U.S. patent application number 15/242108 was filed with the patent office on 2016-12-08 for system and methods for identifying and remedying traffic imbalances and inequities between networks.
This patent application is currently assigned to Level 3 Communications, LLC. The applicant listed for this patent is Level 3 Communications, LLC. Invention is credited to Isaac K. Elliott, Rebecca Greenawalt, Michael Mooney, Nicolas Pujet, Kevin John Royer, John Ryan, Mark Taylor.
Application Number | 20160359749 15/242108 |
Document ID | / |
Family ID | 57400061 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160359749 |
Kind Code |
A1 |
Taylor; Mark ; et
al. |
December 8, 2016 |
SYSTEM AND METHODS FOR IDENTIFYING AND REMEDYING TRAFFIC IMBALANCES
AND INEQUITIES BETWEEN NETWORKS
Abstract
Implementations described and claimed herein provide a system
and methods for balancing network loads across distinct provider
networks. In one implementation, a virtual network representative
of at least a first provider network is established having at least
one interconnection point where network traffic is exchanged
between the first provider network and a second provider network
and having at least one provider edge port and at least one
potential interconnection point. A measurement of a bandwidth
between the at least one provider edge port and the at least one
interconnection point is obtained. A measurement of a distance
between the at least one provider edge port and a geographically
closest of the at least one potential interconnection point or the
at least one interconnection point is obtained. A network load
indication for the first provider network as a function of the
bandwidth measurement and the distance measurement is obtained.
Inventors: |
Taylor; Mark; (Boulder,
CO) ; Royer; Kevin John; (Denver, CO) ; Pujet;
Nicolas; (Boulder, CO) ; Mooney; Michael;
(Arvada, CO) ; Ryan; John; (Longmont, CO) ;
Elliott; Isaac K.; (Broomfield, CO) ; Greenawalt;
Rebecca; (Denver, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Level 3 Communications, LLC |
Broomfield |
CO |
US |
|
|
Assignee: |
Level 3 Communications, LLC
Broomfield
CO
|
Family ID: |
57400061 |
Appl. No.: |
15/242108 |
Filed: |
August 19, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13913062 |
Jun 7, 2013 |
|
|
|
15242108 |
|
|
|
|
13683903 |
Nov 21, 2012 |
9054981 |
|
|
13913062 |
|
|
|
|
61594814 |
Feb 3, 2012 |
|
|
|
61657535 |
Jun 8, 2012 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 41/0896 20130101;
H04L 41/0654 20130101; H04L 47/125 20130101; H04L 12/46 20130101;
H04L 45/02 20130101; H04L 43/0876 20130101; H04L 12/5691 20130101;
H04L 43/0888 20130101 |
International
Class: |
H04L 12/803 20060101
H04L012/803; H04L 12/46 20060101 H04L012/46; H04L 12/54 20060101
H04L012/54; H04L 12/751 20060101 H04L012/751; H04L 12/26 20060101
H04L012/26 |
Claims
1. A method to identify a network load imbalance between
interconnected provider networks, the method comprising:
establishing a virtual network representative of at least a first
provider network, the virtual network with at least one
interconnection point where network traffic is exchanged between
the first provider network and a second provider network, the
virtual network with at least one provider edge port where the
first provider network connects to a third party network, the
virtual network with at least one potential interconnection point
where the first provider network is configurable to exchange
traffic with the second provider network; obtaining a measurement
of a bandwidth of network traffic between the at least one provider
edge port and the at least one interconnection point; assigning
either the at least one potential interconnection point or an
interconnection point of the first provider network to the at least
one provider edge port; obtaining a measurement of a distance
between the at least one interconnection point and the assigned
interconnection point, the assigned interconnection point being the
closest in geographical distance to the at least one provider edge
port of either the at least one potential interconnection point or
the interconnection point; obtaining a network load indication for
the first provider network as a function of the bandwidth
measurement and the distance measurement; and detecting a network
load balance between the network load indication and a network load
indication of the second provider network.
2. The method of claim 1, wherein the at least one potential
interconnection point is restricted to a location at which the
third party network can interconnect at a threshold scale and
exchange traffic at a threshold bandwidth.
3. The method of claim 1, wherein the at least one potential
interconnection point is restricted to a location not closer than a
specified distance to another potential interconnection point or
interconnection point in the first provider network.
4. The method of claim 3, wherein the specified distance is 50
miles.
5. The method of claim 1, wherein the at least one potential
interconnection point is served on net by at least three provider
networks.
6. The method of claim 1, wherein the first provider network allows
the second provider network to elect to access the at least one
potential interconnection point.
7. The method of claim 1, wherein the detected network load balance
indicates an imbalance between the first provider network and the
second provider network, the imbalance being indicated by the
network load indication of the second provider network being less
than a threshold percentage of the network load indication of the
first provider network.
8. The method of claim 1, wherein the distance is measured based on
the geographical latitude and longitude of two locations and the
radius of the Earth.
9. The method of claim 1, wherein the bandwidth is measured based
on a percentage of sampled bandwidth usage.
10. The method of claim 1, wherein the detected network load
balance indicates a network load imbalance between the first
provider network and the second provider network.
11. The method of claim 10 further comprising: remedying the
network load imbalance by providing an indication of a remuneration
from the second provider network to the first provider network, the
remuneration being a function of the network load indication of the
first provider network.
12. The method of claim 10 further comprising: remedying the
network load imbalance by advertising multi-exit discriminators to
the second provider network and interconnecting the first provider
network with the second provider network according to the
advertised multi-exit discriminators until a threshold is met.
13. The method of claim 10 further comprising: remedying the
network load imbalance by advertising multi-exit discriminators to
the second provider network and interconnecting the first provider
network with the second provider network according to the
advertised multi-exit discriminators until all multi-exit
discriminators are used as interconnections.
14. The method of claim 10 further comprising: remedying the
network load imbalance by establishing an interconnection between
the first provider network with the second provider network at a
potential interconnection.
15. The method of claim 1 further comprising: if the first network
provider does not allow an interconnection at the potential
interconnection point, excluding the potential interconnection
point from the operation of obtaining a measurement of a distance
between the at least one interconnection point and the assigned
interconnection point.
