1. Introduction to Frame Relay

2. Lesson 3 - Agenda Functions and Benefits Network Evolution
Bit Oriented Protocol Family
Frame Relay Internetworking
Frame Relay/ATM Interworking

3. Lesson 3 - Objectives
On Completion of this lesson you will be able to:
List the functions and benefits of Frame Relay.
Illustrate the evolution of TDM, BOP, SNA, X.25, LANs, WANs, FR and ATM.
List the members of the BOP family
Define Internetworking and Interworking.

4. Why Frame Relay? Technical Enablers Business Needs
Increased intelligence of user and network attached devices
Availability of error-free (or nearly error free) transmission lines
Business Needs
Increased productivity
Increased competition
Distributed work
Distributed data
Why Was Frame Relay Developed?
It was developed primarily to accommodate modern LAN/WAN Internetworking demands for high capacity bandwidth sharing with exceptionally low delay.
It was developed to address industry trends such as increasing need for speed across network platforms, increasing intelligence of network devices, improved transmission facilities, the need for Internetworking and the need for connection to LANs and WANs.
Driving forces such as Inter-Exchange carriers needed to offer fast, reliable broadband WAN services.
Wide acceptance in the market place
Attractive pricing, low delay, and high throughput allowed the “exponential” growth of the Frame Relay technology in just a few years.

5. Frame Relay Functions Efficient Bandwidth Utilization
Availability of high-capacity transmission facilities
Multi-protocol Support
Upper-layer protocol encapsulation
Reliability and Predictability
Frame discard, congestion notification, upper-layer protocol recovery mechanisms
Network and Service Interoperability
International standards
High Speed Capacity Transmission Facilities
Frame Relay has become the data technology of choice for organizations around the world implementing networks at speeds of T1/E1 and below.
New applications are creating the demand for access speeds up to 45 Mbps (DS3).
Initially, customers ordered 64 kbps access (DS0) for remote office locations and 1.55 Mbps (DS1) for the headquarters site.
With the advent of higher speed Frame Relay, customers can now gain higher-speed access from their service providers.
Some of the major Internet service providers are deploying high-speed Frame Relay backbones to guarantee customers’ network availability.
Increasingly, Internet users are demanding 56/64 kbps, T1 and even T3 connectivity.
To keep pace with these bandwidth requirements, Internet service providers are choosing Frame Relay to provide high performance, cost-effective solutions to their customers.
High-speed Frame Relay provides a viable alternative to end users who are not ready to commit to ATM services.
With the ability to reach to DS3 speeds, the investment in Frame Relay equipment and services can be maximized for years to come.

6. Frame Relay Benefits Interconnection of entire enterprise
Higher performance to cope with more data
Lower cost services
Better availability
Easier to maintain
Today's network manager faces complex requirements, which include building an efficient, integrated network; reducing total costs; and building-in high levels of flexibility for the future.
Frame Relay has become one of the most popular solutions for addressing these network goals.
Frame Relay lowers overall networking costs, improves response times, and is easier to maintain.
Frame Relay has proved to be the right choice for enterprise networks, geographically dispersed locations, or for those organizations that need to reduce costs, eliminate leased lines, or minimize data center resources.

7. $ Frame Relay Benefits Reduces Internetworking Costs
Consolidates leased lines
Fewer access points required
Bandwidth better utilized
Low cost per transmitted byte
Increased Performance and Efficiency
Uses statistical multiplexing
Utilizes data bursting
Improved response times and throughput $
Reduces Internetworking Costs
Frame Relay is the technology of choice for businesses concerned about reducing line costs, improving their network performance, and protecting their installed base investment.
Private frame relay networks can reduce the number of communications circuits, and corresponding costs, required to support applications over the wide area. Similarly, public frame relay services represent cost savings when compared with equivalent dedicated leased line services.
Frame Relay prices are lower than prices of dedicated lines.
Users can choose competitive CIR pricing -- for example, Zero-CIR.
In LAN interconnection applications, Frame Relay can provide substantial cost savings by consolidating leased lines and reducing the number of links and ports required, thus lowering the cost of network equipment at each site.
Users implementing Frame Relay can eliminate or reduce expenses associated with leased lines. Many customers report savings of 30 to 50 percent!. Savings are greatest where an enterprise has several locations separated by geographically long distances.

