简介
在Cisco IOS®软件版本12.1(3)XG中，为Cisco Small Office/Home Office(SOHO)77引入了以太网点对点协议(PPPoE)客户端功能。此功能允许将PPPoE功能移至路由器。多台PC可以安装在Cisco SOHO77后面，在其流量发送到PPPoE会话之前，可以对数据进行加密和过滤，并运行网络地址转换(NAT)。
本文档显示在Cisco SOHO77的异步传输模式(ATM)接口（DSL接口）上配置的PPPoE客户端。此配置也可在具有非对称数字用户线路(ADSL)WAN接口卡(WIC)的Cisco 1700上使用。
Cisco 6400节点路由处理器(NRP)上的配置也可用于用作聚合器和ATM接口的另一台路由器。
先决条件
要求
本文档没有任何特定的要求。
使用的组件
本文档中的信息基于以下软件和硬件版本：
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思科SOHO77客户端设备(CPE)IOS软件版本12.1(3)XP2
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Cisco 6400 UAC-NRP IOS软件版本12.1(3)DC1
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Cisco 6400 UAC-NSP IOS软件版本12.1(3)DB
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Cisco 6130 DSLAM-NI2 IOS软件版本12.1(5)DA
本文档中的信息都是基于特定实验室环境中的设备创建的。本文档中使用的所有设备最初均采用原始（默认）配置。如果您是在真实网络上操作，请确保您在使用任何命令前已经了解其潜在影响。
规则
有关文档规则的详细信息，请参阅 Cisco 技术提示规则。
配置
本部分提供有关如何配置本文档所述功能的信息。
注：要查找有关本文档中使用的命令的其他信息，请使用命令查找工具(仅注册客户)。
网络图
本文档使用以下网络设置：
配置
本文档使用以下配置：
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Cisco SOHO77
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Cisco 6400
PPPoE在Cisco SOHO77上使用虚拟专用拨号网络(VPDN)命令进行配置。确保先配置这些命令。
| Cisco SOHO77 |
|---|
!
vpdn enable
no vpdn logging
!--- Default.
!
vpdn-group pppoe
request-dialin
!--- The PPPoE client requests a session with the aggregation unit (6400 NRP).
protocol pppoe
!
!--- Internal Ethernet network.
!
interface Ethernet0
ip address 10.92.1.182 255.255.255.0
ip nat inside
!--- DSL interface.
!
interface ATM0
no ip address
no atm ilmi-keepalive
bundle-enable
dsl operating-mode auto
hold-queue 224 in
!--- all defaults
!--- PPPoE runs on top of AAL5SNAP, but the encap aal5snap command is not used.
!
interface ATM0.1 point-to-point
pvc 1/1
pppoe-client dial-pool-number 1
!--- pvc 1/1 is an example value that you must change to match the value !--- used by the Internet Service Provider (ISP).
!
!--- The PPPoE client code ties into a dialer interface, upon !--- which a virtual-access interface is cloned.
!
interface Dialer1
ip address negotiated
ip mtu 1492
!--- Ethernet MTU is 1500 by default. In other words, 1492 + PPPoE headers = 1500.
ip nat outside
encapsulation ppp
dialer pool 1
!--- Ties to ATM interface.
ppp authentication chap callin
ppp chap hostname <hostname>
ppp chap password <password>
!
!--- The ISP instructs you about the type of authentication to use. !--- To change from PPP CHAP to PPP PAP, replace the following three lines: !--- ppp authentication chap callin !--- ppp chap hostname
|
| Cisco 6400 |
|---|
*** local ppp user
!--- You can also use AAA.
username
|
验证
当前没有可用于此配置的验证过程。
故障排除
本节提供可用于排除配置故障和调试配置的信息。
要在Cisco SOHO77或Cisco 6400上调试PPPoE客户端，必须考虑协议栈。从底层协议层开始排除故障。
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DSL 物理层
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ATM 层
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以太网层
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PPP 层
DSL 物理层
确保线路已建立并接受培训。
输入show命令，如本例所示。结果输出指示行的状态。
show int atm0
ATM0 is up, line protocol is up
Hardware is PQUICC_SAR (with Alcatel ADSL Module)
show dsl interface atm0
!--- Look for "Showtime" in the first few lines.
