五、ISDN
　
1. 綜合數(shù)字業(yè)務網(wǎng)（ISDN）
綜合數(shù)字業(yè)務網(wǎng)（ISDN）由數(shù)字電話和數(shù)據(jù)傳輸服務兩部分組成，一般由電話局提供這種服務。ISDN的基本速率接口（BRI）服務提供2個B信道和1個D信道（2B+D）。BRI的B信道速率為64Kbps,用于傳輸用戶數(shù)據(jù)。D信道的速率為16Kbps，主要傳輸控制信號。在北美和日本，ISDN的主速率接口（PRI）提供23個B信道和1個D信道，總速率可達1.544Mbps，其中D信道速率為64Kbps。而在歐洲、澳大利亞等國家，ISDN的PRI提供30個B信道和1個64Kbps D信道，總速率可達2.048Mbps。我國電話局所提供ISDN PRI為30B+D。
2. 基本命令
任務 命令
設置ISDN交換類型 isdn switch-type switch-type1
接口設置 interface bri 0
設置PPP封裝 encapsulation ppp
設置協(xié)議地址與電話號碼的映射 dialer map protocol next-hop-address [name hostname] [broadcast] [dial-string]
啟動PPP多連接 ppp multilink
設置啟動另一個B通道的閾值 dialer load-threshold load
顯示ISDN有關信息 show isdn {active | history | memory | services | status [dsl | interface-type number] | timers}
注：1.交換機類型如下表,國內(nèi)交換機一般為basic-net3。
按區(qū)域分關鍵字 交換機類型
Australia
basic-ts013 Australian TS013 switches
Europe
basic-1tr6 German 1TR6 ISDN switches
basic-nwnet3 Norway NET3 switches (phase 1)
basic-net3 NET3 ISDN switches (UK, Denmark, and other nations); covers the Euro-ISDN E-DSS1 signalling system
primary-net5 NET5 switches (UK and Europe)
vn2 French VN2 ISDN switches
vn3 French VN3 ISDN switches
Japan
ntt Japanese NTT ISDN switches
primary-ntt Japanese ISDN PRI switches
North America
basic-5ess AT&T basic rate switches
basic-dms100 NT DMS-100 basic rate switches
basic-ni1 National ISDN-1 switches
primary-4ess AT&T 4ESS switch type for the U.S. (ISDN PRI only)
primary-5ess AT&T 5ESS switch type for the U.S. (ISDN PRI only)
primary-dms100 NT DMS-100 switch type for the U.S. (ISDN PRI only)
New Zealand
basic-nznet3 New Zealand Net3 switches
3. ISDN實現(xiàn)DDR（dial-on-demand routing）實例:
設置如下：
Router1:
hostname router1
user router2 password cisco
!
isdn switch-type basic-net3
!
interface bri 0
ip address 192.200.10.1 255.255.255.0
encapsulation ppp
dialer map ip 192.200.10.2 name router2 572
dialer load-threshold 80
ppp multilink
dialer-group 1
ppp authentication chap
！
dialer-list 1 protocol ip permit
!
Router2:
hostname router2
user router1 password cisco
!
isdn switch-type basic-net3
!
interface bri 0
ip address 192.200.10.2 255.255.255.0
encapsulation ppp
dialer map ip 192.200.10.1 name router1 571
dialer load-threshold 80
ppp multilink
dialer-group 1
ppp authentication chap
！
dialer-list 1 protocol ip permit
!
Cisco路由器同時支持回撥功能，我們將路由器Router1作為Callback Server,Router2作為Callback Client。
與回撥相關命令:
任務 命令
映射協(xié)議地址和電話號碼，并在接口上使用在全局模式下定義的PPP回撥的映射類別。 dialer map protocol address name hostname class classname dial-string
設置接口支持PPP回撥 ppp callback accept
在全局模式下為PPP回撥設置映射類別 map-class dialer classname
通過查找注冊在dialer map里的主機名來決定回撥. dialer callback-server [username]
設置接口要求PPP回撥 ppp callback request
設置如下：
Router1:
hostname router1
user router2 password cisco
!
isdn switch-type basic-net3
!
interface bri 0
ip address 192.200.10.1 255.255.255.0
encapsulation ppp
dialer map ip 192.200.10.2 name router2 class s3 572
dialer load-threshold 80
ppp callback accept
ppp multilink
dialer-group 1
ppp authentication chap
！
map-class dialer s3
dialer callback-server username
dialer-list 1 protocol ip permit
!
Router2:
hostname router2
user router1 password cisco
!
isdn switch-type basic-net3
!
interface bri 0
ip address 192.200.10.2 255.255.255.0
encapsulation ppp
dialer map ip 192.200.10.1 name router1 571
dialer load-threshold 80
ppp callback request
ppp multilink
dialer-group 1
ppp authentication chap
！
dialer-list 1 protocol ip permit
!
