Manuale d’uso / di manutenzione del prodotto L2TP del fabbricante Nortel Networks
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Part No. 303532-A Rev 00 Oc tob er 1998 BayRS V ersi on 13.0 0 Site Manager Soft ware Version 7. 00 Configurin g L2TP Se rvices.
ii 303532-A Rev 00 4401 Great America P arkw ay 8 F ed eral Stree t Santa Cl ar a, CA 95054 Bil lerica , MA 01821 Copyr ight © 1998 Bay N et w orks, Inc. All rights rese rved . Pr inted in the USA. October 1998. The inf orma tion i n thi s do cumen t is subje ct t o cha nge with out not ice .
303532- A Re v 00 iii Ba y Netw orks, Inc . Software Li cense Agreement NO TICE: Ple as e caref ul ly r ead this li ce nse agr eement befo re c opy ing or us in g the a cco mpanyi ng s oft ware or in st al li ng the har dware unit with pr e- enabled s oftwa re (e ach of w h ic h is ref er red to as “Sof tw are” i n t hi s Ag ree ment).
iv 303532 - A Re v 00 its o wn data and in fo rmatio n and for mai nt aining ad equate p ro ced ure s apa r t fr om the So ft wa re t o re construc t lost or alte red f iles, data , or p rogra ms.
303532- A Re v 00 v Contents Preface Bef ore Y ou Begi n ... .. ..... ..... .... ... ..... .... ..... ....... ..... ..... .... ..... .. ..... ..... ..... .... ..... .. ..... ..... ..... .... x iii T ext Co n v entio n s ... ....... ..... .. ..... .. .
vi 303532 - A Re v 00 L2TP I P Int erf ace Add resses .. .... ..... ..... .. ..... ..... .... ..... ..... .. ..... ..... .... ..... ..... .. ..... ..... . 1-15 Remot e Ro uter Co nfig urat i on ... ..... .... ..... ..... ..... .. ..... .... ..... ....
303532- A Re v 00 vi i Appendi x B Co nfi gur a t io n Ex a mpl e s Exa mple 1: Remo te PC C alling t he Cor porat e Ne twork ....... ....... ....... . .... . ...... ....... . .... . .. B -1 Confi gurin g t he Remo te Host s .. ..... .... ..... .. ...
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303532- A Re v 00 ix Figures Fi gure 1-1. L2TP Netwo rk Usin g a LA C .... ..... ..... .... ..... ..... .. ..... ..... .... ....... ..... ..... ..... ... 1-7 Fi gure 1-2. L2TP Netwo rk Usin g a RA S .. .... ... ..... .... ..... ..... ..... .. ..... ..
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303532- A Re v 00 xi T a bles T able C-1. Comm on L2T P Network Problems and Solutions ............... ................... C-1.
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303532- A Re v 00 xiii Preface This guide describes La yer 2 T unneling Proto col (L2TP) and what you do to st art and customi ze L2TP services on a Bay Networks ® r outer . Bef or e Y ou Begin Before using this guide, you must complete the follo wing procedur e s.
Configuring L2 TP Services xiv 3 03532 -A Re v 00 T ext Con v e n t ions This g uide uses the follo wing t ext con venti ons: bold t e xt Indica tes text tha t you need to enter and command names and options. Example: Enter s how ip { al ert s | route s } Example: Use t he dinfo c omman d.
Prefac e 303532- A Re v 0 0 xv Acr on yms CHAP Challe nge Ha ndshak e Authent icati on Protoc ol IP Int ernet Protocol ISDN Int egr a ted Services Digital Ne twork ISP Int ernet Servic e Provid er L2T.
Configuring L2 TP Services xvi 3 03532-A Rev 00 Ba y Netw or ks T e c hnical Publ i catio ns Y ou can now pr int Bay Networks te chnical manua ls and relea se notes free, direc tly from the Interne t. Go to support. baynetworks. com/libr ary/ tpubs/ .
303532- A Re v 00 1-1 Chapter 1 L2TP O verview The Layer 2 T unneling Protocol ( L2TP) provi des remote use rs , suc h as telec ommuters, mobi le professionals , an d personne l in remote branch of fic es, with d ia l-in a ccess to a corpor ate network.
