Making the most of OC-48 broadband requires that you understand the purpose of this level of Internet service. OC48 broadband frequently serves as the backbone for many regional Internet Service Providers (ISPs) and may also be used by larger ISPs for transit purposes. The only common connections that surpass a OC-48 connection are OC-192 and 10 gigabit Ethernet.

OC-48 stands for Optical Carrier 48 with the number specifying the multiplier of the base rate of carrier level, which is 51.84 million bits per second (Mbit/s). The speed of an OC-48 fiber optic network conforms to the Synchronous Optical Networks (SONET) standard. There are three additional methods of describing the OC-48 carrier service:

1. Synchronous Transport Module (STM-16); This is a multiple of the Synchronous Digital Hierarchy (SDH) fiber optic network transmission standard STM-1 which has a bit rate of 155.52 Mbit/s.
2. Synchronous Transport Signal (STS-48); This is a multiple of the basic unit of measure STS-1 used by SONET.
3. A network line that carries data at a maximum rate of up to 2488.32 Mbit/s; A maximum of 2405.376 Mbit/s for an OC48 internet connection may be payload.

Action Steps
The best contacts and resources to help you get it done

Learn technical information about OC 48 speed

There is a great deal of technical information available on transmission protocols. A thorough understanding of the technology involved will aid in your search for a service provider for your business. It is especially important to know the relative transmission speeds of these different technologies.

I recommend: Searchnetworking.com describes the OC system and provides a conversion chart for each OC level. Learn more about SONET technology, including the OC levels of data transmission, at Infocellar.

Access data sheets for equipment used by OC48 service providers to create WAN connections for ISPs

Service providers frequently need OC-48 equipment to incrementally expand existing infrastructures in a cost-effective manner. These units should have features that will allow diverse deployment options that include DS1, Ethernet and optical services delivery to their subscribers.

I recommend: Finisar provides detailed product specification sheets for its OC-48 equipment. DatasheetCatalog.com maintains datasheets for OC-48 equipment from a variety of manufacturers.

Look for current news that informs OC48 providers about increasing T-1 lines

ISPs frequently resell their telecommunications capacity to their subscribers in the form of T-1 service. Many websites keep regular blogs and posts that offer helpful news and information about OC-48 equipment and ISPs.

I recommend: Converge! Network Digest reports on network news including OC-48 equipment and is able to search articles for keywords. Read current news articles on OC-48 equipment at EE Times.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Many OC48 service providers offer this level of broadband service in burstable or fractional rates. A burstable line has a minimum transmission speed although the exact throughput is variable. Fractional service is a fixed percentage of the full rate.

OC-48 broadband is the 48^th Optical Carrier (OC) level carried on a Synchronous Optical NETworking (SONET) fiber optic network. The OC level is directly proportional to the data rate of the digital signal with each level representing approximately 51.84 million bits per second (Mbps). OC-48 speed is therefore 155.52 Mbps of which 2405.376 Mbps is payload and 82.944 Mbps is overhead (including the path overhead).

An OC-48 line is a 2.5G SONET or Synchronous Transport Module 16 (STM-16) line, which is 16 times faster than the basic transmission rate of the Synchronous Digital Hierarchy (SDH) International Telecommunication Union Telecommunication (ITU-T) standard. SONET SDH is currently the standard for optical telecommunications and will probably provide the data transmission infrastructure for telecommunications until at least the year 2030.

OC-48 lines usually offer a better value than OC-3 and OC-12 line and are faster than gigabit Ethernet. The only common connections that surpass it are OC-192 and 10 gigabit Ethernet. OC-48 broadband is the backbone for many regional Internet Service Providers and is commonly used by large ISPs for transit purposes.

In order to obtain OC-48 service you will need to:

1. Obtain quotes from multiple providers on customized OC-48 service packages.

2. Locate the available flat rates on standardized OC-48 service packages.

3. Find any ongoing discounts or specials on OC-48 services in your area.

Action Steps
The best contacts and resources to help you get it done

Look for broadband OC from a carrier with nationwide partners

These carriers are able to offer private, leased lines through partners which allow them to cover a wide area. They can usually offer as many IP addresses as needed with 24/7 monitoring from a central location.

I recommend: Go to ntt.net to review the types of services available from this nationally known OC-48 Internet provider. They have a number of brochures available and also provide case studies.

Find companies that offer OC-48 Internet service in specific locations

You may already be interested in a broadband OC carrier that offers service in your area. These carriers usually base their prices on the port speed, which allows you to manage your costs easily.

I recommend: Get OC-48 service from a business like wvfibernet.net. They specialize in large customers with high bandwidth needs like ISPs, cell phone companies and banks.

Take advantage of current discounts when planning to purchase OC-48

Many OC-48 providers list their discounts on a centralized site. They usually target large enterprises who wish to obtain all of their service from a single carrier.

I recommend: Look at the current specials at broadband.com. Their participating carriers also provide pricing options for all types of OC-48 service.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  OC-48 service is frequently leased in fractional amounts and burst modes. A fractional OC-48 line is simply a fixed percentage of the full OC-48 transmission rate. The rate on burstable OC-48 can be highly variable so you need to determine the lowest allowable speed when considering this type of OC-48 service.