相關調(diào)試命令：
debug dialer
debug isdn event
debug isdn q921
debug isdn q931
debug ppp authentication
debug ppp error
debug ppp negotiation
debug ppp packet
show dialer
show isdn status
舉例:執(zhí)行debug dialer命令觀察router2呼叫router1,router1回撥router2的過程.
router1#debug dialer
router2#ping 192.200.10.1
router1#
00:03:50: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up
00:03:50: BRI0:1PP callback Callback server starting to router2 572
00:03:50: BRI0:1: disconnecting call
00:03:50: %LINK-3-UPDOWN: Interface BRI0:1, changed state to down
00:03:50: BRI0:1: disconnecting call
00:03:50: BRI0:1: disconnecting call
00:03:51: %LINK-3-UPDOWN: Interface BRI0:2, changed state to up
00:03:52: callback to router2 already started
00:03:52: BRI0:2: disconnecting call
00:03:52: %LINK-3-UPDOWN: Interface BRI0:2, changed state to down
00:03:52: BRI0:2: disconnecting call
00:03:52: BRI0:2: disconnecting call
00:04:05: : Callback timer expired
00:04:05: BRI0:beginning callback to router2 572
00:04:05: BRI0: Attempting to dial 572
00:04:05: Freeing callback to router2 572
00:04:05: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up
00:04:05: BRI0:1: No callback negotiated
00:04:05: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to up
00:04:05: dialer Protocol up for Vi1
00:04:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1, changed state
to up
00:04:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, chang
ed state to up
00:04:11: %ISDN-6-CONNECT: Interface BRI0:1 is now connected to 572
#router1
4. ISDN訪問首都在線263網(wǎng)實例:
本地局部網(wǎng)地址為10.0.0.0/24,屬于保留地址，通過NAT地址翻譯功能，局域網(wǎng)用戶可以通過ISDN上263網(wǎng)訪問Internet。263的ISDN電話號碼為2633，用戶為263，口令為263，所涉及的命令如下表：
任務 命令
指定接口通過PPP/IPCP地址協(xié)商獲得IP地址 ip address negotiated
指定內(nèi)部和外部端口 ip nat {inside | outside}
使用ppp/pap作認證 ppp authentication pap callin
指定接口屬于撥號組1 dialer-group 1
定義撥號組1允許所有IP協(xié)議 dialer-list 1 protocol ip permit
設定撥號，號碼為2633 dialer string 2633
設定登錄263的用戶名和口令 ppp pap sent-username 263 password 263
設定默認路由 ip route 0.0.0.0 0.0.0.0 bri 0
設定符合訪問列表2的所有源地址被翻譯為bri 0所擁有的地址 ip nat inside source list 2 interface bri 0 overload
設定訪問列表2，允許所有協(xié)議 access-list 2 permit any
具體配置如下：
hostname Cisco2503
!
isdn switch-type basic-net3
!
ip subnet-zero
no ip domain-lookup
ip routing
!
interface Ethernet 0
ip address 10.0.0.1 255.255.255.0
ip nat inside
no shutdown
!
interface Serial 0
shutdown
no description
no ip address
!
interface Serial 1
shutdown
no description
no ip address
!
interface bri 0
ip address negotiated
ip nat outside
encapsulation ppp
ppp authentication pap callin
ppp multilink
dialer-group 1
dialer hold-queue 10
dialer string 2633
dialer idle-timeout 120
ppp pap sent-username 263 password 263
no cdp enable
no ip split-horizon
no shutdown
!
ip classless
!
! Static Routes
!
ip route 0.0.0.0 0.0.0.0 bri 0
!
! Access Control List 2
!
access-list 2 permit any
!
dialer-list 1 protocol ip permit
!
! Dynamic NAT
!
ip nat inside source list 2 interface bri 0 overload
snmp-server community public ro
!
line console 0
exec-timeout 0 0
!
line vty 0 4
!
