Service of Process
`Transmittal
`07/14/2014
`CT Log Number 525312047
`
`TO:
`
`RE:
`
`FOR:
`
`Diane Barnes
`CenturyLink, Inc. (Denver)
`1801 California Street, Suite 900
`Denver, CO 80202
`
`Process Served in Delaware
`
`CenturyLink Communications, LLC (Domestic State: DE)
`
`ENCLOSED ARE COPIES OF LEGAL PROCESS RECEIVED BY THE STATUTORY AGENT OF THE ABOVE COMPANY AS FOLLOWS:
`
`TITLE OF ACTION:
`
`DOCUMENT(S) SERVED:
`
`COURT/AGENCY:
`
`NATURE OF ACTION:
`
`Network Congestion Solutions, LLC, Pltf. vs. CenturyLink Communications, LLC, Dft.
`
`Summonses, Proof(s) of Service, Notice(s), Complaint(s), Prayer for Relief,
`Exhibit(s), Cover Sheet, Report, Statement(s)
`
`Delaware District - U.S. District Court, DE
`Case # 14899
`
`Intellectual Property Litigation - Patent infringement - 620 Patent, "Network
`Congestion Control System and Method"
`
`ON WHOM PROCESS WAS SERVED:
`
`The Corporation Trust Company, Wilmington, DE
`
`DATE AND HOUR OF SERVICE:
`
`By Process Server on 07/14/2014 at 10:35
`
`JURISDICTION SERVED :
`
`Delaware
`
`APPEARANCE OR ANSWER DUE:
`
`Within 21 days after service, not counting the day of receipt
`
`ATTORNEY(S) / SENDER(S):
`
`Timothy Devlin
`1220 N. Market Street
`Suite 850
`Wilmington, DE 19801
`302-449-9010
`
`ACTION ITEMS:
`
`SIGNED:
`PER:
`ADDRESS:
`
`TELEPHONE:
`
`CT has retained the current log, Retain Date: 07/14/2014, Expected Purge Date:
`07/19/2014
`Image SOP
`Email Notification, Diane Barnes Diane.Barnes@centurylink.com
`Email Notification, Mary Sheets mary.sheets@centurylink.com
`Email Notification, Terri Dunnington terri.dunnington@centurylink.com
`
`The Corporation Trust Company
`Gretchen McDougal
`1209 Orange Street
`Wilmington, DE 19801
`302-658-7581
`
`Information displayed on this transmittal is for CT Corporation's
`record keeping purposes only and is provided to the recipient for
`quick reference. This information does not constitute a legal
`opinion as to the nature of action, the amount of damages, the
`answer date, or any information contained in the documents
`themselves. Recipient is responsible for interpreting said
`documents and for taking appropriate action. Signatures on
`certified mail receipts confirm receipt of package only, not
`contents.
`
`Page 1 of  1 / AP
`
`CTL 1002 - Page 1
`
`

`
`. I ·' '·
`
`AO 440 (Rev. 12/09) Summons in a Civil Action
`
`UNITED STATES DISTRICT COURT
`for the
`
`District of Delaware
`
`NETWORK CONGESTION SOLUTIONS, LLC
`
`Plaintiff
`
`v.
`CENTURYLINK COMMUNICATIONS, LLC
`
`Defendant
`
`)
`)
`)
`)
`)
`)
`)
`
`Civil Action No.
`
`4 - 8 9 9
`
`SUMMONS IN A CIVIL ACTION
`
`To: (Defendant's name and address) Centurylink Communications, LLC
`c/o The Corporate Trust Company
`Corporate Trust Center
`1209 Orange Street
`Wilmington, DE 19801
`
`A lawsuit has been filed against you.
`
`Within 21 days after service of this summons on you (not counting the day you received it)- or 60 days if you
`are the United States or a United States agency, or an officer or employee of the United States described in Fed. R. Civ.
`P. 12 (a)(2) or (3) -you must serve on the plaintiff an answer to the attached complaint or a motion under Rule 12 of
`the Federal Rules of Civil Procedure. The answer or motion must be served on the plaintiff or plaintiff's attorney,
`whose name and address are: Timothy Devlin, Esq. (#4241)
`Devlin Law Firm LLC
`1220 N. Market St., Suite 850
`Wilmington, DE 19801
`
`lfyou fail to respond, judgment by default will be entered against you for the relief demanded in the complaint.
`You also must file your answer or motion with the court.
`
`Date•7Jr'<H>/d
`
`Signature of Clerk or Deputy Clerk
`
`CTL 1002 - Page 2
`
`

