text:
The Duty of Promoting Christian Education.
BrowseBrowseInterestsBiography & MemoirBusiness & LeadershipFiction & LiteraturePolitics & EconomyHealth & WellnessSociety & CultureHappiness & Self-HelpMystery, Thriller & CrimeHistoryYoung AdultBrowse byBooksAudiobooksComicsSheet MusicBrowse allUploadSign inJoinBooksAudiobooksComicsSheet MusicWelcome to Scribd! Start your free trial and access books, documents and more.Find out moreTHE DUTY OF PROMOTI G CHRISTIA EDUCATIO . BY JOH BIRD SUM ER, D.D.Matt. xix. 13. Suffer little children, and forbid them not, to come unto me. THESE words were mercifully spoken, and are mercifully left for our instruction. Little children were brought to the Lord Jesus by their friends or parents, " that he should put his hands upon them, and pray ; and the disciples rebuked them." He was engaged in solemn discourse, and they did not approve the interruption. But Jesus said, Suffer little children, and forbid them not, to come unto me, for of such is the kingdom of heaven. As much as to say, I am come into the world to give the very thing which these parents desire : to give a blessing. Do not deprive these children of
THE DUTY OF, &C. 115 it. Partakers of Adam's sinful nature, let them also be " partakers of the divine nature." Inheritors of that ruin, under which " the whole creation groaneth and travaileth in pain," let them also share in that restoration which comes through " the second Adam." Let them be "renewed in knowledge, after the image" which they have lost. Born to labour and sorrow, let them also inherit that which can alleviate sorrow, and cheer the weariness of labour. Suffer little children to come unto me. They who enter into the heavenly kingdom must be such as these are now, in the time
of their innocence; and nothing can preserve them, or make them such, except my blessing. This, we may believe, must have been the mind of the compassionate Saviour, when he rebuked his disciples in these words. And thus he has left to all ages a practical proof of his will ; his perpetual will. He has still the same pity for our fallen race ; still the same desire to save those who are encompassed by outward temptation, and betrayed by inward frailty. He still invites them to come to him, and desires that they should be brought to him, that they may find rest in his word, and protection in his love. And whilst we consider this subject, with a view to fulfil his merciful desire, may He who has proi2
116 THE DUTY OF mised to be with his people, " whenever two or three are gathered together in his name," may he realise his gracious assurance, and be with us and bless us I Let us then pursue the subject opened to us in the text, and inquire, first, What it is for the young to come to Christ : next, The need for coming to Him : thirdly, The end of coming to Him. I. Jesus said, Suffer little children to come unto me. But, Lord, thou art in heaven, and we thy weak and sinful creatures are on earth ! It is long since the angels sang, " Lift up your heads, O ye gates,
and be ye lift up, ye everlasting doors : and the king of glory shall come in !" True, the parents of the present day cannot bring their children to the Lord in the lowly form of man, which for our sake he vouchsafed to bear ; they cannot now behold the condescending goodness with which he took them in his arms, or laid his hands upon them. But there is a way of applying to Christ, more sure than the movement of the body. Many of the Jews had come to him by the movement of their bodies, and were standing round him at the
PROMOTI G CHRISTIA EDUCATIO . 117 very time when he said, " Ye will not come unto me, that ye might have life." 1 And again, on the other hand, the Ethiopian had come to him, whom Philip baptized : had come to him when he said, " I believe that Jesus Christ is the Son of God ;" 2 though in the flesh he had never seen him. It is the heart, brethren, and not the body, which comes to Christ. The coming to him is the surrender of the soul to him for all that it needs : for pardon, justification, redemption, instruction ; in a word, for salvation. " I will arise, and go to my father," thought the prodigal in his extremity. ow it was the mind here which really sought this refuge. Before the body moved, the mind had gone. And thus it must be with the child ; thus we
desire it may be through the influence of early teaching and continued instruction. In our christian land, the parent does what the Jewish parents did when they brought their little children to the Lord. He offers up his child to him in the way and ordinance which he has himself appointed ; he prays that the child may be received into his flock, and regenerated by the Holy Spirit. He does this with a definite object; with a clearness of view and 1 John vi. 40. "- Acts viii. '37.
118 THE DUTY OF knowledge which the Jewish parents could not have. He feels that he has imparted a corrupt nature to his children ; and that unless they be " born again, born of water and of the Spirit, they cannot enter into the kingdom of God." But there is a remedy, and he brings them to the author of that remedy, and prays that their sinfulness may be atoned for, their corruption purified, their children made " members of Christ, children of God, and inheritors of the kingdom of heaven." This is the beginning, but only the beginning. Painful experience teaches us how much is still required, that the child may remain a partaker of these covenanted blessings ; and, when the eyes of the understanding are opened, may come to Christ in inward feeling, as well as by outward ceremony. And, therefore, we desire that the young creatures growing up around us should be continually reminded of the covenant made for them, and of the obligations to which it binds them. We desire that as they advance in age, and are involved in the business and temptations of the world, they should understand the circumstances in which they are
placed; the dangers which encompass them, the defence which may secure them. We desire that as they enter into life, it should be said to them, " Behold,
PROMOTI G CHRISTIA EDUCATIO . 119 you go forth as lambs among wolves." Such is the nature of the world to which you belong. You have enemies on every side, seeking to devour ; but there is a good Shepherd, " who laid down his life for his flock." He is glad "to gather the lambs in his bosom, and gently lead the feeble and the young ;" if only they will " hear his voice, and follow him." He who is ready to save, is greater than he who would destroy : and none shall pluck out of his hand those who commit themselves to his care. Thus we desire that from their earliest infancy these children should be acquainted with the Redeemer ; familiarised to think of him as the Giver of heavenly things ; habituated to come to him in their minds for that which is needful to their souls, that they may be delivered from this present evil world, and attain eternal life. For, whether we speak of youth or age, this is to come to Christ : habitually to look to him for " all things that pertain to life and godliness:" to look to him for the ransom which he has paid ; to look to him for the justification which he procures ; to look to him for the wisdom which he supplies ; to look to him for the grace which he bestows; to look to him for the rules which he prescribes : naturally to look to him, as the scholar looks to his
120 THE DUTY OF master for instruction ; as the soldier looks to his general for commands ; as the child looks to his parent for support, and assistance, and encouragement, and protection, and for all that life requires. II. Why so? will any ask? Why is it thus needful ? What reason have the young for coming to a Saviour ? The strongest reason ; the most urgent need. They perish without him ; they have the sentence of death, eternal death in themselves, which he alone can set aside. My brethren, were you to see a child labou ringunder some severe disorder; daily becoming weaker, and less and less able to prevail against the inward disease ; you would not ask, What need of a physician ? ow, sin is the worst disorder ; and sin is bound up in the heart of every child. 3 Christ is the physician, who has the only remedy against sin. And therefore the child has need of Him at the earliest age. The sooner we oppose natural corruption, the better hope we have of curing it. And the longer we suffer the evil heart to rule, the more unwilling to yield will it become. Again, brethren, if you saw a child entering Prov. xxii. 1.3.
PROMOTI G CHRISTIA EDUCATIO . 121 upon a thick and tangled wilderness, through
which it was to find its way, you would not ask why that child should need a guide. ow the world is such a wilderness ; it has many wrong ways, easy to find and follow ; many temptingways, holding out to the young much pleasant fruit, which grows along the path-side : and, besides, many companions are wandering along those unsafe paths, and will persuade, if they can, others to follow them. There is but one right way leading unto life, and that " a narrow way :" do we ask, why the child should need a guide ? why the guardian of the narrow way should say, Suffer little children, and forbid them not, to come unto me ? But, brethren, I trust that it is needless for me to give reasons why it is good to come to Christ. I trust that you are ready to say, like the people of Samaria to their countrywoman : " ow we believe, not for thy saying, for we have seen him ourselves, and know that this is indeed the Christ, the Saviour of the world." 4 The sheep know the value of their shepherd, who has long directed them by his voice, and fed them by his hand, and preserved them by his power. The soldiers understand the worth of their commander, who has never deserted 4 John iv. 42.
