  ADSL HOWTO for Linux Systems

  David Fannin, dfannin@sushisoft.com
  v0.92, 10 April 1999
  , linusben@kldp.org
  20 December 1999

   ý Ͽ Ż翡 ϴ ο   ȸ
   ADSL(Asymmetric Digital Subscriber Loop; Ī  
  ȸ) ϴ   Ѵ. ADSL   ȸ(DSL)
      ̿Ͽ 384kbps 1.5 Mbps
  ӵ / 񽺸   ִ.    ADSL 
  Ұ ġ    ϰ ִ.
  ______________________________________________________________________

  

  1. Legal Stuff
  2. Ұ
  3. ADSL 
     3.1 ADSL̶ ΰ?
     3.2 ADSL 
     3.3 xDSL/DSL̶ ΰ?
     3.4  ׷ پ ӵ ϳ?

  4.  ۵ϴ°.
     4.1 CPE: ADSL ANT  NIC
     4.2 ø Ǵ ø  
     4.3 DSLAM
     4.4 ISP 

  5.  ûϱ
     5.1  ʿ ׵
     5.2  ȸ ɼ
     5.3 ISP ɼ

  6.  .
     6.1 ø/NID 輱 (SNI)
     6.2 (ǻ ʿ) DSL  ϱ
     6.3 (ǻ ) ANT ġϱ

  7. Linux ġϱ
     7.1 NIC ī ġϰ ϱ
     7.2 ̴ ̽ ϱ
     7.3  ϱ
     7.4 ȭ/ŽĿ̵ 

  8. η
     8.1   (FAQs)
     8.2 ũ
     8.3  
     8.4  

  ______________________________________________________________________

  1.  Legal Stuff

  ADSL HOWTO for Linux Systems

  Copyright (C)1998,1999 David Fannin.

  This document  is free; you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free
  Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This document is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You can get a copy of the GNU GPL at at
  <http://www.gnu.org/copyleft/gpl.html>.

  2.  Ұ

    ADSL 񽺸  ýۿ ϱ  ֹ, ġ,
     ٷ ִ.

  ADSL Ȥ Ī 

   ȸ̶   ȭ(  ϰ ִ Ͱ 
  ) ̿ϴ  ͳ   Ѵ. ̱ 80 ۼƮ ̻
  ȭ   ϸ, ȸ  Ŀ  384 kbps
  1.5 Mbps ӵ       ͸  
    ӵ ̸ ´(  " Ī " 
  Ѵ). ADSL ͳ ȸ (ISP)  Ǿ ִ.

  ADSL 5-30 ý   ü(SOHO)  
  뿪 ϰ  ӵ    ǻ簡 ִ  ڸ
   Ǿ.     뿪   
   α׷ ۿ  پϴ. ADSL T1 ISDN  ݴ
  Ǿµ, T1  ϸ  ξ  ·
   T1  ӵ ϰ ִ. ADSL ڿ  
   Ǳ  ISDN  ִ 뿡 ϴ ̳ ü
  (delay) .

   Ͽ  ADSL 񽺿   ϴ  Ͽ
  񽺸 ϴ ҵ鿡   ̾׷ 캸  ̴.
  , ADSL ֹϱ    ̴.  ADSL ȸ
  ϰ  ý ϴ   ͵  ̴. 
   ִ ũ FAQ,   ڿ η ÷״.

      ȵ ȯѴ. dfannin@dnai.com 
  ֱ ٶ.

    Ե  ֽ FAQ
  <http://www.sushisoft.com/adsl/>   ִ.

  3.  ADSL 

  3.1.  ADSL̶ ΰ?

  Ī   ȸ(ADSL)̶:

  o   ȭ ϴ ȭ ȸ (A Telephone Loop
     Technology)

  o    ۰ Ƴα  

  o  IP      ȸ

  o  (Ϲ  )   ӵ  :
     ε/ٿε
     256 kbps/256 kbps
     384 kbps/128 kbps
     384 kbps/384 kbps
     384 kbps/1.5 Mbps
     ...

  o  ̴ 10baseT ̽ ϴ   CPE ɼ

  o  ISP  (/ ּ)

  o  IP    (ISP  ٸ   254   IP
     巹 )

  o  ȸ(T1)  

  3.2.  ADSL 

  ADSL ͳ/Ʈݿ   ȭ ̿Ͽ  
    ϱ Ͽ Ǿ.   ̱  ִ
  ȭ 60-80 ۼƮ ƹ ȭ    ִ.  ߰,
  ADSL  T1  ӵ(1.5Mbps) ϴµ ̴  
  ȸ ϴ Ƴα (56kbps)̳ ISDN (128kbps)
  Ͽ ſ  ӵ̴.   ADSL ٸ   ȸ Ͽ
    ޵Ǹ    ISDN T1 ̿
  ݴ밡 ȴ.

  Ż ̺ ȸ ̺ 𵩰   ִ 𵨷 ADSL
  ϰ   ̳   ־  ġ ִ.
  ̺  10-30 Mbps 뿪 ٰ   ̰
  ϳ   ڿ ϱ  ٸ ڵ 
  Ʈ 翡     ũ ϰ ȴ.

