3Com Router User Manual
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10 CONFIGURING WAN INTERFACE This chapter contains information on the following topics: ■WAN Interface Introduction ■Asynchronous Serial Interface ■AUX Interface ■Synchronous Serial Interface ■ISDN BRI Interface ■CE1/PRI Interface ■CT1/PRI Interface ■E1-F Interface ■T1-F Interface ■CE3 Interface ■CT3 Interface WAN Interface IntroductionThe wide area network (WAN) can be divided into X.25 network, frame relay network, ATM network and ISDN network according to the line type. Accordingly, the router has synchronous/asynchronous serial interface, ATM interface, ISDN BRI and CE1/PRI. Presently, the 3Com Router-supported WAN interfaces include asynchronous serial interface, AUX interface, synchronous serial interface, ISDN BRI interface CE1/PRI interfaces, CT3, CT1/PRI interface, E1-F interface, T1-F interface, CE3 interface. Asynchronous Serial InterfaceThere are two asynchronous serial interfaces in the 3Com Router. One is Serial, which sets the synchronous/asynchronous serial interface to work in asynchronous mode. The other is Async, a special asynchronous serial interface. You can set asynchronous serial interface to dedicated line mode or dialup mode. When the asynchronous serial interface is connected with Modem or ISDN terminal adapter (TA) externally, it can serve as a dialup interface, encapsulating link layer protocol SLIP or PPP, and supporting IP and IPX. Configure Asynchronous Serial InterfaceAsynchronous serial interface configuration includes: ■Set the synchronous/asynchronous serial interface to work in asynchronous mode ■Enter the view of specified asynchronous serial interface
118CHAPTER 10: CONFIGURING WAN INTERFACE ■Set the asynchronous serial interface to work in dialup or dedicated line mode ■Set link layer protocol ■Set baud rate ■Set link establishment mode ■Set the check mode in flow mode ■Set stop bit in flow mode ■Set data bit in flow mode ■Set flow control mode ■Enable or disable level detection ■Enable or disable internal loopback and external loopback ■Set MTU ■Setting the coding format of Modem The asynchronous serial interface may also need to be configured with SLIP parameter, PPP parameter, BDR parameter, IP address, firewall and standby center parameter as required. 1Set the synchronous/asynchronous serial interface to work in asynchronous mode If the physical interface to be configured is synchronous/asynchronous serial interface, it must be set to work in asynchronous mode by executing the following commands. Please use the following command in the view of synchronous / asynchronous serial interface Ta b l e 94 Set the synchronous/asynchronous serial interface to work in asynchronous mode The synchronous/asynchronous serial interface works in synchronous mode by default. 2Enter the view of specified asynchronous serial interface Please use the following commands to enter the view of the specified serial interface in all views. Ta b l e 95 Enter view of specified asynchronous interface 3Set the asynchronous serial interface to work in dialup or dedicated line mode. For special asynchronous serial interface or the asynchronous serial interface set from synchronous/asynchronous serial interface, it is possible to dialup with modem command. Please see Operation Manual - Dial-up for other settings and detailed OperationCommand Set the synchronous/asynchronous serial interface to work in asynchronous mode.physical-mode async OperationCommand Enter the view of specified asynchronous serial interface interface async number Enter the view of the specified synchronous/asynchronous serial interface (which has been set to work in asynchronous mode)interface serial number
Asynchronous Serial Interface119
instructions in dialup mode. In dedicated line mode, ensure that modem
command is not configured, i.e. disable dial with
undo modem command.
Please use the following commands in the view of asynchronous serial interface.
Ta b l e 96 Set the work mode of asynchronous serial interface
The asynchronous serial interface works in dial mode by default, i.e. modem
command is configured by default. Both calling in and calling out are allowed with
modem in and modem out command. The async/sync serial interface working in
asynchronous mode works in dedicated line mode by default.
4Set link layer protocol
The link layer protocol of asynchronous serial interface can be set as SLIP and PPP.
Please use the following command in the view of the asynchronous serial
interface.
Ta b l e 97 Set the link layer protocol of asynchronous serial interface
The default link layer protocol is PPP.
5Set baud rate
Please use following command in the view of the asynchronous serial interface.
Ta b l e 98 Set the baud rate of asynchronous serial interface
Default value for baud rate is 9600bps.
When the asynchronous serial interface is used in dialup mode, the baud rate only
refers to the communication rate between the asynchronous serial interface of the
router and Modem. And the rate between two Modems must be determined
according to the line quality after mutual consultation. Therefore, baud rate
settings of asynchronous serial interfaces of two routers at two ends of the line
can be inconsistent.
When the asynchronous serial interface is used in dedicated line mode, the baud
rate setting must be consistent with the opposite equipment.
After the synchronous/asynchronous serial interface is set to work in asynchronous
mode, the router will automatically change the baud rate to 9600bps.