122 THE DUTY OF them in the hour of danger, never left them unsupported on their post, never led them but to victory. The mariners are sensible of their pilot's skill, who has steered them in safety through rocks on the one side and quicksands on the other, and is bringing their vessel, frail and shaken as it is, towards the haven where they would be. And so I trust that you know why others should be led to Christ,
because you have been led by him yourselves ; because you know the excellence of his pastures, and the security of his fold : because you, through him, are " more than conquerors " against all the enemies of your salvation. III. And thus I have arrived at the last of those inquiries which I proposed ; and have only to consider, thirdly, What is gained by those who come to Christ, obeying his invitation ? My brethren, there are many paths through life, but there can be only two terminations. There are the paths followed by them " that are contentious, and do not obey the truth, but obey unrighteousness." The end of those paths is " indignation and wrath, tribulation and anguish, reserved for every soul of man that doeth evil." Then there is the path followed by them, who, " by
PROMOTI G CHRISTIA EDUCATIO . 123 patient continuance in well-doing, seek for glory and honour and immortality." The termination of this path is life eternal: this path leads to the kingdom of God, prepared for the righteous from the beginning of the world, " where is fulness of joy and pleasures for evermore." And this is gained by those who come to Christ. They are withdrawn from the paths to which nature would carry them, and example would direct them, the end of which is death ; and they are conducted into the path which leads to everlastingsalvation. " He that hath the Son hath life ; and he that hath not the Son of God hath not life."
Look, brethren, for a moment, at these different terminations : consider the two sentences. " Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels." " Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world." 5 Suppose that you were hearing these different sentences pronounced ; that you were seeing the vast assembly on the left hand, " shut out from the presence of the Lord and the glory of his power :" 5 Matt. xxv. 41 44.
124 THE DUTY OF whilst, on the other hand, a bright kingdom was displayed, such as " eye hath not seen, neither hath it entered into the heart of man to conceive." What would be given at such a moment, if any of those on " the left hand," now about to inherit the consequences of their unrepented sins, could be rescued from misery, and received among " the children of light !" It is, then, impossible. The final sentence hath gone forth. " He that is unjust, let him be unjust still ; and he that is filthy, let him be filthy still ; and he that is righteous, let him be righteous still; and he that is holy, let him be holy still." 6
Here, then, is seen the gain of those who have lived in the world as disciples of Christ Jesus. That is gained, which at the last will alone be valuable ; that which is beyond price, and which then no price can attain ; no, which not even the price of Christ's own blood can purchase then, if not sought at " the accepted time," not secured in the " day of salvation." ow, then, is the season when we must provide for that, which, too late, we might desire in vain. ow, in the beginning of their days, must children 6 Rev. xxii. 11.
PROMOTI G CHRISTIA EDUCATIO . 125 be suffered to come unto Him, that he may secure them in his fold, and nurture them in safe pastures, and lead them in the way everlasting. And the way to suffer this, is to provide for it. There is no surer course by which those who possess the gifts of God, and desire to use them as faithful stewards, can benefit those who are less favoured. This blessing they who are themselves instructed can give to others who are ignorant. This, they who have been taught of God the value of the soul, can do for those who have no sense of its importance. And too often if we do not actually provide for this, we virtually forbid it. The children cannot procure instruction for themselves ; nor always their parents for them, even if they knew its value. And think of the blessed result, if God favour the effort, and the young are bred up "in the nurture and admonition of the Lord." Such is human nature, that to be without knowledge is to be
without religion ; not to be the servant of Christ, is to be the slave of sin. And to serve sin, is to serve that cruel tyrant, the destroyer both of body and of soul. How grievous is the return he makes, the wages which he pays ! There is pain, anguish of body, ruined constitutions ; there is, still worse,
126 THE DUTY OF anguish of mind, the stings of conscience and of sorrow, ending, perhaps, in a broken heart ; there is disgrace, indigence ; there are prisons, banishment, death. It would be less, if this were all ; if death, the last consequence of sin which we actually see, were indeed the last consequence of sin. But, beyond the death of the body, " outer darkness" awaits the soul, "weeping and gnashing of teeth;" 11 the worm that dieth not, the fire that never shall be quenched." When, then, we ask you to provide the means of education, religious education, to those who would otherwise be wanting it, we ask the means of deliverance from all these. We ask that the children of corruption and the subjects of temptation maybe brought to Him, who has engaged that sin shall not " have dominion over them," neither shall " the world overcome them." 7 He will show them what is safer than sin, and better than the world. Bring them to Him, and he will show them their real state, and raise them out of it ; disclose to them the evil which is in their hearts, and cleanse them from it. Bring them to Him, who will teach them thatindustry is more cheerful than idleness, and contentment better than murmuring ; that sobrietv 7 See Rom. vi. 14. 1 John v. 4, 5.
PROMOTI G CHRISTIA EDUCATIO . 127 is happier than excess, and chastity than impurity. Bring them to Him, who shows that godliness has real charms, that profaneness is hateful and abominable ; that there is comfort in meekness and kindness, but none in malice and revenge. Bring them to Him, who shows that there is more blessing in " the peace of God," than in anything this world can give ; who can bestow on them what they can never find elsewhere, rest of soul.
The Duty of Promoting Christian Education. by GLENN DALE PEASE2 viewsEmbedDownloadDescriptionBY JOHN BIRD SUMNER, D.D. Matt. xix. 13. Suffer little children, and forbid them not, to come unto me.BY JOHN BIRD SUMNER, D.D.Matt. xix. 13. Suffer little children, and forbid them not, to come unto me. Interests: Topics, Religious & Bible StudyRead on Scribd mobile: iPhone, iPad and Android.Copyright: Attribution Non-Commercial (BY-NC)Download as PDF, TXT or read online from ScribdFlag for inappropriate contentShow moreShow less
RelatedThe Rejected Thief on the Crossby GLENN DALE PEASEChrist, Our Loving Comforter and Restorerby Aleksandar Iksioksi DomicConfession Necessary to Forgiveness.by GLENN DALE PEASESantification Everyday by John Piperby Melina Santos VanderlinderLoving Your Enemiesby Jo-Anne LerouxThe Christian Crucified With Christ.by GLENN DALE PEASEMy Burden is Lightby GLENN DALE PEASEThe Humanity of Christ 2by venlorLUKE 5 1-3by GLENN DALE PEASEFollower Of Christby Robert WoegerThe Agony of Jesus.by GLENN DALE PEASEGreat Texts Rev. 22 14by GLENN DALE PEASEThe Faithful Sayingby GLENN DALE PEASE4th Quarter 2013 Lesson 7 Powerpoint Presentation.pptxby Ritchie FamarinTrue Christians Not of the Worldby GLENN DALE PEASEExpository Discourses on First Peter Vol. 3by GLENN DALE PEASESpurgeon is Conversion Necessaryby gogelLaw, Henry - Gospel in Genesis (b)by api-26121206Inside Story ESVby tomsav1The Threefold Overthrow of Selfby Rob CallisonMary's Boy Childby grummcTGP01V01S Unit3 Session9 PersonalStudyGuideby David ClossonThe School of Christ.by GLENN DALE PEASE69 1 Johnby MJust4DRightOneThe Contempt Poured on Christ.by GLENN DALE PEASEJohn P. Manoussakis (2009), 'At the Recurrent End of the Unending. Bonhoeffer's Eschatology of the Penultimate'by Constantin BalasoiuHebrews 1 1-4by richard5049The History of Sinby buenomel68Similar to The Duty of Promoting Christian Education.The Rejected Thief on the CrossChrist, Our Loving Comforter and RestorerConfession Necessary to Forgiveness.Santification Everyday by John PiperLoving Your EnemiesThe Christian Crucified With Christ.My Burden is LightThe Humanity of Christ 2LUKE 5 1-3Follower Of ChristThe Agony of Jesus.Great Texts Rev. 22 14The Faithful Saying4th Quarter 2013 Lesson 7 Powerpoint Presentation.pptxTrue Christians Not of the WorldExpository Discourses on First Peter Vol. 3Spurgeon is Conversion NecessaryLaw, Henry - Gospel in Genesis (b)Inside Story ESVThe Threefold Overthrow of SelfMary's Boy ChildTGP01V01S Unit3 Session9 PersonalStudyGuideThe School of Christ.69 1 JohnThe Contempt Poured on Christ.John P. Manoussakis (2009), 'At the Recurrent End of the Unending. Bonhoeffer's Eschatology of the Penultimate'Hebrews 1 1-4The History of SinZac Poonen_ Knowing God's Ways -The Gospel of the Resurrection

