Frame Relay Switched Virtual Circuits

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Understanding Frame Relay

Frame Relay Presentation by Jeff K. Esquibel

Presentation Overview


Frame Relay Benefits


Frame Relay Components


Understanding Frame Relay Services


Competing Technologies


Frame Relay’s Market Success


Future Competition


Frame Relay Vs. ATM


Frame Relay Vs. IP


Co
-
Existence


Frame Relay’s Continued Success

Benefits of Frame Relay


Savings over Private Lines


Reduces number of dedicated devices which
reduces equipment costs


Reduces complexity for network managers


Greater Bandwidth Flexibility than Private Lines


Higher Reliability and Resiliency than Private
Lines


Lower Cost of Ownership and Better Bandwidth
Utilization


Growth of Branch Office Networks

Benefits of Frame Relay (cont’d)


Consolidation of LAN, SNA, On
-
net Voice,

and/or Packetized Video


Simplifies Network Architecture


Reduces Operations and Administrative Costs


Improves Application Performance and

Network Efficiency


Smooth migration to ATM


Service and Network Interworking with ATM
(FRF.5 and FRF.8)

Frame Relay Basics: Terms And Definitions


User to Network Interface (UNI)


Specifies signaling and management functions between a frame
relay network device and the end user’s device


Network to Network Interface (NNI)


Specifies signaling and management functions between two frame
relay networks


Virtual Circuit (VC)


The connection between two frame relay ports


Permanent Virtual Circuit (PVC)


A pre
-
defined VC


Switched Virtual Circuit (SVC)


A VC that is established dynamically


Data Link Connection Identifier (DLCI)


Virtual Circuit Identification Number


Differences between PVCs And SVCs


PVCs


Staticly Defined at
Configuration,
Unless PVC
Parameters Need to
be Modified


Connection is
Always Configured
Whether There is
Information to Send
or Not


SVCs


Dynamically
Established When
There is Information
to Send (Call
-
by
-
Call
Basis)


Connection is
Released When
There is No More
Information to Send

Benefits Of SVCs


Simplified Network Design, Particularly for
Large and Highly Meshed Networks


Scalable Network Design


Provisioning N*(N
-
1)/2 Connections Not
Required


Easier to Maintain and Manage


Supports Any
-
to
-
Any

Connectivity

Benefits Of SVCs


Can Offer a More Cost
-
Effective Solution


Pay Based on Usage: Call Length, Bandwidth
Used, Number of Frames Sent, Etc.


Only Pay When Using the Network


Offers a Migration Path to PVCs


Locations Already Have Connections

to the Frame Relay Network


Can Easily Transition to PVCs as Traffic
Volumes Increase

How Does Frame Relay Work?

Frame Relay Structure

Frame Relay Terms And Definitions (cont’d)


Committed Information Rate (CIR)


The bandwidth defined for a VC


Bc = Committed Burst


Maximum number of committed bits to be transmitted over
time interval


Be = Excess Burst


Number of Excess bits that will be transmitted over time


Tc Time interval


Time measurement based how much bandwidth is available
for data to burst on to the network


Frame Relay Terms And Definitions (cont’d)


FECN Forward Explicit Congestion Notification


Bit set by the network node (FR Switch) that is experiencing
congestion


Sent in the direction of the receiver (destination)


BECN Backward Explicit Congestion Notification


Bit set by the network node that is experiencing congestion


Sent in the direction of the sender (source)


DE Discard Eligible bit


Set by either the DTE (access device FRAD, router etc.) or
the network nodes (switches)


May be set selectively by some DTE devices


May be set by network nodes in the event the user has
exceeded CIR and the network is experiencing congestion


Frame Relay Components

Frame Relay

Network

Frame Relay

Network

UNI

DTE

DCE

PVC

SVC

NNI

DTE

DCE

DCE

DTE

DCE

Service Comparison

Engineer Network for Peak

Traffic Needs


CSU/DSU per Leased Line per

remote site


Time Division Multiplexing



Resiliency is Not Inherent

Engineer Network for Average
Traffic Needs


CSU/DSU per Leased Line that
can access many remote sites


Statistical Multiplexing and Burst
Capability


Resiliency is Inherent in Network

Private Lines (TDM)

Frame Relay

Networking for the New Millennium

Frame
Relay

Frame Relay’s Market Success
-

U.S.