Configuring L2 TP Services 1-2 303532 - A Re v 00 L2TP Bene fi ts L2TP has se ve ral adv anta ges : • Use r s and busi nesses can tak e adva ntage of exist ing networ k eq uipment and resou rces . Corpor ations do not need to maintain a nd manage remote access se rv er s and other spe cial netw orking equipment f or remote users.
L2TP Overview 303532- A Re v 0 0 1-3 Multip le users can communicate t hrough a single tunnel betwee n th e same LA C and LNS pa ir . Eac h user trans mits and r ecei v es data in a n indi vidual L2TP sessi on. The LA C brings do wn the tu nnel for any one of the follo wing reasons: • A ne twor k fa ilur e occurs.
Configuring L2 TP Services 1-4 303532 - A Re v 00 Components of an L2TP Netw ork The follo win g section s desc ribe t he component s of a n L2TP ne twor k. F or illust r ati ons of L2TP netw or ks, see Figure s 1-1 and 1-2 on pa g e 1-7 . Remote Host At the remote si te is the user who wants to dial in to the c orporat e network.
L2TP Overview 303532- A Re v 0 0 1-5 L2TP Access Concentrator (LAC) The L2TP access conce ntrator (LA C) resi des at the ISP networ k. The LA C establi shes the L2TP t unnel b etween i tself a nd the LN S. When the remote user pla ces a call to the ISP networ k, this call goes to the LA C .
Configuring L2 TP Services 1-6 303532 - A Re v 00 L2TP Netw ork Server (LNS) The L2TP network se rver (LNS) is a router that reside s at the corporate net wor k and serv es as the termina tion point for L2TP tunn els and sessions . The LNS authenti cate s the PPP connect ion request and allo ws the end-to-e nd PPP tunne led connection.
L2TP Overview 303532- A Re v 0 0 1-7 Examples of L2TP Networks Figure 1- 1 shows an L2 TP net work that uses a LA C t o connect t o t he LNS. The tunne l i s betwee n the LA C a nd the LNS. Figu re 1 -1. L2T P Network Usi ng a LA C Figure 1- 2 shows a n L2TP network that use s a RAS to conne ct to the LNS.
Configuring L2 TP Services 1-8 303532 - A Re v 00 L2TP P ac ket Encapsul ation The PC or route r at t he r emote s ite s ends PPP pa cke ts to the LAC. The LA C encaps ulates thes e incoming pack ets in an L2TP packet and sends it acr oss a n IP netw ork t hrough a bidir ectiona l tunne l.
L2TP Overview 303532- A Re v 0 0 1-9 Making a Connection Ac r os s an L2TP Netw ork The follo wing steps expla in how a remote user connects across an L2 TP network that inclu des a B ay Ne tworks LA C, TMS, and LNS (se e Fi gure 1-1 on page 1-7 ): 1.
Configuring L2 TP Services 1-10 303532 - A Re v 00 Security in a n L2TP Network Y ou can conf igure tw o layer s of security in an L2TP netw ork: • T unnel authenti c ation T unnel a uthenti cation i s t he proc ess of negotia ting the est ablishment of a tunne l betwe en t he LA C an d the LNS.
L2TP Overview 303532- A Re v 0 0 1-11 Ba y Netw orks L2TP Implementation In an L2TP netw or k , the Bay Networ ks router is the LNS. LNS soft ware ope r ates on the BLN ® , BCN ® , and ASN ™ platforms.
Configuring L2 TP Services 1-12 303532 - A Re v 00 T unnel Man a gement The Bay Netw orks t unnel m anagement se rv er (TMS), which resi des at the I SP netw ork, stores the TMS dat abase.
L2TP Overview 303532- A Re v 0 0 1-13 Y ou c an enab le tun nel authe nti cation on th e Bay Networks LNS . If tunne l authenti c ati on is disable d, whi ch is the de f ault, the LNS sends a d efault c hallen ge response to the LA C during the aut hen tic ation process so that the tunne l can be establi shed.