  ADSL  ͳ ȯ ϴ / ȸ(SOHO) ַ
  ǰ ִ. ̴   ϱ   뿪 
  ͳ Ͽ    ְ, ̸ ؼ 5-20 
  ǻͰ ִ 繫 ȯ濡  Ǹ ý   ִ.
  ̴   ͳݿ   ϴ   ڿԵ
  Ǹ ذå  ̴:-).

  3.3.  xDSL/DSL̶ ΰ?

    ȸ(DSL)  ִ  ȸθ Ż ߾
  繫 Ƴα ȭ ̿Ͽ  ϴ ̴. DSL 
   ȭ ȣ(, ѽ, ) ̿ϴ и ü ϱ
    ȸ Ͽ ̵  ÿ  ְ 
  ִ.  DSL 0kHz-4kHz  ļ Ƴα  ȣ 
  ϸ 4kHz-2.2MHz    Ѵ. xDSL  
  񽺸 Īؼ Ϲ θ  $dquot x$dquot 
   ǹ̸ Ѵ.

  o  ADSL Asymmetric Digital Subscriber Line(Ī   ȸ)
     :       1.5 Mbps-384kbps/384-128kbps

  o  HDSL High-bit-rate Digital Subscriber Line(   ȸ)
     :       1.5 Mbps/1.5 Mbps  (4Wire)

  o  SDSL Single-line Digital Subscriber Line(ܼ   ȸ) :
     1.5 Mbps/1.5 Mbps  (2Wire)

  o  VDSL Very high Digital Subscriber Line(ʰ   ȸ) :
     13 Mbps-52 Mbps/1.5 Mbps- 2.3 Mbps.

  o  IDSL ISDN Digital Subscriber Line(ISDN   ȸ) :
     128 Kbps/128 Kbps.

  o  RADSL Rate Adaptive Digital Subscriber Line(ӵ   ȸ)
     :       384kbps/128kbps

  o  UDSL Universal Digital Subscriber Line(   ȸ) :
     1.0Mbps-384kbps/384kbps-128kbps
     øͰ ʿ  " splitterless" DSL or DSL-Lite̶
     Ҹ.

  ⼭ Xbps/Ybps X ٿε ӵ, Y ε ӵ Ѵ.

  3.4.   ׷ پ ӵ ϳ?

  ADSL  ȭ ̿ ε 100  
  ȭ  ſ     ̾(FAQ 亯
  ٸ  ߰  ٶ). , ADSL ο ̱
    ޻  忡  ݰ  
  ǰ Ͽ ϰ Ѵ.

     Ϲ ڿ  캸 ذ  ̴.

  o   Ϲ 

       ӵ 384kbps-128kbps, Ī

  o   ޻ڿ Ϲ 繫

       ӵ 1.5Mbps-384kbps, Ī

  o   

       ӵ +2.0Mbps-1.1kbps, Ī

  4.   ۵ϴ°.

  ADSL  κ ȴ (׸ 1 2 ):

  o  ADSL Network Termination(ANT)  Network Interface Card (NIC)

  o  Splitter Ȥ Splitterless Design

  o  DSLAM  Ż ȸ

  o  ISP 

  ׸ 1: ADSL  ̾׷ (POTS Splitter)

  <-------/ȸ------------------->               <-----Ż ߾ 繫---->
                                 NID
                                -----               -----
  2 wire     X-------------=| S |               | D |
  phone                         | P |               | S |=-----  ġ
  line                          | L |    2 wire     | L |
                                | I |=-------------=| A |
                                | T |   Local Loop  | M |=----- ISP 
  10baseT       ----------| T |               |   |
   ̴   X--=|        |=----=| E |               -----
    Ȥ        ----------      | R |
  ATMF            ADSL          -----
  NIC             ANT

  4.1.  CPE: ADSL ANT  NIC

  ADSL    (Customer Premises Equipment;CPE) ANT
  NIC ī ȴ.  ADSL Ʈũ (ANT) ׸ 1  
   ̳ 繫ǿ ġǸ IP  Ѵ. ANT 
     ִ:

  o  10/100baseT ̽   ANT

  o  10/100baseT ̽  긴 ANT

  o  ATMF ̽  ANT

  o  USB ̽  ANT

  o  ANT/NIC ī ü

   , ANT/NIC ISP ؼ  ּҸ Ѵ. Ż
   ϴ ANT پѵ,  ڿԴ    
    10baseT ̽ ̿ϴ   ٶϴ. ٸ
  쿡 Ư ̹ ʿѵ,  κ  ̹
   ȵȴ.   ޾ü  ̹  ANT/NIC PCI
  ī常 ϴ 쵵 ִ.

  ! OEM ĵ  third party ANT/NIC ī 쿡
   ȸ ȣȯ ִ ݵ Ȯؾ Ѵ. ADSL ڵϴ
   ΰ (CAP, DMT) ְ IP (encapsulation) 
  ɼ ϱ ̴.  ȸ и   ɼǵ 
   ̴.

