Enterprise Systems Technologies Sarl v. Apple Inc.

Filing 1

COMPLAINT FOR PATENT INFRINGEMENT filed with Jury Demand against Apple Inc. - Magistrate Consent Notice to Pltf. ( Filing fee $ 400, receipt number 0311-1535772.) - filed by Enterprise Systems Technologies Sarl. (Attachments: # 1 Exhibit A, # 2 Exhibit B, # 3 Exhibit C, # 4 Exhibit D, # 5 Exhibit E, # 6 Civil Cover Sheet)(els)

US006236642B1

(12) United States Patent

(10) Patent N0.:

Shalfer et al.

(54)

US 6,236,642 B1

(45) Date of Patent:

APPARATUS AND METHOD FOR
NETWORK RESOURCE PRESERVATION

*May 22, 2001

4,991,204 *
5,003,534

2/1991 Yamamoto et al. ............... .. 379/221
3/ 1991 Gerhardt et a1- -

5,012,469

4/1991 Sardana.

5,229,993

7/1993 P5116261 eet

(75) Inventors: Shmuel Sha?'er, Palo A110; William J.

geclllltecrhettal-l

Beyda’ Cupemno’ both of CA (US)
Assigneez

Siemens Information and

*

Communication Networks, Inc., Iselin,
NJ (Us)
_

5,331,631

7/1994

ThlS patent issued on a continued pros-

5,388,097

2/1995 Baugher er a1, _

5,430,710 *

7/1995 Mueller et al. ...................... .. 370/16

1.53(d), and is subject to the twenty year

5,432,845

7/1995 Burd et al. .

patent term provisions of

Notice:

_

_

12/1993 Andrews et
'
3/1994 Gilbert 61 al..

ecution application ?led under 37 CFR

(*)

_

5’271’058
5,297,144

.'
al. ............... .. 371/112

5,502,722 *

3/1996 Natarajan ............................. ..
Fulghum.

154(a)(2).

5,528,583

.

.

12/1996

5 590 118
5,590,126

Jul. 17, 1997

Cadd .

12/1996 Nederlof
12/1996 Mishra et al. .

5,602,839
5,812,524 *

Appl. N0.: 08/897,161

Filed:

6/1996 Cadd et a1‘ '

5,586,120

patent is extended or adJusted under 35
U-S-C- 154(k)) by 0 days-

(22)

6/1996 Acampora et al. .

5’528’622

Subject to any disclaimer, the term of this

(21)

Teraslinna.

2/1997 Annapareddy et al. .
9/1998 Moran et al. ...................... .. 370/228

* cited by examiner

Int. (:1-7 .............................. ..

Primary Examiner_l—luy

H04L 12/28; H04L 12/56

Vu

Assistant Examiner—M. Phan

(52)

US. Cl. ........................ .. 370/237; 370/228; 370/238;

(58)

Field Of Search ................................... .. 370/400, 254,

A data routing System for dynamically Optimizing band_

370/255> 238> 351> 394> 237> 468> 410>

Width Which includes a network control unit, a route

370/400; 370/410

252; 340/827
_

(56)

(57)

ABSTRACT

comparator, a reroute control unit and a packet reordering
unit. The network control unit reserves the initial route from

References Clted

the source node to the end node. The route comparator

U_S_ PATENT DOCUMENTS

determines Whether an alternate route is more optimal than

4,494,138 *

_
1/1985 ShFIIP -

1213/
’
’
/
4,873,517 * 10/1989

the initial route and the reroute control unit establishes the
alternate route and reroutes the data over the alternate route.

gl?hnan """"""""""""""" " 379/221

The packet reordering unit maintains the sequence of the

e Y et a ' '
BaratZ et al. ...................... .. 340/825

data packets on the alternate route.

4,907,224

3/1990 Scoles et al. .

4,929,940

5/1990 Franaszek et al. .

19 Claims, 4 Drawing Sheets

/

100

(104
Route

Comparator

( 106
Reroute
Control
Unit

(108
Packet

Reordering
Unit

U.S. Patent

May 22, 2001

150

151

154

(

Q

(

Sheet 1 0f 4

US 6,236,642 B1

156

157

158

159

Node 2

Node 1

(

)

152

<

161

Node 3

(

)

160

S

1355?

