3Com Router User Manual

							Typical MP Configuration Example177
[Router]local-user router-c password simple router-c
bSpecify the virtual interface templates for the two users and begin PPP 
negotiation for the NCP information using this template
[Router]ppp mp user router-b bind virtual-template 1
[Router]ppp mp user router-c bind virtual-template 2
cConfigure virtual interface template
[Router]interface virtual-template 1
[Router-Virtual-Template1]ip address 202.38.166.1 255.255.255.0
[Router]interface virtual-template 2
[Router-Virtual-Template2]ip address 202.38.168.1 255.255.255.0
dAdd the interfaces serial2:1, serial2:2, serial2:3 and serial2:4 into MP channel. 
Here, take serial2:1 as an example, and other interfaces are configured 
similarly. 
[Router]interface serial 2:1
[Router-Serial2:1]link-protocol ppp
[Router-Serial2:1]ppp mp
[Router-Serial2:1]ppp authentication-mode pap
[Router-Serial2:1]ppp pap local-user router-a password simple 
router-a
2Configure router-b:
aAdd a user for router-a
[Router]local-user router-a password simple router-a
bSpecify the virtual interface template for this user and begin PPP negotiation 
for the NCP information using this template
[Router]ppp mp user router-a bind virtual-template 1
cConfigure working parameters of the virtual interface template
[Router]interface virtual-template 1
[Router-Virtual-Template1]ip address 202.38.166.2 255.255.255.0
dAdd the interfaces serial2:1 and serial2:2 into MP channel. Here, take serial2:1 
as an example, and configure other interfaces similarly
[Router]interface serial2: 1
[Router-Serial2:1]ppp mp
[Router-Serial2:1]ppp authentication-mode pap
[Router-Serial2:1]ppp pap local-user router-b password simple 
router-b
3Configure router-c:
aAdd a user for router-a
[Router]local-user router-a password simple router-a
bSpecify the virtual interface template for this user and begin PPP negotiation 
for the NCP information using this template
[Router]ppp mp user router-a bind virtual-template 1
cConfigure working parameters of the virtual interface template
[Router]interface virtual-template 1
[Router-Virtual-Template1]ip address 202.38.168.2  255.255. 255.0
dAdd the interfaces serial2:1 and serial2:2 into MP channel. Here, take serial2: 1 
as an example, and other interfaces are configured similarly. 
						

							178CHAPTER 12: CONFIGURING PPP AND MP
[Router]interface serial2: 1
[Router-Serial2:1]ppp mp
[Router-Serial2:1]ppp authentication-mode pap
[Router-Serial2:1]ppp pap local-user router-c password simple 
router-c
Fault Diagnosis and 
Troubleshooting of 
PPPFault 1: Link always fails to turn to up status.
Troubleshooting: It is possible that PPP authentication parameter is not configured 
correctly, resulting in the failure of PPP authentication.
Turn on the debugging switch of PPP, if LCP negotiation is successful and turns to 
Up status, then begin PAP or CHAP negotiation and LCP turns to Down status.
Fault 2: Physical link fails to turn to Up status.
Troubleshooting: Execute display interface serial interface-number 
command to view the current interface status, including five status:
serial number is administratively down, line protocol is down
Indicates that the interface is shutdown.
serial number is down, line protocol is down
Indicates that the interface is not activated or the physical layer does not turn to 
Up status.
serial number is up, line protocol is up(spoofing)
Indicates that this interface is a dialup interface and the call is not connected 
successfully.
serial number is up, line protocol is up
Indicates that data can be transmitted through this interface.
serial number is up, line protocol is down
Indicates that this interface is activated, but link negotiation is not successful.
Fault 3: Fail to ping through the peer although the link is UP and LCP and 
IPCP are all opened.
Troubleshooting:
■Execute the display running-configcurrent-configuration interface 
command on the local end to check whether the IP address is configured and 
whether IP address negotiation is configured with the 
ip address 
ppp-negotiate 
command.
■Check the configuration of the peer to see whether it assigns IP address to the 
local end with the 
remote address command.
■Directly specify IP address for the local end or assign IP address to the peer. 
Then reset the interface with the 
shutdown and undo shutdown command.  
						