`
`AO 440 (Rev. 12/09) Summons in a Civil Action (Page 2)
`
`Civil Action No.
`
`PROOF OF SERVICE
`(This section should not be filed with the court unless required by Fed. R. Civ. P. 4 (I))
`
`This summons for (name of individual and title. if any)
`
`was received by me on (date)
`
`0
`
`I personally served the summons on the individual at (place)
`
`----------------------------------------
`on (date)
`; or
`
`0
`
`I left the summons at the individual's residence or usual place of abode with (name)
`
`--------------------------------
`on (date)
`, and mailed a copy to the individual's last known address; or
`---------------
`
`, a person of suitable age and discretion who resides there,
`
`0
`
`I served the summons on (name of individual)
`
`, who is
`
`designated by law to accept service of process on behalf of (name of organization)
`
`----------------------------------------------
`0
`I returned the summons unexecuted because
`
`on (date)
`
`-----------------
`
`; or
`
`-----------------------------------------
`
`; or
`
`0 Other (specify):
`
`My fees are$
`
`-----------
`
`for travel and $
`
`-----------
`
`for services, for a total of$
`
`0.00
`
`I declare under penalty of perjury that this information is true.
`
`Date:
`
`Server's signature
`
`Primed name and title
`
`Additional information regarding attempted service, etc:
`
`------------·--------· -----------
`Server's address
`
`CTL 1002 - Page 3
`
`

`
`AO 85A (Rev. 01/09) Notice, Consent, and Reference of a Dispositive Motion to a Magistrate Judge
`
`UNITED STATES DISTRICT COURT
`for the
`District ofDelaware
`
`Plaintiff
`v.
`
`Defendant
`
`)
`)
`)
`)
`)
`
`Civil Action No.
`
`NOTICE, CONSENT, AND REFERENCE OF A DISPOSITIVE MOTION TO A MAGISTRATE JUDGE
`
`Notice of a magistrate judge 's availability. A United States magistrate judge of this court is available to conduct
`all proceedings and enter a final order dispositive of each motion. A magistrate judge may exercise this authority only if
`all parties voluntarily consent.
`
`You may consent to have motions referred to a magistrate judge, or you may withhold your consent without
`adverse substantive consequences. The name of any party withholding consent will not be revealed to any judge who
`may otherwise be involved with your case.
`
`Consent to a magistrate judge 's consideration of a dispositive motion. The following parties consent to have a
`United States magistrate judge conduct any and all proceedings and enter a final order as to each motion identified below
`(identify each motion by document number and title).
`
`Motions: --------------------------------------------------------
`
`Parties' printed names
`
`Signatures of parties or attorneys
`
`Dates
`
`IT IS ORDERED: The motions are referred to a United States magistrate judge to conduct all proceedings and
`enter a fmal order on the motions identified above in accordance with 28 U.S.C. § 636(c).
`
`Reference Order
`
`Date:
`
`District Judge 's signature
`
`Printed name and title
`
`Note: Return this form to the clerk of court only if you are consenting to the exercise of jurisdiction by a United States
`magistrate judge. Do not return this form to a judge.
`
`CTL 1002 - Page 4
`
`

`
`IN THE UNITED STATES DISTRICT COURT
`FOR THE DISTRICT OF DELAWARE
`
`NETWORK CONGESTION
`SOLUTIONS, LLC,
`
`Case No.
`
`v.
`
`Plaintiff,
`
`PATENT CASE
`
`JURY TRIAL DEMANDED
`
`CENTURYLINK COMMUNICATIONS,
`LLC,
`
`Defendant.
`
`COMPLAINT FOR PATENT INFRINGEMENT
`
`PlaintiffNetwork Congestion Solutions, LLC (''NCS" or "Plaintiff') files this Complaint
`
`against CenturyLink Communications, LLC ("CenturyLink" or "Defendant") for infringement of
`
`U.S. Patent No. 6,826,620 ("the '620 patent").
`
`THE PARTIES
`
`1.
`
`NCS is a Delaware limited liability company with its principal place of business
`
`located at 604 East 4th Street, Suite 201, Fort Worth, Texas 76102.
`
`2.
`
`Century Link is a Delaware company with its principal_ place of business at 100
`
`CenturyLink Drive, Monroe, Louisiana 71203.
`
`3.
`
`Defendant maintains a registered agent for service of process in Delaware at The
`
`Corporate Trust Company, Corporate Trust Center, 1209 Orange Street, Wilmington, Delaware
`
`19801.
`
`JURISDICTION AND VENUE
`
`4.
`
`NCS brings this action for patent infringement under the patent laws of the United
`
`States, namely 35 U.S.C. §§ 271, 281, and 284-285, among others. This Court has subject matter
`
`jurisdiction pursuant to 28 U.S.C. §§ 1331, 1338(a), and 1367.
`
`1
`
`CTL 1002 - Page 5
`
`

