OutlinesReceived

due 13 March 2000

OutlinesReceived

due 13 March 200024 %

HomeworkHomework Review for Midterm (1 March 2000)Review for Midterm (1 March 2000) Research PaperResearch Paper ReadingsReadings

[9] “MPLS: Special Delivery”[9] “MPLS: Special Delivery”[10] “Diversifying Internet Delivery”[10] “Diversifying Internet Delivery”

Frame RelayFrame Relay ANSI Standard covering OSI Layer 2ANSI Standard covering OSI Layer 2 Accessed by Routers or FRAD’sAccessed by Routers or FRAD’s Derived from X.25 ProtocolDerived from X.25 Protocol

Dumps almost all error checkingDumps almost all error checkingRequires fiber on the long haulRequires fiber on the long haul

Uses Uses Permanent Virtual Circuits (PVC’s)Permanent Virtual Circuits (PVC’s)VC differs from DatagramVC differs from DatagramLong Term ConnectionLong Term ConnectionRequires Carrier intervention to changeRequires Carrier intervention to change

Frame RelayFrame Relay

Committed Information Rate (CIR)Committed Information Rate (CIR)Is a Quality of Service GuaranteeIs a Quality of Service Guarantee‘Guaranteed’ minimum Bandwidth‘Guaranteed’ minimum BandwidthShould be set > average traffic duringShould be set > average traffic during

appropriate peak periodappropriate peak period Port Connection SpeedPort Connection Speed

a.k.a. Port Speed or Burst Speeda.k.a. Port Speed or Burst SpeedBandwidth you can burst to Bandwidth you can burst to providedprovided

network capacity exists.network capacity exists.

Ex) 1.54 Mbps Leased LinesEx) 1.54 Mbps Leased Lines

IXC & Local Carriers dedicate 1.54 Mbps to our use via Circuit Switching & TDM.

OKC

Detroit

NYC

IXC LeasedLine Network

Router

Leased Line

Carrier Leased Line NetworkCarrier Leased Line Network

Leased Line ‘Cloud’ Trunks use TDM & Circuit Switching

Cross-ConnectCross-Connect

TrunksLeased Line

Ex) Frame RelayEx) Frame Relay

Local Carriers dedicate 1.54 Mbps to our use. IXC provides random Packet Switched StatMux connectivity via PVC’s.

OKC

Detroit

NYC

IXC FrameRelay Network

PVC, OKC - D

etroit

PVC, NYC - OKCRouter

Frame Relay BackboneFrame Relay Backbone

Frame Relay ‘Cloud’ Trunks use StatMux & Packet Switching

FR Switch

TrunksLeased Line

Ex) InternetEx) Internet

Local Carriers dedicate 1.54 Mbps to our use. ISP provides random Packet Switched StatMux connectivity via datagrams.

OKC

Detroit

NYC

ISP Network

Router

Internet Service Provider BackboneInternet Service Provider Backbone

ISP ‘Cloud’ Trunks use StatMux & Packet Switching

Router

TrunksLeased Line

WAN Design (Link Reduction)WAN Design (Link Reduction)

Start with Traffic MatrixStart with Traffic Matrix Examine Full MeshExamine Full Mesh Consider eliminating lightly used linksConsider eliminating lightly used links Compare costs at each iterationCompare costs at each iteration

Circuit Switched connections waste bandwidth for bursty traffic.Circuit Switched connections waste bandwidth for bursty traffic.

time

trafficNYCto OKC

1.54 Mbps Line Speed

146 Kbps Average

Idle Time >> Active Time

Frame RelayFrame Relay

End-to-End DelayEnd-to-End DelayFrame Relay > equivalent sized LeasedFrame Relay > equivalent sized Leased Line Network Line Network

Cost TendencyCost TendencyFrame Relay < equivalent sized LeasedFrame Relay < equivalent sized Leased Line Network Line Network

Frame Relay (Inside the Cloud)Frame Relay (Inside the Cloud) Examined a specific caseExamined a specific case

Frame Relay Switch

100 Mbps Trunk

?? 1.54 Mbps ConnectionsP(Access Line is Active) = 10%

How many access lines can this switch support?