163

Router

J

(

Node 1

165

(

r162

Node 2

164

1539

<

171

Node 1

l:- I B

)

2
/ 100
/

( 102
N

( 104
C Home t

Unit

ompar a Cl’

( 106

( 108

Reroute

Packet

Control

Reordering

Unit

Unit

FIH__I

167

)

rfé‘dde

U.S. Patent

May 22, 2001

Sheet 2 0f 4

US 6,236,642 B1

200

Call Reservation

Request

A 202

Reserve Best Route
Available at This Time

Compare Cost of

f 206

Reserved Route to

Best Route
208

Best
Available Route
Reserved?

Determine Which
Router Requested
Alternate Route

Yes

/

207

i
Have Router Maintains
List of Congested Route -/ 209

Requests
l

l
Tag Selected Route

for Optimization

_/ 210

V

Assign Cost to

i

Route

Assign Cost for

Reserved Route and —/ 212
Assign Cost to Best

_

Comparison

—>

Begin Optimization
216

FIIE=_3

/ 214

U.S. Patent

May 22, 2001

Sheet 3 of 4

US 6,236,642 B1

Begin Optimization
256

254

(

Previously
Congested

Less Than

Optimal Route

Maintain Current
Route

Route Now
Available?

Reserved?

258

Delay

J

Allocate Route Based

257

on Router Table of J

Congested Routes
‘7

Request New
Reservation from
Network

253

‘J

l

Compare Cost of

263

I

Compare Cost of

255

New Reservation to j
Current

Is the
New Route

J

New Reservation to
Current

Is the
New Route
More Cost

Effective?

262

Reroute

TIE_4

U.S. Patent

May 22, 2001

Sheet 4 0f 4

US 6,236,642 B1

216

262

(

Begin Optimization )
A

Insert Delay

J 300

304

/
Remove Delay

(Std. Method)
A

f 312

f 314

K 316

Remove Delay -

Remote Delay ‘
Eliminate Silence

Eliminate Frames
Having Small

Change

I

_

gienrngg'teeDse'zée
.p.
of No Activity

Delay
Eliminated?

US 6,236,642 B1
1

2

APPARATUS AND METHOD FOR
NETWORK RESOURCE PRESERVATION

travel from the second intermediate node to the end node. In
addition, each of the intermediate nodes may require a one
millisecond transmit time. Therefore, the total travel time for
the packet Would be nineteen milliseconds on the alternate

CROSS REFERENCE TO RELATED
APPLICATIONS

This invention is related to APPARATUS AND
METHOD FOR PREVENTING NETWORK
REROUTING, Ser. No. 08/896,321 ?led on even date
herewith.

route.

As can be seen, the eXemplary alternate route may require
tWo milliseconds longer travel time for each transmitted
packet to reach the end node. Therefore, When the route is
changed from the original route to the less optimal alternate
10

BACKGROUND OF THE INVENTION

sloWer route Will reach at a time later than the last packet
transmitted on the original faster route. Similarly, When a

1. Field of the Invention
This invention generally relates to netWork resource res
ervation system and, more particularly, to a netWork rerout

15

ing system for enabling continuous dynamic optimiZation of
netWork connections anytime during call set-up and during
particular, real-time data.
2. Description of the Prior Art
It is Well knoWn that modern packet, frame, or cell based
telecommunications reservations protocols require the res

original route is seventeen milliseconds long and the alter
nate route is nineteen milliseconds long, the last data packet
transmitted on the sloWer route may reach the end node at a
time after a later sent packet on the more optimal route

ervation of bandWidth in a netWork for a particular connec
25

routes are chosen to form a connection over Which the data

Will travel.
In certain instances, the most advantageous links may be
congested at call set-up time or the requested bandWidth

reaches the end node. Because the later sent packet reaches
the end node ahead of a prior sent packet, the packets
become disordered.
Therefore, there is a need for a rerouting system Wherein
an alternate route for a communication netWork that is more

optimal than the original reserved route may be dynamically
chosen anytime both during call set-up and during the

may not be available. This causes a reservation to be made
on a route having links that are less than optimal.

