Configuring a Synchronous WAN Port   6

  This chapter describes the steps required to configure a PortMaster 4 synchronous wide area network (WAN) port.

  This chapter discusses the following topics:

•  "Synchronous Port Uses" on page 6-1
•  "Configuring WAN Port Settings" on page 6-2

  See the PortMaster 4 Command Line Reference for more detailed command descriptions and instructions.

  You can also configure the PortMaster 4 using the PMVision application for Microsoft Windows, UNIX, and other platforms supporting the Java Virtual Machine (JVM). PMVision replaces the PMconsole interface to ComOS.

       Synchronous Port Uses

  Synchronous WAN ports are used for high-speed dedicated connections between two remote local area networks (LANs). Once a connection is established between two remote sites, a wide area network (WAN) is created. Synchronous WAN connections can be achieved through the use of dedicated leased lines, Frame Relay connections, switched 56Kbps lines, or ISDN lines. Connection rates can range from 9600bps to 2.048Mbps (E1). The PortMaster 4 supports any of these connection types using one or more synchronous ports.

  For most applications, a dedicated line connects two PortMaster routers, each located on a separate remote network

  The following examples describe various uses for synchronous ports.

  Routing over Leased Lines.  A synchronous port can be used to connect to synchronous leased lines from 9600bps to T1 (1.544Mbps) or E1 (2.048Mbps) for continuous operation. The Quad T1 boards on a PortMaster 4 have a built-in channel service unit/digital service unit (CSU/DSU). For more information, see Chapter 14 "Using Synchronous Leased Lines."

  Routing over Frame Relay.  Frame Relay provides connectivity using a packet-switched network. Its two advantages over a leased line network are lower cost and the ability to have multiple permanent virtual circuits (PVCs) come into a single physical port. It is especially popular for hub-and-spoke network arrangements. For example, a dozen field offices with 56Kbps or fractional T1 Frame Relay connections can connect to a central office using a fractional T1 or T1 Frame Relay connection. The central office requires only one CSU/DSU and synchronous port on the PortMaster, instead of 12. For more information, see Chapter 13 "Using Frame Relay."

  Routing over ISDN.  Integrated Services Digital Network (ISDN) provides fast dial-up connectivity for applications where the expense of a dedicated Frame Relay or leased line connection is not called for by the amount and nature of the traffic. For more information, see Chapter 11 "Configuring T1, E1, and ISDN PRI."

  Once you have determined the type of synchronous connection to use between your remote locations, the synchronous port on each end of the connection must be configured.

       Configuring WAN Port Settings

  The WAN port settings described in this section enable you to configure your synchronous port for your needs. "General Synchronous Settings" on page 6-2 includes settings that are available for all connection types. The settings in "Settings for Hardwired Connections" on page 6-5 are available only for network hardwired connections.

       Setting the View

  To configure a synchronous serial line as a WAN port, you must first set the view to the slot containing the board for the line that you want to configure. To set the view, enter the show boards  command to determine the identification number of the line board you want to configure.

  The board identification number is the same as the number of the slot in which the T1 or E1 line board is installed.

  Command> show boards

  Use the following command to set the view to a slot with an installed T1 or E1 line board:

  Command> set view Slotnumber

  Setting the view for a specific board gives you administrative access to that board.

       General Synchronous Settings

  The following settings can be used on synchronous ports configured for all connection types.

 

Displaying Extended Port Information

  The PortMaster can display synchronous port information in brief or extended modes. The default setting is off .

  To enable or disable extended information for a port, use the following command:

  Command> set  W1 extended on |off 

  Note ¯ This command affects only the display of port information. It does not affect port behavior.

 

Setting the Port Type and Connection Type

  Use the following command to set the port and connection type:

  Command> set  W1 network  dialin |dialout |twoway |hardwired 

  The port type for synchronous ports is always network , but you must explicitly set it. You also must specify the kind of connection to use on the synchronous port. Although you can configure a network port to allow dial-in and dial-out connections, a network  port is typically used for a dedicated connection between two points known as hardwired . A hardwired connection does not use modem control.

  To configure a port for a dedicated network connection, use the following command:

  Command> set  W1 network  hardwired 

  Table 6-1 describes the four connection types available on synchronous ports.

