Contents

Configuring SMDS

The Switched Multimegabit Data Service (SMDS) is a WAN service offered by a variety of service providers.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for SMDS

You must have already obtained your SMDS addresses from your service provider. You need the following two types of addresses:

  • The group address for broadcasts
  • The SMDS hardware (individual) address for each router that interfaces directly into the SMDS network (that is, customer premises equipment)

Information About SMDS

SMDS Hardware Requirements

You need the following hardware, equipment, and special software to configure SMDS:

  • CSC-MCI or CSC-SCI serial interface controller card, or a HSSI interface on chassis-based systems, or the serial port on a router

To operate on CSC-SCI or CSC-MCI cards, SMDS requires that the appropriate microcode version be installed. Version numbers are 1.2 (or later) for CSC-SCI and 1.7 (or later) for CSC-MCI.

  • EIA/TIA-449 or V.35 applique
  • SMDS data service unit (SDSU) device

The figure below illustrates the connections among the components.

Figure 1. Typical SMDS Configuration

SMDS Addresses

All addresses for SMDS service are assigned by the service provider and can be assigned to individuals and groups.

You must enter addresses in the Cisco SMDS configuration software using an E prefix for multicast addresses and a C prefix for unicast addresses.

Cisco IOS software expects the addresses to be entered in E.164 format, which is 64 bits (15-digit addressing). The first 4 bits are the address type, and the remaining 60 bits are the address. If the first 4 bits are 1100 (0xC), the address is a unicast SMDS address, which is the address of an individual SMDS host. If the first 4 bits are 1110 (0xE), the address is a multicast SMDS address, which is used to broadcast a packet to multiple end points. The 60 bits of the address are in binary-coded decimal (BCD) format. Each 4 bits of the address field presents a single telephone number digit, allowing for up to 15 digits. At a minimum, you must specify at least 11 digits (44 bits). Unused bits at the end of this field are filled with ones.


Note

The arp smdscommand supports 48-bit addresses only (C or E followed by 11 digits). The addresses must be entered in dotted notation--for example, C141.5556.1414.

An example of a 15-digit E.164 address follows:

C14155561313FFFF

Note

Older versions of Cisco IOS software supported 48-bit SMDS addresses. If, when using the current version of the software, you write the configuration to NVRAM, the full 64-bit SMDS address is written. Older versions of the software will no longer be able to read the new SMDS configuration from NVRAM. However, the current version of the software can read previous versions of the configuration in NVRAM.

The addresses can be entered with periods in a manner similar to Ethernet-style notation, or simply as a string of digits.

The following is an example of an individual address entered in Ethernet-style notation:

C141.5555.1212.FFFF

The following is an example of a group address:

E180.0999.9999.FFFF

An SMDS network can be thought of in much the same way as an X.25 cloud. The premises equipment (in this case Cisco routers) represents the edge of the cloud. The service provider enables communication across the cloud. However, proper configuration is needed for communication to occur. This configuration will differ from one protocol family to another.

One major difference between protocol families is dynamic versus static routing among the routers (called remote peers ) on the periphery of the cloud. For IP, routing across the SMDS cloud is fully dynamic. No action on the user’s part is needed to map higher-level protocol addresses to SMDS addresses. Both IP and ARP can be configured and a dynamic ARP routing table enabled.


Note

The arp smds command requires 12-digit dotted-notation SMDS addresses--for example, C141.5678.9012.

Customizing the SMDS Network

Configuring Specific Protocols

Some protocol families are dynamically routed. For IP and CLNS, routing is fully dynamic, and no action on your part is needed to map higher-level protocol addresses to SMDS addresses. But for the other supported protocols, you must make a static entry for each router to communicate with all other peer routers. The static entries need to be made only for those routers that are SMDS remote peers. Nothing additional needs to be done to assure communication with other nodes behind the peer routers.

For an example of how to configure specific protocols, see the section "Typical Multiprotocol Configuration Example" later in this chapter.

The table below lists protocol families and the multicasts that are needed.

Table 1 Protocol Families and Types of Multicasts Needed

Protocol Family

Multicasts Needed

IP

IP

DECnet

DECNET, DECNET_NODE, DECNET_ROUTER-L1, DECNET_ROUTER-L2

CLNS

CLNS, CLNS_ES,CLNS_IS

Novell IPX

IPX

XNS

XNS

AppleTalk

APPLETALK, AARP

Banyan VINES

VINES

Configuring ARP and IP

For both IP and ARP, the multicast address must be configured and ARP must be enabled. ARP multicast is required only for ARP servers; the IP multicast is used for ARP and routing updates.

Configuring DECnet

Static maps must be configured for DECnet. In addition, a separate smds multicast command is needed for DECNET, DECNET_NODE, DECNET_ROUTER-L1, and DECNET_ROUTER-L2.

Configuring CLNS

Multicasts must be configured for CLNS_ES and CLNS_IS. No static maps are necessary. End system hello (ESH), intermediate system hello (ISH), and router hello packets are sent to the multicast address, and neighbor entries are created automatically.

Configuring IPX

For Novell IPX, the multicast address must be configured. A static map entry can be made for each remote peer, or you can use the smds glean command to dynamically map addresses. Static map entries override any dynamic map entries.

Routing Information Protocol (RIP) routing packets, Service Advertisement Protocol (SAP) packets, NetBIOS Name Lookups, directed broadcasts, and traffic to the helper addresses (if that helper address is a broadcast address) are sent to the SMDS IPX multicast address.

Configuring XNS

For XNS, the multicast address must be configured, and a static map entry must be made for each remote peer. Only RIP, directed broadcasts, and helper traffic are sent to the XNS multicast address.

Configuring AppleTalk

The SMDS cloud must be treated by all AppleTalk routers connected to it as either extended or nonextended. The network types cannot be mixed on the same SMDS cloud. Instead, all AppleTalk routers on an SMDS cloud must agree about the network type: extended or nonextended.