  ANT   ȸ( ȭ) ȴ.   ȸ POTS
  ø   ǰų, øͰ  쿡 
  ȸ  ȴ.  ׸ 1 POTS ø ȸ ָ, ׸
  2 øͰ  ȸ ش.

   쿡 Alcatel ANT ޾Ҵµ, ̰ 10baseT(ũν ȸ)
  RJ45  ϴ ̾.  PC  ġϴ NIC ī尡 
  ʿ ̶ ߴ.

  ׸ 2: ADSL  ̾׷(Splitterless Design)

  <-------Home/Office--------------->           <-----Telco Central Office---->
                               SNI
                                -               -----
  2 wire    X-[RJ11]--------|               | D |
  phone                     |               | S |=-----  ȯ
  line                          |    2 wire     | L |
                                |=-------------=| A |
                                |   Local Loop  | M |=----- ISP 
  10baseT       ---------- Data |               |   |
  ̴    X--=|        |=-----|               -----
    Ȥ        ----------
  ATMF            ADSL
  NIC             ANT

  4.2.  ø Ǵ ø  

  ·, ̵ ο а Ƴα ȣ и ʿ䰡 ִ.
   ȣ    ġ Ͱ ؾ Ѵ. 
     ִµ ٷ POTS ø͸ ϴ Ͱ RJ11
  ȭ ͸ ϴ ̴.

  켱, POTS ø͸ ϴ   , Ż 
  /ȸ  谡 ġϰ ȴ.    (demarcation
  point) ϴµ  ȸ Ż ȸ ϴ  νĵȴ.
    Żκ  ȣ  üΰ  üη иϰ
  ȴ.  ü Ϲ Ƴα ȭ(2 wire)̸  ü
  ANT  ȴ. øʹ  ۵ϴ  ʿ
  ̱  /ȸ   ʴ 쿡 
  ü ۵  ְ ȴ. Ż ȣ /ȸ翡 ϴ
   2 wire ȸ Ͽ øͷ .  øʹ
  /ȸ ܺο NID(Network Interface Device) ġȴ.

  ׸ 2  øͰ   , ܺ  ȸ 
  Ʈũ ̽(SNI; Subscriber Network Interface) 
  ȴ. ȭ Ű ϴ Ȯ忬    ȣ 
   ִ ͸  Ư  ġؾ Ѵ. ̰ RJ11 Ͷ
  Ѵ(RJ11 4/6 ȭ ϴ Ż  Ī̴).  ANT
  Ǵ κ ͸  ʴ´(ϸ ۵  ̴).
  ̰ Ͱ   ϴ  δ.   ӵ ADSL RJ-11
  Ͱ ʿ  쵵 ִ.

  ȸ  ø   ſ ȣϴµ, ġ 
     ADSL     ֱ ̴.
  κ  쿡 -  ߿  ƴ - RJ11 
  ̵ Ƴα ȭ    ̴(ȭ    
   ణ 鸮  ̴). ,   ȭ
  ջŰų Ÿ ٸ ǿ   Ƿ ׷  ʴ
    ̴.

  4.3.  DSLAM

  DSLAM ȸ ߾ 繫ǿ ȣ иϰ  ȣ 
  ȯ ISP  ִ ̴.  忡 
  ˸ ȴ.

  4.4.  ISP 

  ISP DSLAM   ȸ( T3(45Mbps) OC-3(155Mbps) ̻
  ATM) Ǿ ִ. ⼭ ߿   ϴ Ż
  ISP ̷ ῡ    üϰ ִ ̴.

  5.   ûϱ

  ⺻   :

  o  ADSL 񽺸  ʿ  ȮѴ.

  o   ȸ ISP ϰ ׵ ϴ  ȮѴ.

  o  Ż翡 ȭϰ 񽺸 ûѴ.

  ѹ 񽺸 ûϸ,  ȸ  񽺸 ġ ְڴٴ
    ̴.   ѹ ȭ  ֹ  
  ־  ISP ᵵ ־. 1  񽺸 ġ
  ְڴٴ  ޾Ұ, ƹ    ð 񽺸 
  ־.

  5.1.   ʿ ׵

  o   NIC ī

     ADSL ANT    ִ ý(PC, ũ̼, ,
     Ȥ ) ĪѴ.

  o   ȸ

      ȸ   (demarcation point) ǻͰ 
         ִ  ȸ(2 Ȥ 4 wire) ʿϴ.
      ϴ ȭ ״   ִ. , ̷ ϳ
      ȸ ANT ؼ Ǿ ϸ ٸ ȭ ἱ
      Ǿ ȵȴ.  ȸ糪 ٸ ȸ縦  ο
     ȸ ġ   ̴.

  o  ġ

       ȸ  ΰ? ø 輱    
     ְ (   ȸ 輱 õ   輱 
       ־) ߰  ϰ 輱 Ź 
     ִ.     Ѵٸ $ 150-250   
       ġ ߻  ִ  ġ Ϸκ ع 
     ִ.  м Ե  о    ΰ
     ϶.  Ʒ    ȭ Ʈũ LAN 
     ϰ Ǿ   ϰ   ֵ  ְ ۼǾ.
        а ڽŰ  ʰų  ȸ翡 
     ϰ ִٸ ׳ ׵鿡 ðܶ.