Furthermore, once the reservation is made, the reserved
route may become sub-optimal at a later time, either before
or after the call is made. Unfortunately, therefore, the most
optimal routes become unavailable for use by the netWork.

call is placed on a route having relatively loW bandWidth, the
data packets Will reach the end node more sloWly than When
traveling on a route having greater bandWidth. Accordingly,

no packet ordering problem Will arise.
HoWever, packet ordering may be a problem during
fall-back. In particular, using the above eXample, if the

the duration of the call for netWorks carrying data and, in

tion. Generally, this bandWidth is reserved at the time the
call is set up. Based on the requested bandWidth, particular

route, the order of the packets Will remain unchanged
because the ?rst packet being transmitted on the alternate

duration of the call. In addition, there is a need for a system

Wherein packet ordering problems are eliminated and route

optimiZation through rerouting is enabled for real-time data.
35

Although rerouting algorithms for choosing alternate data

SUMMARY OF THE INVENTION

Brie?y, the present invention relates to a method and
apparatus for routing data in a communications netWork for
dynamically optimiZing bandWidth. The system includes a
netWork control unit for establishing an initial communica
tions route, a route comparator for determining Whether the
initial communications route is optimal, and a rerouting
control unit for establishing an alternate communications

routes for non real-time or non-isochronous data are knoWn,

they are used speci?cally in the instances of route failure and

fall-back. In particular, rerouting is used in instances Where
the originally reserved route for some reason, such as a link

failure, becomes unavailable and the connection must be

rerouted onto an alternate route. These knoWn rerouting
algorithms cause each node in a netWork to be assigned to
route When the alternate communications route is deter
one or more predetermined alternate routes. HoWever, the 45 mined to be more optimal than the initial communications

alternate routes are less optimal than the originally chosen
route because they usually have less bandWidth or a greater
number of nodes and hops than the initial route. Therefore,
rerouting is also used in a fall-back mode Wherein once the

route.

A data routing system for dynamically optimiZing band
Width according to one embodiment of the present invention

further includes a packet reordering unit for reordering data
packets to maintain the originally transmitted packet

original route becomes available again, the connection is
routed back to the original route. As mentioned above,

sequence of the data packets on the alternate route.

hoWever, route optimiZation for selecting a route more

optimal than the original reserved route is not possible.

BRIEF DESCRIPTION OF THE DRAWINGS

During any type of rerouting procedure, packet ordering
issues must be dealt With. For example, When a call is
rerouted because of a link failure, as mentioned above, the
alternate route is a less optimal one. In particular, the
original route may have only one intermediate node and tWo

hops. In this case, the total travel time for the packet may
only be eight milliseconds per hop and one millisecond at
the intermediate node, for a total of seventeen milliseconds
travel time. In contrast, the alternate route may have, for

eXample, tWo intermediate nodes and three hops. In that
case, the packet may take ?ve milliseconds to travel the hop
from the source node to the ?rst intermediate node, seven
milliseconds to travel from the ?rst intermediate node to the
second intermediate node, and another ?ve milliseconds to

55

Other features, objects and advantages of the present
invention Will become readily apparent and understood upon
consideration of the folloWing detailed description and
attached draWings, Wherein:
FIG. 1 is an overall block diagram of the netWork resource

preservation system in accordance With the present inven
tion.
FIG. 2 is a schematic diagram illustrating a typical
communication netWork.
FIG. 3 is a How diagram for establishing the initial
65 communications route.

FIG. 4 is a How diagram for optimiZing the route over
Which the data travels by selecting a more desirable route.

US 6,236,642 B1
3

4

FIG. 5 is a How diagram for rerouting the data from the
initial route to the alternate route and maintaining packet

of a communications route. The router 151 determines the

nodes and hops that are used in completing a particular
connection.
Generally, in communication netWorks, the best routes are
ones having the feWest number of hops betWeen the source
and the endpoint, Which alloWs for faster travel over the
route, or the routes having the greatest amount of bandWidth,

sequence.
DETAILED DESCRIPTION OF THE
INVENTION

The present invention is a system and method for dynamic
optimiZation of bandwidth in a communications netWork

carrying data, Which is particularly useful for real-time or
isochronous data such as voice, video or other data. The