6Set link establishment mode
There are three link establishment modes for the asynchronous serial interface:
■Protocol: After the setup of a physical connection, the local end directly uses
the set link layer protocol parameter to establish link with the opposite end.
OperationCommand
Set the asynchronous serial interface to work in dial mode.modem { in | out }
Set the asynchronous serial interface to work in dedicated
line mode.undo modem
OperationCommand
Set the link layer protocol of the asynchronous serial
interfacelink-protocol { slip | ppp }
OperationCommand
Set baud rate of the asynchronous serial interfacebaudrate baudrate
120CHAPTER 10: CONFIGURING WAN INTERFACE
Dedicated mode is usually used when asynchronous serial interfaces are directly
connected.
■Flow: Also called the Interactive mode, which means two ends of the link
interact with each other after the setup of a physical connection. The calling
end sends configuration command to the receiving end (with the same effect
as the user inputs configuration command remotely), sets working parameters
of the link layer protocol at the receiving end and then establishes the link. This
mode is usually used for such man-machine interactions as dumb terminal and
dialing, etc.
■Dumb terminal access (TTY) mode: It is one type of flow mode. When the
asynchronous serial interface of the router is used for dumb terminal access
service, this key word and other related parameters could be used to set the
number of physical terminal and virtual terminal (VTY) to be accessed. For
detailed configuration, see Terminal Service User Manual.
Please use the following commands in the view of the asynchronous serial
interface.
Ta b l e 99 Set the link establishment mode of asynchronous serial interface
Establish the link in dedicated mode by default.
7Set flow control mode
There are two types of data flow control methods, hardware flow control and
software flow control, when an asynchronous serial interface adopts the flow
mode to establish links. If hardware flow control is adopted, the data transmission
on the asynchronous serial interface will be controlled by the hardware signal on
the interface. When transmitting data, the interface will automatically detect the
CTS signal. If there are CTS signals, it will transmit data. If no signals are detected,
it will terminate the data transmission. If software flow control is adopted, the
data transmission on the asynchronous serial interface will be controlled by the
software flow control characters. When transmitting data, the interface will
transmit data if receiving the flow control characters XON (0x11). It will terminate
the transmitting, if receiving the flow control characters XOFF (0x13).
Please perform the following configuration in asynchronous serial interface view.
Ta b l e 100 Set the method of data flow control on an asynchronous serial interface
By default, the function of hardware flow control is enabled in the inbound
direction, and the function of flow control is disabled in the outbound direction.
Hardware and software flow controls cannot be simultaneously used in the same
direction. If configuring the software flow control in a direction already configured
with the hardware flow control, the hardware control will be removed, and vice
versa.
8Set the check mode in flow mode
OperationCommand
Set the asynchronous serial interface to establish the link in
protocol modeasync mode protocol
Set the asynchronous serial interface to establish the link in flow
modeasync mode flow
OperationCommand
Set the method of data flow control on an
asynchronous serial interfaceflow-control { none | software |
hardware } [ inbound | outbound ]
Asynchronous Serial Interface121
When the link establishment mode of async serial interface is flow or TTY, the two
ends of the link will interact with each other after the setup of a physical
connection. The calling end will send configuration command to the receiving end
and set the interactive parameters of link layer protocol on the receiving end
before the establishment of the link. In practical application (such as terminal
server), the router will send configuration command to the terminal and transmit
interactive operating parameters of the link layer that are set at local end to the
opposite end.
This command is used to set the interactive operating parameter of the link layer
protocol ---check mode.
Please perform the following configuration in asynchronous serial interface view.
Ta b l e 101 Set the check mode when the async serial interface works in flow mode
By default, none is adopted for non-parity check.
9Set stop bit in flow mode
This command is used to set another interactive operating parameter of the link
layer protocol---the stop bit.
Please perform the following configuration in asynchronous serial interface view.
Ta b l e 102 Set the stop bit when the asynchronous serial interface works in flow mode
By default, there is only 1 stop bit.
10Set data bit in flow mode
This command is used to set another interactive operating parameter of the link
layer protocol--- the data bit.
Please perform the following configuration in asynchronous serial interface view.
Ta b l e 103 Set the data bit when the asynchronous serial interface works in flow mode
5, 6, 7 and 8 stand for 5, 6, 7 and 8 data bits respectively. By default, there are 8
data bits.
11Enable or disable level detection
If the level detection is disabled for the asynchronous serial interface, the system
will only detect whether the asynchronous serial interface connects cables
externally and automatically report its state (UP or DOWN) to the user. If the level
detection is enabled, the system will detect DSR signal in addition to the
above-mentioned detection. Only when this signal is effective will the system
regard the asynchronous serial interface as UP. Otherwise, it is regarded as DOWN.