  5.2.   ȸ ɼ

  o    ȸ

      ȸ  û 񽺸 óϱ  ȸ ADSL
     ȣ ó  ִ Ȯ ̴. ߾ 繫ǿ 2-3 (3-5
     km)  ġ Ұ ־ ϸ loading coil̳ bridge taps,
     DAMLs  ֹ  ȸ̾ Ѵ. κ ISDN
     ϴ ȸ ADSL   , ADSL  ̱
           .  ȸ翡 ü 
        ̴.

  o  ȸ翡 ADSL   

     ADSL/DSLM  ߾ 繫ǿ  Ѱ? ٽ ѹ 
     ȸ翡  ġϰ ϴ  ADSL 񽺰 
     Ȯ ̴.  ̱  ֿ  ȸ ο ADSL 
      ü ADSL  ȹ ǥϰ ִ. 1Q99 а 
     ̶ Ѵ.

  o   ӵ

     ADSL  ӵ   Ű ȴ -  ȸ翡 Ȯ
     .   128k, 256k, 384k, Ȥ 1.5M   ӵ 
     ֹ  ̴. Ȥ  ȸ ° ֹ  ִ 
     ӵ ϰ   ִ.  ̿ϴ  ȸ  ڰ
      繫    ϰ ִ.

  o  POTS 

        ü( ū ȸ) 쿡 POTS ADSL
     Բ ֹϱ⵵ Ѵ.  ̰ ϸ  Ȥ ű ȭ
     ȣ  ʿ䰡 ִ.    ϴ POTS 񽺸
     ؼ ADSL ̿ , ƴϸ Ƴα ȭ  ο
     ȭ ȣ ο  ؾ  ̴.  ISDN
     񽺸 ް ־µ  ȸ ϰ Ѵٸ ISDN 
     ؾ Ѵ.   ȸ ( DSL   ü)  ɼ
        ִ.

  5.3.  ISP ɼ

  o  ISP (presubscription)

       ִ ISP ̸ ADSL  ȸ  Ǿ 
     ̴.  ϰ ϴ ISP ADSL  ȸ  Ǿ
     ִ Ȯ϶.  ׵  ʾҴٸ  ISP
     üϰų ׵ ADSL  ȸ  ϵ ϰų
     ADSL  ʰų     ϳ ؾ Ѵ.

  o  IP ݰ ּ.

     켱 ϴ IP ּҰ   Ȯ϶.  ּҶ
     DHCP ؾ Ѵ.

     ߰,  IP ּ , ISP 1 254 IP 巹 
     ADSL   ϳ ּҸ ġϴ VLSM(Variable Length
     Subbet Mask) Բ  ̴.

      ϴ ISP ȣƮ  þ  ߰ 
     䱸Ѵ.   κ  α׷ 1 ȣƮ(32 Ʈ
     ũ) Ȥ 6 ȣƮ(29 Ʈ ũ) Ѵٰ ߾.
      ŵ ȥٸ IP-Subnetting HOWTO ϶.  
      ȣƮ ϴ  쿡 ׵ ȣƮ  ϳ
     ISP  ּҷ ؾ Ѵ(ٽ ϸ 6 ȣƮ ̷
      Ѵٸ     ִ ȣƮ 5
     ̴).  LAN ؼ Ҵ  ̻ ּҸ ̿ϰ
     Ѵٸ IP ŽĿ̵(HOWTO )̳ Ʈũ ּ ȯ(NAT;
     Network Address Translation)   ִ.   30
     ̻ ȣƮ Ѵٸ ISP ϴ Ư Ŀ ° û
     ؾ  ̴.

  o  Ʈ ּ

     ⺻ Ʈ ּҸ Ѵ. Ϲ ̰  ݿ
     ִ ù° ȣƮ ּҷ Ѵ(   
      ũ 192.168.1.240/29, ȣƮ  .241
     .246 Ǹ ⺻ Ʈ ּҴ .241 ȴ.

  o  MAC ּ 

     ANT 긴¡  MAC ּҵ   ִ.  , ADSL
     ANT 16 MAC ּҿ    ִ. ̰ κ
     뿡 ־ ϰ, ANT 꿡    迡
       ȹ̶   󸶳 Ǵ Ȯ  ʿ䰡
     ִ.

  o  DNS 

     ISP ϳ ̻ DNS  ּҸ Ͽ   ã
     ۾  ̴.  ISP     ȣ
     (primary or secondary)   Ű Ѵ.  ڼ
        ISP ϱ ٶ.

  o   ID йȣ

     ISP  ̳     α ID/йȣ Ȯ
     ̴.  ISP  Ȩ    , ׸
     Ÿ  񽺸 Ѵ.

  6.   .

     ȸ翡 ϴ ġ ɼ ߴٸ  
  ǳʶٰ "  ġ"  ٶ. Ʒ ϴ κ 輱
  ῡ  ̴.  ý ġϰ ϴ   
   ٸ  ִٴ  ϶. Ʒ ϰ ִ  
  Ģ Ǳ  ٶ.