16. One or more non-transitory computer-readable storage media
storing computer-executable instructions for performing a computer
process on a computing system, the computer process comprising:
establishing a virtual network representative of at least a first
provider network, the virtual network with at least one
interconnection point where network traffic is exchanged between
the first provider network and a second provider network, the
virtual network with at least one provider edge port where the
first provider network connects to a third party network, the
virtual network with at least one potential interconnection point
where the first provider network is configurable to exchange
traffic with the second provider network; obtaining a measurement
of a bandwidth of network traffic between the at least one provider
edge port and the at least one interconnection point; assigning
either the at least one potential interconnection point or an
interconnection point of the first provider network to the at least
one provider edge port; obtaining a measurement of a distance
between the at least one interconnection point and the assigned
interconnection point, the assigned interconnection point being the
closest in geographical distance to the at least one provider edge
port of either the at least one potential interconnection point or
the interconnection point; obtaining a network load indication for
the first provider network as a function of the bandwidth
measurement and the distance measurement; and detecting a network
load balance between the network load indication and a network load
indication of the second provider network.
17. The one or more non-transitory computer-readable storage media
of claim 16, wherein the at least one potential interconnection
point is restricted to a location at which the third party network
can interconnect at a threshold scale and exchange traffic at a
threshold bandwidth.
18. The one or more non-transitory computer-readable storage media
of claim 16, wherein the at least one potential interconnection
point is restricted to a location not closer than a specified
distance to another potential interconnection point or
interconnection point in the first provider network.
19. The one or more non-transitory computer-readable storage media
of claim 16, wherein the detected network load balance indicates a
network load imbalance between the first provider network and the
second provider network, the computer process further comprising:
remedying the network load imbalance by providing an indication of
a remuneration from the second provider network to the first
provider network, the remuneration being a function of the network
load indication of the first provider network.
20. The one or more non-transitory computer-readable storage media
of claim 16, wherein the detected network load balance indicates a
network load imbalance between the first provider network and the
second provider network, the computer process further comprising:
remedying the network load imbalance by advertising multi-exit
discriminators to the second provider network and interconnecting
the first provider network with the second provider network
according to the advertised multi-exit discriminators until a
threshold is met.
21. The one or more non-transitory computer-readable storage media
of claim 16, wherein the detected network load balance indicates a
network load imbalance between the first provider network and the
second provider network, the computer process further comprising:
remedying the network load imbalance by establishing an
interconnection between the first provider network with the second
provider network at a potential interconnection.
22. The one or more non-transitory computer-readable storage media
of claim 16, wherein the computer process further comprises: if the
first network provider does not allow an interconnection at the
potential interconnection point, excluding the potential
interconnection point from the operation of obtaining a measurement
of a distance between the at least one interconnection point and
the assigned interconnection point.
23. A system comprising: a network optimizer module executable by a
processor and configured to establish a virtual network
representative of at least a first provider network, with at least
one interconnection point where network traffic is exchanged
between the first provider network and a second provider network,
the virtual network with at least one provider edge port where the
first provider network connects to a third party network, the
virtual network with at least one potential interconnection point
where the first provider network is configurable to exchange
traffic with the second provider network, the network optimizer
module being configured to: obtain a measurement of a bandwidth of
network traffic between the at least one provider edge port and the
at least one interconnection point; assign either the at least one
potential interconnection point or an interconnection point of the
first provider network to the at least one provider edge port;
obtain a measurement of a distance between the at least one
interconnection point and the assigned interconnection point, the
assigned interconnection point being the closest in geographical
distance to the at least one provider edge port of either the at
least one potential interconnection point or the interconnection
point; obtain a network load indication for the first provider
network as a function of the bandwidth measurement and the distance
measurement; and detect a network load imbalance between the
network load indication and a network load indication of the second
provider network.
24. The system of claim 23, wherein the at least one potential
interconnection point is restricted to a location at which the
third party network can interconnect at a threshold scale and
exchange traffic at a threshold bandwidth.
25. The system of claim 23, wherein the at least one potential
interconnection point is restricted to a location not closer than a
specified distance to another potential interconnection point or
interconnection point in the first provider network.
26. The system of claim 23, wherein the network optimizer module is
further configured to detect a network load balance between the
network load indication of the first provider network and a network
load indication of the second provider network.
27. The system of claim 23, wherein the detected network load
balance indicates a network load imbalance between the first
provider network and the second provider network, the network
optimizer module further configured to: remedy the network load
imbalance by providing an indication of a remuneration from the
second provider network to the first provider network, the
remuneration being a function of the network load indication of the
first provider network.
28. The system of claim 23, wherein the detected network load
balance indicates a network load imbalance between the first
provider network and the second provider network, the network
optimizer module further configured to: remedy the network load
imbalance by advertising multi-exit discriminators to the second
provider network and interconnecting the first provider network
with the second provider network according to the advertised
multi-exit discriminators until a threshold is met.
29. The system of claim 23, wherein the detected network load
balance indicates a network load imbalance between the first
provider network and the second provider network, the network
optimizer module further configured to: remedy the network load
imbalance by establishing an interconnection between the first
provider network with the second provider network at a potential
interconnection.
30. The system of claim 23, wherein the network optimizer module is
further configured to: if the first network provider does not allow
an interconnection at the potential interconnection point, exclude
the potential interconnection point from the operation of obtaining
a measurement of a distance between the at least one
interconnection point and the assigned interconnection point.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation-in-part of U.S.
patent application Ser. No. 13/913,062, entitled "System and
Methods for Identifying and Remedying Traffic Imbalances and
Inequities between Networks," filed Jun. 7, 2013, which is
incorporated by reference in its entirety herein for all purposes.
application Ser. No. 13/913,062 is a continuation-in-part of U.S.
patent application Ser. No. 13/683,903, entitled "System and
Methods for Identifying and Remedying Traffic Imbalances and
Inequities between Networks," filed Nov. 21, 2012, which claims
benefit under 35 U.S.C. .sctn.119(e) to U.S. Provisional Patent
Application No. 61/594,814, entitled "System and Methods for
Identifying and Remedying Traffic Imbalances and Inequities between
Networks," filed Feb. 3, 2012, both which are incorporated by
reference in their entireties herein for all purposes. application
Ser. No. 13/913,062 also claims benefit under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application No. 61/657,535,
entitled "Visualization and Modeling Tool for a System of
Identifying and Remedying Traffic Imbalances and Inequities between
Networks," filed Jun. 8, 2012, which is incorporated by reference
in its entirety herein for all purposes.
TECHNICAL FIELD
[0002] Aspects of the present disclosure relate to communication
networks, and in particular, methods and systems for identifying
and remedying traffic imbalances between networks, and particularly
for backbone imbalances between provider networks carrying Internet
traffic.