Configuring L2 TP Services 1-14 303532 - A Re v 00 After tunnel authent ication is comple te, it does not need to be rep eate d f or other calls to the same LA C.
L2TP Overview 303532- A Re v 0 0 1-15 RADIUS Accounting The RADIUS se rver can pr ovide acc ounting se rvic es i n addit ion to its authenti c ation s e rvices. RADIUS ac counting is enabled by def ault o n the Bay Netw orks LNS. The RADIUS accounti ng serve r calculates bil ling charges for an L2TP sess ion betwee n th e remo te user and the LNS .
Configuring L2 TP Services 1-16 303532 - A Re v 00 Remote Router Configuration If the hos t at the remote site is a Bay Networ ks route r , you m ay need to c onf igure a dial -on-d emand circuit f o r the re mote rou ter’ s dial- up interfac e to the L A C at the ISP networ k.
L2TP Overview 303532- A Re v 0 0 1-17 Where to Go Ne x t Go to one of the follo wing chapters for more infor mation: If y ou want to Go to Start L2TP on a router usin g def a ult par amet er sett ing s. Chapter 2 Change de fault set tings f or L2TP para m eters .
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303532- A Re v 00 2-1 Chapter 2 Starting L2TP The quicke st way to sta r t L2TP is to enabl e it with the defaul t configu r ati on that Bay Ne tworks softw are s uppli es. This con fi guration u ses a ll a va ilable p arameter defa ult s. Y ou need to supply v alue s for se v eral par ameters that do not ha ve def ault val ue s.
Configuring L2 TP Services 2-2 303532 - A Re v 00 Plannin g Considerations for an L2TP Network This guide primarily e xplains how to confi gure a Bay Networ ks BLN, BCN, or ASN route r a s a n LNS i n an L2TP networ k. T o suc cessful ly opera te i n an L2TP netw ork, obtain the fol lo win g informat ion to conf igure the LNS.
Starting L2 TP 303532- A Re v 0 0 2-3 Preparing a Configurat ion File Before starti ng L2TP , yo u must c reat e and save a co n figurat ion file with a t least one W AN i nte rface , for exam ple , a synchronous or MCT1 port.
Configuring L2 TP Services 2-4 303532 - A Re v 00 Enabling L2TP on an Unconfig ured W AN Interface T o enable L2TP on an unc onf igured W AN int erfac e, comp l ete the f ollo wing t a s ks: Site Manager Procedu r e Y ou do this System respo nds 1. In the Conf igu ration M anage r win dow , choose a W AN c onnector .
Starting L2 TP 303532- A Re v 0 0 2-5 Enabling L2TP on an Existing P PP Interface T o enable L2TP on an inte rface with PPP and IP already e nabled, compl ete the foll o wing ta sks: 11. Clic k on OK . 12. Clic k on Done . Y ou r et ur n to t he Conf igur atio n Man ager windo w .
Configuring L2 TP Services 2-6 303532 - A Re v 00 9. Set the f o l l ow ing parame ter s: • L2TP IP Interfa ce Addre ss • Subnet Mas k Clic k on Hel p or see th e par amete r descript i ons beginn ing on pag e A-11 . Site Manager displ ay s a mes sage alerting y ou of th e time dela y t o cr eate the L2TP tu nnel cir cui ts.
Starting L2 TP 303532- A Re v 0 0 2-7 Ena b ling L2 TP on an Exis ti ng Frame Rel ay I nter face T o enable L2TP on a n inte rface with fram e relay and IP al ready enabled , compl ete the follo wing tasks: Site Manager Procedu r e Y ou do this System respo nds 1.
Configuring L2 TP Services 2-8 303532 - A Re v 00 11. Clic k on OK . Y ou retu r n to th e L2 TP IP In ter f ace Li st windo w , which displa ys the IP i nter fac e addres s and the s ubnet mas k. A mess age windo w opens that rea ds, L2TP Conf ig urati on i s co mple ted .