							13
CONFIGURING PPPOE CLIENT
This chapter contains information on the following topics:
■PPoE Overview
■Configure PPPoE Client
■Display and Debug PPPoE Client
■Typical PPPoE Configuration Example
PPoE OverviewPoint-to-Point Protocol over Ethernet (PPPoE) can be used for connecting Ethernet 
hosts to a remote access concentrator through a simple bridging device. With 
PPPoE, the remote access device can control and implement billing on the 
accessed subscribers. Compared with traditional access approaches, PPPoE is more 
cost-effective. Therefore, it is widely put in many applications, such as residential 
quarter networks. As a popular broadband access approach at present, ADSL 
(Asymmetric Digital Subscriber Line), adopts this protocol. 
PPPoE adopts the client/server approach, encapsulates PPP packets in Ethernet 
frames, and provides PPP connection over Ethernet.
PPPoE is implemented at two phases, the discovery phase and the PPP session 
phase.
■Discovery phase
When a host initiates a PPP session, it must first go through the discovery phase 
to confirm the remote Ethernet MAC address, and establish a PPPoE session ID. 
Different from PPP, PPPoE establishes a client/server relationship at this phase, 
whereas PPP establishes a peer relationship. Through the discovery phase, the 
host (client) can discover an access concentrator (server). After this phase ends 
normally, the host and the access concentrator can establish a PPPoE session by 
using the MAC address and the session ID.
■PPP session phase
As the PPP session begins, the host and the access concentrator implement 
negotiation and transmit PPP data according to PPP. The PPP packets are 
encapsulated in Ethernet frames as payload of PPPoE frames, and transmitted 
to the peers of the PPPoE link. In this case, all the Ethernet frames are unicast. 
Refer to RFC2516 for PPPoE.
Introduction to PPPoE client
PPPoE is widely used in ADSL broadband access. Normally, if a host wants to 
access the Internet via ADSL, it must have been installed with a PPPoE client 
dial-up software. The 3Com Router series can work as PPPoE clients (that is,  
						

							180CHAPTER 13: CONFIGURING PPPOE CLIENT
implement the client dial-up function of PPPoE), so the subscribers can access the 
Internet without installing a PPPoE client software on PCs. Furthermore, all the PCs 
on the same LAN can share an ADSL account.
Figure 52   Networking for PPPoE
As shown in the above figure, the PCs on an Ethernet are connected to a 3Com 
Router running PPPoE client. The data destined for the Internet first reach the 
router where PPPoE encapsulates the data, and then go through the ADSL access 
server via the ADSL Modem attached to the router, and finally access the Internet. 
The overall Internet-accessing process can be implemented, without requiring the 
subscribers to install any PPPoE client dial-up software.
Configure PPPoE 
ClientThe fundamental PPPoE configuration includes:
■Configure dialer interface
■Configure PPPoE session
The high-level PPPoE configuration includes:
■Reset or delete PPPoE session
1Configure Dialer Interface
Before configuring a PPPoE session, you should configure a dialer interface and a 
dialer bundle on the interface. Each PPPoE session should uniquely associates with 
a dialer bundle, which is uniquely associated to a dialer interface. In other words, 
only a PPPoE session can be created on a dialer interface.
Perform the commands dialer-rule and interface dialer in system view and 
other commands in dialer interface view.
Ta b l e 213   Configure a dialer interface
Ethernet
ADSL Modem
PPPoE Session
PPPoE ServerPPPoE Client
PCPC
OperationCommand
Configure a dialer ruledialer-rule dialer-group { 
protocol-name { permit | deny } | acl 
acl-number }
Create a dialer interfaceinterface dialer number 
						