  켱 ؾ    ȸ ȸ ϴ ̴. 񽺰 
  ȸ ϰ øͿ DSL  ġ Ѵ.

  6.1.  ø/NID 輱 (SNI)

   øͰ   Ѵٸ  κ پѾ ȴ.

  øʹ  κ ̷ ִµ, øͿ ܿ ġǴ
   (NID ; Network Interface Device) װ̴. øͿ
  ȸ翡 ϴ NID   Ͽ  Ʈũ
  ̽(SNI ; Subscriber Network Interface -  ȭ ִ
  ̴) Ѵ. ȭ ȸ / Ͽ øͿ 
   ֱ  ȭ ȸ  ۾  ϱ Ͽ ٱ 
  ü ġϴ  ٶϴ. ø " LINE"   ȸ
  Ǵ 2 wire ȸ Ѵ. ׸  ȭ  "
  VOICE" Ѵ.  ANT  ȸ " DATA " Ѵ.

  Ȯ ⼭ ø   ȣ   ־ Ѵ.
   ׷ ʴٸ   輱 ƲȰų ADSL 񽺰 ȸ
       ̴.

  6.2.  (ǻ ʿ) DSL  ϱ

  DSL(RJ11) ǻ  Ѵ(ø DATA Ѵ).
  Ȳ   ٸ 찡 ߻  ִµ, ⺻δ DSL 
   2 wire pair   ̴. DSL-RJ11 輱 ȭ ADSL
  迡  ٸ   Ȯؾ Ѵ.  쿡 / 
  ȭ 迡 ǰ(RJ11   ), Ȳ/  ADSL 迡 ȴ
  (RJ11  ٱ ).

  6.3.  (ǻ ) ANT ġϱ

  ANT  ϰ ȭ(īװ 3 ̺) DSL  ANT ̿
  Ѵ.  ̺  ȴ.

   Ȯδܰ ⼭ ANT  ȸ ȣ ġϴ ȮѴ.
  κ ANT ȣ   LED   ̴. ġ
  ʴ´ٸ 輱 Ȯϰų ȸ翡  ñ׳  Ǿ
  ִ ȮѴ(̰ ȸ翡 ȭ ɾ 񽺰 
  Ȯϸ ȴ. ȣ ٰ ؼ ADSL  ñ׳ ̶
    ٴ  ϶).

    ܰ踦  ƴٸ   ý 
  ̴.

  7.  Linux ġϱ

  ANT 輱 ġ  ñ׳ Ȯߴٸ  ý
  Ͽ ISP  Ȯ ̴ܰ. ⼭  ý
  ϰ, ANT 10baseT Ÿ   ̵(ͳ , PC,
  Ȥ ϰ ϴ ٸ )   ִ.

   ! ISP ϱ , ADSL  ͳݿ   ߻ 
  ִ  Ȱ  Ȯؾ Ѵ. ISP  ٸ 
  κ ܺ ڰ  ýۿ  ϰ   
  ȭ ġϰų,   Ʈ/񽺸 ϰ,  
  ִ йȣ 켱 ϴ  ۾ ʿϴ. Security-
  HOWOTO       ̴.

  7.1.  NIC ī ġϰ ϱ

  NIC ī带  ӽſ ġϰ Ŀ ϰ, ..  ۾
  ʿϴ.  ۾ ؼ   ڷᰡ  װ
  ϶.  Ethernet-HOWTO  ڼ   ̴.

  RJ45 ̺ ̿Ͽ NIC ANT ̸ Ѵ.    ANT
   10baseT ũν  輱 Ǿ  ִµ,  쿡
  ̷Ʈ īװ 5 ̺ ũν ̺  ʿϴ.  
   ˾Ƴµ 12ð Һ  ֱ ,  
  Ǽ ݺ ʱ⸦ ٶ. 켱   о.

  7.2.  ̴ ̽ ϱ

  IP ּҸ ϰ,  ũ, ⺻ Ʈ, DNS   
   ش.   (, , , SuSE)
     ֱ   ϰ ϴ ýۿ ´
   ãƺ ٶ. ifconfig route ɾ ̿Ͽ  
      ִ. NET3-HOWTO  ڼ  
  ̴.

  ѹ ý   ISP  ⺻ Ʈ ּҷ
  ping Ͽ   Ȯ  ִ.  ping 
  ̸, 20 ms  roundtrip delay Ȯ   ̴.
  Ѵ, ͳݿ Ǿ!

  7.3.   ϱ

   Ʈũ  ϴ°  ٸ  ٸ 
  Ȯؾ Ѵ. ̰ ȭ ̳ ٸ ִ  Ѵ.
  ׸ 3   ִ  ,  486 ǻ͸ ADSL 
  ǻ ̿ ȭ/  ϵ Ͽ.   
   LAN ݿ  IP ּҸ ϰ Ͱ LAN ͳ 
  ̿ ȭ/IP ŽĿ̵ ۾ ϵ Ͽ.
  IP_Masquerading-HOWTO Firewall-HOWTO ϸ   ڷḦ
     ̴.  迡 ϸ   Ǹ
  /ȭ    ,  ĵα ؼ ⲯ
   386/486 踦 ̿  Ƿ  Ϳ  
         ִ.

