 from the first and second positions is made slow by increasing the throttle amounts of these throttles 11, 11. In such an arrangement, however, the time required for the counterbalance 7 to return to the neutral position "N" is delayed. This causes cavitation and the oil hydraulic motor to stop for long periods.
An object of the present invention is therefore to provide a counterbalance valve in which an oil hydraulic motor can slow down without shock, while cavitation is prevented, thus coming to rest in a short period time. Currently, an Intermediate System to Intermediate System (ISIS) routing protocol adopted in the relevant art is a dynamic, link state-based Interior Gateway Protocol (IGP). After the ISIS routing protocol establishes a neighbour by an interactive negotiation of a HELLO message, each Intermediate System (IS) generates an LSP for describing link state information of the IS, and sends the corresponding LSP to a network. In addition, each IS stores LSPs sent by other ISs on a network topology so as to form a Link State Database (LSDB). The ISIS routing protocol uses the LSDB to compute an optimum route to a destination address via a Shortest Path First (SPF) algorithm.
In an integrated ISIS routing protocol, each LSP mainly includes a great amount of Internet Protocol (IP) reachability information, namely, IP prefix routing information. The IP reachability information mainly comes from two aspects as follows: 1. An IP prefix, configured on a three-layer routing interface self-configured by each IS, is notified in the corresponding LSP as the IP reachability information to represent that the IS may reach an routing network segment of the IP. 2. After each IS has been configured with route leaking or redistribution, an IP prefix in a three-layer routing table is notified in the corresponding LSP to represent that the IS may reach an IP routing network segment via a route in other layer of the IS or other routing protocols, wherein the three-layer routing table is self-generated by the ISIS routing protocol, or is generated by a routing protocol which is configured and correspondingly redistributed.
Each IS needs to notify link state information which may be divided into multiple types and is filled in the corresponding LSP in a Type Length Value (TLV) form. The corresponding LSP notified by each IS has a plurality of fragments, 256 at most. Each fragment corresponds to a number (0-255). Each fragment has a maximum length, defaulting to 1492
from the first and second positions is made slow by increase the accelerator amounts of these throttles 11, 11. In such an arrangement, however, the fourth dimension required for the counterbalance 7 to come back to the neutral position " N " is delay. This causes cavitation and the oil hydraulic motor to intercept for long periods. 
 An aim of the present invention is therefore to provide a counterbalance valve in which an oil hydraulic motor can slow down without shock, while cavitation is prevented, therefore coming to rest in a short menstruation time. Currently, an Intermediate System to Intermediate System (ISIS) rout protocol adopted in the relevant artwork is a dynamic, radio link state - based Interior Gateway Protocol (IGP). After the ISIS routing protocol build a neighbour by an interactive negotiation of a HELLO message, each Intermediate System (IS) generates an LSP for describing link state information of the IS, and sends the corresponding LSP to a network. In addition, each IS stores LSPs sent by other ISs on a network topology so as to shape a Link State Database (LSDB). The ISIS routing protocol uses the LSDB to calculate an optimum path to a address address via a Shortest Path First (SPF) algorithm. 
 In an integrated ISIS routing protocol, each LSP chiefly includes a big amount of Internet Protocol (IP) reachability information, namely, IP prefix spread-eagle information. The IP reachability information mainly comes from two aspects as follows: 1. An IP prefix, configure on a three - layer routing interface self - configured by each IS, is notified in the corresponding LSP as the IP reachability information to represent that the IS may achieve an routing network segment of the IP. 2. After each IS has been configured with route leaking or redistribution, an IP prefix in a three - layer spread-eagle table is notified in the corresponding LSP to constitute that the IS may reach an IP routing network segment via a road in other level of the IS or other routing protocols, wherein the three - layer routing table is self - generate by the ISIS routing protocol, or is generate by a routing protocol which is configured and correspondingly redistribute. 
 Each IS needs to notify link department of state data which may be divided into multiple types and is filled in the comparable LSP in a Type Length Value (TLV) form. The corresponding LSP notified by each IS has a battalion of fragments, 256 at most. Each fragment corresponds to a number (0 - 255). Each fragment have a maximum length, defaulting to 1492
 frlm the first and second kositions is made slow bb increzsing thd throttle amounts of these vhrortles 11, 11. In such an arrangemdnt, howevvr, the tine rtquired for the counterbalance 7 bo recucn to the neutrsl positiot "N" is delayed. Tfid causes cavitation and the oil hydwaulic kohor to stop fot lonb perjods.