ATU-R (DS) ATU-C (US)
Modem Status: Showtime (DMTDSL_SHOWTIME)
ATM 层
如果ATM接口处于打开状态，则可以使用debug atm packets命令查看ISP是否有任何内容。
注意：由于数据包的处理方式，因此使用此命令将看不到传出数据包。
输入debug atm packets命令，如本示例所示。
debug atm packet 03:21:32: ATM0(I): VCD:0x2 VPI:0x1 VCI:0x1 Type:0x0 SAP:AAAA CTL:03 OUI:0080C2 TYPE:0007 Length:0x30 03:21:32: 0000 0050 7359 35B7 0001 96A4 84AC 8864 1100 0001 000E C021 09AB 000C 0235 03:21:32: 279F 0000 0000 03:21:32:
如上所示的输出必须包含相同的Type、SAP、CTL和OUI字段，以指示传入的ATM数据包是AAL5SNAP。
以太网层
AAL5SNAP数据包中包含完整的以太网帧。没有debug ethernet packet命令，但是必须执行一些VPDN调试操作才能查看PPPoE帧。
作为参考，实际是PPPoE帧的以太网帧包含二种以太网类型中的一种。
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0x8863 Ethertype = PPPoE控制数据包（处理PPPoE会话）。
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0x8864 Ethertype = PPPoE数据包（包含PPP数据包）。
一个重要注意事项是PPPoE中有两个会话。PPPoE会话，即VPDN L2TP类型会话和PPP会话。因此，要建立PPPoE，我们有PPPoE会话建立阶段和PPP会话建立阶段。
终端通常介入一个PPP终止阶段和一个PPPoE终止阶段。
PPPoE建立阶段包括两个步骤：
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步骤 1：确定PPPoE客户端和服务器（MAC地址）。
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步骤 2：分配会话ID。
完成此步骤后，正常的PPP建立过程与任何其他PPP连接一样。
要进行调试，请使用VPDN PPPoE调试确定PPPoE连接阶段是否成功。
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输入debug命令，如以下示例所示：
#debug vpdn pppoe-events 06:17:58: Sending PADI: vc=1/1 !--- A broadcast Ethernet frame (here, encapsulated in ATM) requests !--- a PPPoE server with the message, "Is there a PPPoE server out there?" 06:18:00: PPPOE: we have got our pado, and the pado timer went off !--- This is a unicast reply from a PPPoE server (similar to a DHCP offer). 06:18:00: OUT PADR from PPPoE tunnel !--- This is a unicast reply to accept the offer. 06:18:00: IN PADS from PPPoE tunnel !--- This is a confirmation that completes the establishment.
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启动PPP连接。现在，PPP的建立将像任何其他PPP启动一样开始。建立PPPoE会话后，您可以使用show vpdn命令获取状态，如下所示：
#show vpdn %No active L2TP tunnels %No active L2F tunnels PPPoE Tunnel and Session Information Total tunnels 1 sessions 1 PPPoE Tunnel Information Session count: 1 PPPoE Session Information SID RemMAC LocMAC Intf VASt OIntf VC 1 0050.7359.35b7 0001.96a4.84ac Vi1 UP AT0 1 1
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使用show vpdn session all命令获取数据包计数信息，如下所示：
show vpdn session all %No active L2TP tunnels %No active L2F tunnels PPPoE Session Information Total tunnels 1 sessions 1 session id: 1 local MAC address: 0001.96a4.84ac, remote MAC address: 0050.7359.35b7 virtual access interface: Vi1, outgoing interface: AT0, vc: 1/1 1656 packets sent, 1655 received, 24516 bytes sent, 24486 received其他可能有用的debug命令包括debug vpdn pppoe-data、debug pppoe-errors和debug pppoe-packets。
PPP 层
建立PPPoE会话之后，PPP调试与其他PPP建立模式相同。使用同样debug ppp negotiation和debug ppp authentication指令。
注意：在以下示例中，主机名为“client1”，远程Cisco 6400的名称为“nrp-b”。
从命令行激活PPP协商或PPP身份验证。结果输出将如下所示：
