Frame Relay is a standardized wide area network technology that specifies the physical and logical
link layers of digital telecommunications channels using a packet switching methodology.
Originally designed for transport across Integrated Services Digital Network (ISDN)
infrastructure, it may be used today in the context of many other network
interfaces. Frame relay is also a protocol standard for LAN internetworking
which provides a fast and efficient method of transmitting information from a
user device to LAN bridges and routers.
The Frame Relay
protocol uses a frame structured similar to that of LAPD, except that the frame
header is replaced by a 2-byte Frame Relay header field. The Frame Relay header
contains the user-specified DLCI field, which is the destination address of the
frame. It also contains congestion and status signals which the network sends
to the user.
Virtual Circuits
The Frame Relay frame is transmitted to its destination by way of
virtual circuits (logical paths from an originating point in the network) to a
destination point. Virtual circuits may be permanent (PVCs) or switched (SVCs).
PVCs are set up administratively by the network manager for a dedicated
point-to-point connection; SVCs are set up on a call-by-call basis.
Dedicated,
High-Speed Internet Connection for Your Business
Frame
Relay service gives you a direct connection to the Internet with a high-speed,
dedicated line. As a step above DSL business services, it is most appropriate
for businesses located outside metropolitan areas needing highly reliable
Internet connectivity
Advantages
of Frame Relay Service
- Scalable
access speeds ranging from 56Kbps to 42Mbps.
- Committed
information delivery rates (CIR) up to 10Mbps.
- Flat
rate pricing (no mileage or usage charges apply).
- LAN-to-LAN
connectivity that protects the integrity of network data.
- Easy
migration path for existing LANs or SNA private-line networks, protecting
existing or future investments.
- Support
for multiple communication architectures, including hierarchical and
client/server networks.
- Mature
technology with industry-wide support, service and availability.
- Provides
a migration path to ATM.
Enhanced
Features
- High-Speed
Frame Relay
- Frame
to ATM Service Internetworking
- Complementary
Service Providers
- Multicast
Service
Applications
- High-speed
Internet access
- LAN/WAN
interconnection
- SNA
transport
- Client/server
transactions
- File
and data transfers
- Remote
Database Access
Frame
Relay Devices
There are two types of devices attached to a frame
relay WAN, DTE, and DCE.
·
DTEs (Data
Terminal Equipments) are generally terminating equipments for a specific
network. They are typically located on the customer's premises and include:
personal computers, terminals, bridges, and routers.
·
DCEs (Data Circuit-terminating
Equipments) are carrier owned internetworking devices and they provide clocking
and switching services in a network.
Physical layer component and link layer component
connect the DTE and DCE devices. A physical layer component defines the
electrical, functional, mechanical, and procedural specifications while a link
layer component defines the protocols.
Frame
Relay vs ATM
Similarities between the frame relay and ATM:
·
They are virtual
circuit based.
·
They are NBMA
technologies.
·
They have burst
rate features.
·
They have
congestion avoidance techniques.
·
They have traffic
shaping or management techniques.
·
FECN of frame
relay is equivalent to the EFCI of ATM.
·
BECN of frame
relay is equivalent to the RRM of the ATM.
Differences
between frame relay and ATM:
·
Frame relay is
not cell based while ATM is cell based.
·
Frame relay is
not asynchronous while ATM is asynchronous.
·
Frame relay does
not have a LANE deployment while ATM does.
·
Frame relay LMI
is completely different from ATM ILMI.