  ׸ 3.  SOHO Ʈũ 

  <- -->      <- -->     <-ADSL --------->
                                       |
                                  X----|
                                       |
       X------|                   X----|     |----|
              |      |--------|        |     |ADSL|            ISP
              |      | Linux  |        |-----|ANT |----------> 
       X------|------| System |--------|     |    |
              |    E1|(Router)|E0      |     |----|
              |      |--------|        |
       X------|        IP_Masq      10baseT
                     IP_Firewall     Hub

       ̴ ̽ ̿Ͽ ͸  
   ̴(  5.0 i486 ġϿ Ͽ). ϳ
  ̽ ISP /Ʈ̿ ϰ, ٸ ϳ
  ̽  Ʈũ ּ(192.168.2.x  ) Ͽ.
   ʿ ġϴ  Ʈũ ּҴ ISP ܺο  ν
    ּ̱   ýۿ    
  ̴. ͳݿ ϱ ؼ ߰  ּҵ鿡 
  ŽĿ̵ ־ Ѵ.

   IP  ɰ Բ Ŀ ϰ   Ѿ
  Ѵ.     Ȯ  ִ.

  cat /proc/sys/net/ipv4/ip_forward

  1  ǰ  ǹϸ, 0    ǹѴ.
     ٲٰ ʹٸ echo ̿Ͽ ϴ   ȴ.

  (.) echo 1 > /proc/sys/net/ipv4/ip_forward

  ̷ IP   ۵ ̴.

  7.4.  ȭ/ŽĿ̵ 

   ͳݿ   Ǿ, ȭ ɰ ŽĿ̵ ɵ
  ϱ  ̴. ׸ 4 ̰Ϳ  ׸̴.

  !       ȯ  Ϳ Ϻκ̶ 
     . Ftp telnet, Ϳ  Ÿ ٸ 񽺸
  ´ٰų йȣ, α    å   Ǿ
  Ѵ. Security-HOWTO Ȯ϶.

  ׸ 4: ADSL  ȭ/ŽĿ̵

         |-------|       |-------|     |-X
  ======X| ADSL  |=------| Linux |-----|
  ADSL   |  ANT  |     E0|       |E1   |-X    Ʈũ
  Line   |-------|       |-------|     |     (. 192.168.2.x)
                 <------->             |...
               ISP Subnet or host
              ( Ʈũ ּ)

   ͷ ϱ ؼ Ŀο IP /ŽĿ̵ 
  ϰ  ؾ ϸ, ipfwadm(IP ȭ Ʈ) 
   ġؾ Ѵ:

  file: /etc/rc.d/rc.firewall  ( 5.0 rc.sysinit)

  echo "ȭ "
  #
  # From the "Firewall-HOWTO"
  #
  #   ʱȭ
  #
  ipfwadm -F -f
  #
  # ȭ 
  #
  ipfwadm -F -p deny
  #
  # 192.168.2.x ּ  ӽ ŽĿ̵ 
  #
  ipfwadm -F -a accept -m -S 192.168.2.0/24 -D 0.0.0.0/0
  #
  #    (udp 53)i
  #
  ipfwadm -F -a accept -b -P udp -S 0.0.0.0/0 53 -D 192.168.2.0/24
  ipfwadm -F -p masquerade
  #
  #   ˾Ƽ ϼ
  #
  ipfwadm -F -l
  ipfwadm -O -l
  ipfwadm -I -l

    α׷ Ư  ̴ ۵   
  ؾ Ѵ(ftp real audio ). ipfwadm  Ȯ . 
          ֵ   ִ.

  ߰,  Ʈũ ּҸ ϰ Ǹ  LAN ý
  ̸ ΰ   ִ. ŽĿ̵   
     ִ  ȣƮ     IP 
  α׷ ȣƮ ּҸ  ʵ忡 ų  
  ۵   ִٴ  ̰ ̺ ̴.

  8.  η

  8.1.    (FAQs)

   ADSL Ͽ  Ǵ ׵鿡  亯̴.

  1. Q: ADSL ǥ ϴ°?

     A: κδ Ѵ. ̱ ȭ ȸ(The U.S. Bell Operating
     Companies)  ҿ -ȣ(DMT ; Discrete Multi-Tone)
     ANT  ǥ س ִ (ANSI T1.413). κ ٸ
     鵵  Ȳ   ȴ.  ȣ ȣȯ 
     ʴ ٸ  ANT - CAP(Carrier-less Amplitude Phase Modulation)
      -  ϰ ֱ ϴ.

     DMT ַ ϴ ü     忡 
      м  Aware <http://www.aware.com> ã  ִ.
     , ̰    ߿  ڼ   ִ.

       ANSI ǥ  ֹ  ִ.  A rather expensive copy
     of the ANSI standard can be ordered at: American National Standards
     Institute ANSI Home Page <http://www.ansi.org>
     Asymmetric Digital Subscriber Line (ADSL) Metallic Interface
     ANSI TI.413-1995
     : ANSI TI.413 Issue 2  1997 9 26Ͽ ǥǾ.