  Table 6-1 Port and Network Types

Type	Description
hardwired	Allows you to establish a dedicated network connection between two sites without modem dialing or authentication. In this mode, the port immediately begins running the specified protocol. If the port is set for a hardwired connection, it cannot be used for any other purpose. A hardwired connection must be used for a leased line or Frame Relay connection.
dialin	Allows the port to accept dial-in network connections, for use with switched 56Kbps or ISDN connections. The dial-in user is required to enter a username and password before the connection is established. Authorized users are managed through the user table described in Chapter 5 "Configuring Dial-In Users," or through RADIUS.  PPP users wishing to authenticate with PAP or CHAP can start sending PPP packets. When the packets are received, the PortMaster automatically detects PPP and requests PAP or CHAP authentication.
dialout	Allows dial-out users to establish connections with remote locations. Dial-out network destinations are managed through the location table. This network type can be used for ISDN and switched 56Kbps connections.
twoway	Allows the port to accept dial-in users and use dial-out locations. This network type can be used for ISDN and switched 56Kbps connections.

 

Setting the Port Speed Reference

  The true port or line speed is set either by the external clock signal on the device to which the PortMaster is connected, or by the telephone company. You can record this value as a reference associated with a synchronous port, but it has no effect on PortMaster behavior.

  To record the port speed, use the following command:

  Command> set  W1 speed  Speed

  You can substitute any of the following for Speed:

9600	19200	56000	64000	115200	1536k	t1	e1
14400	38400	57600	76800	1344k	2048k	t1e

 

Setting Modem Control

  When modem control is on, the PortMaster uses the condition of the carrier detect (DCD) signal from an attached modem to determine whether the line is in use.

  Modem control is off for synchronous connections by default. With modem control set off, the PortMaster assumes the carrier detect line is always asserted. Table 6-2 describes the effects of DCD condition on port behavior.

  Table 6-2 Effects of Carrier Detect Condition on Port Behavior

 

Connection Type	Carrier Detect Asserted	Carrier Detect De-asserted
hardwired	Port attempts to establish a network connection.	Port is unavailable.
dialin	PortMaster initiates authentication and displays a login prompt.	Port is unavailable.
dialout	No effect.	Transition from asserted to de-asserted resets the port.
twoway	Port attempts to establish a network connection.	Port is available.

  Set modem control on only if you want to use the DCD signal from the attached device. In general, set modem control on for network dial-in or dial-out configurations. Modem control is usually off for leased line or Frame Relay connections, but you can use it if the channel service unit/digital service unit (CSU/DSU) is configured accordingly.

  To set modem control, use the following command:

  Command> set  W1 cd  on |off 

 

Assigning a Port to a Dial Group

  You can create modem pools for dial-out connections by associating ports and dial-out locations with dial groups. Dial groups can be used to reserve ports for dial-out to specific locations, or to differentiate among different types of modems that are compatible with the remote location. Dial groups are numbered 0 to 99. The default dial group is 0.

  To assign a port to a dial group, use the following command:

  Command> set  W1 group  Group

 

Setting Hangup Control

  You can control whether the data terminal ready (DTR) signal on the synchronous port is dropped after a user session terminates. Hangup is set to on  by default. In this state, DTR is dropped for 500 milliseconds, causing a hangup on the line.

  To set the hangup control, use the following command:

  Command> set  W1 hangup on |off 

  The reset  command always drops the DTR signal.

 

Setting the Port Idle Timer

  The idle timer indicates how long the PortMaster waits after activity stops on a synchronous port before disconnecting a dial-in or dial-out connection.

  You can set the idle time in seconds or minutes, to any value from 0 to 240. The default setting is 0 minutes. If the value is set to 2 seconds or a longer interval, the port is reset after having no traffic for the designated time. The idle timer is not reset by RIP, keepalive, or SAP packets. To disable the idle timer, set the value to 0.

  To set the idle timer, use the following command:

  Command> set  W1 idle  Number [minutes |seconds ]

       Settings for Hardwired Connections

  The following settings can be used only when the synchronous port is configured for network hardwired connections.

 

Setting the Transport Protocol

  The transport protocol for synchronous connections must be set for a network hardwired synchronous port. Choose PPP for leased line, switched 56Kbps, and ISDN connections, or Frame Relay for a Frame Relay connection. Additional Frame Relay settings must be configured for Frame Relay connections, described in Chapter 13 "Using Frame Relay."

  To set the transport protocol, use the following command:

  Command> set  W1 protocol slip |ppp |frame |x75-sync 

 

Setting the Port IP Address

  You can set the local IP address of the network hardwired synchronous port to create a numbered interface.