end
5. Cisco765M通過ISDN撥號上263
由于Cisco765的設置命令與我們常用的Cisco路由器的命令不同，所以以下列舉了通過Cisco765上263訪問Internet的具體命令行設置步驟。
>set system c765
c765> set multidestination on
c765> set switch net3
c765> set ppp multilink on
c765> cd lan
c765:LAN> set ip routing on
c765:LAN> set ip address 10.0.0.1
c765:LAN> set ip netmask 255.0.0.0
c765:LAN> set briding off
c765:LAN>cd
c765> set user remotenet
New user remotenet being created
c765:remotenet> set ip routing on
c765:remotenet> set bridging off
c765:remotenet> set ip framing none
c765:remotenet> set ppp clientname 263
c765:remotenet> set ppp password client
Enter new Password: 263
Re-Type new Password: 263
c765:remotenet> set ppp authentication out none
c765:remotenet> set ip address 0.0.0.0
c765:remotenet> set ip netmask 0.0.0.0
c765:remotenet> set ppp address negotiation local on
c765:remotenet> set ip pat on
c765:remotenet> set ip route destination 0.0.0.0/0 gateway 0.0.0.0
c765:remotenet> set number 2633
c765:remotenet> set active
命令描述如下：
任務 命令
設置路由器系統(tǒng)名稱 set system c765
允許路由器呼叫多個目的地 set multidestination on
設置ISDN交換機類型為NET3 set switch net3
允許點到點間多條通道連接實現(xiàn)負載均衡 set ppp multilink on
關掉橋接 set briding off
建立用戶預制文件用于設置撥號連接參數(shù)- 可以設置多個用戶預制文件用于相同的物理端口對應于不同的連接。 set user remotenet
使用PPP/IPCP set ip framing none
設置上網(wǎng)用戶帳號 set ppp clientname 263
設置上網(wǎng)口令 set ppp password client Enter new Password: 263 Re-Type new Password: 263
允許地址磋商 set ppp address negotiation local on
設置地址翻譯 set ip pat on
設置默認路由 set ip route destination 0.0.0.0/0 gateway 0.0.0.0
設置ISP的電話號碼 set number 2633
激活用戶預制文件 set active
　
返回目錄
　
六、PSTN
　　電話網(wǎng)絡(PSTN)是目前普及程度最高、成本最低的公用通訊網(wǎng)絡，它在網(wǎng)絡互連中也有廣泛的應用。電話網(wǎng)絡的應用一般可分為兩種類型，一種是同等級別機構之間以按需撥號(DDR)的方式實現(xiàn)互連，一種是ISP為撥號上網(wǎng)為用戶提供的遠程訪問服務的功能。
1. 遠程訪問
1.1.Access Server基本設置：
選用Cisco2511作為訪問服務器,采用IP地址池動態(tài)分配地址.遠程工作站使用WIN95撥號網(wǎng)絡實現(xiàn)連接。
全局設置：
任務 命令
設置用戶名和密碼 username username password password
設置用戶的IP地址池 ip local pool {default | pool-name low-ip-address [high-ip-address]}
指定地址池的工作方式 ip address-pool [dhcp-proxy-client | local]
基本接口設置命令：
任務 命令
設置封裝形式為PPP encapsulation ppp
啟動異步口的路由功能 async default routing
設置異步口的PPP工作方式 async mode {dedicated | interactive}
設置用戶的IP地址 peer default ip address {ip-address | dhcp | pool [pool-name]}
設置IP地址與Ethernet0相同 ip unnumbered ethernet0
line撥號線設置：
任務 命令
設置modem的工作方式 modem {inout|dialin}
自動配置modem類型 modem autoconfig discovery
設置撥號線的通訊速率 speed speed
設置通訊線路的流控方式 flowcontrol {none | software [lock] [in | out] | hardware [in | out]}
連通后自動執(zhí)行命令 autocommand command
訪問服務器設置如下：
Router:
hostname Router
enable secret 5 $1$EFqU$tYLJLrynNUKzE4bx6fmH//
!
interface Ethernet0
ip address 10.111.4.20 255.255.255.0
!
interface Async1
ip unnumbered Ethernet0
encapsulation ppp
keepalive 10
async mode interactive
peer default ip address pool Cisco2511-Group-142
!
ip local pool Cisco2511-Group-142 10.111.4.21 10.111.4.36
!
line con 0
exec-timeout 0 0
password cisco
!
line 1 16
modem InOut
modem autoconfigure discovery
flowcontrol hardware
!
line aux 0
transport input all
line vty 0 4
password cisco
!
end
相關調(diào)試命令：
show interface
show line
1.2. Access Server通過Tacacs服務器實現(xiàn)安全認證：
使用一臺WINDOWS NT服務器作為Tacacs服務器，地址為10.111.4.2,運行Cisco2511隨機帶的Easy ACS 1.0軟件實現(xiàn)用戶認證功能.