06:36:03: Vi1 PPP: Treating connection as a callout 06:36:03: Vi1 PPP: Phase is ESTABLISHING, Active Open [0 sess, 1 load] 06:36:03: Vi1 PPP: No remote authentication for call-out 06:36:03: Vi1 LCP: O CONFREQ [Closed] id 1 len 10 06:36:03: Vi1 LCP: MagicNumber 0x03013D43 (0x050603013D43) 06:36:03: Vi1 LCP: I CONFACK [REQsent] id 1 len 10 06:36:03: Vi1 LCP: MagicNumber 0x03013D43 (0x050603013D43) 06:36:05: Vi1 LCP: I CONFREQ [ACKrcvd] id 2 len 15 06:36:05: Vi1 LCP: AuthProto CHAP (0x0305C22305) 06:36:05: Vi1 LCP: MagicNumber 0x65E315E5 (0x050665E315E5) 06:36:05: Vi1 LCP: O CONFACK [ACKrcvd] id 2 len 15 06:36:05: Vi1 LCP: AuthProto CHAP (0x0305C22305) 06:36:05: Vi1 LCP: MagicNumber 0x65E315E5 (0x050665E315E5) 06:36:05: Vi1 LCP: State is Open 06:36:05: Vi1 PPP: Phase is AUTHENTICATING, by the peer [0 sess, 1 load] 06:36:05: Vi1 CHAP: I CHALLENGE id 9 len 26 from "nrp-b" 06:36:05: Vi1 CHAP: Using alternate hostname client1 06:36:05: Vi1 CHAP: Username nrp-b not found 06:36:05: Vi1 CHAP: Using default password 06:36:05: Vi1 CHAP: O RESPONSE id 9 len 28 from "client1" 06:36:05: Vi1 CHAP: I SUCCESS id 9 len 4 06:36:05: Vi1 PPP: Phase is FORWARDING [0 sess, 1 load] 06:36:05: Vi1 PPP: Phase is AUTHENTICATING [0 sess, 1 load] 06:36:05: Vi1 PPP: Phase is UP [0 sess, 1 load] 06:36:05: Vi1 IPCP: O CONFREQ [Closed] id 1 len 10 06:36:05: Vi1 IPCP: Address 0.0.0.0 (0x030600000000) 06:36:05: Vi1 CDPCP: O CONFREQ [Closed] id 1 len 4 06:36:05: Vi1 IPCP: I CONFREQ [REQsent] id 1 len 10 06:36:05: Vi1 IPCP: Address 8.8.8.1 (0x030608080801) 06:36:05: Vi1 IPCP: Address 8.8.8.1 (0x030608080801) 06:36:05: Vi1 IPCP: Address 9.9.9.2 (0x030609090902) 06:36:05: Vi1 IPCP: O CONFREQ [ACKsent] id 2 len 10 06:36:05: Vi1 IPCP: Address 9.9.9.2 (0x030609090902) 06:36:05: Vi1 LCP: I PROTREJ [Open] id 3 len 10 protocol CDPCP (0x820701010004) 06:36:05: Vi1 CDPCP: State is Closed 06:36:05: Vi1 IPCP: I CONFACK [ACKsent] id 2 len 10 06:36:05: Vi1 IPCP: Address 9.9.9.2 (0x030609090902) 06:36:05: Vi1 IPCP: State is Open 06:36:05: Di1 IPCP: Install negotiated IP interface address 9.9.9.2 06:36:05: Di1 IPCP: Install route to 8.8.8.1 06:36:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to up
调试
要调试Cisco 6400（PPPoE服务器），您可以使用与Cisco SOHO77（客户端）相同的自下而上过程。 区别在于DSL物理层，您需要在该层检查DSLAM。
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DSL 物理层
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ATM 层
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以太网层
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PPP 层
DSL 物理层
检查DSL物理层，您需要查看DSLAM上的DSL统计数据。对于Cisco DSLAM，请使用show dsl interface命令。
ATM 层
在Cisco 6400端，您还可以使用debug atm packet命令，并为特定PVC启用Cisco 6400。
在命令行中输入debug atm packet和相应的参数，如下所示：
debug atm packet interface atm 0/0/0.182 vc 1/82
结果输出如下所示：
4d04h: ATM0/0/0.182(I): VCD:0x3 VPI:0x1 VCI:0x52 Type:0x900 SAP:AAAA CTL:03 OUI:0080C2 TYPE:0007 Length:0x30 4d04h: 0000 0001 96A4 84AC 0050 7359 35B7 8864 1100 0001 000E C021 0A2E 000C 65E3 4d04h: 15E5 0000 0000
注意：由于数据包的处理方式，因此使用此命令将看不到传出数据包。
以太网层
在Cisco SOHO77上使用的相同VPDN show命令和调试可在Cisco 6400上用于查看PPPoE建立。
以下示例说明了上下文中的show和debug命令及其输出。根据需要使用这些命令。
#debug vpdn pppoe-events
4d04h: IN PADI from PPPoE tunnel
4d04h: OUT PADO from PPPoE tunnel
4d04h: IN PADR from PPPoE tunnel
4d04h: PPPoE: Create session
4d04h: PPPoE: VPN session created.