							Configure PPPoE Client181
Depending on the needs, it is probably required to configure the parameters such 
as PPP authentication on a dialer interface. The dialer interface configuration will 
not be covered in this section, however. Please see Operation Manual - Dial-up for 
reference.
2Configure PPPoE Session
Perform the following configuration in Ethernet interface view.
Ta b l e 214   Configure PPPoE session
The 3Com Router support two types of PPPoE connections, which are permanent 
connections and packet-triggered connections.
■In permanent connection, the router will originate a PPPoE call to automatically 
and immediately set up a PPPoE session. And this session will be always in place 
unless the user uses the 
undo pppoe-client command to delete it.
■In packet-triggered connection, the router will not originate a PPPoE call 
immediately. Instead, the router will originate a PPPoE call to establish a PPPoE 
session only when there is data waiting for transmission. And the router will 
automatically terminate the PPPoE session if the PPPoE link has been idle for 
the specified period.
3Reset or delete PPPoE Session
Perform the reset pppoe-client command in all views and the undo 
pppoe-client
 command in Ethernet interface view.
Ta b l e 215   Reset or delete PPPoE session
The commands reset pppoe-client and undo pppoe-client differ in the sense 
that the former only resets a PPPoE session temporarily whereas the latter deletes 
a PPPoE session permanently.
If a permanent PPPoE session has been reset by executing the reset 
pppoe-client
 command, the router will automatically re-establish the PPPoE 
session 16 seconds later. If a packet-triggered PPPoE session has been reset by 
executing the same command, however, the router will re-establish the session 
only when there is data waiting for transmission. 
Assign an IP address to the interfaceip address { address mask | 
ppp-negotiate }
Configures a dialer bundle on the 
interfacedialer bundle bundle-number
Assigns the interface to a dialer groupdialer-group group-number
OperationCommand
Configure a PPPoE session (permanently 
online)pppoe-client dial-bundle-number number 
[ no-hostuniq ]
Configure a PPPoE session (triggered by 
packets)pppoe-client dial-bundle-number number 
[ no-hostuniq ] idle-timeout seconds [ 
hold-queue packets ]
Delete the PPPoE sessionundo pppoe-client dial-bundle-number 
number
OperationCommand
Reset a PPPoE session but it will be re-established 
laterreset pppoe-client { all 
|dial-bundle-number number }
Delete a PPPoE session and it will not be 
re-establishedundo pppoe-client 
dial-bundle-number number 
						

							182CHAPTER 13: CONFIGURING PPPOE CLIENT
Regardless of whether a PPPoE session is permanent or packet-triggered, 
executing the 
undo pppoe-client command will permanently delete the session. 
Hence, you need to make reconfiguration for establishing a new PPPoE session.
Display and Debug 
PPPoE ClientPerform the display and debugging command in all views.
Ta b l e 216   Display and debug PPPoE Client
Typical PPPoE 
Configuration 
Example
Access a LAN to the 
Internet via ADSLI. Networking Requirements
The PCs on a LAN access the Internet via RouterA, and RouterA adopts the 
permanent approach to accesses the Internet via ADSL. It uses “3com as the user 
name of the ADSL account, and the password is 12345. Enable the PPPoE client 
function on the router, so that the hosts on the LAN can access the Internet, even 
installed with no PPPoE client software.
II. Networking Diagram
Figure 53   Access a LAN to the Internet via ADSL
III. Configuration Procedure
1Configure a dialer interface
[Router]dialer-rule 1 ip permit
[Router]interface dialer 1
[Router-Dialer1]dialer bundle 1
[Router-Dialer1]dialer-group 1
OperationCommand
Display state of the PPPoE session and the 
statistic information as welldisplay pppoe-client session { 
summary | packet } 
[dial-bundle-number number ]
Enable debugging of PPPoE clientdebugging pppoe-client option [ 
interface type number ]
LAN
ADSL Modem Eth0
Eth1 192.168.1.1
RouterA
Internet
PCPCPC 
						