value: This website is an American e-book and audiobook subscription service that includes one million titles.


text:
Patent US8155030 - Method and apparatus for network tree management - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThere is disclosed a manner of managing the active topology, that is the scheme for forwarding data, in a computer network such as an Ethernet local area network. A root bridge is selected from a plurality of bridges in the network; the root bridge calculating at least one spanning tree from a topology...http://www.google.com/patents/US8155030?utm_source=gb-gplus-sharePatent US8155030 - Method and apparatus for network tree managementAdvanced Patent SearchPublication numberUS8155030 B2Publication typeGrantApplication numberUS 12/523,781PCT numberPCT/IB2008/000119Publication dateApr 10, 2012Filing dateJan 18, 2008Priority dateJan 19, 2007Also published asEP2103048A2, EP2103048B1, US8467317, US20100054157, US20120170489, WO2008087547A2, WO2008087547A3Publication number12523781, 523781, PCT/2008/119, PCT/IB/2008/000119, PCT/IB/2008/00119, PCT/IB/8/000119, PCT/IB/8/00119, PCT/IB2008/000119, PCT/IB2008/00119, PCT/IB2008000119, PCT/IB200800119, PCT/IB8/000119, PCT/IB8/00119, PCT/IB8000119, PCT/IB800119, US 8155030 B2, US 8155030B2, US-B2-8155030, US8155030 B2, US8155030B2InventorsJ�nos Farkas, Csaba Antal, Attila Tak�cs, Panagiotis SaltsidisOriginal AssigneeTeleaktiebolaget L M Ericsson (Publ)Export CitationBiBTeX, EndNote, RefManPatent Citations (10), Non-Patent Citations (2), Referenced by (2), Classifications (14), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetMethod and apparatus for network tree management
US 8155030 B2Abstract
There is disclosed a manner of managing the active topology, that is the scheme for forwarding data, in a computer network such as an Ethernet local area network. A root bridge is selected from a plurality of bridges in the network; the root bridge calculating at least one spanning tree from a topology database that has been populated by bridge neighbor information gleaned from link state advertising messages. The root bridge may also calculate an alternate topology for implementation in the event a failure condition that affects the primary spanning tree is detected. The root bridge then advertises the spanning tree and remotely configures the port states of the bridges in the spanning tree through tree advertising messages that the bridges are arranged to process and set their ports accordingly.
1. A method for setting up and updating a tree in a computer network having a plurality of network nodes controlled in a link state manner where in said plurality of network nodes are interconnected using a plurality of bridges wherein each node includes one or more ports for connecting a bridge with a neighboring node, wherein a topology database is available at each network node, said method comprising the steps of:
calculating a topology of a tree using only a root bridge of the tree;
configuring, by the root bridge, one or more of its ports participating in the tree;
advertising, by the root bridge, the topology of the tree by sending a tree topology advertisement to the neighboring network nodes participating in the tree;
configuring, by the neighboring network nodes, the one or more ports for each of the network nodes participating in the tree according to the tree topology advertisement; and
forwarding the tree topology advertisement through the configured ports of the neighboring network nodes along the tree.
2. The method of claim 1, wherein the step of calculating the topology of the tree is based on a topology database populated with neighbor information obtained from link state advertisement messages, the topology database being maintained by a link state protocol.
3. The method of claim 1, wherein the step of advertising the topology of the tree comprises sending a message containing all port configurations of all bridges.
4. The method of claim 1, wherein the tree topology advertisement comprises sending a message containing a description of all links taking part in the tree.
5. The method of claim 1, wherein the tree topology advertisement provides an identification of nodes in the tree and port configuration of each node in the tree.
6. The method of claim 1, wherein bridges not calculating the tree, configure the tree received in the tree topology advertisement to avoid transient loops.
7. The method of claim 6, wherein the bridges not calculating the tree only configure active links taking part in the tree received in the tree topology advertisement after configuring blocked links.
8. The method of claim 1, wherein the nodes not calculating the tree forward the tree topology advertisement after configuring the tree.
9. The method of claim 1, wherein nodes not calculating the tree forward a modified tree topology advertisement containing only the relevant subtree of the tree.
10. The method of claim 1, further comprises the steps of:
recalculating the topology of the tree using the root bridge if the topology database changes;
advertising the new tree topology using the root bridge;
updating the tree by the non-calculating bridges based on the advertisement of the new tree topology; and
distributing the topology advertisement along the new tree.
11. A system for setting up and updating a tree in a computer network having a plurality of network nodes controlled in a link state manner where in said plurality of network nodes are interconnected using a plurality of bridges wherein each node includes one or more ports for connecting a bridge with a neighboring node, wherein a topology database is available at each network node, comprising:
means for calculating a topology of a tree using only a root bridge of the tree;
means for configuring, by the root bridge, one or more of its ports participating in the tree;
means for advertising. by the root bridge, the topology of the tree by sending a tree topology advertisement to the neighboring network nodes participating in the tree;
means for configuring, by the neighboring network nodes, the one or more ports for each of the network nodes participating in the tree according to the tree topology advertisement; and
means for forwarding the tree topology advertisement through the configured ports of the neighboring network nodes along the tree.
12. The system of claim 11, wherein the means for calculating the tree topology is based on a topology database populated with neighbor information obtained from link state advertisement messages, the topology database being maintained by a link state protocol.
13. The system of claim 11, wherein the means for advertising the tree topology comprises means for sending a message containing all port configurations of all bridges.
14. The system of claim 11, wherein the means for advertising comprises means for sending a message containing a description of all links taking part in the tree.
15. The system of claim 11, wherein the means for advertising provides an identification of nodes in the tree and port configuration of each node in the tree.
16. The system of claim 11, wherein bridges not calculating the topology of the tree, configures the tree received in the tree topology advertisement to avoid transient loops.
17. The system of claim 11, wherein the bridges not calculating the topology of the tree only configures active links taking part in the tree received in the tree topology advertisement after configuring blocked links.
18. The system of claim 11, wherein the nodes not calculating the topology of the tree forward the tree topology advertisement after configuring the tree.
19. The system of claim 11, wherein nodes not calculating the topology of the tree forward a modified tree topology advertisement containing only the relevant subtree of the tree.
20. The system of claim 11, further comprises:
means for recalculating the topology of the tree using the root bridge if the topology database changes;
means for advertising the new tree topology using the root bridge;
means for updating the tree by the non-calculating bridges based on the advertisement of the new tree topology; and
means for distributing the topology advertisement along the new tree. Description
This application is related to and claims benefit of the filing date of U.S. Provisional Patent Application No. 60/885,667 filed Jan. 19, 2007, which is entirely incorporated by reference herein.
The present invention is directed, in general, to controlling data traffic in computer networks and, more specifically, to a method and system for tree management in Ethernets and similar networks using link state principles.
Computers, broadly speaking, are electronic machines capable of storing and manipulating information, often called data, to useful ends. Frequently, a number of computers are connected together in such a way that they are able to send data to each other. A collection of computers so connected is often called a network, and the connector between two network nodes is referred to as a link. One type of computer network is called a LAN (local area network), and may be found, for example, in the offices of a small business or educational institution. A number of LANs or other networks may also be brought into communication with each other. As might be expected, a system of rules or set procedures must be put in place so that the computers and networks can communicate with each other effectively. Such a system of rules and procedures is often called a protocol, and several have been developed for communications involving computer networks.
A widely accepted set of protocols for LAN communications has been developed under the auspices of the IEEE (Institute of Electrical and Electronics Engineers). A standard generally referred to as IEEE 802, for example, covers general network architecture, IEEE 802.1 deals with bridging and management, and IEEE 802.3 is the Ethernet protocol. An Ethernet LAN is generally one that handles traffic, that is, the flow of data from one computer to one or more other, using a system of collision detection and avoidance. (A ‘collision’ occurs when two or more computers attempt to send data over the same link at the same time.) These standards are regularly reviewed and updated as necessary to improve networks operations and account for developments in technology.
In a typical Ethernet network, data sent from one computer to another, or from one network to another, is not transmitted all at once or continuously, but is instead broken up into discrete ‘frames’. Using frames of data better allows the network computers to take turns sending data. The frames may vary in length, but each frame includes sufficient address information (in addition to the actual data) so it may be routed to its desired destination or destinations. Routing is necessary because every computer is not connected directly to every other. Instead, computers and networks are connected to intermediary devices that receive data, determine its destination address, and then route it accordingly. One such intermediary device is referred to as a bridge. A bridge is a type of software switch resident on a network component. A frame of data may be routed through many bridges on its way from source to destination.