If any router in the SMDS cloud uses Cisco IOS Release 10.3(3) (or earlier), use a nonextended AppleTalk configuration for the SMDS cloud. To use nonextended AppleTalk, use the appletalk address command and configure static maps.

If all routers in the SMDS cloud use Cisco IOS Release 10.3(4) (or later), you can use extended AppleTalk to support dynamic AARP for SMDS addresses. To use extended AppleTalk, use the appletalk cable-range command.

For information on the appletalk addressand appletalk cable-range commands, refer to the Cisco IOS AppleTalk and Novell IPX Command Reference .

For an example of how to configure AppleTalk, see the section "AppleTalk Configuration Examples" later in this chapter.

Configuring Banyan VINES

For Banyan VINES, the multicast address must be configured. Also note that VINES works only with static maps.

Transparent Bridging over SMDS

You can enable transparent bridging for SMDS encapsulated serial and HSSI interfaces. Cisco’s implementation of IEEE 802.6i transparent bridging for SMDS supports 802.3, 802.5, and FDDI frame formats. The router can accept frames with or without frame check sequence (FCS).

Fast-switched transparent bridging is the default and is not configurable. If a packet cannot be fast switched, it will be process switched.

For more information about bridge groups and the bridge-group command, see the "Configuring Transparent Bridging" chapter in the Cisco IOS Bridging and IBM Networking Configuration Guide .

SMDS Subinterfaces for Multiple Logical IP Subnetworks

Multiple logical IP subnetworks are supported as defined by RFC 1209. This RFC explains routing IP over an SMDS cloud where each connection is considered a host on one specific private network, and describes cases where traffic must transit from network to network.

This solution allows a single SMDS interface to be treated as multiple logical IP subnetworks and to support routing of packets from one network to the next without using intervening routers. When multiple logical IP subnetworks are enabled, the router performs routing between the subnetworks using IP addresses on an SMDS interface. Each supported subnetwork has an IP address, a unicast SMDS E.164 address, and a multicast SMDS E.164 address configured on the SMDS interface. Broadcast packets are duplicated and transmitted to all IP networks on the specified SMDS interface and use the associated multicast SMDS address for the network.

Only routers that require knowledge of multiple IP networks need to be configured with multipoint subinterfaces that correspond to different networks.

Reenabling Data Exchange Interface Version 3.2 with Heartbeat Support

By default, SMDS provides the Data Exchange Interface (DXI) Version 3.2 heartbeat process as specified in the SIG-TS-001/1991 standard. The DXI mechanism encapsulates SMDS packets in a DXI frame before they are transmitted. The heartbeat mechanism automatically generates a heartbeat poll frame every 10 seconds. The Interim Local Management Interface (ILMI) is not supported. See the Cisco IOS Wide-Area Networking Command Reference for more information about DXI 3.2.


Note

If you are running serial lines back-to-back, disable keepalive on SMDS interfaces. Otherwise, DXI declares the link down.

Pseudobroadcasting

Some hosts do not support multicast E.164 addresses. This is a problem in IP where frequent broadcast packets are sent because routing updates are generally broadcast. IP and ARP depend on the use of multicast addresses to determine a route to a destination IP address. A mechanism was needed to artificially support the use of broadcast where multicast E.164 addresses do not exist; the result is pseudobroadcasting . If a multicast address is not available to a destination, pseudobroadcasting can be enabled to broadcast packets to those destinations using a unicast address.

Fast Switching

SMDS fast switching of IP, IPX, and AppleTalk packets provides faster packet transfer on serial links with speeds above 56 kbps. Use fast switching if you use high-speed, packet-switched, datagram-based WAN technologies such as Frame Relay offered by service providers.

By default, SMDS fast switching is enabled.

SMDS Configuration Task List

Enabling SMDS on the Interface

Setting SMDS Encapsulation

To set SMDS encapsulation at the interface level, use the following command in interface configuration mode:

Command

Purpose

 
Router(config-if)# encapsulation smds

Enables SMDS on the interface.

Specifying the SMDS Address

To specify the SMDS individual address for a particular interface, use the following command in interface configuration mode:

Command

Purpose

 
Router(config-if)# smds address smds-address

Enters an individual address provided by the SMDS service provider.

Establishing Address Mapping

Routing tables are configured dynamically when DECnet, extended AppleTalk, IP, IPX, and ISO CLNS routing are configured. However, you can configure static mapping for these protocols, if needed. For other protocols, you must configure a static map between an individual SMDS address and a higher-level protocol address.

To establish address mapping, use the following command in interface configuration mode:

Command

Purpose

 
Router(config-if)# smds static-map  protocol protocol-address smds-address [broadcast]

Defines static entries for those routers that are SMDS remote peers.

The supported protocols and the keywords to enable them are as follows:

  • AppleTalk--appletalk
  • Banyan VINES--vines
  • DECnet--decnet
  • IP--ip
  • ISO CLNS--clns
  • Novell IPX--ipx
  • XNS--xns

Mapping a Multicast Address to an SMDS Address

You can map an SMDS group address to a broadcast or multicast address used by a higher-level protocol. If you do so, you need not specify the broadcast keyword in the smds static-map command, and the Cisco IOS software need not replicate each broadcast address.

To map an SMDS group address to a multicast address, use the following command in interface configuration mode:

Command

Purpose

 
Router(config-if)# smds multicast protocol smds-address

Maps an SMDS group address to a multicast address used by a higher-level protocol. The protocols supported and the keywords to enable them are as follows:

  • AppleTalk--appletalk
  • AppleTalk ARP address--aarp
  • Banyan VINES--vines
  • Bridging--bridge
  • DECnet--decnet
  • DECnet multicast address for all Level 1 routers--decnet_router-L1
  • DECnet multicast address for all Level 2 routers--decnet_router-L2
  • DECnet multicast address for all end systems--decnet_node
  • IP--ip
  • ISO CLNS--clns
  • Multicast address for all CLNS intermediate systems--clns_is
  • Multicast address for all CLNS end systems--clns_es
  • Novell IPX--ipx
  • XNS--xns
Note   

Bridging is not a protocol, but the bridge keyword is valid for providing a map to a multicast address.