Which alloWs more data to travel concurrently over the same

line, thereby effectively increasing data throughput through
10

Width or links may not be available and the call may be

sequence to accommodate for a more optimal route being

chosen While continuously monitoring the data stream for an
opportunity to remove the delay.
Thus, the system of the present invention provides a
platform for enabling rerouting of data over an alternate

15

placed over relatively less optimal links.
In order to take advantage, hoWever, of the most optimal
connections as resources become available, the present

invention monitors the condition of all possible links in the
netWork in real-time. This rerouting process is repeated
many times both during call set up and While a call is in
progress. Furthermore, the invention enables the rerouting

route in a communications netWork to take advantage of
available routes that provide a more optimal route than the

initially reserved route. A more optimal route generally
provides greater bandWidth or less routing delay time for the

process to utiliZe routes that are more optimal than the

original route.

same or less cost. The packet resequencing ability alloWs

rerouting to take place continuously in order to optimiZe the
call, Without causing the packet sequence to be altered at any
time. Furthermore, the system is dynamic in that alternate
routes may be established and implemented automatically
by the system at anytime during the call setup procedure and

the route. Since the most advantageous links may be con

gested When the call is being set-up, the requested band

system has the ability to insert delays for maintaining packet

In a ?rst optimiZation method, at a predetermined time
25

interval, the system veri?es that the reservation placed is still
optimal by requesting a neW reservation from the netWork.
For eXample, the NCU 102 requests a neW reservation

betWeen the currently active link connecting node 150 and
node 152. The route selected by the NCU 102 is then

at anytime While the call is in progress.
Turning noW to the draWings and With particular attention
to FIG. 1, a block diagram illustrating a netWork rerouting
and optimiZation system according to an embodiment of the

compared to the previous route. More particularly, the
eXisting route stored in the NCU 102 has a corresponding
cost determined by RC 104. The stored route’s cost is then

present invention is shoWn. The rerouting and optimiZation

compared to a neWly-calculated neW route’s cost. If found to

system 100 includes a netWork control unit (“NCU”) 102 for

be more cost effective, the reservation is changed. That is,
the RC 102 effects the route change by inserting, for

establishing an initial route betWeen a source node and an

end node. The NCU 102 stores in a memory (not shoWn) the
initially assigned route. The NCU 102 is coupled to a route
comparator (“RC”) 104 for assigning a cost for the estab

35

route. The RC 104 cooperates With the NCU 102, for

eXample, by accessing the NCU’s memory. The costs of the

routes, if the neW route is more cost effective.

routes may be based on the number of hops, the number of
nodes, or the time required per hop or per node, or any

pared against one another to determine the most advanta

108 inserts or removes delay as necessary. In another

optimiZation method, if a less than optimal reservation Was
originally placed, the router that used an alternate route
keeps a list of congested route requests. When any of the
congested routes becomes available, the system allocates the
neWly available bandWidth to one of these more optimal

lished initial route and for assigning a cost to each subse
quent route that may be contemplated as a possible alternate

combination thereof. The costs of the routes are then com

eXample, additional routing control information. The PRU

Referring to FIG. 3, a How diagram is shoWn depicting
reroute procedures to enable alternate routes to be chosen to
45 carry data. Each time a call is placed as illustrated in step

200, the NCU 102 requests a call reservation in step 202 and

geous or cost-effective alternate route. The RC 104 is

coupled to a Reroute Control Unit (“RCU”) 106 for enabling

surveys all the routes on the netWork in search of the most

the initial route to be interrupted and the neW alternate route

optimal route. A reservation is then placed for the best

to be connected, based on the cost comparison performed by
the RC 104. The RC 104 outputs its cost comparison to the

available route in step 204. Generally, the term “best” as
used herein, describes the most optimal route available
during call set-up time, based on cost comparison data. Cost
may be a function of the number of links, link speeds and
bandWidth. Therefore, the best route is a route optimally
providing fast links and greatest bandWidth at the loWest