(in $Ms)

$9.6B

$10.4B

$10.9B

$11.3B

$11.8B

PL Revs:

Source: Vertical Systems Group
-

1997

Frame Relay’s Market Success

International

(in $Ms)

$10.3B

$12.2B

$12.6B

$13.1B

$13.5B

PL Revs:

Source: Vertical Systems Group
-

1997

Market Forecast by WAN Technology

Network Service Market

Worldwide 1997 and 2000
Estimates



Leased Lines

Sources: Vertical Systems Group 1997 and Data Comm 1998 Forecast

Frame Relay

ATM

X.25

SMDS

$3.9B

$.128B $.167B

$.242B

$1.6B

$2.7B $2.6B

$6.8B

$22.6B

$27.7B

Frame Relay Complements Other Technologies

LAN

LAN & SNA

Data & On
-
net Voice

Data, On
-
net Voice

& Packetized Video

Application

Technology

FR, SMDS, ATM

FR, ATM

FR, ATM

FR, ATM

< 1.5 Mbps


1.5
-

45 Mbps


>45 Mbps

Speeds

Technology

FR


FR, ATM


ATM

FR
-

ATM



FR
-

SMDS

Interworking

Agreement

FR or

ATM

FR or

ATM

Dedicated

or Dial FR

Dial Remote Access


or

Dial FR

HQ

Regional

Sites

Remote Sites

Mobile Workers &

Telecommuters

FRF.5 and FRF.8



SIP


Technology Comparison

The Competitive Road Ahead


ATM / Frame Relay Battle Joined By IP


Deployment of VPDNs (i.e. Intra/Extranets) Power IP
adoption for Businesses


Majority of End Users Migrating Private Line
Networks Will Look to Frame Relay and IP


Legacy Applications Demanding Frame Relay Performance;
New Applications a Result of IP Features and Benefits


Frame Relay at the Edge, ATM at the Core


Frame Relay Transport for IP Services


High Speed IP Environments


Solutions/Technologies Outside Frame Relays’
Intended Scope are Servicing the Very High
Speed IP Environments and Campus Backbone


IP Over SONET Offers Users a Simple and
Efficient High Speed Transport Option for IP at
OC
-
3 and Greater Speeds


Gigabit Ethernet Delivers the Mass Bandwidth
Many Campus Backbones Operating in a Pure
Data Environment Require


Co
-
Existence

Frame Relay

ATM

IP

VPN’s, Intranet,

Extranet, etc.


Even as Buying Decisions Move Away from Underlying
Connectivity, Frame Relay will Continue to Play a Major
Role In Service Delivery


Summary


Frame Relay is Widely Accepted and Deployed,
Building Upon its Own Momentum


Frame Relay’s Longevity and Visibility as a
Technology is Fostered by its Ability to Co
-
exist
and Complement Legacy as well as Emerging
Technologies


Standards Continue to Evolve to Meet Changing
End User Environments and Requirements


Frame Relay Will Continue to Play an Integral Part
in Layer 2 Connectivity


Accelerated Growth in Frame Relay
Implementations is Expected to Continue


Market Maturity of ATM and IP Still Years Away


Frame Relay Reference Material


Frame Relay Forum Web page www.frforum.com


Data Communications Magazine
www.datacomm.com


Network World www.nwfusion.com


Internet Week (formerly CommWeek)
www.internetwk.com


Black, Uyless.
Frame Relay Networks:
Specifications and Implementations
. 2nd ed. New
York: McGraw
-
Hill, 1996.


Smith, Philip.
Frame Relay: Principles and
Applications

Wokingham, England: Addison
-
Wesley, 1995.


Questions?

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appreciated!!!