Starting L2 TP 303532- A Re v 0 0 2-9 Enabl ing L2TP on an E xisting A TM Interface T o enable L2TP on an int erface w i th A T M and IP alrea dy enabl ed, you can enable L2TP in tw o ways. If your interf ace uses a COM connector , c omplete the ta sks in the follo wing table.
Configuring L2 TP Services 2-10 303532 - A Re v 00 If y our A TM inte rface us es an A TM conn ecto r , co mple te th e followi n g t asks: 12. Clic k on Done . Y ou r eturn t o the Circ uit D efi niti on windo w . 13. Choose File . The Fil e menu open s.
303532- A Re v 00 3-1 Chapter 3 Customiz ing L 2TP Services When y ou ena ble L2 TP , defa ult v alues a re in ef fe ct for most parameter s (se e parame ter descrip tions in Appendix A , “ L2TP Para meters ”). Y o u m ay wa nt to change some of t hese v alue s, de pending on the requir ements of y our ne twork .
Configuring L2 TP Services 3-2 303532 - A Re v 00 Modifying the L 2TP Pr otocol Configuration T o modify how da ta is transmitte d across an L2TP networ k, suc h as the number , freq uency , a nd timi ng of data a nd acknowl edgment pack ets e xchanged between the LNS and LA C, you can modify the L2TP protoc ol pa rameters.
Custom izing L2TP Services 303532- A Re v 0 0 3-3 Modifying RA DIUS Ser v er Information If you change the add ress of the RADIUS ser ver tha t you are usin g to authen ticate remote users and manage accounti ng functi ons, you mu st upda te the server addre ss information on the LNS.
Configuring L2 TP Services 3-4 303532 - A Re v 00 Changing th e LNS Sy stem Name The LNS syste m name i s t he name o f the router . This name i s u sed during tun nel setup to ident ify th e LNS uniq ue ly . By def ault , Si te Manage r e nters th e syst em name that you initial ly conf igured when fi rst a ccessi ng the router .
Custom izing L2TP Services 303532- A Re v 0 0 3-5 Modifying the Number of L2TP Se ssions P erm i tte d Y ou ca n m od ify th e ma xi mum nu m ber of ac tive L2TP sess ions tha t the LNS ca n manage. The de fault is 100 se ssi ons. Fo r more information ab out L2TP sessions, se e “ L2TP Sessions ” o n page 1-3 .
Configuring L2 TP Services 3-6 303532 - A Re v 00 K ee ping the Rem ote User ’ s Dom ain Name The LNS remov es the domain name from the complete use r name b y default, befor e passing it on to the RADIUS serve r for user authen tic ation.
Custom izing L2TP Services 303532- A Re v 0 0 3-7 Changing the Domain Name De limiter In the complet e user name there is a single -cha racter delimiter tha t separ ates the user na me from t he domain na m e. By defaul t, the LNS remov es the do m ain na me when it rece iv e s a ca ll.
Configuring L2 TP Services 3-8 303532 - A Re v 00 En abli ng T un nel A uth ent ica tio n T o prev ent unauthorize d users from accessi ng t he cor porate networ k, you can enable t unnel auth entic ation. Dur ing tunnel ne gotiati on, the LA C s e nds it s tunne l authenti c ation p a ssword to t he LNS.
Custom izing L2TP Services 303532- A Re v 0 0 3-9 Modifying L2TP IP Interface Ad d resses The L2TP I P Int e rface List windo w lists the L2TP IP interf a ce addresses f or each slot tha t has L2TP c onf igure d. The LNS uses the address es interna lly to ide ntify the remote si tes.
Configuring L2 TP Services 3-10 303532 - A Re v 00 Disab ling RIP RIP is enabled on the LNS b y de f a ul t so that the LNS can learn routes f rom the remote dial-in router .
Custom izing L2TP Services 303532- A Re v 0 0 3-11 Deleting L2 TP fr om a P P P Inte rfa ce T o delete L2TP from a PPP inte rface , comp lete t he f ollo w i ng ta s ks: 6. Set t he Enable L2TP par amet er to Disabl e . Clic k on Help or see the paramet er des cri pti on on page A- 3 .