相關設置：
任務 命令
激活AAA訪問控制 aaa new-model
用戶登錄時默認起用Tacacs+做AAA認證 aaa authentication login default tacacs+
列表名為no_tacacs使用ENABLE口令做認證 aaa authentication login no_tacacs enable
在運行PPP的串行線上采用Tacacs+做認證 aaa authentication ppp default tacacs+
由TACACS+服務器授權運行EXEC aaa authorization exec tacacs+
由TACACS+服務器授權與網(wǎng)絡相關的服務請求。 aaa authorization network tacacs+
為EXEC會話運行記帳.進程開始和結束時發(fā)通告給TACACS+服務器。 aaa accounting exec start-stop tacacs+
為與網(wǎng)絡相關的服務需求運行記帳包括SLIP,PPP,PPP NCPs,ARAP等.在進程開始和結束時發(fā)通告給TACACS+服務器。 aaa accounting network start-stop tacacs+
指定Tacacs服務器地址 tacacs-server host 10.111.4.2
在Tacacs+服務器和訪問服務器設定共享的關鍵字，訪問服務器和Tacacs+服務器使用這個關鍵字去加密口令和響應信息。這里使用tac作為關鍵字。 tacacs-server key tac
訪問服務器設置如下：
hostname router
!
aaa new-model
aaa authentication login default tacacs+
aaa authentication login no_tacacs enable
aaa authentication ppp default tacacs+
aaa authorization exec tacacs+
aaa authorization network tacacs+
aaa accounting exec start-stop tacacs+
aaa accounting network start-stop tacacs+
enable secret 5 $1$kN4g$CvS4d2.rJzWntCnn/0hvE0
!
interface Ethernet0
ip address 10.111.4.20 255.255.255.0
!
interface Serial0
no ip address
shutdown
interface Serial1
no ip address
shutdown
!
interface Group-Async1
ip unnumbered Ethernet0
encapsulation ppp
async mode interactive
peer default ip address pool Cisco2511-Group-142
no cdp enable
group-range 1 16
!
ip local pool Cisco2511-Group-142 10.111.4.21 10.111.4.36
tacacs-server host 10.111.4.2
tacacs-server key tac
!
line con 0
exec-timeout 0 0
password cisco
login authentication no_tacacs
line 1 16
login authentication tacacs
modem InOut
modem autoconfigure type usr_courier
autocommand ppp
transport input all
stopbits 1
rxspeed 115200
txspeed 115200
flowcontrol hardware
line aux 0
transport input all
line vty 0 4
password cisco
!
end
2. DDR（dial-on-demand routing）實例
此例通過Cisco 2500系列路由器的aux端口實現(xiàn)異步撥號DDR連接。Router1撥號連接到Router2。其中采用PPP/CHAP做安全認證，在Router1中應建立一個用戶，以對端路由器主機名作為用戶名，即用戶名應為Router2。同時在Router2中應建立一個用戶，以對端路由器主機名作為用戶名，即用戶名應為Router1。所建的這兩用戶的password必須相同。
相關命令如下：
任務 命令
設置路由器與modem的接口指令 chat-script script-name EXPECT SEND EXPECT SEND (etc.)
設置端口在掛斷前的等待時間 dialer idle-timeout seconds
設置協(xié)議地址與電話號碼的映射 dialer map protocol next-hop-address [name hostname] [broadcast] [modem-script modem-regexp] [system-script system-regexp] [dial-string]
設置電話號碼 dialer string dial-string
指定在特定線路下路由器默認 使用的chat-script script {dialer|reset} script-name
Router1:
hostname Router1
!
enable secret 5 $1$QKI7$wXjpFqC74vDAyKBUMallw/
!
username Router2 password cisco
chat-script cisco-default "" "AT" TIMEOUT 30 OK "ATDT \T" TIMEOUT 30 CONNECT \c
!
interface Ethernet0
ip address 10.0.0.1 255.255.255.0
!
interface Async1
ip address 192.200.10.1 255.255.255.0
encapsulation ppp
async default routing
async mode dedicated
dialer in-band
dialer idle-timeout 60
dialer map ip 192.200.10.2 name Router2 modem-script cisco-default 573
dialer-group 1
ppp authentication chap
!
ip route 10.0.1.0 255.255.255.0 192.200.10.2
dialer-list 1 protocol ip permit
!
line con 0
line aux 0
modem InOut
modem autoconfigure discovery
flowcontrol hardware
Router2:
hostname Router2
!
enable secret 5 $1$F6EV$5U8puzNt2/o9g.t56PXHo.
!
username Router1 password cisco
!
interface Ethernet0
ip address 10.0.1.1 255.255.255.0
!
interface Async1
ip address 192.200.10.2 255.255.255.0
encapsulation ppp
async default routing
async mode dedicated
dialer in-band
dialer idle-timeout 60
dialer map ip 192.200.10.1 name Router1
dialer-group 1
ppp authentication chap
!
ip route 10.0.0.0 255.255.255.0 192.200.10.1
dialer-list 1 protocol ip permit
!
line con 0
line aux 0
modem InOut
modem autoconfigure discovery
flowcontrol hardware
!
相關調(diào)試命令：
debug dialer
debug ppp authentication
debug ppp error
debug ppp negotiation
debug ppp packet
show dialer
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