OperationCommand
Set the check mode when the async serial
interface works in flow modeparity { even | mark | none |
odd | space }
OperationCommand
Set the stop bit when the asynchronous serial interface
works in flow modestopbits { 1 | 1.5 | 2 }
OperationCommand
Set the data bit when the asynchronous serial interface
works in flow modedatabits { 5 | 6 | 7 | 8 }
122CHAPTER 10: CONFIGURING WAN INTERFACE Please use the following commands in the view of the asynchronous serial interface. Ta b l e 104 Enable or disable the level detection for the asynchronous serial interface By default the level detection is enabled for the asynchronous serial interface. 12Enable or disable internal loopback and external loopback On performing special function test, the internal loopback and external loopback is enabled for the asynchronous serial interface. Please use following commands in the view of the asynchronous serial interface. Ta b l e 105 Enable or disable internal loopback and external loopback for the asynchronous serial interface The internal loopback and external loopback are disabled by default. 13Set MTU MTU of asynchronous serial interface influences the fragmentation and reassembling of IP network protocol message on this interface. Please use the following commands in the view of the asynchronous serial interface. Ta b l e 106 Set MTU of asynchronous serial interface The unit of mtu is byte, ranging from 128 to 1500, with 1500 as default. 14Set the coding format of Modem Please perform the following configurations in asynchronous serial interface mode. Ta b l e 107 Set the coding format of Modem AUX InterfaceAUX interface is a fixed port provided by the 3Com Router. It can be used as a common asynchronous serial interface with the highest rate of 115200bps. It can also implement functions such as remote configuration of the router and line backup. OperationCommand Enable the level detection for the asynchronous serial interface.detect dsr-dtr Disable the level detection for the asynchronous serial interface.undo detect dsr-dtr OperationCommand Enable internal loopback and external loopback for the asynchronous serial interface.loopback Disable internal loopback and external loopback for the asynchronous serial interface.undo loopback OperationCommand Set MTU of asynchronous serial interfacemtu size Recover MTU defaultundo mtu OperationCommand Set the coding format of Modemcountry-code area-name
Synchronous Serial Interface123 Configure AUX interface 1Enter AUX interface view Perform the following configuration in the all views. Ta b l e 108 Enter AUX interface view 2Configure AUX interface The configuration of AUX interface is basically the same with that of common asynchronous serial interfaces. The following items should be noted: aThe operating mode of AUX interface is Flow mode by default, and AUX interface work in dial mode by default. bWhen the data bit is configured on AUX interface, the parameter of the databits command cannot be 5. That is, AUX interface does not support the data bit 5. cWhen the stop bit is configured on AUX interface, the parameter of the stopbits command cannot be 1.5. That is, AUX interface does not support the stop bit 1.5. In addition to the above points, AUX interface is configured in the same way as that of the asynchronous serial interface. Synchronous Serial InterfaceFeatures of synchronous serial interface: ■It can work in two modes: DTE and DCE. Usually, the synchronous serial interface serves as DTE and receives DCE-provided clock. ■The synchronous serial interface can connect multiple cables externally, such as V.24 and V.35. The 3Com Router can automatically detect types of cables connected externally and select electrical characters. There is no need to configure manually. ■The link layer protocols supported by synchronous serial interface include PPP, frame relay, LAPB and X.25. ■It supports IP and IPX network layer protocol. ■Type of external cable and the working mode (DTE/DCE) of the synchronous serial interface can be viewed with display interfaces serial command. Configure Synchronous Serial InterfaceSynchronous serial interface configuration includes: ■Set the synchronous/asynchronous serial interface to work in synchronous mode. ■Enter the view of specified synchronous serial interface. ■Set link layer protocol ■Set the digital signal encoding format ■Set baud rate. ■Select working clock ■Set clock inversion OperationCommand Enter AUX interface viewinterface aux 0
124CHAPTER 10: CONFIGURING WAN INTERFACE
■Enable or disable level detection
■Enable or disable data carrier detection
■Setting the synchronous serial interface to work in full duplex or half duplex
mode
■Enable or disable internal loopback/external loopback
■Set MTU
■Set the time interval for sending keepalive packets
■Set the idle coding of synchronous serial interface
PPP/X.25/FR parameters, BDR parameters, IP address, firewall parameters and
standby center parameters should be configured on the synchronous serial
interface if needed. Refer to the relevant chapters in this manual for details.
1Set the synchronous/asynchronous serial interface to work in synchronous mode.
Before further configuration, please set the synchronous/asynchronous serial
interface to work in synchronous mode with the following command in the view
of synchronous/asynchronous serial interface.
Ta b l e 109 Set the synchronous/asynchronous serial interface to work in synchronous
mode
The synchronous/asynchronous serial interface works in synchronous mode by
default.
2Enter the view of the specified synchronous serial interface
In all views, enter the view of the specified synchronous serial interface with the
following command.