BACKGROUND
[0003] Large Internet Service Providers (ISPs) maintain their own
networks with backbones stretching from coast to coast. Because no
single major ISP controls the market, it is beneficial for the
major ISPs to interconnect their networks so that users perceive
that they are interacting with a single, transparent network.
Typically, the interconnections are based on a combination of
public multi-access facilities (e.g., MAE-EAST, MAE-WEST) and
private point-to-point connections between routers controlled by
distinct providers. However, the difference in cost borne by each
of the ISPs may be so high that it is not in the interest of an ISP
to interconnect at high speed with another ISP. For example, one
ISP may bear greater costs where network traffic loads across
distinct ISPs are asymmetric resulting in a greater bandwidth use
on one network and/or where one ISP carries network traffic over a
greater distance.
[0004] It is with these observations in mind, among others, that
various aspects of the present disclosure were conceived and
developed.
SUMMARY
[0005] Implementations described and claimed herein address the
foregoing problems by providing a system and methods for balancing
network loads across distinct provider networks. In one
implementation, a virtual network representative of at least a
first provider network is established. The virtual network has at
least one interconnection point where network traffic is exchanged
between the first provider network and a second provider network.
The virtual network has at least one provider edge port where the
first provider network connects to a third party network, and the
virtual network has at least one potential interconnection point
where the first provider network may be configured to exchange
traffic with the second provider network. A measurement of a
bandwidth between the at least one provider edge port and the at
least one interconnection point is obtained. A measurement of a
distance between the at least one provider edge port and a
geographically closest of the at least one potential
interconnection point or the at least one interconnection point is
obtained. A network load indication for the first provider network
as a function of the bandwidth measurement and the distance
measurement is obtained. A network load balance between the network
load indication and a network load indication of the other provider
network is detected.
[0006] Other implementations are also described and recited
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Example implementations are illustrated in referenced
figures of the drawings. It is intended that the implementations
and figures disclosed herein are to be considered illustrative
rather than limiting.
[0008] FIG. 1 is an example network architecture connecting two
national ISPs;
[0009] FIG. 2 is a diagram illustrating traffic imbalances and
otherwise illustrating asymmetric routing which may result in
traffic imbalances;
[0010] FIG. 3 is an example network architecture for identifying
and remedying traffic or other load imbalances between
networks;
[0011] FIG. 4 is a flow chart illustrating example operations for
identifying and remedying traffic or other load imbalances between
networks;
[0012] FIGS. 5A and 5B illustrate an example network architecture
implementing multi-exit discriminators to remedy a load imbalance
between two providers;
[0013] FIGS. 6A and 6B illustrate an example network architecture
interconnecting two providers at a mutual potential interconnection
to remedy a load imbalance between the providers; and
[0014] FIG. 7 is an example computing system that may implement
various systems and methods discussed herein.
DETAILED DESCRIPTION
[0015] Aspects of the present disclosure involve peering principals
and associated systems and methodologies to remedy network load
imbalances between interconnected provider networks. In one
implementation, a bandwidth and a distance of network traffic is
measured for each of the provider networks. The measurement may be
in the form of a bit mile measurement. Specifically, bit miles for
each provider network are measured between a provider edge (PE)
port, where traffic ingresses from or egresses to a third party,
and an interconnection point, where the traffic is handed off to
another provider network. In other words, bit miles for each
provider are obtained, measured, or otherwise calculated as a
function of an amount of traffic bandwidth between the PE port and
the interconnection point and a geographical distance between the
interconnection point and a potential interconnection point or an
interconnection point assigned to the PE port using PE port
mapping. In one implementation, PE port mapping is the process of
assigning an interconnection point or a potential interconnection
point, whichever is geographically closest, to each PE port for the
purpose of measuring the distance traffic is carried. The bit miles
are measured between each relevant location, and the total measured
bit miles for a provider network is the sum of all measured bit
miles. Bit mile information for each provider network may be
exchanged to identify load imbalances between the provider
networks. Variously remedies, including, but not limited to,
payments, multi-exit discriminators, mutual potential
interconnection points, and other remedies, may be implemented to
roughly balance the bit miles between the provider networks.
[0016] In one particular aspect, provider networks exchange
Internet traffic using the border gateway protocol ("BGP"). BGP is
a telecommunications industry standard for an inter-autonomous
system routing protocol (i.e., a connected group of one or more IP
prefixes run by one or more network operators which has a single
and clearly defined routing policy), including support for both
route aggregation and Classless Inter Domain Routing (CIDR) between
the provider's Internet networks at one or more interconnection
points. As discussed herein, the term Internet network refers to an
Internet protocol network that includes interconnection points
utilizing BGP to govern the exchange of Internet traffic at the
interconnection points. In one particular example referring to
providers with Internet networks in the United States, the term
Internet network may further involve a backbone network node in at
least seven of the nine U.S. Census Bureau Divisions. The nine
divisions of the United States are generally described as New
England, Middle Atlantic, South Atlantic, East South Central, East
North Central, West North Central, West South Central, Mountain,
and Pacific. A provider's Internet network may involve one or more
of several such communications networks operated by the provider or
by entities related to the provider, each of which may have its own
autonomous system number, but all of which are directly or
indirectly connected and collectively connected to the
interconnection points.
[0017] An interconnection point is any location where providers
exchange Internet traffic (i.e., network traffic regardless of the
source, destination, or technology used to deliver the traffic
(including IPv4 and IPv6 Internet traffic)) between the providers'
Internet networks. Again, referring to a United States based
example, the initial interconnection points may be in at least six
of the nine U.S. Census Bureau Divisions and may include at least
one city on the east coast, one in the central region, and one on
the west coast.
[0018] Traffic delivered from a customer of an ISP to a destination
that is not on the ISP's network traverses an end-to-end path that
includes three segments: (1) a segment from the ISP's customer
through the ISP's network; (2) a segment represented by the
interconnection point between the ISP and a target ISP that serves
the destination; and (3) a segment across the target ISP to the
destination. To reduce congestion, it is often desirable to build
both a network and a service model that reduces bottlenecks on all
three of these path segments.
[0019] An ISP may only have direct control over bandwidth in the
first segment, while being dependent on the target ISP partially
with respect to the second segment and entirely with respect to the
third segment. An ISP may reduce these dependencies by implementing
a "local delivery" or "best exit"-like service model that engineers
end-to-end paths utilizing the ISP's own network as much as
possible.