`
`5.
`
`Venue is proper in this judicial district pursuant to 28 U.S.C. §§ 1391(c) and
`
`1400(b ). On information and belief, Defendant is deemed to reside in this judicial district, has
`
`committed acts of infringement in this judicial district, has purposely transacted business involving
`
`the accused products in this judicial district, and/or has regular and established places of business
`
`in this district.
`
`6.
`
`Defendant is subject to this Court's specific and general personal jurisdiction
`
`pursuant to due process, due at least to its substantial business in this State and judicial district,
`
`including: (A) committing acts of infringement in this judicial district as described herein; (B)
`
`having a corporate headquarters in this judicial district; and/or (C) regularly conducting or
`
`soliciting business, engaging in other persistent conduct, and/or deriving substantial revenue from
`
`goods and products sold and services provided to Delaware residents. Further, this Court has
`
`personal jurisdiction over Defendant because it is incorporated in Delaware and has purposely
`
`availed itself of the privileges and benefits of the laws of the State of Delaware.
`
`COUNT I
`
`(INFRINGEMENT OF U.S. PATENT NO. 6,826,620)
`
`NCS incorporates paragraph 1 through 6 herein by reference.
`
`This cause of action arises under the patent laws of the United States, and in
`
`7.
`
`8.
`
`particular, 35 U.S.C. §§ 271, et seq.
`
`9.
`
`NCS is the owner of the '620 patent, entitled "Network Congestion Control System
`
`and Method," with all substantial rights to the '620 patent, including the exclusive right to enforce,
`
`sue, and recover damages for past and future infringement. A copy ofthe '620 patent is attached
`
`as Exhibit 1.
`
`2
`
`CTL 1002 - Page 6
`
`

`
`10.
`
`The '620 patent is valid, enforceable, and was duly issued in full compliance with
`
`Title 35 ofthe United States Code.
`
`11.
`
`Defendant has, and continues to, directly infringe one or more claims of the '620
`
`patent in this judicial district and elsewhere in the United States.
`
`12.
`
`In particular, Defendant has, and continues to, infringe at least claim 1 of the '620
`
`patent by, among other things practicing infringing methods including, but not limited to,
`
`Defendant's practices in conjunction with network congestion management.
`
`13.
`
`NCS has been damaged as a result of Defendant's infringing conduct described in
`
`this Count. Defendant is, thus, liable to NCS in an amount that adequately compensates NCS for
`
`Defendant's infringements, which, by law, cannot be less than a reasonable royalty, together with
`
`interest and costs as fixed by this Court under 35 U.S.C. § 284.
`
`JURY DEMAND
`
`NCS requests a trial by jury pursuant to Rule 38 of the Federal Rules of Civil Procedure.
`
`3
`
`CTL 1002 - Page 7
`
`

`
`PRAYER FOR RELIEF
`
`Plaintiff asks that the Court find in its favor and against Defendant and that the Court grant
`
`Plaintiff the following relief:
`
`a. Judgment that one or more claims of the '620 patent have been infringed, either literally
`and/or under the doctrine of equivalents by Defendant;
`
`b. Judgment that Defendant account for and pay to Plaintiff all damages and costs incurred
`by Plaintiffbecause of Defendant's infringing activities and other conduct complained of
`herein;
`
`c. Judgment that Defendant account for and pay to Plaintiff a reasonable, ongoing, post
`judgment royalty because of Defendant's infringing activities and other conduct
`complained of herein;
`
`d. That Plaintiff be granted pre-judgment and post judgment interest on the damages caused
`by Defendant's infringing activities and other conduct complained of herein;
`
`e. Find this case exceptional under the provisions of 35 U.S.C. § 285 and award enhanced
`damages; and
`
`f. That Plaintiffbe granted such other and further relief as the Court may deem just and proper
`under the circumstances.
`
`4
`
`CTL 1002 - Page 8
`
`

