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This chapter contains the commands used to configure interface features. The commands are in alphabetical order. For hardware technical descriptions and interface configuration tasks and examples, refer to the Cisco 1020 User Guide.
To set the address used on the remote side, use the async default ip address interface configuration command. To remove the default address from your configuration, use the no form of this command.
async default ip address ip-address [netmask]| ip-address | IP Address of the client interface |
| netmask | Netmask of the client's interface |
No interface address is assigned.
Interface configuration
The following example specifies address 182.32.7.51 as the destination of async interface 2:
interface async 2 no modem async default ip address 182.32.7.51
To include an interface in a dialer rotary group, use the dialer rotary-group interface configuration command.
dialer rotary-group number| number | Number of the dialer interface in whose rotary group you want this interface included. An integer from 0 to 99 that you select that indicates the dialer rotary group. |
Group 0.
Interface configuration
site
dialgroup
To configure Serial Line Internet Protocol (SL/IP) encapsulation, use the encapsulation slip interface configuration command. To configure Point-to-Point Protocol (PPP) encapsulation, use the encapsulation ppp interface configuration command.
encapsulation slipThis command has no arguments or keywords.
Interface configuration
SLIP is designed to encapsulate Internet Protocol (IP) datagrams over point-to-point links.PPP can encapsulate IP, IPX, or both over point-to-point links.
This command turns on hardware flow control on an async port using RTS/CTS. To disable hardware flow control use the no version of the command.
flowcontrol hardwareThis command has no arguments or keywords.
Default is hardware flowcontrol on.
Interface Configuration
Always use hardware flow control with SLIP or PPP.
When the console DIP switch is in console mode, interface async 1 is automatically configured for software flow control, 9600 bps. Do not use async 1 for SLIP or PPP with the DIP switch in console mode.
To control access to an interface, use the ip access-group interface configuration command. To remove the specified access group, use the no form of this command.
ip access-group access-list-number {in | out}| access-list-number | Number of an access list. This is a decimal number from 1 through 199. |
| in | Filters on inbound packets (packets coming into interface). |
| out | Filters on outbound packets (packets going out to interface). |
Entering a keyword is strongly recommended, but if a keyword is not specified, out is the default.
Interface configuration
For inbound access lists, after receiving a packet, the communication server checks the packet against the access list. If the access list permits the packet, the communication server continues to process the packet. If the access list rejects the packet, the communication server discards the packet and returns an ICMP Host Unreachable message.
For outbound access lists, after receiving and routing a packet to a controlled interface, the communication server checks the packet against the access list. If the access list permits the packet, the communication server transmits the packet. If the access list rejects the packet, the communication server discards the packet and returns an ICMP Host Unreachable message.
Access lists are applied on either outbound or inbound interfaces, or both.
If the specified access list does not exist, all packets are passed.
The following example applies access list 101 on packets outbound to interface Ethernet 0:
interface ethernet 0 ip access-group 101 out
access-list (extended)
show access-lists
Use the ip address interface configuration command to set an IP address for an interface. Use the no ip address command to remove the specified address.
ip address ip-address [mask]| ip-address | IP address |
| mask | Mask for the associated IP subnet, only used on Ethernet 0. |
No IP address is defined for an interface.
Interface configuration
Async interfaces by default use the same ip address as the Ethernet interface. You can disable IP processing on the Ethernet interface by removing its IP address with the no ip address command.
Netmasks cannot be specified on Async interfaces on the Cisco 1020. They are specified as part of the async default ip address command.
Use the ip broadcast-address interface configuration command to define a broadcast address for an Ethernet interface. Use the no ip broadcast-address command to restore the IP broadcast address to the default.
ip broadcast-address [ip-address]| ip-address | (Optional) IP broadcast address for a network |
Default address: 1s in the host portion of the network address.