  2. Q: ADSL ANT ϱ  ATM   ִ°?

     A: ϴ!  ADSL ANT( Alcatel ) ATM  25Mbps
     ̽  , ̰ PCI NIC ī   ִ.
     , ̷ ī   ̹ ִ   
     ߴ.

  3. Q:  ADSL ӵ ؾ߸ ϴ°?

     A: ⺻   100   ̱ ̴. ̰
     Ƴα ȭ ؼ  Ǹ   , 
     ñ׳ο ؼ    ִ. Ÿ   ӵ
     ݺ   .  ӵ  (Rate-Adaptive
     technologies)    ñ׳ο ؼ  
       뿡 ؼ  뿪  ϴµ,
     Ư ſ ( 5 km) ȸ 쿡   ε巯. 
       ִ پ 뿪 ü ÿ õ ̸ 
     ȸ " ǥ"   ӵ ϱ  ϰ ִ.  
      384k/1.5Mbps δ ǥ ġ   ʹ.
      ӵ Ư   쿡   
     ̴µ, ֳϸ ̷  ȸ   ִ ȸ ׸ 
     ʱ ̴.

         ȸ ϴ ͵鿡   ϶.

  4. Q: ADSL   ǰ Ͻų  ִ ȸ ع(bridge
     taps, loading coils) ?(Bruce Ediger )

     ε : ȭ ȸο  Ľ  Ư  ϱ 
     ȸ  δϽ̴.  " ε" ļ 
      ļ ϴµ, Ϲ  3 km ̻ ſ 
     ȭ ȴ.

     " 긮" " 긮 " ϴ ̶ ȴ.  ϳ
     ȭ ȸ  ּҰ ٸ   ߾.  ϴ
     ȸ    " " 긮 ̶ Ѵ.

      ȸ ɸ(Digital loop carrier) :   
     ȸ ϳ ̻  ȣ  ؼ  ý
     ʿϰ ȴ. ļ 뿪 ϰų  ȣ ȭϿ
     ȭ ð̳ ڵ Ȥ Ÿ ٸ   иϿ
      Ѵ.   Ǵ   " pair gain"̶ Ѵ.

     ̵  ļ ̿ ſ ٸ   ȴ.

     ε ļ ȣ ͸ϰ ļ ȣ Ų.
     ̵  ٸ ļ Ư ļ  ϵ ϴ "
     delay envelope" ȭŰ⵵  ̴. ϳ Ʈ 
     ȣ  Ʈ  ظ ް  ̴.

     긮   ȣ  谡 ִ   shunt
     capacitance  ۵  , ȣ 1/4   band
     pass filter  ۵  ִ. ̰ Ư ļ Ӱ
     Ųٴ  ǹѴ.  DMT  Ư   
      ϰ ǵư  ִµ,   ȭ  뿪
     ٰ ȴ.

     ̳ Ƴα  pair gain ϳ ȸ  ȣ
        ϳ ۿ   뿪 ϰ ȴ.
     DMT        ؼ ɷ.

     Whitham D. Reeve  "  ȸ ȣ  ڵ(Subscriber
     Loop Signaling and Transmission Handbook ; IEE Press 1992 ; ISBN
     0-87942-274-2)" å ȸ ̳ ȭ ִ 긮  
      Ư ġ  ϴ     
     ִ.    å û δ.

  5. Q: ADSL ANT鿡   ֳ?

     A: (ª )ִ. (¥ )   ӵ ſ 
     ϰ ֱ    HOWTO  ȿ ٷ .
     ADSL ANT   ڷ ADSL  Ȩ
     <http://www.adsl.com> ϶.   ǰ ϴ ü
     Ȩ ֱ  ľ   ̴.

     , 1998 6     Ʈ  
     ִ.

  o  10/100baseT ̽   ANT

      : Flowpoint 2000 DSL (CAP), Netspeed Speedrunner 202 (CAP),
     Speedrunner 204 (CAP), 3COM Viper-DSL (CAP), StarNet Ezlink 500/100
     (DMT), Westell ATU-R-Flexcap (CAP), Aware x200

  o  10/100baseT ̽  긮 ANT

      : Alcatel A1000 (DMT),  Westell ATU-R-Flexcap2 (CAP)

  o  ATMF ̽  ANT

      : Alcatel A1000 (DMT), Netspeed Speedrunner 203 (CAP), Ariel
     Horizon II

  o  V.35 ø ̽  긮 ANT (T1, ø )

      : Westell ATU-R

  o  USB ̽  ANT

     Intel Ѵٴ ҹ ִ.(: Alcatel ǰ
     , ϳ ſ ϰ ִ)

  o   ANT/NIC ī

      : Netspeed PCI Runner (CAP), Efficient Networks Speedstream 3020
     (DMT)

     ̵ ǰ Ʈ鿡    ִ   ƴϸ, 
     ֱ  ̴. ;-).