Enabling ARP

When you enable the Address Resolution Protocol (ARP), you can choose to enable either a dynamic ARP cache or one built statically. To enable ARP, use one of the following commands in the specified configuration mode:

Command

Purpose

 
Router(config-if)# smds enable-arp

Enables ARP and dynamic address resolution (interface).

 
Router(config)# arp  ip-address smds-address  smds

Enables ARP with a static entry for the remote router (global).

Enabling Broadcast ARP Messages

When an ARP server is present in the network, you can enable broadcast ARP messages that are sent to all ARP SMDS addresses or to all IP SMDS multicast addresses when ARP addresses are not present.

To enable broadcast ARP messages, use the following commands in interface configuration mode:

SUMMARY STEPS

    1.    Router(config-if)# smds enable-arp

    2.    Router(config-if)# smds multicast arp smds-address[ip-address mask]


DETAILED STEPS
     Command or ActionPurpose
    Step 1 Router(config-if)# smds enable-arp 

    Enables ARP and dynamic address resolution.

     
    Step 2 Router(config-if)# smds multicast arp smds-address[ip-address mask] 

    Enables broadcast ARP messages.

     

    Enabling Dynamic Address Mapping for IPX over SMDS

    To enable dynamic address mapping for IPX on an SMDS interface, use the following command in interface configuration mode:

    Command

    Purpose

    		 
    Router(config-if)# smds glean ipx [timeout-value] [broadcast]

    Enables dynamic address mapping for IPX.

    Customizing Your SMDS Network

    Enabling Transparent Bridging over SMDS

    To enable transparent bridging, use the following commands beginning in global configuration mode:

    SUMMARY STEPS

      1.    Router(config)# interface type number

      2.    Router(config-if)# encapsulation smds

      3.    Router(config-if)# bridge-group bridge-group

      4.    Router(config-if)# smds multicast bridge smds-address


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 Router(config)# interface type number 

      Specifies a serial or HSSI interface.

       
      Step 2 Router(config-if)# encapsulation smds 

      Configures SMDS encapsulation on the serial interface.

       
      Step 3 Router(config-if)# bridge-group bridge-group 

      Associates the interface with a bridge group.

       
      Step 4 Router(config-if)# smds multicast bridge smds-address 

      Configures bridging across SMDS.

       

      Configuring SMDS Subinterfaces for Multiple Logical IP Subnetworks

      To configure the Cisco IOS software to have multipoint subinterfaces for multiple logical IP subnetworks, use the following commands beginning in global configuration mode:

      SUMMARY STEPS

        1.    Router(config)# interface serial interface . subinterface multipoint

        2.    Router(config-if)# ip address ip-address mask

        3.    Router(config-if)# smds address smds-address

        4.    Router(config-if)# smds multicast protocol smds-address

        5.    Router(config-if)# smds enable-arp


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 Router(config)# interface serial interface . subinterface multipoint

        Example:
        

        
        
 

        Example:
        
          
        Router(config)# interface serial slot / port . subinterface multipoint
        

        
        
 

        Example:
        
          
        (for Cisco 7000 series routers1)
        

        
        
 
              		 
          
        
Defines a logical subinterface for each IP network.
        

          
        
          
        

         
      
        

        Step 2
Router(config-if)# ip address ip-address mask 
       
          
        
Configures the subinterface as an IP network.
        

         
      
        

        Step 3
Router(config-if)# smds address  smds-address 
       
          
        
Assigns unicast SMDS E.164 address to the subinterface.
        

         
      
        

        Step 4
Router(config-if)# smds multicast protocol smds-address 
       
          
        
Assigns multicast SMDS E.164 address for each protocol supported on the subinterface.
        

         
      
        

        Step 5
Router(config-if)# smds enable-arp 
       
          
        
Enables ARP on the subinterface, if required by the protocol.
        

         
      
        

        1  Beginning in Cisco IOS Release 11.3, all commands supported on the Cisco 7500 series are also supported on the Cisco 7000 series.
        

        

        

        Reenabling Data Exchange Interface Version 3.2 with Heartbeat Support
        

        
To reenable the DXI heartbeat, use the following command in interface configuration mode:
        


        
              
        
Command
        

                    		

              
        
Purpose
        

                    		

        
        

        
              
        Router(config-if)# smds dxi
        

            
        
        		

              
        
Enables DXI 3.2.
        

                    		

        
        

        

        

        

        

        Configuring Pseudobroadcasting
        

        
To configure pseudobroadcasting, use the following command in interface configuration mode:
        


        
              
        
Command
        

                    		

              
        
Purpose
        

                    		

        
        

        
              
        Router(config-if)# smds static-map  protocol protocol-address smds-address broadcast
        

            
        
        		

              
        
Configures pseudobroadcasting.
        

                    		

        
        

        

        

        
For an example of how to configure pseudobroadcasting, see the section "Pseudobroadcasting Example" later in this chapter.
        

        

        

        Enabling Fast Switching
        

        
      
        
To re-enable fast switching, use the following commands beginning in global configuration mode: 
        

    
        
SUMMARY STEPS
          1.   
      
Router(config)# interface type number
          

          2.   
      
Router(config-if)# encapsulation smds
          

          3.   
      
Router(config-if)# ip route-cache
          

          4.   
      
Router(config-if)# ipx route-cache
          

          5.   
      
Router(config-if)# appletalk route-cache
          


        DETAILED STEPS
           Command or ActionPurpose
          Step 1
Router(config)# interface type number 
       
          
          
Defines and enters interface configuration mode.
          

         
      
          

          Step 2
Router(config-if)# encapsulation smds 
       
          
          
Sets SMDS encapsulation.
          

         
      
          

          Step 3
Router(config-if)# ip route-cache 
       
          
          
Enables the interface for IP fast switching.
          