Interface configuration
The only two broadcast addresses supported on the Cisco 1020 are all 0s in the host portion of the address and all 1s in the host portion of the address.
interface ethernet 0
ip address 172.16.1.1 255.255.255.0
ip broadcast-address 172.16.1.255
Use the ip tcp header-compression interface configuration command to enable TCP header compression on an async interface. Use the no ip tcp header-compression command to disable compression.
ip tcp header-compressionThis command has no arguments or keywords.
Disabled
Interface configuration
You can compress the headers of your TCP/IP packets in order to reduce the size of your packets. TCP header compression is supported on serial lines using SLIP or PPP encapsulation. You must enable compression on both ends of a serial connection. RFC 1144 specifies the compression process. Compressing the TCP header can speed up Telnet connections dramatically. In general, TCP header compression is advantageous when your traffic consists of many small packets, not for traffic that consists of large packets. Transaction processing (usually using terminals) tends to use small packets while file transfers use large packets. This feature only compresses the TCP header, so it has no effect on UDP packets or other protocol headers.
When using SLIP, both ends must agree on whether TCP header compression is to be used. PPP will negotiate for header compression and turn it off if either end is unwilling to support it.
To apply a generic output filter to an interface, use ipx access-group interface configuration command. To remove the access list, use the no form of this command.
ipx access-group access-list-number [in|out]| access-list-number | Number of the access list. All outgoing packets defined with either standard or extended access lists and forwarded through the interface are filtered by the entries in this access list. For standard access lists, access-list-number is a decimal number from 800 to 899. For extended access lists, access-list-number is a decimal number from 900 to 999. |
| in | Apply to IPX packets coming in on the interface. |
| out | Apply to IPX packets before they go out on the interface. |
No filters are predefined.
Interface configuration
Generic filters control which packets are sent in or out on an interface based on the packet's source and destination addresses, IPX protocol type, and source and destination socket numbers. You use the standard access-list and extended access-list commands to specify the filtering conditions.
You can apply only one generic filter to an interface for each of in and out.
In the following example, access list 801 is applied to interface Ethernet 0 for outgoing packets.
interface ethernet 0 ipx access-group 801 out
access-list (standard for ipx)
access-list (extended for ipx)
To enable IPX routing on a particular interface and to optionally select the type of encapsulation (framing), use the ipx network interface configuration command. To disable IPX routing, use the no form of this command.
ipx network number [encapsulation encapsulation-type]| number | Network number. This is an eight-digit hexadecimal number that uniquely identifies a network cable segment. It can be a number in the range 1 to FFFFFFFE.
You do not need to specify leading zeros in the network number. For example, for the network number 000000AA you can enter just AA. |
| encapsulation encapsulation-type | (Optional) Type of encapsulation. It can be one of the following values:
arpa (for Ethernet interfaces only)--Use Novell's Ethernet_II encapsulation. This encapsulation is recommended for networks that handle both TCP/IP and IPX traffic. novell-ether (for Ethernet interfaces only)--Use Novell's "Ethernet_802.3" encapsulation.This encapsulation consists of a standard 802.3 MAC header followed directly by the IPX header with a checksum of FFFF. It is the default encapsulation used by NetWare Version 3.11. sap (for Ethernet interfaces)--Use Novell's Ethernet_802.2 encapsulation.This encapsulation consists of a standard 802.3 MAC header followed by an 802.2 LLC header. This is the default encapsulation used by NetWare Version 4.0. |
IPX routing is disabled.
For Ethernet: novell-ether
Interface configuration
The interface sends only packets with the specified encapsulation, but accepts packets with any encapsulation.
The following two commands also allow you to enable IPX routing on an interface and specify the encapsulation.
ipx network number
ipx encapsulation encapsulation-type
option ipx
To control which services are included in Service Advertisement Protocol (SAP) updates sent by the communication server, use the ipx output-network-filter interface configuration command. To remove the filter, use the no form of this command.
ipx output-sap-filter access-list-number| access-list-number | Number of the SAP access list. All outgoing service advertisements are filtered by the entries in this access list. The argument access-list-number is a decimal number from 1000 to 1099. |
No filters are predefined.