RCU 106. The RCU 106 then causes appropriate control
information to be inserted such that the neW route is accom

plished. The RCU 106 is coupled to a Packet Reordering
Unit (“PRU”) 108 Which ensures that real-time data packets

traveling on the alternate route do not reach the end node out 55 cost.
of proper sequence. The PRU 108 does this, for eXample, by
In step 206 the route comparator 104 compares the cost of
removing gaps inherent in voice or video signals. For
the reserved route to the best route and in step 208 deter
nonisochronous data, standard methods apply.
mines Whether the best route Was reserved. If the best route
Referring to FIG. 2, a simpli?ed route for a netWork
Was not reserved because it Was not available, the system

determines Which router requested the alternate route in step
207. In step 209, the router that requested the alternate route

connection is shoWn. As can be seen, several routes are

available from the source node 150 to the end node 152.

keeps a list in memory of all the routes it found to be

Typically, communications netWorks have one or more
routers 151 and one or more intermediate nodes 154, 156,

158, 160, 162, 164 and one or more hops 157, 159, 161, 163,

165, 167, 169, 171 connecting the intermediate nodes
together. The intermediate nodes are also connected to the
source node 150 and end node 152 to complete connection

65

congested. The reserved route is then tagged for later
optimiZation in step 210 and a cost is assigned and stored to
be used for comparing With other routes in step 212. If the
best route Was reserved in step 208, then the reserved route
is also assigned a cost for comparison. The so-called best

US 6,236,642 B1
5

6

route Will be compared With other routes in the event an even
better route becomes available at a later time. After route

Real-time data, hoWever, presents a problem. For
instance, in the case of a telephone call, a packet ordering

costs have been assigned in step 214, the system then begins

problem at the end node may cause parts of conversation to
become garbled each time a more optimal route is chosen

the optimization process in step 216 to ensure that the best
available route is being utiliZed.

and packets received out of order. Retransmission of packets

Turning to FIG. 4, the optimiZation ?oW diagram 216 is

Would take too long and therefore is not a feasible solution.

shoWn Wherein the system determines Whether the current
reserved route may be optimiZed. In step 252 the system

Accordingly, the present invention monitors real-time data
in the faster link When the sloWer original link has ceased
transmitting. At that time, the added delay is removed by
removing periods of silence inherent in the real-time data.
More particularly, the system in step 302 determines
Whether real-time data is being carried by the netWork. Real
time or isochronous data is identi?ed, for eXample, by a data
type parameter or protocol element. Thus, the system knoWs
Whether the data is, for example, voice, video or other data.
If standard, non-real-time data is being transmitted, the

determines Whether a less than optimal route Was placed. As

discussed above, this may include accessing the stored list of

congested links. If by accessing the stored list, in step 254
the system checks the list of previously congested routes to
determine Whether one of these routes is noW available. If a

previously-congested more optimal route is still not found to
be available, then the current route is maintained in step 256

15

and the system returns to step 204 (FIG. 3). If, hoWever, a
loWer cost, previously-congested route is found to be avail

delay is removed in step 304 using commonly knoWn

able in step 254, then the rerouting control unit 106 Will

methods, as described above. The system then returns to the

allocate a neW route based on one of the previously con

optimiZation process in step 216. HoWever, if real-time data
is being carried on the netWork, the system then determines
if the data is voice in step 306, or video in step 308 or other
real-time data in step 310. If the system cannot determine the
type of real-time data being carried, the system returns to the
optimiZation process in step 216.

gested routes in steps 257. The cost of the neWly reserved
route is then compared to the cost of the current route in step

264. If in step 263 it is determined that the neWly reserved
route is indeed more cost effective than the current route,

then the call is rerouted to the more optimal route in step
262. If the more optimal route is not more cost effective,
then the current route is maintained in step 256.

25

at the end of sentences or pauses in conversation) and
removes the gaps from the transmitted signal. Thus, rather
than continuing to maintain the delay that Was initially
inserted to maintain packet sequence, the system removes
some of the gaps of the audio signal in step 312 and therefore
reduce the added delay. The delay removal process is

Referring once again to step 252, if it is determined that
a less than optimal route Was not reserved, that is, the then
best route Was selected, the system Will Wait a predetermined
amount of time in step 258 before requesting a neW reser
vation from the netWork in step 253. In step 255, the cost of
the neW reservation is compared to the cost of the current
route in a manner similar to that discussed above. If it is

repeated to gradually eliminate all of the delay in step 318
to catch up to the neW delivery rate so as to take best

determined in step 260 that the neW route is more cost

effective, the RCU 106 Will reroute the current call to the
optimal route in step 262. HoWever, if the neW route is not
more cost effective, then the current route is maintained in

If voice data is found to be present, the netWork senses

gaps in the voice (e.g., by detecting loWer signal levels, as

35

advantage of the neW route.