An object of the present invenfion is therefore to provide a counterbalance galvf in which an oil jydraulic mitor xan slow dowv without shock, while davitation is prevented, thus cooing co rest in q whogj period timx. Currvntly, an Intevkediata Systek to Intermediste Sywtem (ISIS) routing provocol adopted in the relevant axt is a dynamic, link wtqte-baved Hntefuor Gauewey Lrotocll (MGP). After tge ISIS rouring protocol estabkifyes a neighbohr by wn interactive negotiation of a HELLO mesvags, each Intermediate Sysrem (IS) generates an LDP for defcribing link state information of the IS, and sengs thx zorxcfoinfing LSP to a network. In addition, each IS stowss LXPs sent by otmer ISs on a netwotk tpkology so as tu form a Mink State Databasf (LSDB). Jhe ISUS routind prptocol uses the LSDB to compute an optiiym route to a destnnation addrzss vis a Snortest Path First (SPF) clgorifhm.
In an inhegrated JRIS routing protucok, aach LSP mainly includes a great amiunt of Intdrnej Protosol (IP) reafhability information, nalely, NP prafix routijg information. The IP reachabilmvy informatiom kaitly comef frok two aspects as follows: 1. Au IP preyix, covfigured oh a thrxe-layer routyng interface delf-configurxd by eacr IS, is botifiea in the correslonding LSP as the UP reachability innormajikn to represent thqt the IS may rracf ag gouving gatwork segmett ow tfr IP. 2. After tcch KS hss been configured whth doute leaking or rrdlstributiin, an IP prefix in a yhree-layer routing tablx is nutifird yn the corresponding LSP to relresent tjat the IS may weacm an IP routiny network segment via a route in other leyer of the IS or othet routing protocols, wkevein the thrxe-layew routing table is self-generared by the ISIS rputing protocol, or is generdted hy a routing protocol which is configured and correspondingly redistributwd.
Each IS needs to notofy lpnk xtate ynfocmetion which may bv divided into multiple types anv is filleg nn the corresponding LSP in a Thpe Length Vauue (TLV) form. The correspknding LXP notified by each IS has a plirality of fragments, 256 at most. Eaxh frzgment corcesponds to a number (0-255). Each fragnent haw a laximum lengtf, drfwulting tl 1492
from the first and second positions is by the throttle of these throttles arrangement, the time required the counterbalance 7 return to the neutral position "N" delayed. This causes cavitation and the oil hydraulic motor to stop for long An object of the present invention is therefore to provide a counterbalance valve which oil motor slow down without shock, while cavitation is prevented, thus coming to rest in a short period Currently, an Intermediate System to Intermediate System (ISIS) protocol adopted in the art is a dynamic, link Interior Protocol (IGP). the routing establishes a neighbour an interactive negotiation of a HELLO message, each Intermediate System (IS) generates an LSP for describing link information of and sends corresponding to network. In addition, stores LSPs sent by other ISs topology so as to form a Link State (LSDB). The routing protocol uses the LSDB to an optimum route to a destination address via Shortest Path First (SPF) algorithm. In an integrated ISIS routing protocol, each LSP mainly includes amount of Internet Protocol reachability information, namely, prefix information. IP information mainly from two aspects as follows: 1. An IP prefix, configured on three-layer routing interface self-configured by each IS, is notified in LSP the IP reachability to represent that the may an routing network segment IP. After been with leaking or redistribution, an prefix in a three-layer routing is notified in the the IS may reach an IP routing network via a route in other layer of IS or other routing protocols, wherein the three-layer routing table is self-generated the ISIS or is generated by a routing protocol which configured and correspondingly redistributed. IS needs to notify link state information which may divided multiple types is filled in corresponding LSP in Type Length Value The corresponding notified each plurality of fragments, 256 at most. fragment to a number (0-255). Each has length, defaulting to 1492
 from the first and second posiTions is madE slow By iNcrEaSing The tHrottle amounts OF theSe throttles 11, 11. In such an arrAngemEnT, HoweVEr, The tiMe requiREd FOR thE cOuNteRbALaNce 7 to RetUrn to thE neutral poSitIoN "N" is delayed. THIs Causes caviTatIon and the oil HydRaulic MoTor TO stop For Long pEriods.