FIG. 15 is a simplified schematic diagram illustrating the bridges of an exemplary network 10, in which embodiments of the present invention may be advantageously implemented. The network 10 may have many components, but for clarity only the bridges themselves are shown. Individual components such as computers and sub-networks may be connected to one of the bridges. In the embodiment of FIG. 15, there are nine bridges, numbered 1 through 9, although the present invention is also suitable for implementation in larger or smaller networks. Each of these bridges 1 through 9 is connected by a link to one or more other bridges. In FIG. 15 the links are numbered according to the bridges it connects, for example link 24 connects bridge 2 directly with bridge 4. A path includes all of the links from one bridge to another, for example one path from bridge 1 to bridge 9 includes links 13, 38, and 89. As should be apparent, there may be more than one path between any two bridges.
When a bridge receives a data frame from, for example, a network computer or another bridge, it examines the address information and forwards the frame accordingly. Data may have to pass through several bridges from its source to destination. Without some governing protocol, however, it is possible that frames of data might inadvertently be sent from bridge to bridge, eventually looping back to a previously-visited bridge from which they are re-sent back into the same loop. As should be apparent, this is not a desirable phenomenon and techniques have evolved for avoiding this looping problem.
One technique to avoid looping would be to use a fixed-configuration network and always route frames intended for a particular destination by the same route. Most networks are subject to change, however, and occasionally encounter break downs or congestion in components and links. A static routing system is therefore not the best solution. In a more successful solution, a ‘spanning tree’ is calculated periodically according to a spanning tree protocol (STP). The spanning tree provides path definitions for the network as it exists at the time of the tree calculation. In the event of a failure or other event, the tree can be recalculated to adjust to the new conditions.
Calculation of a spanning tree preferably involves not only designating a path from each source to each destination, but determining the best pathways for each case so that network communications are accomplished in an efficient manner. IEEE standards, for example, often use distance vector mechanisms to determine an active topology for the network, the active topology referring to the tree of data forwarding paths that will be used to route data traffic. This distance vector technique is well known and will not be discussed here in detail, except to note that the active topology is configured in a distributed manner, and so no bridge in the network is aware of the data distribution scheme in its entirety. It is therefore possible, or even likely, that the topology is not optimal. The distance vector approach is also less efficient at fault handling, that is at recovering from a failure occurring somewhere in the network.
A better solution may be to use a link state spanning tree calculation by applying the core functionality of IP (Internet protocol) using routing protocols such as OSPF (open shortest path first) and IS-IS (intermediate system to intermediate system). IP protocols are typically developed and disseminated by the IETF (Internet engineering task force). In general, the link state approach facilitates application of traffic engineering and allows the active topology to be optimized. Directly implementing IP routing protocols, however, would mean each bridge would have to set up its own forwarding tables. This is not a detriment in and of itself, but it may produce long unavailable periods resulting in at least transient loops. Another complication is that Ethernet frames do not include a TTL (time to live) field (as does an IP packet) so transient loops may be problematic when changes in active topology are occurring. Of course, bridges that notice the topology is changing could simply stop forwarding data frames until a new topology is calculated, but this procedure slows down the recovery significantly.
There is therefore a need in the art for a manner in which to implement a link state approach to spanning tree calculation that retains the advantages of link state protocols, but mitigates or eliminates the problems they have, especially those associated with an occasionally changing active topology. The present invention provides just such a solution.
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide a method and arrangement for configuring the active topology of a computer network, for example an Ethernet LAN. It is a further object of the invention to apply an improved link state approach to network tree management, the improved link state approach having, among other things, an advantageous architecture and an improved recovery time as compared with conventional approaches.
In one aspect, the invention is a method for configuring a network, such as an Ethernet LAN, for efficient forwarding of data traffic, including collecting neighbor information, generating and distributing link state advertisements, populating a topology database for the network, and calculating in a root bridge the port states for each bridge in a tree using from the topology database. The method may further include advertising the tree by selectively distributing tree advertisement messages, receiving tree advertisement messages in bridges of the network, and configuring the ports of each bridge according to the advertisement message. The method may also further include the feature of recognizing, in a network bridge that a link state advertisement has already been processed, and to discard rather than forward them. In this way, a protocol for links states STP is defined that allows the application of flexible sets of routing objectives.
In another aspect, the present invention is a network comprising at least one root bridge, wherein the root bridge is remotely sets the port states of at least one other network bridge. In a preferred embodiment, the active network topology is calculated at the root bridge and imposed on all the other network bridges. A root bridge therefore is arranged to build a topology database and use the topology data base to calculate a spanning tree for the network. The root bridge is further arranged to generate and distribute tree advertisement messages that describe the tree for non-root bridges. Non-root bridges are arranged to receive the tree advertisement messages and process them. The non-root bridges are also arranged to configure their ports according to the description in the tree advertisement message, and to selectively forward the tree advertisement messages in the direction of leaf bridges. Non-root bridges may also be arranged to modify the tree description in the tree advertisement message prior to forwarding them to other bridges. In this manner, problems due to any potential inconsistency in link state databases may be mitigated or eliminated entirely, as the time needed to synchronize databases following a failure is eliminated. In some embodiments, the use of alternate or backup ports is implemented when a failure condition is detected.
In yet another aspect, the present invention is a bridge for use in a network, the bridge arranged to serve as a root bridge by calculating a spanning tree based on collected network information, to configure itself according to the calculated tree, and to remotely configure the other bridges in the spanning tree.
Before undertaking the DETAILED DESCRIPTION, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. In particular, a controller may comprise one or more data processors, and associated input/output devices and memory, that execute one or more application programs and/or an operating system program. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such-defined words and phrases.
FIG. 1 is a flow diagram illustrating a method of performing neighbor discovery according to an embodiment of the present invention.
FIG. 2 is a flow diagram illustrating a method of processing a link state advertisement (LSA) according to an embodiment of the present invention.
FIG. 3 is a flow diagram illustrating a method of calculating a spanning tree according to an embodiment of the present invention.
FIG. 4 is a flow diagram illustrating a method of tree configuration according to an embodiment of the present invention.
FIG. 5 depicts a LSSTP_BPDU (link state spanning tree protocol bridge protocol data unit) according to an embodiment of the present invention.
FIGS. 6 a through 6 c illustrate LSSTP parameters for an LSA_BDPU according to embodiments of the present invention.
FIG. 7 illustrates LSSTP parameters for a TA_BDPU (tree advertisement BDPU) according to an embodiment of the present invention.
FIG. 8 illustrates simplified LSSTP parameters for a TA_BDPU according to another embodiment of the present invention.
FIG. 9 illustrates an exemplary spanning tree topology for which embodiments of the present invention may be advantageously implemented
FIG. 10 illustrates a tree description for the Bridge 1 shown in FIG. 9 according to an embodiment of the present invention.
FIG. 11 illustrates a tree description for the Bridge 2 shown in FIG. 9 according to an embodiment of the present invention.
FIG. 12 illustrates a tree description for the Bridge 3 shown in FIG. 9 according to an embodiment of the present invention.
FIG. 13 illustrates a bridge architecture according to an embodiment of the present invention.
FIG. 14 illustrates an operation of a spanning tree protocol in routing protocol according to an embodiment of the present invention.
FIG. 15 is a simplified schematic diagram illustrating the bridges of an exemplary network, in which embodiments of the present invention may be advantageously implemented.
FIG. 16 is a flow diagram illustrating a method of facilitating data traffic flow according to an embodiment of the present invention.
FIGS. 1 through 16, discussed herein, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged computer network.
The present invention is directed to a new approach to facilitating the management of data traffic flow in a network, such as an Ethernet LAN (local area network), using a spanning tree active topology. FIG. 16 is a flow diagram illustrating a method 20 of facilitating data traffic flow according to an embodiment of the present invention. At START it is assumed that a network operable to communicate data via a plurality of bridges has been formed, such as the one shown in FIG. 15. The network is, for example, an Ethernet LAN network operable according to the IEEE 802 family of protocols, but other similarly arranged networks may be used as well. The process begins when the network is assembled and energized for operation, or at some later time as determined by a network operator. In this embodiment, it is also presumed that a root bridge for the network has been determined. This may be done in a number of ways, although no particular way is required by the present invention unless specifically recited in a given embodiment. Returning to the method 20 of FIG. 16, in step 105 neighbor discovery is undertaken, so that each of the network bridges may learn the other bridges to which they are connected. The information discovered in the neighbor discovery step 105 is then transmitted (step 110) to other bridges via LSAs (link state advertisements). Although the LSAs flood the network, in a preferred embodiment they will be discarded (step not shown) by bridges that, for example, realize they have already learned the information contained in a particular LSA.