4d04h: OUT PADS from PPPoE tunnel
#show vpdn
%No active L2TP tunnels
%No active L2F tunnels
PPPoE Tunnel and Session Information Total tunnels 1 sessions 1
PPPoE Tunnel Information
Session count: 1
PPPoE Session Information
SID RemMAC LocMAC Intf VASt OIntf VC
1 0001.96a4.84ac 0050.7359.35b7 Vi4 UP AT0/0/0 1 82
#show vpdn session all
nrp-b#show vpdn session all
%No active L2TP tunnels
%No active L2F tunnels
PPPoE Session Information Total tunnels 1 sessions 1
session id: 1
local MAC address: 0050.7359.35b7, remote MAC address: 0001.96a4.84ac
virtual access interface: Vi4, outgoing interface: AT0/0/0, vc: 1/82
30 packets sent, 28 received, 422 bytes sent, 395 received
其他debug命令包括debug vpdn pppoe-data、debug pppoe-errors和debug pppoe-packets。
PPP 层
以下是Cisco 6400的PPP调试输出，与Cisco SOHO77早期的调试相对应。
从命令行界面输入以下命令：
debug ppp negotiation and debug ppp authentication
结果输出如下所示：
4d04h: Vi2 PPP: Treating connection as a dedicated line 4d04h: Vi2 PPP: Phase is ESTABLISHING, Active Open [0 sess, 1 load] 4d04h: Vi2 LCP: O CONFREQ [Closed] id 1 len 15 4d04h: Vi2 LCP: AuthProto CHAP (0x0305C22305) 4d04h: Vi2 LCP: MagicNumber 0x65F62814 (0x050665F62814) 4d04h: Vi2 LCP: I CONFREQ [REQsent] id 1 len 10 4d04h: Vi2 LCP: MagicNumber 0x03144FF9 (0x050603144FF9) 4d04h: Vi2 LCP: O CONFACK [REQsent] id 1 len 10 4d04h: Vi2 LCP: MagicNumber 0x03144FF9 (0x050603144FF9) 4d04h: Vi3 LCP: I ECHOREQ [Open] id 60 len 8 magic 0xA60C0000 4d04h: Vi3 LCP: O ECHOREP [Open] id 60 len 8 magic 0x51A0BEF6 4d04h: Vi2 LCP: TIMEout: State ACKsent 4d04h: Vi2 LCP: O CONFREQ [ACKsent] id 2 len 15 4d04h: Vi2 LCP: AuthProto CHAP (0x0305C22305) 4d04h: Vi2 LCP: MagicNumber 0x65F62814 (0x050665F62814) 4d04h: Vi2 LCP: I CONFACK [ACKsent] id 2 len 15 4d04h: Vi2 LCP: AuthProto CHAP (0x0305C22305) 4d04h: Vi2 LCP: MagicNumber 0x65F62814 (0x050665F62814) 4d04h: Vi2 LCP: State is Open 4d04h: Vi2 PPP: Phase is AUTHENTICATING, by this end [0 sess, 1 load] 4d04h: Vi2 CHAP: O CHALLENGE id 10 len 26 from "nrp-b" 4d04h: Vi2 CHAP: I RESPONSE id 10 len 28 from "client1" 4d04h: Vi2 PPP: Phase is FORWARDING [0 sess, 1 load] 4d04h: Vi2 PPP: Phase is AUTHENTICATING [0 sess, 1 load] 4d04h: Vi2 CHAP: O SUCCESS id 10 len 4 4d04h: Vi2 PPP: Phase is UP [0 sess, 1 load] 4d04h: Vi2 IPCP: O CONFREQ [Closed] id 1 len 10 4d04h: Vi2 IPCP: Address 8.8.8.1 (0x030608080801) 4d04h: Vi2 IPCP: I CONFREQ [REQsent] id 1 len 10 4d04h: Vi2 IPCP: Address 0.0.0.0 (0x030600000000) 4d04h: Vi2 IPCP: Pool returned 9.9.9.2 4d04h: Vi2 IPCP: O CONFNAK [REQsent] id 1 len 10 4d04h: Vi2 IPCP: Address 9.9.9.2 (0x030609090902) 4d04h: Vi2 CDPCP: I CONFREQ [Not negotiated] id 1 len 4 4d04h: Vi2 LCP: O PROTREJ [Open] id 3 len 10 protocol CDPCP (0x820701010004) 4d04h: Vi2 IPCP: I CONFACK [REQsent] id 1 len 10 4d04h: Vi2 IPCP: Address 8.8.8.1 (0x030608080801) 4d04h: Vi2 IPCP: I CONFREQ [ACKrcvd] id 2 len 10 4d04h: Vi2 IPCP: Address 9.9.9.2 (0x030609090902) 4d04h: Vi2 IPCP: O CONFACK [ACKrcvd] id 2 len 10 4d04h: Vi2 IPCP: Address 9.9.9.2 (0x030609090902) 4d04h: Vi2 IPCP: State is Open 4d04h: Vi2 IPCP: Install route to 9.9.9.2 4d04h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to up