[0020] Traffic between one ISP and another ISP may be exchanged in
what is known as "shortest-exit" manner. Under a "shortest exit"
exchange, traffic originating from one ISP's customer (the source)
that is destined for another ISP's customer (the destination) is
sent toward the topologically closest interconnection point between
the source and the destination. Where the source and destination
are not geographically or topologically close to each other, the
result tends to be higher costs borne by the destination's ISP. If
a first ISP has only large content sites as customers and a second
ISP provides only connectivity to content consumers, the cost
differences may be so high that it is not in the interest of the
second ISP to interconnect at high speed with the first ISP.
[0021] For example, consider traffic sent by a customer, whose
content is hosted in a data center in San Jose, Calif. by the "ABC"
ISP, across the "XYZ" ISP to a destination located in Washington,
D.C. Assuming that ABC and XYZ can exchange traffic in two
locations: one near San Jose, Calif. and the other near Washington,
D.C., network traffic flows as follows: (1) a Washington,
D.C.-based customer of XYZ sends a request a short distance across
the XYZ network to the interconnection point near Washington, D.C.;
(2) the request enters the ABC network near Washington, D.C. and is
carried a long distance across the ABC network to the San Jose data
center; (3) a reply is created by the content server in the San
Jose data center and is sent a short distance across the ABC
network to the nearest interconnection point near San Jose; and (4)
the reply is carried a long distance across the XYZ network from
the San Jose area to the customer in the Washington, D.C. area. The
traffic flow is asymmetric, with the ABC network carrying the
majority of the content request and the XYZ network carrying the
majority of the content reply. Because content replies are
typically far larger than content requests, often, by many orders
of magnitude (for example, a 100-or-so-byte request can easily
result in a multi-megabyte JPG image being returned), the result is
greater bandwidth use on the XYZ network and thus greater cost to
its ISP. Such traffic imbalances and asymmetric routing is
illustrated in FIGS. 1 and 2.
[0022] Referring to FIG. 1, which is an example network
architecture connecting two national ISPs, an end user 110 located
near San Jose, Calif., may connect to the Internet through an ISP
"A" San Jose point-of-presence (POP) 120. ISP A also may provide
interconnections to one or more other networks, for example, an ISP
B San Jose POP 130. In addition to interconnections with other
providers, ISP A may maintain a wide area network (WAN) 140 to
provide connections between various POPs of ISP A that are
distributed across the country. In FIG. 1, ISP A WAN 140 and ISP B
WAN 150 interconnect San Jose and Washington, D.C. POPs. ISP B DC
POP 160 provides a network connection for a web server 170 as well
as an interconnection with ISP A DC POP 180. The network
architecture shown in FIG. 1 is a simple example of a network
architecture connecting two national ISPs. Other, far more complex
implementations are contemplated.
[0023] FIG. 2 is a diagram illustrating traffic imbalances and
otherwise illustrating asymmetric routing which may result in
traffic imbalances. As shown in FIG. 2, packets sent between the
end-user 110 and the web server 170 are often routed
asymmetrically. In other words, packets sent from the end user 110
to the web server 170 may take a different path than packets
returned from the web server 170 to the end user 110. For example,
if the end user 110 requests a web page from the web server 170,
the request is routed through ISP A San Jose POP 120. Routers at
the San Jose POP maintain routing tables describing how to route
packets based on the destination address. To simplify routing table
information, networks are typically aggregated. For example, ISP B
may be assigned the network address 192.168.x.x. The subnet address
192.168.1.x may be selected for the ISP B DC POP 160 while
192.168.2.x may be selected for the ISP B San Jose POP 130. Instead
of advertising routes to both 192.168.1.x through Washington, D.C.
and 192.168.2.x through San Jose, the routes likely will be
aggregated so that both POPs 130 and 160 advertise a single
192.168.x.x route, thus decreasing the size of routing tables that
must be maintained.
[0024] Because the ISP B San Jose POP 130 advertises routes to ISP
B DC POP 160 networks, the ISP A San Jose POP 120 routes a request
from the end user 110 to the web server 170 through the ISP B San
Jose POP 130. The request travels across ISP B WAN 150 to the ISP B
DC POP 160 and then to web server 170.
[0025] A reply sent from the web server 170 to the end user 110
will likely take a different route, as illustrated in FIG. 2.
Because the ISP A DC POP 180 advertises a route to the network used
by the end user 110, packets are routed from the web server 170
through the ISP B DC POP 160 to the ISP A DC POP 180. Then, the
reply travels across ISP A WAN 140 to the ISP A San Jose POP 120 to
the end user 110.
[0026] Packets sent from the end user 110 to the web server 170
travel most of the distance across ISP B WAN 150, and packets sent
the other direction travel most of the distance across ISP A WAN
140. As discussed above, the reply is often larger than the
request. Thus, ISPs supporting large numbers of end users (e.g.,
ISPs selling directly to consumers) end up carrying a greater
portion of transmitted information than ISPs supporting mostly
information suppliers (e.g., ISPs engaged in server co-location and
web hosting). Connecting customers that are large traffic sources
to POPs that are not close to the interconnection points may
trigger a need for additional backbone capacity.
[0027] Costs of interconnection can be reduced by keeping traffic
sources topologically close to the points where connections to
other ISPs are located, because the bulk of traffic originating at
those sources is usually headed toward destinations on other ISPs'
networks. Keeping the sources close to the exit points reduces the
number of links on the backbone that the traffic must cross and
therefore reduces the cost of transporting the traffic. Traffic
exchange arrangements between ISPs typically have been based on
three principles. First, networks are interconnected at multiple,
geographically-diverse points, typically including at least one
point on the east coast and one point on the west coast, in the
case of the United States. Second, routing information exchanged at
the interconnection points should be identical. Third, network
traffic is routed using a "closest-exit" or "hot-potato" approach
(i.e., traffic is routed through the topologically-closest exit
point on the source ISP's network).
[0028] These arrangements place the bulk of the burden of
distributing traffic across long distances on the receiver of the
traffic. An ISP may have a different cost structure from a distinct
ISP for a variety of reasons. For example, ISPs which are sources
of data (i.e., which house large web farms) tend to have much lower
costs associated with interconnection than those that connect large
numbers of data consumers (i.e., those with lots of dialups or
other end-users) because, on average, they carry traffic much
shorter distances.