Configuring L2 TP Services 3-12 303532 - A Re v 00 Deleting L2 TP fr om a Fr a me Rela y Interface T o delete L2TP from a frame relay int erface, comp l ete t he fo l lowing tasks: Site Manager Procedu r e Y ou do this System respo nds 1. In the Conf igu ration M anage r win dow , clic k on a W AN connect or co nf igured with L2TP .
Custom izing L2TP Services 303532- A Re v 0 0 3-13 Deleting L2TP fr om an A TM Interface T o delete L2TP from an A TM inte rface on a CO M c onnector , complete the foll o wing ta sks: T o delete L2TP from an A TM inte rface on a n A T M c onnector , comple te the foll o wing ta sks: Site Manager Procedu r e Y ou do this System respo nds 1.
Configuring L2 TP Services 3-14 303532 - A Re v 00 6. Clic k on OK . Y ou re tu r n to th e A TM S e r v ic e Rec o rds List window . 7. Clic k on Done . Y ou re tu r n to th e Ed it A T M C o nn e c to r windo w . 8. Clic k on Done . Y ou r eturn t o the Confi gurat ion M anager windo w .
303532- A Re v 00 A-1 Appendix A L2TP P arameter s This appendix contains the Site Manage r parameter descr iptions fo r L2TP servic es. Y ou c an displ a y the same information using Si te Manager online Help. Fo r inf ormatio n about the IP para meters t ha t you set when ena bling L2TP , see Conf igu ring I P Servic es .
Configuring L2 TP Services A- 2 303532 - A Re v 00 The T ech nicia n Interfa ce al l o ws you t o modify para meter s by issu ing set and commit commands with the MIB object ID. This proce ss is eq uiva len t t o modifying pa rameters using Site Manager .
L2TP P arame ters 303532- A Re v 0 0 A-3 Parame ter : Ena ble L2TP Path: Configu r ation M anager > P rotoco ls > I P > L2TP > L2TP C onf iguration Defaul t: Enable Options: Enable | Disabl e Function: Enables or disables L2TP on this i nterface.
Configuring L2 TP Services A- 4 303532 - A Re v 00 Parame ter : Re tra n sm it Time r (s econ ds) Path: Configu r ation M anager > P rotoco ls > I P > L2TP > L2TP C onf iguration Defaul t:.
L2TP P arame ters 303532- A Re v 0 0 A-5 Par ameter: Ack T imeout (millisec onds) Path: Configu r ation M anager > P rotoco ls > I P > L2TP > L2TP C onf iguration Defaul t: 250 Options: 1 .
Configuring L2 TP Services A- 6 303532 - A Re v 00 Par ameter: RADIUS Primary Server Pa ssword Path: Configu r ation M anager > P rotoco ls > I P > L2TP > L2TP C onf iguration Defaul t: None Options: Any alphanum eric string, up to a maximum of 64 c haracte rs Function: S pec if ies the primary RADIUS serv er’ s pa s sword.
L2TP P arame ters 303532- A Re v 0 0 A-7 Par ameter: Remove Domain Name Path: Configu r ation M anager > P rotoco ls > I P > L2TP > L2TP C onf iguration Defaul t: Enable Options: Ena ble |.
Configuring L2 TP Services A- 8 303532 - A Re v 00 L2TP T unnel Securi ty P a ra m eters The L2TP T unnel Security List windo w (Figur e A-2) contains th e tunnel authenti c ation p a rameters . Figu re A- 2. L2T P T un nel Sec urity Lis t Wind ow The paramete r desc riptio ns fol low .
L2TP P arame ters 303532- A Re v 0 0 A-9 Parame ter : Ena ble T u nnel Authe nticatio n Path: Configu r ation M anager > P rotoco ls > I P > L2TP > T unnel Authe nticatio n Defaul t: Disable Options: Enable | Disabl e Function: Enables or disables the use of t unnel a ut he nt ication fo r a sl ot on the LNS.
Configuring L2 TP Services A- 10 303532 -A Rev 00 L2TP IP Int erface P a ramete r s The L2TP IP Interf a ce List wi ndow (Figur e A-3) c on t a i ns t he list of IP i nterface s for e ach sl ot on t he route r conf igured wi th L2 TP .