         
      
          

          Step 4
Router(config-if)# ipx route-cache 
       
          
          
Enables the interface for IPX fast switching.
          

         
      
          

          Step 5
Router(config-if)# appletalk route-cache 
       
          
          
Enables the interface for AppleTalk fast switching.
          

         
      
          

          

          

          

          

          Monitoring the SMDS Connection
          

          
To monitor the SMDS connection, use one or more of the following commands in EXEC mode:
          


          
              
          
Command
          

                      		

              
          
Purpose
          

                      		

          
          

          
              
          Router# show arp
          

            
          
          		

              
          
Monitors ARP activity.
          

                      		

          

          
              
          Router# show smds addresses
          

            
          
          		

              
          
Displays the individual addresses and the interface with which they are associated.
          

                      		

          

          
              
          Router# show smds map
          

            
          
          		

              
          
Displays all SMDS addresses that are mapped to higher-level protocol addresses.
          

                      		

          

          
              
          Router# show smds traffic
          

            
          
          		

              
          
Displays packet traffic activity.
          

                      		

          
          

          

          

          

          

          

          SMDS Configuration Examples
          

          

          Typical Multiprotocol Configuration Example
          

          
The following example is a typical interface configured for IP, DECnet, ISO CLNS, Novell IPX, XNS, and AppleTalk. DECnet needs to be configured globally and at the interface level.
          

          interface serial 4
 ip address 1.1.1.2 255.0.0.0
 decnet cost 4
 appletalk address 92.1
 appletalk zone smds
 clns router igrp FOO
 ipx net 1a
 xns net 17
 encapsulation SMDS
! SMDS configuration follows
 smds address c120.1580.4721
 smds static-map APPLETALK 92.2 c120.1580.4592
 smds static-map APPLETALK 92.3 c120.1580.4593
 smds static-map APPLETALK 92.4 c120.1580.4594
 smds static-map NOVELL 1a.0c00.0102.23ca c120.1580.4792
 smds static-map XNS 17.0c00.0102.23ca c120.1580.4792
 smds static-map NOVELL 1a.0c00.0102.23dd c120.1580.4728
 smds static-map XNS 17.0c00.0102.23aa c120.1580.4727
 smds multicast NOVELL e180.0999.9999
 smds multicast XNS e180.0999.9999
 smds multicast ARP e180.0999.9999
 smds multicast IP e180.0999.9999
 smds multicast APPLETALK e180.0999.9999
 smds multicast AARP e180.0999.9999
 smds multicast CLNS_IS e180.0999.9990
 smds multicast CLNS_ES e180.0999.9990
 smds multicast DECNET_ROUTER e180.0999.9992
 smds multicast DECNET_NODE e180.0999.9992
 smds multicast DECNET e180.0999.9992
 smds enable-arp
          

          

          

          Remote Peer on the Same Network Example
          

          
The following example illustrates a remote peer on the same SMDS network. DECnet needs to be configured globally and at the interface level.
          

          interface serial 0
 ip address 1.1.1.1 255.0.0.0
 decnet cost 4
 appletalk address 92.2
 appletalk zone smds
 clns router igrp FOO
 ipx net 1a
 xns net 17
 encapsulation SMDS
! SMDS configuration follows
 smds address c120.1580.4792
 smds static-map APPLETALK 92.1 c120.1580.4721
 smds static-map APPLETALK 92.3 c120.1580.4593
 smds static-map APPLETALK 92.4 c120.1580.4594
 smds static-map NOVELL 1a.0c00.0102.23cb c120.1580.4721
 smds static-map XNS 17.0c00.0102.23cb c120.1580.4721
 smds static-map NOVELL 1a.0c00.0102.23dd c120.1580.4728
 smds static-map XNS 17.0c00.0102.23aa c120.1580.4727
 smds multicast NOVELL e180.0999.9999
 smds multicast XNS e180.0999.9999
 smds multicast IP e180.0999.9999
 smds multicast APPLETALK e180.0999.9999
 smds multicast AARP e180.0999.9999
 smds multicast CLNS_IS e180.0999.9990
 smds multicast CLNS_ES e180.0999.9990
 smds multicast DECNET_ROUTER e180.0999.9992
 smds multicast DECNET_NODE e180.0999.9992
 smds multicast DECNET e180.0999.9992
 smds enable-arp
          

          

          

          IPX Dynamic Address Mapping Example
          

          
The following example enables dynamic address mapping for IPX on interface serial 0 and sets the time to live (TTL) to 14 minutes.
          

          interface serial 0
 encapsulation smds
 smds address c141.5797.1313
 smds multicast ipx e180.0999.9999
 smds glean ipx 14
          

          

          

          AppleTalk Configuration Examples
          

          
The following two sections provide basic examples of configuration for an extended AppleTalk network and for a nonextended AppleTalk network. For more information on AppleTalk commands, refer to the Cisco IOS AppleTalk and Novell IPX Command Reference.
          

          

          Extended AppleTalk Network Example
          

          
If all AppleTalk routers on the SMDS cloud are running Cisco IOS Release 10.3(4) or later releases, you can use an AppleTalk extended network. To do so, use the appletalk cable-range interface command.
          