The root bridge then compiles a topology database (step 115), and uses the topology database to develop a spanning tree for the network and calculating the necessary port configurations (step 120) for each (non-root) bridge. The port configurations for each bridge, of course, implement the calculated spanning tree in the network. In accordance with the present invention, the root bridge makes these determinations for each of the non-root bridges. The root bridge then advertises the spanning tree (step 125) by sending TAs (tree advertisements) out to the network components. Each bridge then processes the TA messages and sets its ports (step 130) according to the instructions contained in the TA. The spanning tree has at this point been configured according to an embodiment of the present invention and the routing of data traffic (step 135) may either begin, or continue, as the case may be.
One advantage of the present invention, however, is the manner in which a network configured in this manner responds to a failure, that is, the inability to route traffic according to the current active topology. To illustrate this, the method 20 of FIG. 16 continues with the step 140, where a failure condition is detected. Failure, or failure condition, as used herein, refer to an event that prevents or significantly inhibits forwarding data according to a current active topology. That is, failure may include an actual breakdown, but may also include the addition or removal of network bridges, links or other components, or significant bottlenecks. In this embodiment, it is first determined (step 145) whether an alternate (or backup) topology has been established. If so, the alternate topology is implemented (step 150). If not, or if the alternate topology is not successful, the process in this embodiment returns to step 120 and a new tree is calculated. This assumes, of course that the root bridge topology database has been maintained through periodic neighbor discovery messages, and the link state information is up to date. In other embodiments, the process may instead return to the neighbor discovery step 105 or the LSA step 110 prior to generating or updating the topology database and calculating a new spanning tree at step 120. In any case, however, since the root bridge remotely sets the port states of the non-root bridges, there is no need to wait until all bridge databases have been synchronized, and typically resulting in a faster recovery time. Finally, note that the calculation of a backup or alternate topology is optional, but in many cases can help speed recovery after failure. The alternate topology may be calculated when the primary active topology is determined, or at a later time and advertised separately.
The variation operations associated with embodiments of the present invention will now be described in greater detail. For this purpose, it will be presumed that various of the message described above, such as LSAs and TAs, are in the format of standard BPDUs (bridge protocol data units) that have been modified according to the present invention for their respective purpose. The use of modified BPDUs in this way is preferred but not required.
FIG. 1 is a flow diagram illustrating a method 25 of performing neighbor discovery according to an embodiment of the present invention. Again, at START, the network is presumed to be physically assembled and operable according to the method of the present invention. In this embodiment, neighbor information is collected via neighbor discovery messages, and preferably ND_BPDUs (step 205). Other types of messages may be used for collection of neighbor information may be used in other embodiments. In this embodiment, ND_BPDUs are sent and received according to a predetermined time period (the “Hello Time Period”). The received ND_BPDUs are examined and the information stored in a topology database (step not shown) for later reference.
As ND_BPDUs are received each Hello Time Period, many times they will contain information already stored in the topology database. At other times, a new neighbor may manifest itself, or an expected ND_BPDU is not received, signaling a change in the configuration of the network. Therefore, each Hello Time Period each bridge examines the ND_BPDUs received and determines (step 210) if a new link has appeared or an existing one has timed out. That is, entries in the topology database may be timed out and erased after a predetermined number of Hello Time Periods if no ND_BPDU confirming their validity has been received. If no change occurs, the process simply returns to step 205 and collecting neighbor information as it is disseminated each Hello Time Period. If a change has been perceived, the bridge distributes LSA_BPDUs (step 215) to advertise the change. The topology database may also be updated at this time (step not shown). Each bridge then determines if it is currently a root bridge (step 220) and, if so, performs a tree calculation (step 225) with the newly acquired network information. Note that in accordance with the present invention, only root bridges need to perform the tree calculation process. In accordance with the present invention, the root bridge may run any active topology algorithm to build up the tree.
The LSA_BPDUs distributed in step 215 are subsequently received in the various network bridges. FIG. 2 is a flow diagram illustrating a method 30 of processing a link state advertisement (LSA) according to an embodiment of the present invention. When an LSD_BDPU is received (step 230) at a bridge it is first examined (step 235) to determine whether it is outdated or has been received previously. This may be done using one or more techniques. For example, the receiving bridge may examine a sequence number and sending-bridge identifier of the LSA_BPDU. If a newer LSA_BPDU has already been received from that bridge, the one being examined may be discarded. In another embodiment, a path vector mechanism is employed and the receiving bridge checks to see if its own bit is set to determine whether the LSA_BDPU has been seen before. In yet another embodiment, a time-to-live field (TTL) may be utilized, with LSA_BPDUs being examined for age. If one or more of these methods indicates that the LSA_BPDU is no longer useful, it is discarded (step 240). This helps to prevent LSA_BPDUs from continuing to circulate unnecessarily in the network when they are no longer useful (although, depending on the determining technique used, they may under certain conditions be processed more than once in the same bridge).
If the LSA_BDPU has not been received before, then it is forwarded (step 245) on each port of the bridge, except for the one on which it was received, and the bridge's topology database is updated (step 250). As in FIG. 1, each bridge, having updated its topology database, then determines if it is currently a root bridge (step 255) and, if so, performs a tree calculation (step 260) with the newly acquired network information. Note again that in accordance with the present invention, only root bridges need to perform the tree calculation process.
The tree calculation process undertaken by the root bridge according to one embodiment of the present invention is shown in FIG. 3. FIG. 3 is a flow diagram illustrating a method 35 of calculating a spanning tree according to an embodiment of the present invention. The method 35 of FIG. 3 begins with determining whether a change in the tree is necessary (step 265). This determination may be performed at regular intervals, or upon the happening of a triggering event, or both. If a tree change is not necessary, of course, the ordinary operation of the network may simply continue. If a tree change is determined to be necessary, then the method 35 proceeds to calculate a new tree from the current topology database (step 270). (Note that method 35 describes a root bridge operation, so no step of determining root-bridge status is shown.) The root bridge then configures discarding ports (step 275), followed by a configuration of forwarding ports (step 280). The tree configuration is then distributed throughout the network (step 285), for example using TA_BPDU messages.
When the TA_BPDU (or other tree advertisement message) is received at a non-root bridge, it is processed and forwarded as necessary. FIG. 4 is a flow diagram illustrating a method 40 of tree configuration in a non-root bridge according to an embodiment of the present invention. The process begins with determining whether a TA_BPDU has been received (step 290). If not, of course, the routing of data traffic, if any, may continue normally. If so, the TA_BPDU is read (step 295), and the discarding ports, of any, are configured (step 305). The discarding ports do not have to be configured first, but his order is preferred and helpful to creating a loop-free topology. The forwarding ports, if any, are then configured (step 310). Assuming at least one forwarding port has been configured, the TA_BPDU is then forwarded on each of the bridge's forwarding ports (step 315).
The format of BPDU messages follows generally the MSTP BPDU format of IEEE 802, with certain differences and special considerations as set forth below and in FIG. 5 though 12. FIG. 5 depicts a LSSTP_BPDU (link state spanning tree protocol BPDU) 45, according to an embodiment of the present invention. Regarding the fields of the LSSTP_BPDU especially related to implementation of the present invention, the BPDU type field 320 will reflect that this is an LSSTP_BPDU message. The Hello Time field 325 is used only in ND_BPDUs, not in other types of LSSTP_BPDUs. Note that the tree configuration identifier field 330 is the same as is proposed in IEEE 802.1ap Virtual Bridged Local Area Networks—Amendment 9: Shortest Path Bridging, Draft D0.3, dated May 9, 2006. The LSSTP Parameters 335 vary according to the type of LSSTP_BPDU, as described in more detail below.
For an ND_BPDU according to the present invention, the LSSTP Parameters 335 are empty, as the necessary corresponding-link bridge and port identifiers are currently specified in the proposed IEEE 802 MSTP BPDU. In other words, the neighbor discovery process does not require additional LSSTP parameters for successful operation.
For LSA_BPDUs according to the present invention, there are several options available. These options correspond generally with the different embodiments, described above in the context of discarding LSAs when they are outdated or no longer useful. These options are illustrated in FIGS. 6 a through 6 c, which show LSSTP parameters for an LSA_BDPU according to three embodiments of the present invention. In each of these embodiments, the respective LSSTP parameters include a Flags field 340 and a LSSTP Computation Protocol Identifier field 345, followed by link description information 355. In FIG. 6 a, an optional LSA-removal field 350 a includes a Sequence Number along with the Bridge ID of the sending bridge. In FIG. 6 b, optional LSA-removal field 350 b includes a Path Vector. The LSA removal options associated with each of these LSA-removal fields has been described above (in reference to FIG. 2). In a third embodiment, the TTL information already part of the standard BPDU message is used instead—and therefore no LSA-removal field is necessary—as shown in FIG. 6 c. Note that more than one of these LSA-removal options may be used, with appropriate changes made to the LSSTP parameters if needed, but using more than one option is not presently preferred. In an alternate embodiment, no LSA removal option is used at all, but this is not recommended.