`
`DATED: July 9, 2014
`
`NETWORK CONGESTION SOLUTIONS, LLC
`
`By:
`
`/s/ Timothy Devlin
`Timothy Devlin(# 4241)
`Devlin Law Firm LLC
`1220 N. Market Street, Suite 850
`Wilmington, DE 19801
`302-449-9010
`tdevlin@devlinlawfirm. com
`
`Of counsel:
`
`Timothy E. Grochocinski
`Joseph P. Oldaker
`INNOVALAW, P.C.
`1900 Ravinia Place
`Orland Park, Illinois 60462
`P. 708-675-1975
`teg@innovalaw .com
`joldaker@innovalaw .com
`
`COUNSEL FOR PLAINTIFF
`NETWORK CONGESTION SOLUTIONS, LLC
`
`5
`
`CTL 1002 - Page 9
`
`

`
`EXHIBIT 1
`
`CTL 1002 - Page 10
`
`

`
`lll~lln~~ 1111111111111111111111 Ill~ 11111111~ IIIII 1111111111 1111111
`
`US006826620Bl
`
`c12) United States Patent
`Mawhinney et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,826,620 Bl
`Nov. 30, 2004
`
`(54) NETWORK CONGESTION CONTROL
`SYSfEM AND METHOD
`
`(75)
`
`Inventors: Ted Nodine Mawhinney, Clearwater,
`FL (US); Jeffrey Don Davis, Indian
`Rocks, FL (US)
`
`(73) Assignee: Paradyne Corporation, Largo, FL
`(US)
`
`( "') Notice:
`
`Subject to any diSclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 750 days.
`
`(21) . Appl. No.: 09/304,188
`
`(22) Filed:
`
`May 3,1999
`
`Related U.S. Application Data
`( 60) Provisional application No. 60/098,186, filed on Aug. 26,
`1998.
`Int. Cl.7
`(51)
`.........................•...............•...... G06F 15/16
`(52) U.S. Cl ......................... 709/235; 709/234; 370/235
`(58) Field of Search ................................. 709/235, 224,
`709/234; 370/230, 232, 236, 235, 237
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`5,307,484 A * 4/1994 Baker eta!. ................ 707/102
`5,313,454 A • 5/1994 Bustini et a!. ................ 370{13
`5,367,523 A • 11/1994 Chang et a!. ............... 370/235
`5,729,528 A • 3/1998 Salingre eta!. ............. 370/230
`5, 768;1.71 A • 6/1998 Seid et a!. .................. 370/389
`
`5,8(J}.;l.f>l A • 9/1998 Rostoker eta!. ............ 709{250
`5,835,484 A
`• 11{1998 Yamato eta!. .............. 370/230
`5,898,669 A
`• 4/1999 Shimony et al ............. 370{2'n
`6,097,697 A
`• 812000 Yao et a!. ................... 370/230
`6,160,793 A
`• 12{2000 Gbani et al ................. 370{236
`6,178,448 81 • 1{2001 Gray et a!. ................. 709{224
`6;1.08,650 81 • 3{2001 Hassell et a!. ......... ..... 370/392
`* cited by examiner
`Primary Examiner-Fraotz B. Jean
`(74) Attorney, Agent,
`or Finn-Thomas,
`Horstemeyer & Risley LLP
`
`Kayden,
`
`(57)
`
`ABSTRACT
`
`A network congestion control system and method facilitate
`the transmission of information on a communication net(cid:173)
`work by monitoring the data streams coming out of the
`communication network for congestion notifications, and
`actively rate controlling the end user application sessions
`based on such congestion notifications to alleviate the net(cid:173)
`work congestion. This provides congestion control for the
`network and can be used to avoid congestion reaching the
`point where the network bas to discard data. The end user
`sessions can be divided into mission critical sessions and
`non-mission critical sessions. These session types can be
`prioritized so that non-mission critical sessions are rate
`controlled during periods of congestion, while mission criti(cid:173)
`cal sessions remain unaffected. Mission critical sessions are
`effectively reserved a specific amount of bandwidth with the
`rest of the available bandwidth (up to the congestion point)
`being allocated dynamically to the non-mission critical
`sessions.
`
`19 Claims, 6 Drawing Sheets
`
`4a
`END USER
`DEVICE
`
`23
`
`25
`
`11 ........
`
`4c
`END USER
`DEVICE
`
`4d
`END USER
`DEVICE
`
`18
`
`COMMUNICATION
`NElWORK
`16
`··-··-··-c.:19c:·
`··-··---c-1·9i)""
`·-c1·9;··-··-··
`
`CTL 1002 - Page 11
`
`