Bounds on Packet Switch Carrying Capacity 100 Mbps Trunk, 1.54 Mbps Inputs

with 154 Kbps average loads

Bounds on Packet Switch Carrying Capacity 100 Mbps Trunk, 1.54 Mbps Inputs

with 154 Kbps average loads

LowerLower UpperUpper90%90% 559 559 649 64999%99% 494 494 649 64999.9%99.9% 452 452 649 64999.99%99.99% 421 421 649 649Ava

ilab

ilit

y

Where switch could operate

Where switch probably operates

Given 100 Mbps of Bandwidth...Given 100 Mbps of Bandwidth...

6464 1.54 Mbps Circuit 1.54 Mbps Circuit SwitchedSwitched

TDM Customers TDM Customers 421 421 - 649- 649 1.54 Mbps Packet Switched1.54 Mbps Packet Switched

StatMux Customers with StatMux Customers with 154 Kbps average load & 154 Kbps average load & 99.99% availability 99.99% availability

More Bursty Data Traffic can be moved with the Packet Switched StatMux network.

Network Cost...Network Cost...

Can be spread over 64 Leased Line customersCan be spread over 64 Leased Line customers Can be spread over 421 Frame Relay Can be spread over 421 Frame Relay

customerscustomers Frame Relay & the InternetFrame Relay & the Internet

Are Packet Switched StatMux networkAre Packet Switched StatMux networkLargely hauling bursty data trafficLargely hauling bursty data trafficEffectively haul bursty data trafficEffectively haul bursty data traffic

Inexpensive (compared to a Leased Line) Inexpensive (compared to a Leased Line)

Switched Network Carrying CapacitiesSwitched Network Carrying Capacities

0% Data 100% Data100% TST 0% TST

Offered Load

Carrying Capacity

Circuit Switch TDM

Packet Switch StatMux

Voice Over Frame RelayVoice Over Frame Relay

Many of same problems as Voice over IPMany of same problems as Voice over IPDesigned for dataDesigned for dataOne PriorityOne Priority

Quality is worse than Telephone SystemQuality is worse than Telephone System Quality is better than Internet VoiceQuality is better than Internet Voice

CIR guarantees BandwidthCIR guarantees BandwidthFRAD can prioritize voiceFRAD can prioritize voice

Video over FR products now availableVideo over FR products now available

Priorities are a double edged sword...Priorities are a double edged sword... There is only so much pie to go aroundThere is only so much pie to go around

Frame Relay Switch

100 Mbps TrunkHi Priority Voice PVC’s

Lo Priority Data PVC’s

If voice gets preference, data will suffer!

QoSQoS DE bit used by FR switches to police networkDE bit used by FR switches to police network Traffic > CIR enters switch in a 1 second interval? Traffic > CIR enters switch in a 1 second interval?

Marked DEMarked DE If you are behaving...If you are behaving...

...and other users exceed their CIR’s......and other users exceed their CIR’s...

...and FR switch becomes congested......and FR switch becomes congested...

...then other users’ traffic gets dumped 1st......then other users’ traffic gets dumped 1st...

...your traffic is protected....your traffic is protected. Helps shelter you from behavior of othersHelps shelter you from behavior of others

Internet PerformanceInternet Performance

0% 100%Trunk Offered Load

Probability of dropped packets

Average Delay fordelivered packets

Frame Relay PerformanceFrame Relay Performance

0% 100%Trunk Offered Load

Probability of dropped packets*

Average Delay fordelivered packets

*Dashed: If we are transmitting at > CIR Solid: Provided we are transmitting at < CIR

Worldwide Frame Relay RevenuesWorldwide Frame Relay Revenues

$0.2

3B ‘9

4$0

.65B

‘95

$1.2

8B ‘9

6$3

.87B

‘97

$6.2

5B ‘9

8

$0.0

8B ‘9

3

$9.4

5B ‘9

9

Source:Data Communications