FIG. 7 illustrates LSSTP parameters for a TA_BDPU (tree advertisement BPDU) according to an embodiment of the present invention. This type of message also includes a Flags field 360 and a LSSTP Computation Protocol Identifier field 365. A Tree ID field 370 follows, and a Number of Bridges field 375, which of course specifies the number of bridges in the tree. The individual Bridge fields 380 follow, one for each bridge in the identified tree. The individual Bridge fields each identify the port configuration for one of the bridges in the tree. In this embodiment, the designated forwarding ports for each bridge are specified, and the remaining ports at that bridge are assumed to be discarding ports and configured accordingly. As mentioned above, these discarding ports are preferably configured first, prior to setting the forwarding ports. The root port is also specified, in this embodiment immediately following each Bridge ID. An alternate port toward the root bridge may also be listed (but is not shown in FIG. 7).
FIG. 8 illustrates simplified LSSTP parameters for a TA_BDPU according to another embodiment of the present invention. Here, following the Tree ID field 370, a Number of Links field 385 relates the number of links in the tree rather than the number of bridges. Links fields 390 therefore follow the Number of Links field 385, and describe the tree in terms of the links between bridges. This reduces the size of the TA_BPDU, but increases the processing complexity as each bridge has to determine the how to set their ports based on the received tree description. Whether this trade-off is desirable may vary from network to network.
An even more abbreviated form may be useful in some applications. The exemplary tree topology of FIG. 9, for example may be advertised using the TA_BPDU sequences illustrated in FIGS. 10-12. As can be seen in FIG. 9, Bridge 1 has two designated ports and hence two branches leading from it, specifically to Bridges 2 and 3. Bridge 2, in turn, has three branches leading out to Bridges 4, 5, and 6, and Bridge 3 had one branch leading to Bridge 7. Bridges 4 through 7 are leaf bridges, and therefore have no branches leading from them.
According to this embodiment, a first TA_BPDU message is received in Bridge 1; this message (or rather the relevant portion thereof) is illustrated in FIG. 10. This type of message also includes a Flags field 405 and a LSSTP Computation Protocol Identifier field 410. A Tree ID field 415 follows. After the Tree ID field 415 is a first Tree Description field 420. The first Tree Description field includes the information needed at Bridge 1, namely, the relationship of the links and bridges that follow. As represented in FIG. 10, a first set of brackets encloses the identities of all of the links and bridges associated with port 1 of Bridge 1, and a second set of brackets encloses the identities of all the links and bridges associated with port 2 of bridge 1. Regarding the latter, port 2 is designated to a link to Bridge 3, and port 1 of Bridge 3 is designated to link to bridge 7. Port 1 of bridge 1 is also designated to link to a single bridge, Bridge 2, but since Bridge 2 has three ports, each designated to link to a respective one of Bridges 4, 5, and 6, the designations of Bridge 2's ports are each isolated in a set of interior brackets in the Tree Description field 420 of FIG. 10.
Naturally, Bridge 1 uses the information in the Tree Description field 420 to configure its own ports 1 and 2. It then transmits one modified version of TA_BPDU message to Bridge 2 and another to Bridge 3 using the appropriate ports. In each case, the port designations not applicable to the recipient bridge are removed by Bridge 1 prior to sending. The TA_BPDU sent to Bridge 2 is illustrated in FIG. 11. In FIG. 11, it can be seen that in the Tree Description field 420-2, all that remains are the port assignments for Bridge 2; port 1, for example is designated to link to Bridge 4. Similarly, FIG. 12 illustrates the TA_BPDU, which is transmitted from Bridge 1 to Bridge 3. In FIG. 12, it can be seen that in the Tree Description field 420-3, all that remains is the port assignment for port 1 of Bridge 3, which is designated to link to Bridge 7. For example is designated to link to Bridge 4. Note that Bridges 4 through 7 are leaf bridges and as such have no forwarding ports to set. The TA_BPDUs (not shown) sent to these leaf bridges are similar to those depicted in FIGS. 10 through 12, but they will have a NULL value for their Tree Description field.
FIG. 13 illustrates a bridge architecture according to an embodiment of the present invention. Note that IP link state routing protocols such as OSPF or IS-IS are not suitable without modification for application to forwarding control in Ethernet networks because loop prevention is not assured. In accordance with the present invention, however, the routing protocol entity is implemented as a higher layer as shown in FIG. 13. Operation of the STP (spanning tree protocol) entity as a higher layer entity is illustrated in FIG. 14. The routing protocol entity is attached to each port of a bridge similarly to the SPT entity. In this way, the routing protocol entity is able to send and receive frames on each port. For a routing protocol messages that is to flood the network, the routing protocol entity sends out the message on each port except the port on which the message was received. Other messages are processed by the routing protocol entity and only sent out on designated ports.
As mentioned above, the routing protocols are not applicable without some modification. First, IP addresses are replaced by MAC addresses in the routing protocol and each frame is them forwarded according to the MAC address in its header. Second, a tree advertisement is inserted into routing protocol messages and the processing of tree advertisements is implemented in network bridges, as described in more detail above. Note that tree advertisements may be carried in routing protocol objects that are prepared for routing-protocol extensions. For OSPF routing, for example, a new type of Opaque LSA may be required. Opaque LSAs in OSPF provide for generalized for protocol extensions, and tree advertisement may be considered a type of extension. In a preferred embodiment, type-9 (link local) is used for tree advertisement Opaque LSAs. Tree advertisement may also be implemented in an IS-IS routing protocol using similar protocol extensions applicable there.
In accordance with the present invention, tree advertisement messages (TA_BPDUs, for example) should not be flooded, to avoid accidental loops. Rather, they are forwarded only on links that are part of the tree that they advertise, and are sent from the root bridge toward the leaves. The tree topology is calculated in the root bridge, and all other bridges configure their ports according to the received tree advertisement.
Note that processing of the tree advertisement messages accordance with the present invention may represent a new functionality implemented in the bridges' routing protocol entity. This new functionality includes the proper configuration of the ports that are part of the tree. That is, the bridges send the tree advertisement only to selected neighbor bridges instead of flooding all ports. The bridge may in some embodiments (as mentioned above) have to adjust the tree advertisement before forwarded it on the designated ports. The tree description schemes described above may also be implemented in routing protocols with the proper functionality.
In this manner, IP routing protocols may be applied for the control of forwarding, that is, configuration of the active topology, in Ethernet networks.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS6578086 *Sep 27, 1999Jun 10, 2003Nortel Networks LimitedDynamically managing the topology of a data networkUS6614764 *Feb 1, 2000Sep 2, 2003Hewlett-Packard Development Company, L.P.Bridged network topology acquisitionUS7428237 *Jan 6, 2004Sep 23, 2008Cisco Technology, Inc.Fast convergence with topology switchingUS7480258 *Jul 3, 2003Jan 20, 2009Cisco Technology, Inc.Cross stack rapid transition protocolUS7609658 *Aug 3, 2006Oct 27, 2009Cisco Technology, Inc.Method and system for identifying instability or a spanning tree protocol loop in a networkUS7649884 *Dec 1, 2004Jan 19, 2010Hrl Laboratories, LlcCollaborative multicast routing (CMR) for multicasting in unidirectional, hybrid, multi-tiered mobile wireless networkUS20070064628 *Sep 16, 2005Mar 22, 2007Tallet Francois ESystem and method for generating symmetrical spanning treesUS20070159983 *Jan 6, 2006Jul 12, 2007Belair Networks Inc.Virtual root bridgeUS20070206513 *Dec 20, 2006Sep 6, 2007Samsung Electronics Co.; LtdMethod for selecting root bridge in configuration of spanning treeUS20080291823 *Apr 18, 2008Nov 27, 2008Panagiotis SaltsidisData driven connection fault management (ddcfm) in cfm maintenance points* Cited by examinerNon-Patent CitationsReference1Finn, Norman, "Shortest Path Bridging"; Jan. 13, 2006; XP002485131.2Finn, Norman; "Shortest Path Bridging"; Sep. 22, 2005 pp. 1-95 XP002471513.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8982734 *Jun 26, 2012Mar 17, 2015Intel CorporationMethods, apparatus, and systems for routing information flows in networks using spanning trees and network switching element resourcesUS20130343229 *Jun 26, 2012Dec 26, 2013Iosif GasparakisMethods, apparatus, and systems for routing information flows in networks using spanning trees and network switching element resources* Cited by examinerClassifications U.S. Classification370/256, 370/401International ClassificationH04L12/28, H04L12/56Cooperative ClassificationH04L12/462, H04L45/02, H04L45/025, H04L45/48, H04L45/04European ClassificationH04L12/46B7, H04L45/04, H04L45/48, H04L45/02C, H04L45/02Legal EventsDateCodeEventDescriptionJul 24, 2012CCCertificate of correctionDec 2, 2009ASAssignmentFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FARKAS, JANOS;ANTAL, CSABA;TAKACS, ATTILA;AND OTHERS;SIGNING DATES FROM 20090204 TO 20090209;REEL/FRAME:023593/0182Owner name: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL), SWEDENOwner name: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL),SWEDENFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FARKAS, JANOS;ANTAL, CSABA;TAKACS, ATTILA AND OTHERS;SIGNED BETWEEN 20090204 AND 20090209;US-ASSIGNMENT DATABASE UPDATED:20100304;REEL/FRAME:23593/182Owner name: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL), SWEDENFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FARKAS, JANOS;ANTAL, CSABA;TAKACS, ATTILA;AND OTHERS;SIGNING DATES FROM 20090204 TO 20090209;REEL/FRAME:023593/0182Owner name: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL),SWEDENFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FARKAS, JANOS;ANTAL, CSABA;TAKACS, ATTILA;AND OTHERS;SIGNING DATES FROM 20090204 TO 20090209;REEL/FRAME:023593/0182RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services