Similarly, if video data is found to be present in step 308,
the system looks out for video frames having small deltas,
that is, small changes, betWeen them, and removes these
eXtra frames in the video signal in step 314. In step 320, this
process is repeated to gradually eliminate all of the delay to

step 256.
FIG. 5 shoWs a rerouting ?oW diagram Wherein the
original route is interrupted and the optimal route, as
described above, is selected. This process may be repeated

catch-up to the neW delivery rate so as to make the most
ef?cient use of the neW route.

continuously during a single call, thereby enabling the most

Other real-time data in step 310 also has eXcess delays

optimal route available to be used at all times. A packet

reordering unit is used to ensure that data is not received at 45 removed in step 316. Once again, the process is repeated
the endpoint node out of its intended sequence.
until the delay is removed in step 322. In all cases, once the

delay has been removed, the system returns to the optimi

In particular, When the call has been rerouted to the
alternate route in step 262, a delay is entered into the route

Zation process to look for further, even more optimal,
alternate routes.

in step 300. For example, packet transit may be temporarily
paused (i.e., the packet or packets may be brie?y held in a
node buffer or memory unit). By adding this delay, packet
travel time on the neW route Will be the same as, or greater

than, the packet travel time on the original route. As such,
the packets Will be received by the endpoint in the order
transmitted.
HoWever, the advantage of the neW alternate route Would
be lost if the added delay is retained. To enable the system
to make best use of the neWly acquired bandWidth, the added

55

Patent of the United States is:
1. A netWork resource reservation system for dynamically
rerouting data packets to optimiZe bandWidth in a commu

nications netWork during call set-up time and during the
duration of a call, comprising:

delay must be removed. Generally, packet routing issues are
handled quite easily for non real-time data. If packets are
received out of order after the delay has been removed, an
error is generated by the end node or receiving unit and the
sWitched packets may be retransmitted in their proper order
over the rerouted line. With regular data, periods of inac
tivity in Which data is not transmitted can be used to catch
up to the delay. Other knoWn methods are also commonly
available to reorder out of sequence packets.

Obviously, many modi?cations and variations of the
present invention are possible in light of the above teach
ings. Thus, it is to be understood that, Within the scope of the
amended claims, the invention may be practiced otherWise
than as speci?cally described above.
What is claimed and desired to be secured by Letters

a netWork control unit for establishing an initial commu
nications route betWeen a source node and an end node

for carrying the data;
a reroute control unit for establishing an alternate com
65

munications route When said alternate communications
route is determined to be more optimal than said initial

communications route, said determination being made

US 6,236,642 B1
8

7

sequence of the data packets When said alternate predeter

periodically While a communication along said initial
communications route is ongoing, Wherein said deter

mined communications route is enabled.
9. The netWork resource reservation system of claim 8,

mination may be made more than once during said
communication, Wherein more than one alternate route

Wherein said packet reordering unit inserts delays betWeen

may be established during said communication, respon
sive to said determining; and
a packet reordering unit for enabling the real-time data

the data packets to maintain sequence of the data packets
When said alternate predetermined communications route is

enabled, said packet reordering unit for further removing
said inserted delays subsequent to said packet sequence

packets to travel to said end node in the proper
sequence after said reroute control unit establishes said
alternate communications route.
2. The netWork resource reservation system of claim 1
Wherein the data is real-time data.
3. The netWork resource reservation system of claim 1
Wherein said reroute control unit establishes said alternate
predetermined communications route at any time during the
call.
4. A netWork resource reservation system for dynamically
rerouting data packets to optimiZe bandWidth in a commu

being maintained on said alternate predetermined commu
nications route.