          
When SMDS is configured for an extended AppleTalk network, SMDS static maps are not required and not used. Dynamic AARP is supported on the multicast channel. 
          

          interface Serial0
 ip address 192.168.200.1 255.255.255.0
 encapsulation smds
 appletalk cable-range 10-10
 appletalk zone SMDS
 smds address c151.0988.1923
 smds static-map ip 192.168.200.2 c151.0988.8770
 smds multicast APPLETALK e151.0988.2232
 smds multicast AARP e151.0988.2232
 smds multicast IP e151.0988.2232
 smds multicast ARP e151.0988.2232
 smds enable-arp
          

          

          

          Nonextended Appletalk Network Example
          

          
The following example configures SMDS for a nonextended AppleTalk network. When SMDS is configured for a nonextended AppleTalk network, SMDS static maps are required and the appletalk address command is used. Dynamic AppleTalk Address Resolution Protocol (AARP) is not supported on the multicast channel. 
          

          interface Serial0
 ip address 192.168.200.1 255.255.255.0
 encapsulation smds
 appletalk address 10.1
 appletalk zone SMDS
 smds address c151.0988.1923
 smds static-map ip 192.168.200.2 c151.0988.8770
 smds static-map appletalk 10.2 c151.0988.8770
 smds multicast APPLETALK e151.0988.2232
 smds multicast IP e151.0988.2232
 smds multicast ARP e151.0988.2232
 smds enable-arp
          

          

          

          

          Multiple Logical IP Subnetworks over SMDS Example
          

           In the following example, routers A, B, and C are connected to an SMDS cloud by means of two logical subnetworks labeled 1 and 2, as shown in the figure below. 
	 
          

           Router A recognizes two IP networks and can communicate with Routers B and C directly. Router B can communicate with router A directly, and with router C through router A. Router C can communicate with router A directly and with router B through router A. 
	 
          

           Notice that a packet destined to router B from router C must make two hops on the cloud through the same interface on router A. Notice also that this configuration is nonstandard. This issue was considered when the multiple logical IP subnetworks proposal was made, and was deemed not to be critical. 
	 
          

          Figure 2. Multiple Logical IP Subnetworks Configuration

          

           The following example shows all routers as Cisco 7200 routers, but they can be other platforms. 
	 
          

          Configuration for Router A 
           
		 
		
          interface serial 2/0 
 encapsulation smds
!
interface serial 2/0.1 multipoint
 smds addr c111.3333.3333
 ip address 2.2.2.1 255.0.0.0
 smds multicast ip e122.2222.2222
 smds enable-arp
 smds multicast ARP e122.2222.2222
          
 
	 
          

          Configuration for Router B
           
		 
		
          interface serial 4/0
 encapsulation smds
 smds address c111.2222.2222
 ip address 1.1.1.3 255.0.0.0
 smds multicast ip e180.0999.9999
 smds enable-arp
          
 
	 
          

          Configuration for Router C
           
		 
		
          interface serial 1/0
 encapsulation smds
 smds address c111.4444.4444
 ip address 2.2.2.2 255.0.0.0
 smds multicast ip e122.2222.2222
 smds enable-arp
          
 
	 
          

          

          

          Pseudobroadcasting Example
          

          
In the following example, an ARP broadcast from router A is sent to multicast address E180.0999.9999.FFFF to router B and to unicast address C120.1234.5678.FFFF to router C. The reply from router C uses the unicast address C120.1111.2222.FFFF for the return reply if it is the target of the ARP request. IGRP broadcast updates follow the same rules.
          

          Configuration for Router A
          
      
      
          interface s 0
 encapsulation smds
 smds address c120.1111.2222
 ip address 172.20.1.30 255.255.255.0
 smds multicast ip e180.0999.9999
 smds static-map ip 172.20.1.10 c120.1234.5678 broadcast
 smds enable-arp
          

    
          

          Configuration for Router B
          
      
      
          interface s 4
 smds address c120.9999.8888
 ip address 172.20.1.20
 smds multicast ip e180.0999.9999
 smds enable-arp
          

    
          

          Configuration for Router C
          
      
      
          interface serial 2
 smds address c120.1234.5678
 ip address 172.20.1.10
 smds static-map ip 172.20.1.30 c120.1111.2222 broadcast
 smds enable-arp 

          

    
          

          

          

          

          Feature Information for SMDS
          

           
		
          The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature. 
		
          
 
		
          Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to 
		  www.cisco.com/​go/​cfn. An account on Cisco.com is not required. 
		
          
 
	 
          

           
		

          Table 2 Feature Information for Phrase Based on Module Title 
           
				  
           Feature Name
				  
          
 
				          		
 
				  
           Releases
				  
          
 
				          		
 
				  
           Feature Information
				  
          
 
				          		

          
          

           
				  
           Switched Multimegabit Data Service (SMDS)
				  
          
 
				          		
 
				  
           11.2(1) 15.0(1)S
				  
          
 
				          		
 
				  
           The Switched Multimegabit Data Service (SMDS) is a WAN service offered by a variety of service providers. 
				  
          
 
				  
           The following sections provide information about this feature:
				  
          
 
				          		

          
          

          

          
 
	 
          

          

          

          


          















Configuring SMDS

                              

          


          Contents
          Configuring SMDS
          

           
	 
          

           The Switched Multimegabit Data Service (SMDS) is a WAN service offered by a variety of service providers. 
	 
          

          

          Finding Feature Information
          

           Your software release may not support all the features documented in this module. For the latest caveats and feature information, see 
		Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module. 
	 
          

          Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to 
		www.cisco.com/​go/​cfn. An account on Cisco.com is not required. 
	 
          

          

          

          Prerequisites for SMDS
          

          
You must have already obtained your SMDS addresses from your service provider. You need the following two types of addresses:
          

          • 
The group address for broadcasts

            • 

          • 
The SMDS hardware (individual) address for each router that interfaces directly into the SMDS network (that is, customer premises equipment)

            • 

          

          

          

          Information About SMDS
          

          

          SMDS Hardware Requirements
          

           You need the following hardware, equipment, and special software to configure SMDS: 
	 
          

          •  CSC-MCI or CSC-SCI serial interface controller card, or a HSSI interface on chassis-based systems, or the serial port on a router 
		

            • 

          

           To operate on CSC-SCI or CSC-MCI cards, SMDS requires that the appropriate microcode version be installed. Version numbers are 1.2 (or later) for CSC-SCI and 1.7 (or later) for CSC-MCI. 
	 
          

          •  EIA/TIA-449 or V.35 applique 
		

            • 

          •  SMDS data service unit (SDSU) device 
		

            • 

          

           The figure below illustrates the connections among the components. 
	 