  8.2.  ũ

  o  ADSL  Ȩ <http://www.adsl.com> ADSL ü 
     ϱ  Ʈ̴.   ۷ Ѵ.

  o  Dan Kegel ADSL 
     <http://www.alumni.caltech.edu/~dank/isdn/adsl.html> xDSL 
     Ϲ  ڷ - ü,    -  ϰ ִ.
     Dan ISDN  Ǹ   ϰ ִ.

  o  PacBell ADSL 
     <http://www.pacbell.com/products/business/fastrak/adsl/index.html>
     Pacific Bell   ȸ  ADSL 񽺸 ϴ
     ȸ.

  o  Jeremie  Ameritech ADSL FAQ
     <http://www.rc.lsa.umich.edu/~jeremie/adsl/>

  o  Telechoice xDSL  
     <http://www.telechoice.com/xdslnewz/indexDSL.cgi>

  o  ADSL Deployment 'round the World
     <http://www.geocities.com/Paris/Metro/5013/adsl.html>  ADSL
      ü , ӵ   پ   ִ.

  o  Bell Atlantic ADSL Ȩ <http://www.bell-atl.com/adsl>

  o  comp.dcom.xdsl FAQ <http://homepage.interaccess.com/~jkristof/xdsl-
     faq.txt>

  8.3.   

   Ͽ        Ѵ. 
   ϱ       ִٸ   X
  ϰ ̸  ٶ.

  o  B Ediger (Xbediger@csn.net) ȸ ջ(loop impairment)  .

  o  C Wiesner ( Xcraig@wkmn.com)  ADSL URL鿡  Ʈ.

  o  J Leeuw ( Xjacco2@dds.nl) ADSL   (Ư 
     ؼ).

  o  J Kass ( Xjeremie@umich.edu)  Ameritech ADSL FAQ.

  o  N Silberstein ( Xnick@tpdinc.com) Netrunner  US Worst
      .

  8.4.   

  FAQ  鿡  ؼ.

     2 wire Copper Loop
        Ż ߾ 繫ǿ Ͽ   ġ
         2 ȸ ִ .

     ADSL
        Ī   ȸ(Asymmetric Digital Subscriber Line)

     ANT
        ADSL Ʈũ (ADSL Network Termination) ( : ADSL
        )

     ATM
        񵿱  (Asynchronous Transfer Mode) - 155 Mbps
        () 2Gbps ȯ   Ŷ Ѵ. ͳ
        麻(backbond) ַ ȴ.

     ATMF-25Mbps
        ATM Forum Interface -  PCI NIC ī 25Mbps ӵ ϴ.
        ANT PC ϴ ̽  ϳ̴.

     ߾ 繫(Central Office)
         ΰ ǹ  ϳ Ͽ.  1) ȭ ü 
        Ż ǹ 2) ȣ ϴ ȭ  ȯġ

     CPE
          (Customer Premises Equipment) -  
        ´ Ż .   CSU/DSU , ANT, ׸
        ȭ.

     DHCP
         ȣƮ  (Dynamic Host Configuration Protocol) -
         IP ּ Ҵ  IP .

     DS0
        Ż ⺻  ȸ - 56kbps Ȥ 64kbps 񽺸 
         , ϳ Ƴα  ü Ѵ.

     DSLAM
          ȸ  Ƽ÷(Digital Subscriber Line
        Access Multiplexer) - DSL ȸ ߽Ű Ƽ÷ Ű
        Ż .

     xDSL
          ȸ(Digital Subscriber Line) - ADSL, SDSL, VDSL
         DSL 񽺸 Īϴ .

     HDC
        Section 2 .

     ISDN
        ڰ  ʴ ű(Innovations Subscribers Don't Need);
          (I Still Don't kNow) Ȥ Ƹ  
         Ʈũ (Integrated Services Digital Network). 
         2 ̿Ͽ  ȭ ϴ 
        2B(64k) 1D(16k) ü Ͽ ȯ  ͸
        ϴ .

     ISP
        ͳ  (Internet Service Provider)

     NID
        Ʈũ ̽ (Network Interface Device) -   ҵ
         ADSL ø͸ ȣϱ  .

     NIC
        Ʈũ ̽ ī(Network Interface Card) - Ʈũ
        ̽ ϴ PCI/ISA PC ī.  ̴ 10baseT
        ATMF-25Mbps ī... ( ī;)

     POTS
        Ϲ  ȭ (Plain Old Telephone Service) - ܼ
        Ƴα  ȸ (i.e.  ȭ)

     Recursion
        "Recursion" .

     SNI
        Subscriber Network Interface - Ż翡   ġ
        ȭ ȸ  ´ . Ż   ȸ ̸
        ϴ  ġǸ (Demarcation Point) Ҹ.

     Splitter
        ADSL ȣ   üη иϴ SNI (뿪 
        ; low-bandpass filter)

     Splitterless
        øͰ ʿ ADSL ġ.  ӵ ؼ RJ11 Ͱ
        ϰ ִ  Ƴα ȭ 迡 Ǿ NID
        迡 ͸ ־ Ѵ.  ӵ ٸ ͸ 
        ʾƵ ȴ.

     SOHO
        Small Office HOme

     T1 a.k.a DS1 - (24 DS0s)  ο   1.544 Mbps
        ȸ

     T3 a.k.a DS3 - (672 DS0s Ȥ 28 DS1s)  ο 
         44.736 Mbps ȸ