10. A netWork resource reservation method for dynami

cally rerouting real-time data packets to optimiZe bandWidth
in a communications netWork, comprising:
establishing an initial communications route betWeen a
source node and an end node for carrying the real-time

data packets;
determining, While a communication on said initial pre

nications netWork during call set-up time and during the
duration of a call, comprising:

determined communications route is ongoing, Whether
said initial predetermined communications route is

optimal, Wherein said determining may occur periodi

a netWork control unit for establishing an initial commu
nications route betWeen a source node and an end node

cally more than once during said communication;

for carrying the data;
a reroute control unit for establishing an alternate com

munications route When said alternate communications
route is more optimal than said initial communications

25

establishing an alternate communications route When said
alternate communications route is more optimal than
said initial communications route, Wherein more than
one alternate route may be established during said

route; and
a packet reordering unit for enabling the real-time data

communication responsive to said determining; and
enabling the real-time data packets to travel to said end

packets to travel to said end node in the proper
sequence after said reroute control unit establishes said
alternate communications route;
Wherein said reroute control unit may interrupt said

node in the proper sequence after said reroute control
unit establishes said alternate communications route.
11. A netWork resource reservation system for dynami

cally optimiZing bandWidth in a communications netWork
for enabling data to travel from a ?rst point to a second

eXisting alternate predetermined communications route
and establish a subsequent alternate predetermined
communications route multiple times during the con
nection When said reroute control unit determines that

point, comprising:
35

nications route betWeen the ?rst point and the second

said subsequent alternate predetermined communica

point for carrying the data;

tions route is optimal over said existing alternate pre

means for determining Whether said initial predetermined

determined communications route.
5. The netWork resource reservation system of claim 2

Wherein said real-time data is voice data.
6. The netWork resource reservation system of claim 2
Wherein said real-time data is video data.
7. A netWork resource reservation system for dynamically
optimiZing bandWidth in a communications netWork for
enabling data to travel from a ?rst point to a second point,

means for establishing an initial predetermined commu

communications route is optimal While a communica

tion along said initial predetermined communications
route is ongoing, Wherein said determining may peri
odically occur more than once during said communi

cation; and
45

means for establishing an alternate predetermined com
munications route to carry the data When said route

comparator determines that said alternate predeter

comprising:

mined communications route is optimal over said ini

a netWork control unit for establishing an initial prede
termined communications route betWeen the ?rst point

tial predetermined communications route, Wherein
more than one alternate route may be established

and the second point for carrying the data;

during said communication responsive to said deter

mining.

a route comparator for periodically determining Whether
said initial predetermined communications route is
optimal during a communication along said initial
predetermined communications route, Wherein said

12. The netWork resource reservation system of claim 11
further including means for maintaining sequence of the data

packets When said alternate predetermined communications

determining may occur more than once during said 55 route is enabled.

13. Asystem according to claim 4, said packet reordering

communication; and
a reroute control unit for interrupting said initial prede
termined communications route and establishing an
alternate predetermined communications route When
said route comparator determines that said alternate
predetermined communications route is more optimal
relative to said initial predetermined communications

unit adapted to determine Whether said data is voice data or
video data.

route, Wherein more than one alternate route may be

established during said communication responsive to

said determining.
8. The netWork resource reservation system of claim 7

further including a packet reordering unit for maintaining

65

14. A system according to claim 13, Wherein said packet
reordering unit is adapted to remove gaps in voice signals.
15. A system according to claim 14, Wherein said packet
reordering unit is adapted to remove video frames having
small changes from said data.
16. A netWork resource reservation system for dynami
cally rerouting data packets to optimiZe bandWidth in a

communications netWork during call set-up time and during
the duration of a call, comprising:

US 6,236,642 B1
10
a network control unit for establishing an initial commu
nications route betWeen a source node and an end node

for carrying the data;
a reroute control unit for establishing one or more alter
nate cornrnunications routes When said one or more

alternate cornrnunications routes are determined to be

more optirnal than previously established ones of said
initial cornrnunications route or one or more alternate

cornrnunications routes; and
a packet reordering unit for enabling the real-time data
packets to travel to said end node in the proper

sequence after said reroute control unit establishes said
one or more alternate cornrnunications routes.

17. A system according to claim 16, said packet reorder
ing unit adapted to determine Whether said data is voice data
or video data.

18. A system according to claim 17, Wherein said packet
reordering unit is adapted to remove gaps in voice signals.
19. A system according to claim 18, Wherein said packet
reordering unit is adapted to remove video frames having
small changes from said data.
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