							Typical PPPoE Configuration Example183
[Router-Dialer1]ip ppp-negotiate
[Router-Dialer1]ppp pap local-user 3com password cipher 12345
2Configure a PPPoE session
[Router]interface ethernet 1
[Router-Ethernet1]pppoe-client dial-bundle-number 1
3Configure the LAN interface and the default route
[Router]interface ethernet 0
[Router-Ethernet0]ip address 192.168.1.1 255.255.255.0
[Router]ip route-static 0.0.0.0 0.0.0.0 dialer 1
If the IP addresses assigned to the PCs on the LAN are private addresses, Network 
Address Translation (NAT) should also be configured on the router. For the NAT 
configuration, refer to the related chapters contained in Operation Manual - 
Network Protocol.
Use ADSL as Standby 
LineI. Networking Requirements
RouterA uses both DDN leased line and ADSL to connect with the network center 
and ADSL is used as a standby for the DDN leased line. Thus, if the DDN leased line 
fails, RouterA can still originate PPPoE call for connection to the network center 
across ADSL. If ADSL has been idle for two minutes, the PPPoE session will be 
terminated. If new packets are generated for transmission after that, PPPoE 
session will be re-established. 
II. Networking Diagram
Figure 54   Typical networking for PPPoE
III. Configuration Procedure
1Configure a dialer interface
[Router]dialer-rule 1 ip permit
[Router]interface dialer 1
[Router-Dialer1]dialer bundle 1
[Router-Dialer1]dialer-group 1
[Router-Dialer1]ip address ppp-negotiate
2Configure a PPPoE session
[Router]interface ethernet 1
[Router-Ethernet1]pppoe-client dial-bundle-number 1 idle-timeout 120
3Configure the DDN interface Serial 0
[Router]interface serial 0
[Router-Serial0]ip address 10.1.1.1 255.255.255.0
[Router-Serial0]standby interface dialer 1
RouterAADSL
DDNNetwork center 
						

							184CHAPTER 13: CONFIGURING PPPOE CLIENT 
						

							14
CONFIGURING SLIP
This chapter contains information on the following topics:
■SLIP Overview
■Configure SLIP
■Display and Debug SLIP
■Typical SLIP Configuration Example
SLIP OverviewSLIP (Serial Link Internet Protocol) can transmit data over the asynchronous serial 
link. Through SLIP, the user can dial up to access the Internet. Compared with 
other link layer protocols, SLIP is very simple. It does not provide protocol address, 
error check, header compression. In addition, SLIP does not distinguish packet 
types, so it supports only one type of network protocol at one time.
For further details about SLIP, you can refer to RFC1055.
Configure SLIP Because SLIP does not negotiate the name of the remote end, SLIP dialer can only 
be used with the standard BDR.
SLIP dialer on the physical port configuration includes:
■Configure the synchronous/asynchronous serial interface to asynchronous 
mode
■Configure the incoming and outgoing call authorities of Modem
■Enable BDR
■Configure the link layer protocol of the interface to SLIP
■Configure Dialer Group and Dialer Rule of activated calls
■Configure the dial string of interface
For the specific configuration methods of BDR and Modem, please refer to related 
chapters of BDR, Modem in Operation Manual – Dial-up.
1Configure the Sync/Async Serial Interface to Work in Async Mode
Perform the following task in the interface view.
Ta b l e 217   Configure the synchronous/asynchronous serial interface to work in 
asynchronous mode
OperationCommand
Configure the synchronous/asynchronous serial 
interface to work in asynchronous modephysical-mode async 
						

							186CHAPTER 14: CONFIGURING SLIP
By default, the synchronous/asynchronous serial interface operates in synchronous 
mode
2Configure the link layer protocol of the interface to SLIP
Perform the following task in the asynchronous interface view.
Ta b l e 218   Configure the link layer protocol of the interface to SLIP
By default, the link layer protocol of the interface is PPP.
Note the following:
■The link layer protocol of the interface can be set to SLIP only when it operates 
in the asynchronous mode.
■When link layer protocol LAPB, X.25, HDLC or Frame Relay is operating on the 
interface, the physical attributes of the interface cannot be modified to 
asynchronous mode. At this time, you should first modify the link layer protocol 
of the interface to PPP and then you may change the interface attribute to 
asynchronous mode.
Display and Debug 
SLIPPerform the following task in all views to monitor the current state of SLIP in real 
time.
Ta b l e 219   Enable/Disable the information debugging of SLIP
Typical SLIP 
Configuration 
ExampleI. Networking Requirement
Interconnect two Router routers via PSTN and run IP.
II. Networking Diagram
Figure 3-1Networking diagram of SLIP dialer 
OperationCommand
Configure the link layer protocol of the interface to SLIPlink-protocol slip
OperationCommand
Enable the information debugging of SLIP packetdebugging slip { hexadecimal 
| packet | all }
10.110.0.1
8810003
10.110.0.28810026Router A
Router B
PSTN