`
`4a
`END USER
`DEVICE
`
`4b
`END USER
`DEVICE
`
`11-...
`
`4c
`END USER
`DEVICE
`
`4d
`END USER
`DEVICE
`
`~ .
`
`00
`•
`
`23
`
`24
`
`25
`
`Sa
`LAN
`
`6a
`ROUTER
`
`COMMUNICATION
`NETWORK
`1§.
`
`18
`
`6b
`ROUTER
`
`12a
`COMMUNICATION 1-'--'r------1
`12a DEVICE
`
`··-··-··"\:..:·-··
`19c
`··-··-··cfgi)··
`··c··-··-··-··
`19a
`
`12b
`1----+--,....---1 COMMUNICATION
`DEVICE
`
`22
`
`Fig. 1
`
`CTL 1002 - Page 12
`
`

`
`<a JJ31\
`
`LAYER 6
`
`LAYER 5
`
`LAYER 4
`
`.
`End User Device
`38
`LAYER 7 ~ LAYER 7
`APPLIC.
`37
`LAYER 6
`PRESENT.
`36
`LAYER 5
`SESSION
`35
`LAYER 4
`TRANSP.
`34
`LAYER 3
`NETWORK
`33
`LAYER 2
`DATA LINK
`32
`LAYER 1
`PHYSICAL
`
`LAYER 2
`
`LAYER 1
`
`~c
`~30 {31
`i~ End User Device
`LAYER 7
`LAYER 7
`~
`
`LAYER 6 ·
`
`LAYER 6
`
`/41
`
`1
`
`.
`
`Communication
`Network
`
`1Q
`
`LAYER 5
`
`LAYER 4
`
`LAYER 2
`
`LAYER 1
`
`LAYER 5
`
`LAYER 4
`
`LAYER 3
`
`LAYER 2
`
`LAYER 1
`
`LAYER 3 ~1 ~ LAYER 3
`
`FRAU
`
`12a
`
`1---
`
`2a
`ROUTER
`
`·~
`
`25
`
`23
`
`5a
`LAN
`
`4 2
`
`Fi .2
`g
`
`FRAU
`
`12b
`
`6b
`ROUTER
`
`I
`
`5b
`LAN
`
`CTL 1002 - Page 13
`
`

`
`12
`
`FRAU
`
`44 MICRO PROCESSOR
`
`42
`
`NETWORK ACCESS
`MODULE
`
`~ •
`.
`rJ'J
`
`:Jl
`1\r
`
`47
`
`§1
`
`~7
`MEMORY
`
`CONGESTION
`
`TRANSMITTER
`63
`
`TRANSMITIER
`43
`
`~
`I 25 v
`
`66
`
`RECEIVER
`
`RECEIVER
`
`46
`
`67 FRAME
`RELAY
`SWITCH
`
`100
`CONGESTION
`CONTROL
`LOGIC
`
`Fig. 3
`
`l/l
`CONTROL N
`
`100
`
`LOGIC
`T
`FRAME
`RELAY
`57 SWITCH
`
`21 I
`
`CTL 1002 - Page 14
`
`

`
`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 4 of 6
`
`US 6,826,620 Bl
`
`~100
`
`151
`Classify Traffic
`Flow(s) For Each
`DLCI
`
`152
`Assign Traffic-
`Policy For Each
`Traffic Flow
`
`153
`Monitor Each-
`Traffic Flow On
`DLCIAnd
`Bandwidth
`Consumed On
`DLCI
`
`154
`Determine-
`Congestion State
`Of Each DLCI
`
`FIG. 4A
`
`CTL 1002 - Page 15
`
`

`
`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 5 of 6
`
`US 6,826,620 Bl
`
`~100
`
`160
`Monitor MCTFs
`Wrthin Each DLCI
`
`161
`Is An
`Yes
`MCTF Below Its >---------------~ Rate Control
`NMCTFs
`
`No
`
`No
`
`lsBW
`<CIR +Be?
`
`Yes
`
`End
`
`Rate Control
`NMCTFs
`
`165
`Rate Control
`MCTFs (if
`necessary)
`
`FIG. 48
`
`CTL 1002 - Page 16
`
`