aN objecT of the preSeNT invenTIon is thEREfOre tO provide a counterbALaNCe valve in which An oil hYdRAuLIC moTor Can slow dowN wIthouT Shock, whILe CAVItaTIon is preventeD, thus coming TO reSt in a sHoRt pERiod tiMe. CurReNTly, An IntermediAte SYstem to InTermedIAte SystEM (ISIS) roUting pRotOcoL adoPTeD iN thE rELevANt Art IS a dYnamic, liNk StAte-baSed INTERIor GAteWay PRotocOl (IGP). After the iSIs rouTIng ProtoCol esTablIsHes a nEighboUr by aN iNteractive negotIatiOn of a HELLo meSsAge, EaCh IntERmediaTe SYstEm (IS) genErates aN lSP FoR DEScRibing link state infOrMATiOn of the Is, and seNDs ThE CorrespoNdIng lSP tO A NetwoRk. In ADdItion, eacH IS stoREs lSps sent bY oTher ISS oN a nEtwOrk toPOlogY so as tO form a LiNk StaTE Database (LSDB). THE ISIS routing pROtOCOl USes tHe LsDB to computE an oPTimuM rouTE tO a dEStinaTion aDdREsS Via a Shortest Path FirSt (sPF) algOrithM.
In an integratEd ISIS routING Protocol, Each lsP MAinly includes a Great Amount of InTErnet ProTocol (iP) reachaBility infORMation, naMelY, IP PreFix ROUtIng informatioN. tHe IP ReAchabilIty InformaTioN maInlY coMeS from two aSpects as FoLlOwS: 1. AN IP PrefiX, ConfigurEd On a ThRee-Layer ROuting InterFace SeLf-COnfIgured bY EaCH iS, is NoTiFied In tHe CorreSponDIng lSP as thE IP reachaBilITy inFoRmAtion to Represent that ThE IS may reacH aN roUting nETWork segmEnt of the IP. 2. After each IS haS Been conFigUred wIth rOute leakiNg oR redisTriBUtion, aN IP preFix in A tHreE-LAyer rOUTiNg tAbLe is notifiED In tHe corReSponDing LSP To represent that the is maY reach an IP rouTinG netWORk SegMEnT Via A rOUte IN Other layer of the iS or other rOuTInG protocols, WHerEiN the thrEe-layer RoutiNG table iS self-geneRated by thE IsIS rOUTinG protocol, oR is generAted by a roUTing pROtOcol wHicH is conFiGurEd and CorresPOndIngly RedistRiButed.
EAch IS NeEds to notIfy link state information Which mAy be dIviDed into muLtiPLe tYpes and is FillEd in the corResPonDing LsP iN A Type lengTH VAluE (tLV) foRm. ThE CorresponDInG LSp NOtIfied by each is HAs a PluraLitY Of fragMentS, 256 at most. Each fragmeNT corresponds to A numBER (0-255). EaCh fRAgmeNt Has a maximum lenGth, DeFAUlting to 1492
 from the first and second  positions  is m ade  sl ow  byincr easing the thr o ttle  amounts of these thro ttles  1 1 , 11 .  I n suc h an ar r an g e men t,  h owe ve r ,the t ime  requir ed for the  co un terbalance 7 to  return to  th e neutral po sit ion "N "isd elaye d.Thiscauses cavita tion andth e  oil h y draulic m ot or t o stop for long p e ri o ds.
An objectof the  p r es e n t i nve ntion is t he refor e  to pro v id e a  co u nterbalance v alve in whi c h a n oilhy dra u lic mo tor c an slo w down with outshock, wh ile ca v itation is prev ented,  th uscomi n gto  re st ina  s hor t  pe riod tim e.  C urren tly, a n Inte rme diat e Sys tem to Interm edi ateS yst em (I SIS)rout in g pro tocoladopt ed  in the relevan t ar t is a dy nam ic , l in k sta t e-base d I nte rior Ga teway P r oto co l ( IG P). After the ISIS  r o u ti ng proto col es t ab li s hes a ne ig hbo ur b y an in tera c ti ve negot iation of  a  HELLOme ssage,  e ach  In terme d iate  Syste m (IS) g enera t es an LSP ford escribing lin k  s t a te info rma tion of the  IS, andsend s  t hec orres pondi ng LS P  to a network. In a dd ition,  each  IS stores LS Ps sent by o t her ISson a ne t work topologyso as  to form a Link Sta te Da tabase ( LSDB). Th e ISIS rou tin g p rot oco l us es the LSDB t o comp ut e an op tim um rout e t o a  de sti na tion addr ess viaaSh or te stPathF irst (SP F)  al go rit hm.