[0029] The "closest-exit" cost model is easy to implement and
reasonably fair, as long as the providers involved are of
approximately the same size, exchange roughly the same amount of
traffic in each direction, assume comparable costs, and derive
comparable benefits from the interconnection arrangement. As the
Internet has grown and the market has become somewhat divided into
data producers (principally, web-hosting) and consumers (those
which connect end-users), the larger ISPs are recognizing that
being on the receiving side of a traffic imbalance drives up costs
without increasing revenue. The result is that larger ISPs resist
establishing or expanding interconnections with large data
sources.
[0030] FIG. 3 is an example network architecture 300 for
identifying and remedying traffic or other load imbalances between
networks. It should be understood that the network architecture
shown in FIG. 3 is for illustrative purposes, and other more
complex implementations could and would very likely be provided. As
shown in FIG. 3, in an example implementation, a third-party
network 310 connects to a first provider network, Provider 320,
which is configured to exchange network traffic with a second
provider network, Provider 330.
[0031] Generally speaking, neither Provider 320 nor Provider 330 is
configured to restrict Internet traffic flowing through
interconnection points from the other provider network based on the
content, type, or subject matter of the traffic being exchanged,
with some exceptions. Although, Provider 320 and Provider 330 may
be configured with various conventional security measures.
Moreover, Provider 320 and Provider 330 may route and exchange
Internet traffic using third-party networks, data, and content
sources. In a representative example, Provider 320 and Provider 330
each include a fully redundant backbone network, in which the
majority of inter-hub trunking links have a capacity of 9953 Mbps
(OC-192). Moreover, Provider 320 and Provider 330 each maintain a
NOC and a communicated escalation schedule. A NOC is a fully
staffed network operations center that operates on a 24 hours/day,
7 days/week basis. Provider 320 and Provider 330 each register
routes, routing domains, and routing policies of their respective
public Internet subscribers in a public Internet Routing Registry.
Further, Provider 320 and Provider 330 implement configuration
changes to match changes in Internet Routing Registry policy.
Finally, Provider 320 and Provider 330 typically will maintain a
consistent routing announcement. Thus, Provider 320 and Provider
330 present the same Autonomous System number at all
interconnection points, except in circumstances when such is
technically difficult, not possible, or otherwise not
advisable.
[0032] To remedy imbalances in network traffic carried between
Provider 320 and Provider 330, each provider only announces routes
for paid traffic exchanged with their customers, and one or both of
Provider 320 and Provider 330 may not advertise routes restricted
to only the other provider. Notwithstanding, Provider 320 sending
traffic to Provider 330 may send traffic only to the routes
announced by Provider 330 pursuant to the load inequity balancing
methodologies and systems set out herein, for example.
[0033] Provider 320 and Provider 330 may be configured in various
ways to remedy load imbalances and other inequities. For example,
neither Provider 320 nor Provider 330 may be configured with a
route of last resort directed toward the other. Moreover, Provider
320 and Provider 330 may fully exchange explicit routes comprising
public Internet service destinations of entities to which either
Provider 320 or Provider 330 is obligated to handle traffic. In one
particular implementation, all route announcements between Provider
320 and Provider 330 are filtered by prefix. Further, Provider 320
and Provider 330 may each be required to disclose all routes on its
Internet Network through route-views.oregon-ix.org or a similar
site. Finally, Provider 320 and Provider 330 may each be configured
so as not to forward traffic for destinations not explicitly
advertised, reset next-hop, or providing next-hop to other
networks.
[0034] With ever increasing traffic, in one example, the
interconnection points between Provider 320 and Provider 330 are
monitored for actual carried capacity relative to the available
capacity. Further, when the circuit utilization (an example of
actual capacity) exceeds a capacity threshold (e.g., 70% for four
or more consecutive hours on five or more consecutive days), then
an alert or some other form of notice is generated. The notice may
then prompt an augmentation of the interconnection point by either
or both of Provider 320 and Provider 330.
[0035] To identify and remedy a traffic or other load imbalance and
thereby equitably share backbone costs and burdens, the methods and
systems set out herein involve a measurement of the both the
bandwidth and distance of Internet traffic handled by one or both
of Provider 320 and Provider 330. In one particular example, the
measurement is the form of a bit mile measurement and may also take
into account potential interconnection points of a virtual provider
network, as described below.
[0036] In one implementation, the network architecture 300 includes
at least one provider edge port (PE port) 340, at least one
Autonomous System Border Port (ASB port) 350, and at least one a
potential interconnection (PI point) 380. A PE port is a port that
connects a provider network with a network administered by a
third-party network provider, which is typically an ISP. For
example, as shown in FIG. 3, the PE port 340 connects the
third-party network 310 with Provider 320. An ASB port or
"Autonomous System Border Port" is a port on one provider network's
Internet network, running external BGP, that is connected (may be
directly connected) to the Internet network of another provider
network. For example, in FIG. 3, the ASB port 350 is located at an
interconnection point where network traffic is exchanged between
Provider 320 and Provider 330. A PI point is a location where a
provider network may be configured to exchange traffic with another
provider network. For example, as shown in FIG. 3, the PI point 380
is a location that Provider 320 may make available as an
interconnection point to exchange traffic with Provider 330.
[0037] Provider 320 and Provider 330 each include network
intelligence tools, including PE port mapping, to accurately
measure bit miles (and all elements thereof) for all Internet
traffic exchanged over interconnection points. Moreover, Provider
320 and Provider 330 each include network management systems that
enable the equitable balancing of bit miles across Provider 320 and
Provider 330 in accordance with the remedies set out herein.
Further, in some implementations, Provider 320 and Provider 330 can
implement and support multi-exit discriminators (MEDs). For
example, if Provider 320 is advertising MEDs, Provider 320 would be
required to prefer Internet traffic routes to the interconnection
point that is the closest to the egress PE Port for Internet
traffic at each of the PI Points and ASB Ports of Provider 320.
[0038] As can be understood from FIG. 3, bit miles for Provider 320
are measured between the PE port 340, where Internet traffic
ingresses Provider 320 from the third-party network 310, and the
ASB port 350, where part of that traffic was handed off to Provider
330. Bit miles for Provider 320 are then obtained or calculated as
the product of (i) an amount of traffic bandwidth 360 from the PE
port 340 to the ASB port 350 and (ii) a geographical distance 370
between the ASB port 350 and the PI point 380 or an ASB port
assigned to the PE port 340 using PE port mapping. Provider 320 may
only count miles if Provider 330 has an opportunity to interconnect
in new locations (e.g., PI points) to carry traffic that would
otherwise be imbalanced. Miles between a PE port and the PI point
or ASB port assigned to the PE port using PE port mapping (e.g., PE
port mapping 390) are not counted in the bit miles measurement or
calculation.