          

          Figure 1. Typical SMDS Configuration

          

          

          

          SMDS Addresses
          

          
All addresses for SMDS service are assigned by the service provider and can be assigned to individuals and groups. 
          

          
You must enter addresses in the Cisco SMDS configuration software using an E prefix for multicast addresses and a C prefix for unicast addresses.
          

          
Cisco IOS software expects the addresses to be entered in E.164 format, which is 64 bits (15-digit addressing). The first 4 bits are the address type, and the remaining 60 bits are the address. If the first 4 bits are 1100 (0xC), the address is a unicast SMDS address, which is the address of an individual SMDS host. If the first 4 bits are 1110 (0xE), the address is a multicast SMDS address, which is used to broadcast a packet to multiple end points. The 60 bits of the address are in binary-coded decimal (BCD) format. Each 4 bits of the address field presents a single telephone number digit, allowing for up to 15 digits. At a minimum, you must specify at least 11 digits (44 bits). Unused bits at the end of this field are filled with ones.
          


          Note
          
The arp smdscommand supports 48-bit addresses only (C or E followed by 11 digits). The addresses must be entered in dotted notation--for example, C141.5556.1414.
          

          

          
An example of a 15-digit E.164 address follows:
          

          C14155561313FFFF
          


          Note
          
Older versions of Cisco IOS software supported 48-bit SMDS addresses. If, when using the current version of the software, you write the configuration to NVRAM, the full 64-bit SMDS address is written. Older versions of the software will no longer be able to read the new SMDS configuration from NVRAM. However, the current version of the software can read previous versions of the configuration in NVRAM.
          

          

          
The addresses can be entered with periods in a manner similar to Ethernet-style notation, or simply as a string of digits.
          

          
The following is an example of an individual address entered in Ethernet-style notation:
          

          C141.5555.1212.FFFF

          

          
The following is an example of a group address:
          

          E180.0999.9999.FFFF

          

          
An SMDS network can be thought of in much the same way as an X.25 cloud. The premises equipment (in this case Cisco routers) represents the edge of the cloud. The service provider enables communication across the cloud. However, proper configuration is needed for communication to occur. This configuration will differ from one protocol family to another.
          

          
One major difference between protocol families is dynamic versus static routing among the routers (called remote peers
) on the periphery of the cloud. For IP, routing across the SMDS cloud is fully dynamic. No action on the user’s part is needed to map higher-level protocol addresses to SMDS addresses. Both IP and ARP can be configured and a dynamic ARP routing table enabled. 
          


          Note
          
The arp smds command requires 12-digit dotted-notation SMDS addresses--for example, C141.5678.9012.
          

          

          

          

          Customizing the SMDS Network
          

          

          Configuring Specific Protocols
          

           Some protocol families are dynamically routed. For IP and CLNS, routing is fully dynamic, and no action on your part is needed to map higher-level protocol addresses to SMDS addresses. But for the other supported protocols, you must make a static entry for each router to communicate with all other peer routers. The static entries need to be made only for those routers that are SMDS remote peers. Nothing additional needs to be done to assure communication with other nodes behind the peer routers.
	 
          

           For an example of how to configure specific protocols, see the section "Typical Multiprotocol Configuration Example" later in this chapter.
	 
          

           The table below lists protocol families and the multicasts that are needed.
	 
          


          Table 1 Protocol Families and Types of Multicasts Needed
           
				
           Protocol Family
				
          
 
			           		
 
				
           Multicasts Needed
				
          
 
			           		

          
          

           
				
           IP
				
          
 
			           		
 
				
           IP
				
          
 
			           		

          

           
				
           DECnet
				
          
 
			           		
 
				
           DECNET, DECNET_NODE, DECNET_ROUTER-L1, DECNET_ROUTER-L2
				
          
 
			           		

          

           
				
           CLNS
				
          
 
			           		
 
				
           CLNS, CLNS_ES,CLNS_IS
				
          
 
			           		

          

           
				
           Novell IPX
				
          
 
			           		
 
				
           IPX
				
          
 
			           		

          

           
				
           XNS
				
          
 
			           		
 
				
           XNS
				
          
 
			           		

          

           
				
           AppleTalk
				
          
 
			           		
 
				
           APPLETALK, AARP
				
          
 
			           		

          

           
				
           Banyan VINES
				
          
 
			           		
 
				
           VINES
				
          
 
			           		

          
          

          

          

          

          Configuring ARP and IP
          

          
For both IP and ARP, the multicast address must be configured and ARP must be enabled. ARP multicast is required only for ARP servers; the IP multicast is used for ARP and routing updates.
          

          

          

          Configuring DECnet
          

          
Static maps must be configured for DECnet. In addition, a separate smds multicast command is needed for DECNET, DECNET_NODE, DECNET_ROUTER-L1, and DECNET_ROUTER-L2. 
          

          

          

          Configuring CLNS
          

          
Multicasts must be configured for CLNS_ES and CLNS_IS. No static maps are necessary. End system hello (ESH), intermediate system hello (ISH), and router hello packets are sent to the multicast address, and neighbor entries are created automatically.
          

          

          

          Configuring IPX
          

          
For Novell IPX, the multicast address must be configured. A static map entry can be made for each remote peer, or you can use the smds glean command to dynamically map addresses. Static map entries override any dynamic map entries.
          

          
Routing Information Protocol (RIP) routing packets, Service Advertisement Protocol (SAP) packets, NetBIOS Name Lookups, directed broadcasts, and traffic to the helper addresses (if that helper address is a broadcast address) are sent to the SMDS IPX multicast address.
          

          

          

          Configuring XNS
          

          
For XNS, the multicast address must be configured, and a static map entry must be made for each remote peer. Only RIP, directed broadcasts, and helper traffic are sent to the XNS multicast address.
          

