/RG-501-front Smart/RG-501-rear

The power cord connection is black, round, and next to the power on-off rocker switch. This connects to a typical "power brick."
The LAN connector is Yellow. This yellow LAN connector is a standard Ethernet, RJ45 connector.
The Phone Line (Telephone) connector is grey, to the far right. This is a standard telephone RJ11 connector.

Between the Power plug hole and the LAN (yellow) connector is the “Reset” hole — accessed with your basic paperclip.

On the front are 4 lights:

  • Power - Solid green when receiving power from the power supply
  • LAN - Solid green indicates that the device plugged in to the LAN port on the modem is powered up, and electrically connected to the modem via an Ethernet cord.
  • DSL - This light will flash during the handshaking between your modem and the DSLAM. This may take 30 to 60 seconds. It will turn solid green when it has successfully synchronize with hardware - a Digital Subscriber Loop Access Module or DSLAM - in the Central Office of the Masonic Village Telephone system. If it is unable to turn solid green, there may be an issue preventing the physical signal from effectively reaching your modem.
  • Internet - The Internet light represents your modems ability to establish a PPPoE connection with our servers. This PPPoE connection allows you to log in and access MVnet; without it you will not be able to get online.

The Cisco Aironet - WiFi Access Point (AP)

MVnet-cisco-airphone
This device is actually a Cisco Aironet
module mounted on an "Aiphone" stand.

MVnet-cisco-airphone
This device is the CISCO AIR-AP1815W-B-K9
is found in the new smart cottages.

This is a wall plate-mountable access point, intended to blend in to the visual environment. This unit provides 802.11ac Wave 2 wireless standards support and Gigabit Ethernet wired connectivity, providing a data rate of up to 867 Mbps on its 5-GHz radio, simultaneous dual radios and dual band with 802.11ac Wave 2 MU- MIMO functionality.

Note: The access point requires a Gigabit Ethernet (GbE) link to prevent the Ethernet port from becoming a bottleneck for traffic because wireless traffic speeds exceed transmit speeds of a 10/100 Ethernet port.

Functionality of the combined Modem/Router and WiFi Access Point

While housed in the same physical case, and sharing many components, the modem/router has two very distinct functions. That of the router, and that of the modem

The modem only establishes the ability of Ethernet Packets to travel between itself and the DSLAM. It knows nothing about TCP/IP, MVnet or the Internet. That communication ability requires the next device in the Residential Gateway, a Router.

The router, by comparison takes significant configuration. Either by the home owner, or in the case of MVnet, by the IT department before installation. While it is true that today's consumer routers are pretty much "plug and play," in the case of MVnet, the Router must be configured to establish communications with the rest of MVnet and in particular to its RADIUS Authentication Server. It also provides the PPPoE configuration for the Modem. It then must proceed to provide vrious services to the LAN, nominally DHCP and actual route forwarding.

Comparatively speaking, the AP is autonomous. Its electronics and logic perform according to certain international standards. These standards allow the AP and the various devices which connect to it to "simply work." While it is possible to "tweak" certain aspects of their communications, nominally the channel's used, it is rarely necessary. And, the nature of the standards and regulatory approvals necessary for the device's constructin and sale, preclude other adjustments.

DHCP

The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on UDP/IP networks whereby a DHCP server dynamically assigns an IP address and other network configuration parameters to each device on a network so they can communicate with other IP networks.

Generally speaking, the Router or Access Point will assign an IP address dynamically to your local device, using DHCP. A fixed or "static IP Address" is not common with residential internet connections.

Additionally, the Router as part of its DHCP service will provide your device with other information your device needs to function as a peer on the Internet -- a Gateway Address, a Name Server and a Subnet Mask.

The Subnet Mask and the Gateway Address are dependent upon very local conditions an not variable.

DNS Name Server

The Domain Name System (DNS) Name server is a very important part of your Internet configuration.

The DNS Name Server address, is something normally supplied by your ISP during DHCP configuation, but which can be configured on your device and need not match that which is provided by the ISP (MVnet).

There are several more reliable DNS Name Servers available than those provided by Xfinity.

Google and Open DNS are two of the most popular and reliable ones.