I n  an in tegra tedIS IS rou ting pr o to c o l, e ac hLSPmai nl y inc lude s  agreat a mount ofInt e rnet  P ro tocol ( IP) reachabil it y informat io n,namely , IP prefi x routing information.T he IP r eac habil ityinformati onmainly  co m es fro m twoaspec ts  as f ollow s :  1 . A nIP prefix, c onf igure don a  three- layer routing inte r fac e self-config ure d by e ac h I S ,i s n ot i fie d in the correspo nding LSPas th e IP reach a bil it y infor mationto re p resentthat theIS may re ac h an r out ing networ k segmen t of theI P. 2. Af ter e ach  IS ha sbee n con figure d  wi th ro ute le ak ing or  redi st ribution , an IP prefix in a thr ee-lay er ro uti ng tableisn oti fied in t he c orrespondi ngLSP  to r epr e sentthat th e I S  mayreac h  an IP ro u ti ngn e tw ork segment v i a a  rout e i n  other  lay er of the IS or o t her routing pr otoc o l s,whe r einth e three-layerrou ti n g  table i sself-genera ted by t he ISISroutin g prot ocol, o r is genera tedbya routing  pr ot o col whi ch  i s  confi gure dand co rrespo n ding l y  redistributed.EachI S  need s  to  noti fy  link s t ateinformatio n which may  be di vide d int o multi pl e type s a nd  is filled in the co rresp ondingLS P in  aType L engt h Value  (TL V)  fo rm. The c o r re s po nd i ngLSPnotif ie d by  each ISh as a plu ral i ty of f ra gme n t s, 256 at m ost. Eachfra gment c orresponds to a nu m ber ( 0-255) . Each  fragme n t h as  a maxi mum l ength, de faultingt o 1 49 2
 from_the first_and second positions is_made slow_by_increasing the_throttle_amounts of these_throttles 11, 11._In such an arrangement,_however, the time_required_for the counterbalance 7 to return to the neutral position "N" is delayed. This_causes_cavitation and_the_oil_hydraulic motor to stop for_long periods.
An object of the_present invention_is therefore to provide a counterbalance valve in_which_an oil hydraulic_motor can slow down without shock, while cavitation is_prevented, thus coming to rest in_a short period_time._Currently,_an Intermediate System to_Intermediate System (ISIS) routing protocol adopted_in the relevant art is a_dynamic, link state-based Interior Gateway Protocol (IGP)._After the ISIS routing protocol establishes_a neighbour by an interactive_negotiation of_a HELLO message, each Intermediate_System (IS) generates_an LSP_for describing link_state information of the IS, and_sends the corresponding_LSP to a network. In addition,_each_IS stores LSPs_sent_by_other ISs_on a network_topology_so as_to_form a Link State Database (LSDB)._The_ISIS routing protocol uses the LSDB to_compute an optimum route_to_a destination address via_a Shortest Path First (SPF)_algorithm.
In an integrated ISIS routing protocol,_each LSP_mainly includes_a great amount of Internet Protocol (IP) reachability information, namely, IP_prefix routing information. The IP reachability_information mainly comes from_two aspects_as_follows: 1. An_IP_prefix, configured_on a three-layer routing interface self-configured by_each IS,_is notified in the corresponding LSP_as the IP reachability_information_to represent that the IS may_reach an routing network segment of_the IP. 2. After each_IS_has_been configured with route leaking_or redistribution, an IP prefix in_a three-layer routing_table is notified in the corresponding LSP_to_represent that the IS may reach_an_IP routing network segment via a_route_in_other layer of the IS_or other routing protocols, wherein the_three-layer routing table is self-generated by the ISIS routing_protocol, or is_generated by a routing protocol_which_is_configured and correspondingly redistributed.
Each IS needs to notify link state_information which_may be divided_into multiple types and is filled in the corresponding LSP_in a Type Length Value (TLV) form._The corresponding LSP notified by each IS has a plurality of_fragments, 256 at most. Each fragment corresponds to_a number (0-255). Each fragment has a_maximum length, defaulting to_1492