[0039] In one implementation, the amount of traffic bandwidth 360
may be measured using a 95.sup.th Percentile Method, which is a
traffic measurement technique whereby bandwidth usage is sampled
every 5 minutes over a calendar month, the top 5% of such samples
are discarded, and the next highest 95.sup.th percentile
measurement is used. However, it will be appreciated by those of
ordinary skill that other traffic measurement techniques may be
utilized to determine the amount of traffic bandwidth 360.
[0040] The geographical distance 370 is measured between the ASB
port 350 and the geographically closest of a PI point or an ASB
port assigned to the PE port 340 using PE port mapping. In the
example implementation shown in FIG. 3, the PI point 380 is
assigned to the PE port 340 using PE port mapping 390. The PI point
380 is a location that may become an interconnection point to
remedy inequities, particularly in backbone traffic, as identified
using bit mile measurements. Thus, a virtual network representative
of Provider 320 may be established with the PI point 380, as well
as interconnection points, including the ASB port 350, and third
party network ingress ports, such as the PE port 340.
[0041] In some implementations, the PI point 380 is defined using
at least three criteria. First, the PI point 380 is restricted to a
point at which a customer or other network provider of Provider
320, such as the third-party network 310, can interconnect at least
at 10 GE scale using BGP sessions, or as otherwise specified, and
where exchanged traffic would not be less than 3 Gbps, or some
other bandwidth, on a monthly basis. The exchanged traffic may be
measured using the 95.sup.th Percentile Method and aggregating the
traffic of all PE ports that would be mapped to the PI point 380 if
implemented, in this case the PE port 340. Second, the PI point 380
is not closer than 50 miles, or some other distance, to any other
PI Point or ASB Port, such as the ASB port 350, on the Internet
Network of Provider 320. Third, the PI point 380 is either: (a)
served on net by at least three competitive providers of
communications service; or (b) allowed, at the election of Provider
330, to be placed on net by Provider 330 (i.e., by allowing
Provider 330 to access the PI point 380 via fiber or other
connectivity, without charge) or to be accessed at various times
via lit services provided by Provider 320 at commercially
reasonable rates for the relevant metropolitan statistical
area.
[0042] The geographical distance 370 may be measured using various
measures of geographical distance. For example, in one
implementation, the geographical distance 370 is measured using
"Great Circle Miles," which is calculated based on the following
equation, where lat.sub.a,lon.sub.a; lat.sub.b, lon.sub.b are the
geographical latitude and longitude of the two locations a and b,
measured in radians, and 3963 represents the radius of the Earth
measured in miles:
GreatCircleMiles=3963.times.arccos
[sin(lat.sub.a)sin(lat.sub.b)+cos(lat.sub.a)cos(lat.sub.b)cos(lon.sub.b-l-
on.sub.a)]
[0043] As an example, if the amount of traffic bandwidth between
the PE port 340 and the ASB port 350 is measured at 1 Mbps during a
month and the Great Circle Miles between the PI point 380 and the
ASB port 350 is 500 miles, the Measured Bit Miles would be
500,000,000 bit miles (or 500 megabit miles).
[0044] Bit miles for Provider 320 are also measured for each ASB
port where Internet traffic was received from Provider 330 and for
each PE port where part of that traffic then egresses to a third
party, such as the third-party 310. In such instances, bit miles
are measured, calculated or otherwise obtained by the product of
(i) the amount of traffic bandwidth from that ASB port to that PE
port, which may be measured, for example, using the 95.sup.th
Percentile Method and (ii) the geographical distance between that
ASB Port and the PI Point or ASB Port assigned to that PE Port
using PE port mapping, which may be obtained, for example, using
Great Circle Miles, as described herein.
[0045] Bit miles are measured between each relevant location. The
total measured bit miles is the sum of all measured bit mile
calculations. The bit miles and total bit miles are measured and
calculated for Internet traffic carried on each of Provider 320 and
Provider 330.
[0046] FIG. 4 is a flow chart illustrating example operations 400
for identifying and remedying traffic or other load imbalances
between networks. An establishing operation 410 establishes a
virtual network representative of at least a first provider
network. The virtual network including at least one interconnection
point where network traffic is exchanged between the first provider
network and a second provider network. In one implementation, the
establishing operation 410 identifies relevant ports as either PE
ports or ASB ports and identifies PI points. The virtual network
has at least one PE port where the first provider network connects
to a third party network and may have one or more PI points where
the first provider network may be configured to exchange traffic
with the second provider network. The virtuality of the network is
imparted through the identification of one or more PI points, among
other things.
[0047] A bandwidth obtaining operation 420 obtains a measurement of
an amount of traffic bandwidth between the interconnection point
and the PE port. In one implementation, the bandwidth obtaining
operation 420 obtains the measurement using the 95.sup.th
Percentile Method, as described herein. In other implementations,
the bandwidth obtaining operation 420 obtains the measurement using
other traffic measurement techniques.
[0048] A distance obtaining operation 430 maps the PE port to a
geographically closest interconnection point, which may be a PI
point or an interconnection point, such as an ASB port. In some
cases, the geographically closest interconnection point may be in
the same location as the PE port. The distance obtaining operation
430 obtains a measurement of the geographical distance between the
at least one interconnection point and the geographically closest
interconnection point. In one implementation, the distance
obtaining operation 430 obtains the measurement using "Great Circle
Miles," as described herein. In other implementations, the distance
obtaining operation 430 obtains the measurement using other
techniques to measure geographical distance.
[0049] A network load obtaining operation 440 obtains a network
load indication for the first provider network as a function of the
bandwidth measurement obtained in the bandwidth obtaining operation
420 and of the distance measurement obtained in the distance
obtaining operation 430. Specifically, the network load obtaining
operation 440 obtains a measured bit mile calculation between each
relevant location in the first provider network by repeating
operations 420 and 430 as necessary. The network load obtaining
operation 440 obtains a total measured bit miles, which is the sum
of all measured bit mile calculations, for the first provider
network.