8. Network Evolution Back in the 60s In the 70s Early 80s The 90s
Frequency Division Multiplex (FDM)
Circuit Switching
In the 70s
Time Division Multiplex (TDM)
Systems Network Architecture (SNA)
Packet Switching (X.25)
Bit Oriented Protocols
Early 80s
Local Area Network
The 90s
Internetworks
The Internet
Broadband services (Fame Relay & ATM)
1960s
Dial-up data
Frequency Division Multiplex (FDM)
Circuit Switching
1970s
Time Division Multiplex (TDM)
Packet Switching (X.25)
Systems Network Architecture (SNA)
1980s
T1 multiplexers
Local Area Network
1990s
Internet
Internetworking
BISDN
Frame Relay
ATM
SONET Networking
Wireless Data Networking

9. Bit Oriented Protocol Family
SDLC - Synchronous Data Link Control (SNA)
HDLC - High-level Data Link Control
Flag
Address
Control
Information
FCS
Flag
HDLC (High Level Data Link Control)
HDLC is a bit-oriented link layer protocol defined by the ISO for use over serial data links. It includes the definition of a variable length frame format as well as elements of procedure for functions such as link establishment, sequencing, flow control and error recovery.
The HDLC frame format defines the use of flag characters ( ) as delimiters of the data frame, a two byte Frame Check Sequence immediately preceding the closing flag for error detection, and a two byte (or greater with extension options) control field immediately following the opening flag. Inadvertent user data imitation of flag characters is prevented through the use of bit stuffing.
The use of the control field and the elements of procedure are defined in a general way with multiple options. A number of different link layer protocols have been defined which are HDLC-based but use the control field and elements of procedure in different ways.
Examples of HDLC-based protocols are SDLC, LAP (Original X.25 Link Layer), LAP-B (X.25 link layer), LAP-D (Q.921), LAP-Frame relay (Q.922), SS7 Message Transfer Part Level 2 and PPP. Each of these protocols use the standard HDLC frame format but differ in their address field structure, control field structure, and procedures.
8 bits 8 or 16 bits 8 or 16 bits optional (multiple of 8 bits) bits bits
payload (next protocol)
frame type identification, frame numbering
link level addressing

10. More BOP SDLC - Synchronous Data Link Control (SNA)
HDLC - High-level Data Link Control
LAP-B - Link Access Procedure-Balance (X.25)
LAP-D - Link Access Procedure for D-channel (ISDN)
Flag
Address
Control
Information
FCS
Flag
8 bits 8 or 16 bits 8 or 16 bits optional (multiple of 8 bits) bits bits
payload (next protocol)
frame type identification, frame numbering
link level addressing

11. Frame Relay SDLC - Synchronous Data Link Control (SNA)
HDLC - High-level Data Link Control
LAP-B - Link Access Procedure-Balance (X.25)
LAP-D - Link Access Procedure for D-channel (ISDN)
LAP-F - Frame Mode Bearer Service (Frame Relay)
Flag
Address
Control
Information
FCS
Flag
8 bits 8 or 16 bits 8 or 16 bits optional (multiple of 8 bits) bits bits
payload (next protocol)
frame type identification, frame numbering
link level addressing

12. Frame Relay Internetworking
ATM IP
Frame Relay Internetworking
is access to and interoperation
with other services and protocols.
SNA
Frame Relay FR
access
ISDN
Internet
Access
Dial Access
International
Frame Relay
X.25
Dial Access

13. Frame Relay Internetworking
Internet Access
Can use the Internet to extend the network
X-25, IP, Internet, and Private Lines can be used where more available, practical, or cost-effective
Gateways to the Internet reduce cost
LAN Interconnection
Single WAN port, DSU & loop reduce costs
Flexible virtual connections
Inexpensive to add new sites
SNA Transport
Each location is directly connected
Logical multipoint configuration
Increased network performance
SNA and LAN
Network consolidation reduces ownership cost
Active applications get full access to network bandwidth
Dedicated or shared PVCs
Users reduce their leased line costs.
Private frame relay networks can reduce the number of communications circuits, and corresponding costs, required to support applications over the wide area. Similarly, public frame relay services represent cost savings when compared with equivalent dedicated leased line services.
Frame Relay prices are lower than prices of dedicated lines.
Users can choose competitive CIR pricing -- for example, Zero-CIR.
ITU-T, ANSI standards, and Frame Relay Implementation Agreements are well-accepted.

14. Frame Relay/ATM Interworking
ATM Network
Interworking is the interconnection and interoperation of frame relay and ATM networks
FR protects investment and provides smooth migration
Frame Relay can be used at remote locations with ATM, or high-speed Frame Relay at the headquarters
Network Interworking encapsulates FR for ATM transport
Service Interworking translates FR into ATM
FR/ATM interworking has two forms.
In network interworking, an ATM network provides transport of the frame relay traffic and FR terminals (FR TE) communicate with FR TE using frame relay.
In service interworking there is a interworking function that translates frame relay, including management and signaling, to ATM AAL 5 and vice versa. The result is that FR TE may transparently communicate with FT TE or ATM TE.In either case the TE communicate using their native protocol (FR or ATM AAL 5).

15. Lesson 3 - Review You should now be able to:
List the functions and benefits of Frame Relay.
Illustrate the evolution of TDM, BOP, SNA, X.25, LANs, WANs, FR and ATM.
List the members of the BOP family.
Define Internetworking and Frame Relay/ATM Interworking.