          

          

          Configuring AppleTalk
          

          
The SMDS cloud must be treated by all AppleTalk routers connected to it as either extended or nonextended. The network types cannot be mixed on the same SMDS cloud. Instead, all AppleTalk routers on an SMDS cloud must agree about the network type: extended or nonextended.
          

          
If any router in the SMDS cloud uses Cisco IOS Release 10.3(3) (or earlier), use a nonextended AppleTalk configuration for the SMDS cloud. To use nonextended AppleTalk, use the appletalk address command and configure static maps.
          

          
If all routers in the SMDS cloud use Cisco IOS Release 10.3(4) (or later), you can use extended AppleTalk to support dynamic AARP for SMDS addresses. To use extended AppleTalk, use the appletalk cable-range command. 
          

          
For information on the appletalk addressand appletalk cable-range commands, refer to the Cisco IOS AppleTalk and Novell IPX Command Reference
.
          

          
For an example of how to configure AppleTalk, see the section "AppleTalk Configuration Examples" later in this chapter.
          

          

          

          Configuring Banyan VINES
          

          
For Banyan VINES, the multicast address must be configured. Also note that VINES works only with static maps.
          

          

          

          

          Transparent Bridging over SMDS
          

          
You can enable transparent bridging for SMDS encapsulated serial and HSSI interfaces. Cisco’s implementation of IEEE 802.6i transparent bridging for SMDS supports 802.3, 802.5, and FDDI frame formats. The router can accept frames with or without frame check sequence (FCS). 
          

          
Fast-switched transparent bridging is the default and is not configurable. If a packet cannot be fast switched, it will be process switched. 
          

          
For more information about bridge groups and the bridge-group command, see the "Configuring Transparent Bridging" chapter in the Cisco IOS Bridging and IBM Networking Configuration Guide
.
          

          

          

          SMDS Subinterfaces for Multiple Logical IP Subnetworks
          

          
Multiple logical IP subnetworks are supported as defined by RFC 1209. This RFC explains routing IP over an SMDS cloud where each connection is considered a host on one specific private network, and describes cases where traffic must transit from network to network.
          

          
This solution allows a single SMDS interface to be treated as multiple logical IP subnetworks and to support routing of packets from one network to the next without using intervening routers. When multiple logical IP subnetworks are enabled, the router performs routing between the subnetworks using IP addresses on an SMDS interface. Each supported subnetwork has an IP address, a unicast SMDS E.164 address, and a multicast SMDS E.164 address configured on the SMDS interface. Broadcast packets are duplicated and transmitted to all IP networks on the specified SMDS interface and use the associated multicast SMDS address for the network. 
          

          
Only routers that require knowledge of multiple IP networks need to be configured with multipoint subinterfaces that correspond to different networks.
          

          

          

          Reenabling Data Exchange Interface Version 3.2 with Heartbeat Support
          

          
By default, SMDS provides the Data Exchange Interface (DXI) Version 3.2 heartbeat
 process as specified in the SIG-TS-001/1991 standard. The DXI mechanism encapsulates SMDS packets in a DXI frame before they are transmitted. The heartbeat mechanism automatically generates a heartbeat poll frame every 10 seconds. The Interim Local Management Interface (ILMI) is not supported. See the Cisco IOS Wide-Area Networking Command Reference for more information about DXI 3.2.
          


          Note
          
If you are running serial lines back-to-back, disable keepalive on SMDS interfaces. Otherwise, DXI declares the link down.
          

          

          

          

          Pseudobroadcasting
          

          
Some hosts do not support multicast E.164 addresses. This is a problem in IP where frequent broadcast packets are sent because routing updates are generally broadcast. IP and ARP depend on the use of multicast addresses to determine a route to a destination IP address. A mechanism was needed to artificially support the use of broadcast where multicast E.164 addresses do not exist; the result is pseudobroadcasting
. If a multicast address is not available to a destination, pseudobroadcasting can be enabled to broadcast packets to those destinations using a unicast address. 
          

          

          

          Fast Switching
          

          
SMDS fast switching of IP, IPX, and AppleTalk packets provides faster packet transfer on serial links with speeds above 56 kbps. Use fast switching if you use high-speed, packet-switched, datagram-based WAN technologies such as Frame Relay offered by service providers.
          

          
By default, SMDS fast switching is enabled.
          

          

          

          

          

          SMDS Configuration Task List
          

          

          Enabling SMDS on the Interface
          

          

          Setting SMDS Encapsulation
          

          
To set SMDS encapsulation at the interface level, use the following command in interface configuration mode:
          


          
              
          
Command
          

                      		

              
          
Purpose
          

                      		

          
          

          
              
          Router(config-if)# encapsulation smds
          

            
          
          		

              
          
Enables SMDS on the interface.
          

                      		

          
          

          

          

          

          

          Specifying the SMDS Address
          

          
To specify the SMDS individual address for a particular interface, use the following command in interface configuration mode: 
          


          
              
          
Command
          

                      		

              
          
Purpose
          

                      		

          
          

          
              
          Router(config-if)# smds address smds-address
          

            
          
          		

              
          
Enters an individual address provided by the SMDS service provider.
          

                      		

          
          

          

          

          

          

          Establishing Address Mapping
          

          
Routing tables are configured dynamically when DECnet, extended AppleTalk, IP, IPX, and ISO CLNS routing are configured. However, you can configure static mapping for these protocols, if needed. For other protocols, you must configure a static map between an individual SMDS address and a higher-level protocol address. 
          

          
To establish address mapping, use the following command in interface configuration mode:
          


          
              
          
Command
          

                      		

              
          
Purpose
          

                      		

          
          

          
              
          Router(config-if)# smds static-map  protocol protocol-address smds-address [broadcast]
          

            
          
          		

              
          
Defines static entries for those routers that are SMDS remote peers.
          