[0050] The operations 410, 420, 430, and 440 may be performed with
respect to the second provider network to obtain a network load
indication of the second provider network. In one implementation, a
detecting operation 450 uses the network load indications to
identify load or traffic imbalances between the first and second
provider networks, from which the load imbalances may be remedied
through network reconfigurations and otherwise. In one example,
each network provider measures its bit miles using the operations
410, 420, 430, and 440 and exchanges that data with the other
network provider. The detecting operation 450 compares the
exchanged bit mile information to identify imbalances according to
any number of possible factors. In one particular example, the
detecting operation 450 may identify an imbalance if the total
measured bit miles for one provider network is less than 70% of the
bit miles carried on the other provider network. When the detecting
operation 450 identifies an imbalance, a number of remedies may
follow.
[0051] A remedying operation 460 remedies an imbalance or other
inequity, or otherwise provider indication of potential remedies,
between the first and second provider networks identified in the
detecting operation 450. Generally speaking, various remedies are
possible, including altering or augmenting routing practices and/or
the location(s) of the interconnection points in a manner that will
remedy inequities in total measured bit miles. For example, MEDs
may be implemented and/or interconnection points may be placed
closer to the origin/destination locations on the other network
provider's Internet network, provided that the ports at such new
interconnection points are utilized at appropriate levels.
[0052] The following describes several operations that may be
implemented, alone or in combination with the other operations, and
in any particular order, to remedy bit mile inequities. In the
event that during any measurement period (e.g., a calendar quarter)
the measured bit miles carried on the second provider network are
less than a percentage (e.g., 70%) of the measured bit miles
carried on the first provider network and the first provider
network was using first-exit routing for all relevant traffic, then
the first provider network may invoke a remedy to the inequity, in
one particular and possible implementation conforming with various
aspects of the present disclosure. First-exit routing, for example,
is the routing by a network provider of Internet traffic to the
closest interconnection point from where such Internet traffic
ingresses that network provider's Internet network.
[0053] As described below, there are several possible remedies,
including payments, advertising new MEDs and interconnecting in
response at existing interconnection points, and interconnecting at
a point that was defined in the virtual network as a PI point.
These remedies may be used alone or in combination and may include
other remedies, as well.
[0054] When the detecting operation 450 detects or otherwise
discovers an imbalance or inequity, the remedying operation 460 may
remedy the imbalance or inequity by providing indication of a
remuneration that is a function of the network load indications. As
an example, the second provider network, carrying less than 70% of
the bit miles of the first provider network, may account for the
difference through remuneration, which may be electronic, to the
first provider network. In one implementation, the remuneration is
defined in terms of a fee that may be calculated by multiplying a
value (e.g., 2) by the number of total measured bit miles that
would be required to reach 70% of the total measured bit miles
carried on the first provider network. As an example only, if the
total measured bit miles for the first provider network is 1
million and the total measured bit miles for the second provider
network is 500,000, the second provider network transmits or
otherwise provides a fee, which may be calculated monthly, in the
amount of $400,000 (200,000 Bit Miles needed to reach the 70%
threshold, multiplied by value of 2). The payment may be electronic
and determined and invoiced automatically or may be a more
conventional transaction where the first network provider sends and
invoice to the second network provider and payment is made.
[0055] In an alternative, when the detecting operation 450 detects
or otherwise discovers an imbalance or inequity, the remedying
operation 460 may remedy the imbalance or inequity by advertising
MEDs and interconnecting according to the advertised MEDs until a
threshold balance is met or MEDs are used at all interconnections.
For example, the first network provider, carrying the greater of
the bit mile imbalance, may advertise, to the second network
provider, MEDs at all interconnection points on its Internet
network. The second provider network is configured to accept MEDs
at any or all of the then current interconnection points as
necessary to remedy the bit mile imbalance. Following the
implementation of MEDs, each provider network monitors the flow of
Internet traffic to determine whether, over some period of time,
the total measured bit miles carried on the second provider network
is still less than some percentage (e.g., 70%) of the total
measured bit miles carried on the first provider network. This may
be repeated until the bit mile inequity is remedied or until the
second provider network has accepted MEDs at all of the then
current interconnection points, in one example.
[0056] An example of this remedy is illustrated in FIGS. 5A and 5B,
which shows a load imbalance and balance, respectively, between
Provider A and Provider B. The arrows in FIGS. 5A and 5B represent
the path traveled by the network traffic, the dotted lines
represent PE port mapping, the large broken line represents
distance that is measured for the bit mile calculation, and the
broken, dotted line represents the interconnection point between
Provider A and Provider B. As shown in FIG. 5A, Provider B carries
the bit mile burden. Provider A receives traffic from a third-party
on the west coast at a PE port 510 and hands the traffic to
Provider B at ASB port 530. Provider B then carries the traffic to
the east coast via ASB port 540 and PI point 550 to PE port 520. To
remedy the imbalance, Provider B may advertise MEDs to change the
ASB port that is used as an interconnection, thereby shifting bit
miles to Provider A. As shown in FIG. 5B, once MEDs are
implemented, ASB port 560, which may be the same or different than
the ASB port 540, is used as an interconnection. Provider A carries
the traffic through ASB port 530 to ASB port 560, where Provider A
hands the traffic to Provider B, who then carries the traffic to
the east coast via ASB port 540 and PI point 550 to PE port 520.
Accordingly, as shown in FIG. 5B, once the MEDs are implemented,
the bit miles are roughly balanced between Provider A and Provider
B.
[0057] If, after the implementation of MEDs, as set forth above,
the total measured bit miles carried on the second provider network
are still less than some percentage (e.g. 70%) of the total
measured bit miles carried on the first provider network, then the
remedying operation 460 may allow additional interconnection points
by the second provider network. The new interconnection points will
be at existing PI points.
[0058] In one implementation, the selection of the new
interconnection points may be prioritized based on a combination of
traffic and distance. The PI points in the first provider network
will be ranked, highest to lowest, based on the measured bit miles
of some time earlier, such as a period of time immediately
preceding the determination of the inequity. In one example, the
first provider network will identify PI points that allow the
second provider network to alleviate some percentage, e.g., at
least 200%, of the amount of measured bit miles the second network
provider would need to add to its network so that it is carrying at
least the threshold percentage, e.g., 70%, of the total measured
bit miles as are carried on the first provider network. All such PI
points may be available as additional interconnection points. The
second network provider may establish an interconnection at any of
the PI points. In conjunction, the first and second network
providers will implement MEDs at these new interconnection points,
as necessary to correct the inequity. Generally speaking, the first
provider network will advertise MEDs and the second provider
network will honor MEDs.