L2TP P arame ters 303532- A Re v 0 0 A-11 The paramete r desc riptio ns fol low . Parame ter : L2 TP IP Inte rface Ad dress Pa th: Configu r ation M anager > Prot oc ols > IP > L2TP > L2TP.
Configuring L2 TP Services A- 12 303532 -A Rev 00 Par ameter: RIP Enable Pa th: Configu r ati on Manager > Pr otoco ls > I P > L2TP > L2TP I P I nt erface Defaul t: Enable Options: Enable | Disable Function: S pec if ies whether RIP List en is enabled on this inte rface .
303532- A Re v 00 B-1 Appendix B Conf iguration Exa mples This a ppendix prov ide s two e xamples of L2TP ne twork conf igurati ons. It i nclude s only t hose p aram eters that re quire cha nges fr om th eir d efa ult setti ngs for prope r conf iguration.
Configuring L2 TP Services B- 2 303532 - A Re v 00 Figure B-1. L 2TP Netwo rk with PCs at the Remote Site Configuring the Remote Hosts The remote host s i n this ne twork are two PCs run ning Wi ndows 95. Neither PC has inter nal L2TP capabil ities. In this netw ork, one PC has a s ynchron ous dia l connec tion to the ISP via a modem.
Configuration Examp les 303532- A Re v 0 0 B-3 Configuring the LACs and the TMS The LA Cs in this ne two rk are Model 5399 Remote Access Conce ntr ators. Bo th de vi ces ha v e L2 TP modules insta lle d. S ee Model 5399 Remote Acce ss Concent rator documenta tio n for inf ormat ion about conf iguri ng L2TP .
Configuring L2 TP Services B- 4 303532 - A Re v 00 6. In t he L2 TP T un neling Sec urity window , e nable tunn el aut henti cation. 7. In t he L2 TP I P In terface wind ow , e nter the L 2TP I P a ddress. During the L2TP session, the RADIUS serv e r assigns the follo wing IP addre sses: jsmar t@baynetwor ks.
Configuration Examp les 303532- A Re v 0 0 B-5 Exampl e 2: Remote Router Ca ll ing the Corpo ra te Netw o rk Figure B -2 shows a ne tw ork with two B aySta c k™ AN ® route rs at the re mote si te. The AN routers are u s ing dial -o n-d e ma nd servi ce fo r dia l- up c onnections.
Configuring L2 TP Services B- 6 303532 - A Re v 00 Configuring the Dial-on-Demand C ircuit Modify t he dial-on- demand circui t conf igura tion f or t he AN r outers as f ollo ws: 1.
303532- A Re v 00 C-1 Appendix C T r ouble shooting T o monitor your L2TP network a nd solve proble ms that may occur , fir st check the e v ent l og f ile for a ny m essages recorde d b y the LNS.
Configuring L2 TP Services C-2 303532 - A Re v 00 L2TP sessi on is not activ e. The LNS fai l ed to negoti at e the PPP LCP options . Reconfi gure the host at t he remote si te dial ing in to the I SP . For a Bay Net work s rout er at the remote site, chec k the PPP MR U/MRR U s ize .
303532- A Re v 00 Index-1 A acco untin g, RADI US, 1- 15 Ac k T imeout (m ill is eco nds) pa ram e ter , A-5 acro nym s , xv B Bay N etw orks LNS. See LNS C conf i gu rati on e xam p l e s, B-1 conf i.
Ind ex -2 3 03532-A Re v 00 LNS ( con ti nue d) L2TP sec urity , 1- 10 mod ifyi ng pr oto col conf igurati on , 3-2 oper ating wi th LA Cs, 1- 11 LNS Syst em Name par am et er , A-5 LNS s yst em name .
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Nortel Networks L2TP è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Nortel Networks L2TP - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Nortel Networks L2TP imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Nortel Networks L2TP ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Nortel Networks L2TP, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Nortel Networks L2TP.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Nortel Networks L2TP. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Nortel Networks L2TP insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