`
`U.S~ Patent
`
`Nov. 30,2004
`
`Sheet 6 of 6
`
`US 6,826,620 Bl
`
`100
`
`172
`
`Rate Control
`NMCTFs
`
`114
`
`Rate Control
`NMCTFs
`
`175
`Rate Control
`MCTFs (if
`necessary)
`
`Monitor MCTFs Within
`Each DLCI
`
`171
`Is An
`MCTF <Its
`
`Yes
`
`No
`
`Yes
`
`End
`
`FIG. 4C
`
`CTL 1002 - Page 17
`
`

`
`US 6,826,620 Bl
`
`1
`NETWORK CONGESTION CONTROL
`SYSTEM AND METHOD
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`This application claims priority to and the benefit of the
`filing date of co-pending and commonly assigned provi(cid:173)
`sional application entitled METIIOD FOR CONGESTION
`CONTROLIN FRAME RELAY NE1WORKS BY APPLY(cid:173)
`ING ENDPOINT RATE PACING AT TIIE POINT OF
`INGRESS OR EGRESS, assigned Ser. No. 60/098,186, filed
`Aug. 26, 1998, and hereby incorporated by reference.
`
`TECHNICAL RELD
`
`The present invention is generally related to communica(cid:173)
`tion networks, and more particularly, to a system and method
`for allowing a device located at the ingress/egress poiot of
`a communication network to monitor congestion notifica(cid:173)
`tions at the data link layer of the communication network, 2D
`and to proactively control the transmission rate of the end
`user device that is causing such congestion.
`
`25
`
`2
`Ethernet networks. In contrast to the OSI seven-layer
`architecture, TCP/IP (Transmission Control Protocol over
`Internet Protocol) is a five-layer architecture which gener(cid:173)
`ally consists of the network layer and the transport layer
`5 protocols.
`Layer 4, the transport layer, determines bow the network
`layer should be used to provide a point-to-point, virtual,
`error-free connection so that the end user devices send and
`receive uncorrupted messages in the correct order. This layer
`10 establishes and dissolves connections between hosts. It is
`used by the session layer. TCP is an example of the transport
`layer.
`Layer 5, the session layer, uses the transport layer and is
`used by the presentation layer. The session layer establishes
`15 a connection between processes on different hosts. It handles
`the creation of sessions between hosts as well as security
`issues.
`Layer 6, the presentation layer, attempts to minimize the
`noticeability of differences between hosts and performs
`functions such as text compression, and format and code
`conversion.
`Layer 7, the application layer, is used by the presentation
`Ia yer to provide the user with a localized representa lion of
`data which is iodependent of the format used on the network.
`The application layer is concerned with the user's view of
`the network and generally deals with resource allocation,
`network transparency and problem partitioniog.
`The commucications networks that operate withio the
`30 OSI seven-layer model include a number of paths or links
`that are ioterconnected to route voice, video, and/or digital
`data (hereinafter, collectively referred to as "data") traffic
`from one location of the network to another. At each
`location, an interconnect node couples a plurality of source
`35 nodes and destioation nodes to the network. In some cases,
`the sources and destinations are incorporated io a private
`line network that may ioclude a series of offices connected
`together by leased-lioes with switching facilities and trans(cid:173)
`mission equipment owned and operated by the carrier or
`40 service provider and leased to the user. This type of network
`is conventionally referred to as a "circuit-switching net(cid:173)
`work". Accordingly, a source node of one office at one
`location of the network may transmit data to a destination
`node of a second office located· at another location of the
`45 network through their respective switching facilities.
`At any given location, a large number of source nodes
`may desire to communicate through their respective switch(cid:173)
`ing facilities, or ioterconnect node, to destination nodes at
`various other locations of the network. The data traffic from
`so the various source nodes is first multiplexed through the
`source switching facility, and then demultiplexed at the
`destination switchiog facility, and finally delivered to the
`proper destination node. A variety of techniques for effi(cid:173)
`ciently multiplexing data from multiple source nodes onto a
`55 single circuit of the network are presently employed in
`private lioe networks. For instance, time division multiplex(cid:173)
`ing (TOM) affords each source node full access to the
`allotted bandwidth of the circuit for a small amount of time.
`The circuit is divided into defined time segments, with each
`60 segment corresponding to a specific source node, to provide
`for the transfer of data from those source nodes, when.called
`upon, through the network.
`Another type of network is conventionally referred to as
`a "packet-switchiog network." Frame relay networks are one
`65 implementation of a packet-switching network. Packet(cid:173)
`switching networks, as opposed to circuit-switching
`networks, allow multiple users to share data network facili-
`
`BACKGROUND OF THE INVENTION
`