type: global

value: This website is a search engine provided by Google. Handling over 3.5 billion searches per day, it has a 92% share of the global search engine market.


text:
Words containing bodhipakkhiy | Words that contain bodhipakkhiy
https://www.thefreedictionary.com/words-containing-bodhipakkhiy
Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 10,623,971,694 visitors served
Words containing bodhipakkhiy
Found 1 words containing bodhipakkhiy. Browse our Scrabble Word Finder, Words With Friends cheat dictionary, and WordHub word solver to find words that contain bodhipakkhiy. Or use our Unscramble word solver to find your best possible play! Related: Words that start with bodhipakkhiy
19 letter words containing bodhipakkhiySee also
19 letter words containing bodhipakkhiy

value: This website is an American online dictionary and encyclopedia that aggregates information from various sources.


text:
Rody van der Borst, Nope, Netherlands
41297280
Honestly... I find that this is LESS impressive than the earlier examples that only worked with microwaves and such... given that they actually worked in air, and worked from a far larger range of angles.
Having it work in water is MUCH MUCH less impressive, because it is far easier to construct materials with the refractive indexes needed for the effect.
It is however nice that there is now a visible demonstration of the effect.

value: This website is the website of the Daily Mail, a newspaper in the United Kingdom, and of its sister paper The Mail on Sunday. MailOnline is a division of dmg media, which is owned by Daily Mail and General Trust plc.


text:
Sylvester & The Magic Pebble (Audiobook) by William Steig | Audible.com
©1969 William Steig (P)1990 Weston Woods
My son loved Dr. DeSoto, so I’m trying other books by Williams Stein. We all loved this one too!
My kids ask for this story all the time.
Yes, it is a good story and entertaining to listen to.
Love all the background music. Really adds to the feel of the story.
This is a perfect picture story book for young kids ages 3-6. My grandson, age 4 1/2, loves it. Audiobooks for kids should ALL include all the pictures, as this one does! Pictures make it great and absolutely worth the price, and these illustrations are terrific. The story is Wiiliam Steig's usual blend of humor, pathos, action, magical elements, strong morals/positive messages, and a happy ending. The narrator is very good. The only reason I'm not rating it five stars is that the narrator is not quite Meryl Streep, and the story not quite every bit as fabulous as The Amazing Bone. Also, although the sound effects (birds chirping, rain, thunder, etc.) add a lot to the total experience, the music is occasionally a tad intrusive and almost competing with the voice of the narrator.
Sylvester & The Magic Pebble is a wonderful story. Not just for kids. It's a must read for everyone!
Boring for mommy , great for the kids

value: This website is an American online audiobook and podcast service that allows users to purchase and stream audiobooks and other forms of spoken word content. This content can be purchased individually or under a subscription model where the user receives "credits" that can be redeemed for content monthly and receive access to a curated on-demand library of content.


text:
Join the Heart of Illinois HR Council January 2018 Tickets, Fri, Jan 5, 2018 at 4:30 PM | Eventbrite
Join the Heart of Illinois HR Council January 2018
Friday, January 5, 2018 at 4:30 PM - Saturday, June 30, 2018 at 7:30 PM (CST)
National SHRM Member Jun 30, 2018 $75.00 $0.00 Ticket Quantity Select 0 1 2 3 4 5 6 7 8 9 10
Non National SHRM Member Jun 30, 2018 $100.00 $0.00 Ticket Quantity Select 0 1 2 3 4 5 6 7 8 9 10
Membership with Meals - SHRM Member Jun 30, 2018 $310.00 $0.00 Ticket Quantity Select 0 1 2 3 4 5 6 7 8 9 10
Non SHRM Member with Meals Jun 30, 2018 $335.00 $0.00 Ticket Quantity Select 0 1 2 3 4 5 6 7 8 9 10
Share Join the Heart of Illinois HR Council January 2018
HIHRC MEMBERSHIP FOR 2018!
Members will be asked to use a promotional code when registering for meetings in order to receive the discounted membership rate. This code will be emailed to members within 5-days of receiving 2018 membership or renewal dues. (Sooner whenever possible!)
Have questions about Join the Heart of Illinois HR Council January 2018? Contact HIHRC

value: This website is an American event management and ticketing website. The service allows users to browse, create, and promote local events.


text:
NFL: Len Pasquarelli examines how the league awarded the 2013 Super Bowl to New Orleans, a decision he feels was overdue - ESPN
Applauding a Big Easy, Super decision
FORT LAUDERDALE, Fla. -- So, the big game is back in the Big Easy.	Good.	With apologies to Arizona and South Florida, the two other areas that were worthy candidates for the NFL championship game in 2013, awarding Super Bowl XLVII to New Orleans was the absolute right call by the NFL's owners at the conclusion of their two-day meeting here Tuesday afternoon.
Few cities in this country have experienced the kind of travails visited upon New Orleans ...Read full story

value: This website is the official website of ESPN. It is owned by ESPN Internet Ventures, a division of ESPN Inc.