  You can use any IP address. If you set the local address of the WAN port to 0.0.0.0 for PPP, the PortMaster uses the Ether0 address for the end of the serial link. If you set the WAN port address to 0.0.0.0 for a Frame Relay connection, the port is disabled.

  To set the IP address, use the following command:

  Command> set  W1 address  Ipaddress

 

Setting the Destination IP Address

  The destination IP address or hostname of the machine on the other end of the connection is used for leased line connections only. The destination IP address can also be set to 255.255.255.255 for PPP users. This setting allows the PortMaster to learn the IP address of the system on the other end of the connection using PPP IPCP address negotiation.

  Do not set a destination IP address for Frame Relay connections. Instead, use the data link connection identifier (DLCI) list to link IP addresses to DLCIs, or use LMI or Annex-D and Inverse ARP to discover Frame Relay addresses dynamically. See Chapter 13 "Using Frame Relay," for more information.

  For network dial-in or dial-out connections, do not set a destination IP address for the port. Instead, you set the destination address in the user table or RADIUS for dial-in, or in the location table for dial-out. See Chapter 5 "Configuring Dial-In Users" for more information.

  To set the destination IP address for a leased-line connection only, use the following command:

  Command> set  W1 destination Ipaddress [Ipmask]

 

Setting the Subnet Mask

  The default subnet mask is 255.255.255.0. If you have divided your network into subnets, enter the subnet mask that identifies how your network addresses are divided between the network portion and the host portion. The value of Ipmask is dependent upon the size of the IP subnet of which the IP address is a member. This setting is used on network hardwired ports only.

  To set the subnet mask, use the following command:

  Command> set  W1 netmask  Ipmask

  See Appendix A, "Networking Concepts," for more information about using subnet masks.

 

Setting the IPX Network Address

  Note ¯ The PortMaster 4 supports the IPX protocol if it is running ComOS 4.1 or later. IPX is not supported in ComOS 4.0.

  When using IPX, you must identify an IPX network number of the serial link that is unique from every other IPX number on the network. An IPX network address is entered in hexadecimal format, as described in Appendix A, "Networking Concepts."

  Note ¯ The serial link itself must have an IPX network number that is different from4 those at either end of the connection.

  To set the IPX network address, use the following command:

  Command> set  W1 ipxnet  Ipxnetwork

 

Configuring RIP Routing

  As described in the PortMaster Routing Guide, PortMaster products automatically send and accept route information as RIP messages.

  Note ¯ ComOS 4.1 and later releases support RIP-1 and RIP-2. Earlier releases of ComOS support only RIP-1.

  Turn on RIP routing for the port for network hardwired connections only, such as leased lines or Frame Relay. Routing is set in the user table for dial-in connections and in the location table for dial-out connections.

  To configure RIP routing, use the following command:

  Command> set  W1 rip on |off |broadcast |listen |v2  
{broadcast |multicast |on |v1-compatibility }

 

Setting Input and Output Filters

  Input and output packet filters can be attached to a synchronous port for network hardwired ports. Filters allow you to monitor and restrict network traffic. If an input filter is attached, all packets received from the interface are evaluated against the rule set for the attached filter. Only packets permitted by the filter are passed through the PortMaster. If an output filter is attached, packets going to the interface are evaluated against the rule set in the filter and only packets permitted by the filter are sent out of the interface.

  Note ¯ You must define a filter in the filter table before you can apply it. For more information about filters, see Chapter 8 "Configuring Filters."

  To apply an input filter to a synchronous port, use the following command:

  Command> set  W1 ifilter  [Filtername]

  To apply an output filter to a synchronous port, use the following command:

  Command> set  W1 ofilter  [Filtername]

  You can remove filters from the port by entering the command without a filter name. If a filter is changed, you must reset the port for the change to take effect.

  For example, to remove the output filter from a synchronous port, use the following commands:

  Command> set  W1 ofilter
 Command> reset  W1
Command> save  all 

  Note ¯ You must reset the port and re-establish the connection for the new settings to take effect.

 

Setting Compression

  You can set Van Jacobson TCP/IP header compression and/or Stac LZS data compression on the port. To set compression, use the following command:

  Command> set compression on|off|stac|vj

  Van Jacobson TCP/IP header compression and Stac LZS data compression improve performance on asynchronous lines but can degrade performance on high-speed synchronous lines.