`Historically, in the field of data communications,
`modems, data service units (DSU), and channel service units
`(CSU) have been used to convey information from one
`location to another. Digital technology now enables modems
`and other communication devices, such as frame relay data
`service units (DSU's) and frame relay access units
`(FRAU's) to communicate large amounts of data at higher
`speeds. The communication scheme employed by these
`devices generally adheres to a model, known as the Open
`Systems Interconnect (OSI) seven-layer model. This model
`specifies the parameters and conditions under which infor(cid:173)
`mation is formatted and transferred over a given communi(cid:173)
`cations network. A general background of the OS! seven(cid:173)
`layer model follows.
`[n 1978, a framework of ioternational standards for com(cid:173)
`puter network architecture known as "OSI" (Open Systems
`Interconnect) was developed. The OSI reference model of
`network architecture consists of seven layers. From the
`lowest to the highest, the layers are: (1) the physical layer;
`(2) the data link layer; (3) the network layer; (4) the transport
`layer; (5) the session layer; (6) the presentation layer; and (7)
`the application layer. Each layer uses the layer below it to
`provide a service to the layer above it. The lower layers are
`implemented by lower level protocols which define the
`electrical and physical standards, perform the byte ordering
`of the data, and govern the transmission, and error detection
`and correction of the bit stream. The higher layers are
`implemented by higher level protocols which deal with,
`ioter alia, data formattiog, termioal-to-computer dialogue,
`character sets, and sequencing of messages.
`Layer 1, the physical layer, controls the direct host-to-host
`communication between the hardware of the end users' data
`termioal equipment (e.g., a modem connected to a PC).
`Layer 2, the data link layer, generally fragments the data
`to prepare it to he sent on the physical layer, receives
`acknowledgment frames, performs error checkiog, and
`re-transmits frames which have been incorrectly received.
`Layer 3, the network layer, generally controls the routing
`of packets of data from the sender to the receiver via the data
`link layer, and it is used by the transport layer. An example
`of the network layer is the Internet Protocol (lP), which is
`the network layer for the TCP/IP protocol widely used on
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`15
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`3
`ties and bandwidth, rather than providing a specific amount
`of dedicated bandwidth to each user, as in TDM. Instead,
`packet switches divide bandwidth into connectionless, vir(cid:173)
`tual circuits. VIrtual circuits can be permanent virtual cir(cid:173)
`cuits (PVC's) or switched virtual circuits (SVC's). As is 5
`known, virtual circuit bandwidth is consumed only when
`data is actually transmitted. Otherwise, the bandwidth is not
`used. In this way, packet-switching networks essentially
`mirror the operation of a statistical multiplexer (whereby
`multiple logical users share a single network access circuit).
`Frame relay generally operates within layer 2 (the data link
`layer) of the OSI model, and is an improvement over
`previous packet switching techniques, such as the industry
`standard X.25, in that frame relay requires significantly less
`overhead.
`In frame relay networks, as in all communication
`networks, access to the .network is provided by a network
`service provider. lbese service providers generally provide
`the communication and switching facilities over which the
`above-mentioned communication devices operate.
`Typically, an end user desirous of establishing a communi(cid:173)
`cations network provisions the network services in the form
`of a public switched service network. An example of a
`public switched network is the public switched telephone
`network (PSTN) or a public data network (PDN). These
`public networks typically sell network services, in the form
`of connectivity, to end users.
`Typically a user of a public network will purchase a
`particular level of service from the network service provider.
`This level of service can be measured by, for example,
`network availability as a percentage of total time on the
`network, the amount of data actually delivered through the
`network compared to the amount of data attempted, or
`possibly the network latency, or the amount of time it takes
`for a particular communication to traverse the network.
`As is generally known, communications among devices in
`contemporary communication networks generally implicate
`the lower three to four layers of the OSI model. These
`include the physical, data link, network, and transport layers.
`For example, in packet-switched and frame relay
`technologies, internode communications affect, and are con(cid:173)
`trolled by, the lower three layers (physical, data link, and
`network). However, the higher level transport layer may be
`utilized for purposes of error control.