text:
Відгуки про перебування в New Mitrapap Hotel в Чіанг-Май в Таїланд - сторінка 25
panasin з Таїланд
good location value for money, just stone trow from airport or busterminal. free wifi, clean and comfortable. near central market kad luang
near market and good rate
New Mitrapap Hotel is good price rate(), with refrigertor. the hotel is near to market. The surrounding of the market during the night will have night stall set up along the roadside selling all kind of cooked food and clothing. Opposite the hotel, there is good noodle stall.
Yes indeed most compatative rates in Chiang Mai with good location and a good thai restaurant opposite but no 7/11 around.But for me the bargin hunting stops at the point where i risk my health and with no ventilation in the bath rooms its no wonder that the whole place is covered in mould.
Combined with the heartless design of the rooms its a sure "never again" no save Locker for yor bags if you want to leave them for some days they just put them, in a room where everybody can take them away so its the same like you put your bags on the street.
Dayan з Бразілія
Very cheap, and good space
i was worried about this hotel, but after some reviews and since but family had left already i tried and i did not regret. the room was big and clean, and location was ok,near few places i needed to go, walking distance to night bazaar.
Conveniently located hotel, with friendly staff
The location of the hotel is okay, it’s a walk from the market (there was also a night market when I walked about the area in the evening). There’s a good restaurant fronting the hotel that sells good Thai food for a good price. You can take a walk around the neighbourhood and you can find a lot of temples (wats) where you can take photos. The hotel itself is okay, though the design of the floors looked like a prison. I thought it looked strange! The people at the front desk were very friendly. They can be very accommodating when needed. There’s a huge map fronting the reception counter showing the hotel’s proximity with some of the major sights in the area, wats included. There’s free standard breakfast available every morning. Generally, the room I was in was moderately clean. At least the bathroom didn’t stink. There was a small tv, a table and a chair provided. The lock made me worry because I thought it wasn’t as strong, but everything turned out okay when I was there. Just don’t leave your valuables when you go out of your hotel room.
Переглянуто 07 листопада 2011
wan з Південна Корея
i travelled chiangmai for 5 days alone and so i stayed at new mitrapap hotel for 4 nights. it's facility is not good but the price is unbelievably cheap and the location is near to market and night bazaar. so in total i would give a good score. so if you like to spend most of your time travelling, this place is really good for you, but if you want to take a good rest at your hotel this is not for you. and actually i d like to say this new mitrapap is not a hotel, looking like a kind of inn. there r many thai people staying also. anyway i just wanted a place to sleep, it was good for me. ^^ Переглянуто 04 листопада 2011
kamonlak з Таїланд
this was a repeat, visit when we visit for shopping this place is perfect.
close to the markets, and a short stroll to the famous chiangmai night market. space for car parking if you are a driver, but it seems to fill fairly fast.
close by is good thai food and a stroll away restaurants if you want western meals. Переглянуто 01 листопада 2011
Зупинявся на 13 ночей в Жовтень 2011 р.
Your get what you paid for, this hotel is nothing fancy but it is cheap so you end up with a few more dollars to buy food or souvenirs. Переглянуто 29 жовтня 2011
The room was nothing special, the service was good. It was clean for a cheap room. Across the street is an awesome restaurant Переглянуто 29 жовтня 2011
Light з Малайзія

value: This website is a Singaporean online travel agency and metasearch engine for hotels, vacation rentals, flights, and airport transfer. It is owned by Agoda Company Pte.


text:
BBC Radio 4 - You and Yours, Tripoli tourists, big headphones and Christmas ads - Illegal Downloads The BBC has updated its cookie policy. We use cookies to ensure that we give you the best experience on our website. This includes cookies from third party social media websites if you visit a page which contains embedded content from social media. Such third party cookies may track your use of the BBC website. We and our partners also use cookies to ensure we show you advertising that is relevant to you. If you continue without changing your settings, we'll assume that you are happy to receive all cookies on the BBC website. However, you can change your cookie settings at any time. Continue Change settings Find out more ]]> Accessibility links Skip to content Accessibility Help BBC iD Notifications
HomeEpisodesClipsPodcastPresentersContact Us Illegal Downloads The growing problem of people illegally downloading electronic games. 5 minutes This chapter is from You and Yours — Tripoli tourists, big headphones and Christmas ads Christmas TV adverts, big headphones and tourists in Tripoli. View Programme information You may also like View all HomeHelpScheduleDownloadsBlog {{/each}}

value: This website is the BBC's online service. It is a large network of websites including such high-profile sites as BBC News and Sport, the on-demand video and radio services co-branded BBC iPlayer, the children's sites CBBC and CBeebies, and learning services such as Bitesize.


text:
Czynnki Panujące Na Lądzie I W Wodzie | eBay Please enable JavaScript Our new search experience requires JavaScript to be enabled. Please enable JavaScript on your browser, then try again.
Skip to main contenteBayShop by categoryEnter your search keywordAll CategoriesAntiquesArtBabyBooksBusiness & IndustrialCameras & PhotoCell Phones & AccessoriesClothing, Shoes & AccessoriesCoins & Paper MoneyCollectiblesComputers/Tablets & NetworkingConsumer ElectronicsCraftsDolls & BearsDVDs & MovieseBay MotorsEntertainment MemorabiliaGift Cards & CouponsHealth & BeautyHome & GardenJewelry & WatchesMusicMusical Instruments & GearPet SuppliesPottery & GlassReal EstateSpecialty ServicesSporting GoodsSports Mem, Cards & Fan ShopStampsTickets & ExperiencesToys & HobbiesTravelVideo Games & ConsolesEverything ElseAdvanced or register':' style="margin-right:3px">Hi -User-!'.replace(/-User-/,escape(a)))+"")}catch(b){document.write("")}})();Hi (Sign in to bid or buy)Daily DealsGift CardsSellHelp & ContactMy eBayExpand My eBaySummaryBids/OffersWatch listWish listAll listsPurchase historySellingMy CollectionsFollowed searchesMessagesNotification Refine your search for Czynnki Panujące Na Lądzie I W Wodzie
0 results found for Czynnki Panujące Na Lądzie I W Wodzie
Czynnki Panujące Na Lądzie I W Wodzie: This is the median price based on sales of this product in the same condition from all listings on ebay.com in the past 14 days, or if there are any insufficient number of listings for a meaningful calculation, the past 90 days.

value: This website is an American multinational e-commerce corporation based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website.


text:
Hadrian Eiendom AS: Board Committees & Members - Bloomberg
To contact Hadrian Eiendom AS, please visit . Company data is provided by S&P Global Market Intelligence. Please use this form to report any data issues.

value: This website is an international news agency headquartered in New York City and a division of Bloomberg L.P. Content produced by Bloomberg News is disseminated through Bloomberg Terminals, Bloomberg Television, Bloomberg Radio, Bloomberg Businessweek, Bloomberg Markets, Bloomberg.com, and Bloomberg's mobile platforms. Since 2015, John Micklethwait has served as editor-in-chief.


text: _.mj=function(){this.H=[];this.R=[]};_.g=_.mj.prototype;_.g.Cf=function(){return this.H.length+this.R.length};_.g.ke=function(){return _.zb(this.H)&&_.zb(this.R)};_.g.clear=function(){this.H=[];this.R=[]};_.g.contains=function(a){return _.yb(this.H,a)||_.yb(this.R,a)};_.g.remove=function(a){var b=this.H;var c=(0,_.oba)(b,a);0<=c?(_.Bb(b,c),b=!0):b=!1;return b||_.Cb(this.R,a)}; _.g.Fe=function(){for(var a=[],b=this.H.length-1;0<=b;--b)a.push(this.H[b]);var c=this.R.length;for(b=0;bAutomot Success - Google+Press question mark to see available shortcut keysSign inSearchSign in1 member - PublicAutomot SuccessAsk to joinSearch CommunityAbout CommunityYoutubebloggerFacebookAutomot SuccessAsk to join1 member - PublicAutomot SuccessAsk to joinAbout CommunityYoutubebloggerFacebook Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion32wHow to Build Garage storage cabinets | “Best garage storage cabinets review”automotsuccess.blogspot.com no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33w♦Automotive Success - Best line brake flaring Tool..... no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33w♣How to Use a brake caliper piston tool Review- AutomotSuccess no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33wBest drum brake tools Review | The ultimate guide no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33w♦Achieving Extraordinary Success | Automotsuccess no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33wBest brake spring pliers Review | The ultimate Automotive tools no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33wHow To Changing Brake Pads | TOP 5 Performance no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33wHow to Replace Brake Pads | Best brake pad Review no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33wHow To Quickly brake bleeding tool | Best Review no plus ones no comments no shares Post has attachmentAutomot SuccessOwnerAutomot SuccessDiscussion33wThe Best Brake Caliper Tools Master | World best Review no plus ones no comments no sharesLooks like you've reached the endLooks like you've reached the endUnable to load more. RetryWait while more posts are being loadedDrag photos anywhere to start a new post

value: This website .


text:
MVF: The Good Samaritan by Lois Rock | NOOK Book (NOOK Kids Read to Me) | Barnes & Noble® Books by Author Books by Series Collectible Editions Coming Soon by Date Coming Soon by Subject New Releases NY Times Bestsellers Signed Books Top Books of the Month
MVF: The Good Samaritan
MVF: The Good Samaritan by Lois Rock
My Very First Bible published to high acclaim in 2003 and its popular stories and bright illustrations have since gone onto provide the basis for a number of additional series including board books, big books, sticker and activity books. 12 key Bible stories have now been made available to collect. An ideal way of collecting multiple books for use in groups and classes, or for anyone wanting a pocket-money gift.
9780745967462

value: This website is an American bookseller. It is a Fortune 1000 company and the bookseller with the largest number of retail outlets in the United States.