Ta b l e 110 Enter view of specified synchronous interface
3Set link layer protocol
The link layer protocol of synchronous serial interface can be set to PPP, LAPB,
X.25, Frame Relay, HDLC or SDLC.
Please use the following command in the view of the synchronous serial interface.
Ta b l e 111 Set the link layer protocol of synchronous serial interface
Select PPP link layer protocol by default.
4Set the digital signal encoding format
The synchronous serial interface support two digital signal encoding formats: NRZ
(nonreturn to zero) and NRZI (nonreturn to zero, inverted).
OperationCommand
Set the synchronous/asynchronous serial interface in
synchronous mode.physical-mode sync
OperationCommand
Enter the view of the specified synchronous/asynchronous
serial interface (which has been set to work in synchronous
mode)interface serial number
OperationCommand
Set link layer protocollink-protocol { fr | hdlc |
lapb | ppp | sdlc | x25 }
Synchronous Serial Interface125 Perform following commands in synchronous serial interface view. Ta b l e 112 Set the digital signal encoding format of synchronous serial interface By default, the digital signal encoding format of synchronous serial interface is NRZ. 5Set baud rate Please use the following command in the view of the synchronous serial interface. Ta b l e 113 Set the baud rate of synchronous serial interface When two synchronous serial interfaces are connected, the baud rate on line is determined at DCE-side. Therefore, when the synchronous serial interfaces are working in DCE mode, the baud rate is to be set. However, if the interfaces act as DTE, then the baud rate need not be configured. Default baud rate of synchronous serial interface is 64000 bps. After the synchronous/asynchronous serial interface is set to synchronous mode from asynchronous mode, the system will automatically change the default baud rate to 64000 bps. 6Select work clock The synchronous serial interface works in two modes: DTE and DCE. Different working modes have different working clocks. ■If the synchronous serial interface is used as DCE, it is necessary to provide clock to the opposite DTE by choosing DCEclk. ■If the synchronous serial interface is used as DTE, the clock provided by the opposite DCE needs to be accepted. As the receiving clock and transmitting clock of the synchronous equipment are independent, the receiving clock of DTE can be the transmitting clock or receiving clock of DCE or the sending clock of DTE can be the transmitting clock or receiving clock of DCE. Thus, there will be four combinations, i.e. four kinds of clock selections are available at DTE side. Figure 46 Schematic diagram of synchronous serial interface clock selection Ta b l e 114 Selection method with synchronous serial interface serving as DTE-side clock OperationCommand Using NRZI encoding formatcode nrzi Using NRZ encoding formatundo code OperationCommand Set baud rate of the synchronous serial interfacebaudrate baudrate Selection methodMeaning DCEDTE TxClk RxClk
126CHAPTER 10: CONFIGURING WAN INTERFACE
TxClk stands for transmitting clock, RxClk for receiving clock, the clock before “=”
is DTE-side clock, and that behind “=” is DCE-side clock.
Please use the following commands in the view of the synchronous serial
interface.
Ta b l e 115 Select work clock
The clock of DCE-side synchronous serial interface is dceclk by default, and that of
DTE side is dteclk3 by default.
7Set clock inversion
In some special cases, the clock will generate half-period delay on the line, which
may cause failed interconnection of equipment at two ends or large amount of
messages discarded. In this case, the transmit clock signal of DTE-side synchronous
serial interface can be inverted to eliminate the influence of delay.
Please use the following commands in the view of the synchronous serial
interface.
Ta b l e 116 Set clock inversion
The inversion is disabled by default.
This command is only effective to certain clock signals provided by some DCEs.
Usually, clock inversion should not be set.
8Enable or disable level detection
By default, when the system decides whether the synchronous serial interface is in
UP status or DOWN status, it detects the DSR signal, DCD signal and whether the
interface connects a cable at the same time. Only when the three signals are
effective, will the system regard the interface is in UP status, otherwise, in DOWN
status. If level detection is disabled for the synchronous serial interface, the system
will not detect the DSR signal.
Please use the following commands in the view of the synchronous serial
interface.
Ta b l e 117 Enable or disable level detection for the synchronous serial interface
DTE1TxClk = TxClk, RxClk = RxClk
DTE2TxClk = TxClk, RxClk = TxClk
DTE3TxClk = RxClk, RxClk = TxClk
DTE4TxClk = RxClk, RxClk = RxClk
OperationCommand
Select DCE-side synchronous serial interface
clockclock dceclk
Select DTE-side synchronous serial interface
clock.clock { dteclk1 | dteclk2 |
dteclk3 | dteclk4 }
OperationCommand
Enable the inversion of transmit clock signal of
DTE-side synchronous serial interfaceinvert transmit-clock
Disable the inversion of transmit clock signal of
DTE-side synchronous serial interfaceundo invert transmit-clock
OperationCommand