`By way of a more particular illustration, networked trans(cid:173)
`missions on the World Wide Web of the Internet are gener(cid:173)
`ally governed by TCP/IP (Transmission Control Protocol/
`Internet Protocol), which is a family of protocols. The
`TCP/IP protocols affect the network layer, transport layer,
`and application layer, but are generally transparent to the
`remaining layers of the OSI model. Within the network
`layer, TCP/IP offers a variety of protocols, of which the
`Internet Protocol (IP) offers the ability to move data between
`hosts. The remaining protocols offer services to assist IP in
`its functions. The transport layer provides services that allow
`one application program on a particular host to communicate
`with another application program on a remote host. Trans(cid:173)
`mission Control Protocol (TCP) is utilized at the transport
`layer to effect bi-directional handshaking for the transmis(cid:173)
`sion and control of data packets being sent between hosts.
`The application layer of TCP/IP generally formats data that
`is to be communicated to a remote host and performs other
`services that are necessary to accommodate this communi(cid:173)
`cation. In summary, the application layer creates data that is
`passed to the transport layer, which in turn employs trans(cid:173)
`mission control. The transport layer then passes the data/
`messages to the network layer, which divides the messages
`
`4
`into defined, discrete pieces, al·so called packets. As is
`known, these packets are further divided into frames at the
`data link layer and bits at the physical layer for transmission
`to remote nodes.
`With respect to the network layer of the OSI model, the
`IP provides an unreliable, connectionless method of deliv(cid:173)
`ering data from one host to another. It is characterized as
`unreliable because the method does not guarantee delivery
`and, in fact, provides no particnlar sequencing to assure that
`10 data packets are received in the order in which they are
`transmitted. It is referred to as connectionless, because no
`initialization sequence is necessary in order for one host to
`connect with another using the IP protocol. Furthermore,
`each data packet is independent of every other data packet.
`Above the network layer is the transport layer, which
`handles the TCP protocol. While the packet transmission at
`the network layer is deemed to be unreliable, error and flow
`control may be iniplemented at the higher, transport layer. In
`this regard, TCP is utilized to establish reliable end-to-end
`20 transmissions. More particularly, ·and as is known, TCP
`places certain handshaking requirements on the transmission
`of data packets. For each data packet transmitted, an
`acknowledgment packet must be received. The reception of
`an acknowledgment informs the transmitting node (that
`25 received the acknowledgment) that the packet was success(cid:173)
`fully reoeived at the other end. Unless an acknowledgment
`is "piggy-backed" onto a return data packet, the acknowl(cid:173)
`edgment packet is generally very short in length.
`Most contemporary communication networks, such as
`30 frame relay and asynchronous transfer mode (ATM)
`networks, provide congestion notification mechanisms to the
`network user at the point of ingress/egress to the network.
`Unfortunately, the user equipment at the edge of the
`network, which is typically a router, generally ignores any
`35 congestion notifications since this equipment is normally
`implementing the network layer and bas no ability to control
`the flow of data at the end user session. The result is that
`when a user session is sending data at a rate higher than the
`network can handle, congestion builds within the network
`40 until the network starts discarding data. This discarded data
`is detected by the end. user session, typically through the
`TCP, which responds by slowing the data rate for the
`session. Since the discarded data must be retransmitted,
`which adds to the congestion on the network, this is a very
`45 inefficient method of providing flow control for a congested
`communication network.
`The following discussion offers an explanation of network
`congestion with reference to frame relay networks.
`However, similar mechanisms apply to most other contem-
`50 porary communication networks, such as AJM. Frame relay
`networks provide for the transport of information within a
`"committed" information rate (Cffi) as well as allowing for
`bursts of data above the committed rate, which is called the
`burst rate (Be). The network makes a best effort to deliver
`55 the burst data, as long as there is excess capacity available
`in the network. When capacity is not available, network
`congestion can occur, which generally results in information
`being discarded by the network. To prevent this loss of data
`from occurring, most communication networks, and frame
`60 relay networks in particular, provide "congestion indicators"
`that are used to notify the end users of the network when data
`on a particular connection is experiencing congestio