[0059] To prevent gaming and otherwise ensure proper management of
the networks, when the provider network carrying more total
measured bit miles chooses not to allow deeper interconnections,
such as through providing access at PI points, some or all of the
measured bit miles involving the PI point refused as an
interconnection point may be excluded from the total measured bit
mile measurements going forward until such interconnection point is
allowed and implemented. In such event, the first and second
network providers reassess the effect of the removal of such
traffic from the total measured bit mile calculations, and if the
total measured bit miles carried on the second provider network are
still less than the established threshold (e.g., 70%) of the total
measured bit miles carried on the first provider network, then some
or all of the inequity remedies set out herein may be
implemented.
[0060] An example of implementation interconnecting two providers
at a mutual PI point to remedy a load imbalance between the
providers is illustrated in FIGS. 6A and 6B, which shows a load
imbalance and balance, respectively, between Provider A and
Provider B. The arrows in FIGS. 6A and 6B represent the path
traveled by the network traffic, the dotted lines represent PE port
mapping, the large broken line represents distance that is measured
for the bit mile calculation, and the broken, dotted line
represents the interconnection point between Provider A and
Provider B. As shown in FIG. 6A, Provider A carries the bit mile
burden. Provider A receives traffic from a third-party on the east
coast at a PE port 610 and carries the traffic via PI points 630
and 640 to ASB port 650, where Provider A hands the traffic to
Provider B. Provider B then carries the traffic a short distance
via PI point 660 to PE port 620. To remedy the imbalance, Provider
A and Provider B may interconnect at a mutual PI point 670, thereby
shifting bit miles to Provider B. As shown in FIG. 6B, once
Provider A and Provider B interconnect at the mutual PI point 670,
the bit miles are roughly balanced between Provider A and Provider
B. Provider A carries the traffic through to ASB port 670, where
Provider A hands the traffic to Provider B, who then carries the
traffic to PE port 620 via ASB ports 650 and 670 and PI point
660.
[0061] If after the various steps set out herein failure to remedy
the bit mile inequity, then some additional remedy may be possible.
In a simple example, the second network provider may provide
remuneration to the first network provider in accordance with
various possibilities, including those set out above.
[0062] Additional practical actions may be required by either
network provider to fully realize the resolution of inequities. For
example, if an interconnection point is owned or controlled by one
network provider but is not on-net to the other network provider,
then the owning or controlling provider should allow the
interconnection point to be y) placed on net by the other provider
(i.e., by allowing them to access the location via fiber or other
connectivity), or z) accessed via lit services provided by the
owning or controlling provider or (ii) ensure that the
interconnection point is served on-net by other competitive
providers of communications service.
[0063] FIG. 7 is an example computing system 700 that may implement
various systems and methods discussed herein. The computer system
700 includes one or more processors 710. The processor 710 may
include one or more internal levels of cache (not shown) and a bus
controller or bus interface unit to direct interaction with the
processor bus 705. The processor 710 may include a network
optimizer module 760 that specifically implements the various
methods discussed herein. The main memory 720 may include one or
more memory cards and a control circuit (not shown), or other forms
of removable memory, and may store a network optimizer application
765 including computer executable instructions, that when run on
the processor, implement the methods and system set out herein.
Other forms of memory, such as a mass storage device 735, a read
only memory 730, and a removable storage memory 725, may also be
included and accessible, by the processor (or processors) 710 via
the bus 705.
[0064] The computer system 700 may further include a communication
port 715 connected to a transport and/or transit network 755 by way
of which the computer system 700 may receive network data useful in
executing the methods and system set out herein as well as
transmitting information and network configuration changes
determined thereby. The computer system 700 may include an I/O
device 740, or other device, by which information is displayed,
such as at display screen 750, or information is input, such as
input device 745. The input device 745 may be alphanumeric input
device, including alphanumeric and other keys for communicating
information and/or command selections to the processor. The input
device 745 may be another type of user input device including
cursor control, such as a mouse, a trackball, or cursor direction
keys for communicating direction information and command selections
to the processors 710 and for controlling cursor movement on the
display device 750. In the case of a tablet device, the input may
be through a touch screen, voice commands, and/or Bluetooth
connected keyboard, among other input mechanisms. The system set
forth in FIG. 7 is but one possible example of a computer system
that may employ or be configured in accordance with aspects of the
present disclosure.
[0065] In the present disclosure, the methods disclosed may be
implemented as sets of instructions or software readable by a
device. Further, it is understood that the specific order or
hierarchy of steps in the methods disclosed are instances of
example approaches. Based upon design preferences, it is understood
that the specific order or hierarchy of steps in the method can be
rearranged while remaining within the disclosed subject matter. The
accompanying method claims present elements of the various steps in
a sample order, and are not necessarily meant to be limited to the
specific order or hierarchy presented.
[0066] The described disclosure may be provided as a computer
program product, or software, that may include a machine-readable
medium having stored thereon instructions, which may be used to
program a computer system (or other electronic devices) to perform
a process according to the present disclosure. A machine-readable
medium includes any mechanism for storing information in a form
(e.g., software, processing application) readable by a machine
(e.g., a computer). The machine-readable medium may include, but is
not limited to, magnetic storage medium (e.g., floppy diskette),
optical storage medium (e.g., CD-ROM); magneto-optical storage
medium, read only memory (ROM); random access memory (RAM);
erasable programmable memory (e.g., EPROM and EEPROM); flash
memory; or other types of medium suitable for storing electronic
instructions.
[0067] The description above includes example systems, methods,
techniques, instruction sequences, and/or computer program products
that embody techniques of the present disclosure. However, it is
understood that the described disclosure may be practiced without
these specific details.
[0068] It is believed that the present disclosure and many of its
attendant advantages will be understood by the foregoing
description, and it will be apparent that various changes may be
made in the form, construction and arrangement of the components
without departing from the disclosed subject matter or without
sacrificing all of its material advantages. The form described is
merely explanatory, and it is the intention of the following claims
to encompass and include such changes.
[0069] While the present disclosure has been described with
reference to various embodiments, it will be understood that these
embodiments are illustrative and that the scope of the disclosure
is not limited to them. Many variations, modifications, additions,
and improvements are possible. More generally, embodiments in
accordance with the present disclosure have been described in the
context of particular implementations. Functionality may be
separated or combined in blocks differently in various embodiments
of the disclosure or described with different terminology. These
and other variations, modifications, additions, and improvements
may fall within the scope of the disclosure as defined in the
claims that follow.
* * * * *