Interface configuration
The router applies output SAP filters prior to sending SAP packets.
You can issue only one ipx output-sap-filter command on each interface.
When configuring SAP filters for NetWare 3.11 and later servers, use the server's internal network and node number (the node number is always 0000.0000.0001) as its address in the SAP access-list command. Do not use the network.node address of the particular interface board.
The following example denies service advertisements about server 0000.0000.0001 on network aa from being sent on network 4d (via interface Ethernet 0). All other services are advertised via this network.
access-list 1000 deny aa.0000.0000.0001access-list 1000 permit -1interface ethernet 0ipx net 4dipx output-sap-filter 1000
access list (SAP filtering)
To configure a line for both incoming and outgoing calls, use the modem line configuration command. The command enables a line to be used for both incoming and outgoing calls on dial-in/dial-out modems.
modem {in|out|inout}| in | Only allow incoming calls on this line. |
| inout | Allow both incoming and outgoing calls on this line. |
| out | Only allow outgoing calls on this line. |
inout
Interface configuration
This command defines the type of modem attached to an asynchronous interface using the definitions created by modem-def.
modem-type modem| modem | A modem name previously defined by modem-def. |
Interface Configuration
The initialization string defined by modem-def is sent to the modem when the clear interface async port command is given.
interface async 1 modem-type usrv32 ! interface async 2 modem-type pcmcia-att-288
clear interface
modem-def
To adjust the maximum packet size or maximum transmission unit (MTU) size, use the mtu interface configuration command. Use the no mtu command to restore the MTU value to its original default value.
mtu bytes| bytes | Desired size in bytes |
Table 4-1 lists default MTU values according to media type.
| Media Type | Default MTU |
|---|---|
| Ethernet | 1500 |
| Serial | 1500 |
Interface configuration
Each interface has a default maximum packet size or maximum transmission unit (MTU) size. This number generally defaults to the largest size possible for that type interface. On serial interfaces, the MTU size varies, but cannot be set smaller than 64 bytes.
When used on an interface this command controls whether routing updates will be sent or listened to on the interface. Without arguments it will both broadcast and listen for updates. When used in the no form it neither broadcasts nor listens for routing updates.
routing rip| broadcast | Send routing updates on this interface but do not listen for them. |
| listen | Listen for routing updates on this interface but do not broadcast them. |
On
Interface Configuration
 | Caution This command controls both IP and IPX routing updates for this interface. Caution should be used when passing routing packets unidirectionally. |
To disable an interface, use the shutdown interface configuration command. To restart a disabled interface, use the no shutdown command.
shutdownThis command has no arguments or keywords.
Enabled
Interface configuration
The shutdown command disables all functions on the specified Ethernet interface. Not supported on async interfaces.
show interfaces
To set the async port baud rate, use the speed line configuration command. The command sets both the transmit (to modem) and receive (from modem) speeds.
speed bps| bps | Baud rate in bits per second (bps); see Table 4-2 for settings. |
9600 bps
Interface configuration
This command pertains to the asynchronous ports only. Set the speed to match the baud rate of whatever device you have connected to the port. Some baud rates available on devices connected to the port might not be supported on the router. The router will indicate if the speed you select is not supported. Use the following table as a guide for setting the line speeds.
| Router Model | Baud Rates |
|---|---|
| Cisco 7000, AGS, CGS, MGS | 50, 75, 110, 134, 150, 200, 300, 600, 1050, 1200, 2000, 2400, 4800, 9600, 19200, 38400 |
| IGS, Cisco 2000, Cisco 3000, Cisco 4000 | 75, 110, 134, 150, 300, 600, 1200, 2000, 2400, 4800, 1800, 9600, 19200, 38400 |
| Cisco 1020 | 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 |
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