              
          
The supported protocols and the keywords to enable them are as follows: 
          

              
          • 
AppleTalk--appletalk

            • 

          • 
Banyan VINES--vines

            • 

          • 
DECnet--decnet

            • 

          • 
IP--ip

            • 

          • 
ISO CLNS--clns

            • 

          • 
Novell IPX--ipx

            • 

          • 
XNS--xns

            • 

          

                      		

          
          

          

          

          

          

          Mapping a Multicast Address to an SMDS Address
          

          
You can map an SMDS group address to a broadcast or multicast address used by a higher-level protocol. If you do so, you need not specify the broadcast keyword in the smds static-map command, and the Cisco IOS software need not replicate each broadcast address. 
          

          
To map an SMDS group address to a multicast address, use the following command in interface configuration mode:
          


          
              
          
Command
          

                      		

              
          
Purpose
          

                      		

          
          

          
              
          Router(config-if)# smds multicast protocol smds-address
          

            
          
          		

              
          
Maps an SMDS group address to a multicast address used by a higher-level protocol. The protocols supported and the keywords to enable them are as follows: 
          

              
          • 
AppleTalk--appletalk

            • 

          • 
AppleTalk ARP address--aarp

            • 

          • 
Banyan VINES--vines

            • 

          • 
Bridging--bridge

            • 

          • 
DECnet--decnet

            • 

          • 
DECnet multicast address for all Level 1 routers--decnet_router-L1

            • 

          • 
DECnet multicast address for all Level 2 routers--decnet_router-L2

            • 

          • 
DECnet multicast address for all end systems--decnet_node

            • 

          • 
IP--ip

            • 

          • 
ISO CLNS--clns

            • 

          • 
Multicast address for all CLNS intermediate systems--clns_is

            • 

          • 
Multicast address for all CLNS end systems--clns_es

            • 

          • 
Novell IPX--ipx

            • 

          • 
XNS--xns

            • 

          

              
          Note   
                
              
          
Bridging is not a protocol, but the bridge keyword is valid for providing a map to a multicast address.
          

          

                      		

          
          

          

          

          

          

          Enabling ARP
          

          
When you enable the Address Resolution Protocol (ARP), you can choose to enable either a dynamic ARP cache or one built statically. To enable ARP, use one of the following commands in the specified configuration mode:
          


          
              
          
Command
          

                      		

              
          
Purpose
          

                      		

          
          

          
              
          Router(config-if)# smds enable-arp
          

            
          
          		

              
          
Enables ARP and dynamic address resolution (interface).
          

                      		

          

          
              
          Router(config)# arp  ip-address smds-address  smds
          

            
          
          		

              
          
Enables ARP with a static entry for the remote router (global).
          

                      		

          
          

          

          

          

          

          Enabling Broadcast ARP Messages
          

          
      
          
When an ARP server is present in the network, you can enable broadcast ARP messages that are sent to all ARP SMDS addresses or to all IP SMDS multicast addresses when ARP addresses are not present. 
          

      
          
To enable broadcast ARP messages, use the following commands in interface configuration mode:
          

    
          
SUMMARY STEPS
            1.   
      
Router(config-if)# smds enable-arp
            

            2.   
      
Router(config-if)# smds multicast arp smds-address[ip-address mask]
            


          DETAILED STEPS
             Command or ActionPurpose
            Step 1
Router(config-if)# smds enable-arp 
       
          
            
Enables ARP and dynamic address resolution.
            

         
      
            

            Step 2
Router(config-if)# smds multicast arp smds-address[ip-address mask] 
       
          
            
Enables broadcast ARP messages.
            

         
      
            

            

            

            

            Enabling Dynamic Address Mapping for IPX over SMDS
            

            
To enable dynamic address mapping for IPX on an SMDS interface, use the following command in interface configuration mode:
            


            
              
            
Command
            

                        		

              
            
Purpose
            

                        		

            
            

            
              
            Router(config-if)# smds glean ipx [timeout-value] [broadcast]
            

            
            
            		

              
            
Enables dynamic address mapping for IPX.
            

                        		

            
            

            

            

            

            

            

            Customizing Your SMDS Network
            

            

            Enabling Transparent Bridging over SMDS
            

            
      
            
To enable transparent bridging, use the following commands beginning in global configuration mode:
            

    
            
SUMMARY STEPS
              1.   
      
Router(config)# interface type number
              

              2.   
      
Router(config-if)# encapsulation smds
              

              3.   
      
Router(config-if)# bridge-group  bridge-group
              

              4.   
      
Router(config-if)# smds multicast bridge  smds-address
              


            DETAILED STEPS
               Command or ActionPurpose
              Step 1
Router(config)# interface type number 
       
          
              
Specifies a serial or HSSI interface.
              

         
      
              

              Step 2
Router(config-if)# encapsulation smds 
       
          
              
Configures SMDS encapsulation on the serial interface.
              

         
      
              

              Step 3
Router(config-if)# bridge-group  bridge-group 
       
          
              
Associates the interface with a bridge group.
              

         
      
              

              Step 4
Router(config-if)# smds multicast bridge  smds-address 
       
          
              
Configures bridging across SMDS.
              

         
      
              

              

              

              

              Configuring SMDS Subinterfaces for Multiple Logical IP Subnetworks
              

              
      
              
To configure the Cisco IOS software to have multipoint subinterfaces for multiple logical IP subnetworks, use the following commands beginning in global configuration mode:
              

    
              
SUMMARY STEPS
                1.   
      
Router(config)# interface serial interface . subinterface  multipoint
                

                2.   
      
Router(config-if)# ip address ip-address mask
                

                3.   
      
Router(config-if)# smds address  smds-address
                

                4.   
      
Router(config-if)# smds multicast protocol smds-address
                

                5.   
      
Router(config-if)# smds enable-arp
                


              DETAILED STEPS
                 Command or ActionPurpose
                Step 1
Router(config)# interface serial interface . subinterface  multipoint 

                Example:
                
          
                

        
                
 

                Example:
                
          
                Router(config)# interface serial slot / port . subinterface multipoint
                

        
                
 

                Example:
                
          
                (for Cisco 7000 series routers1)
                

        
                
 
                      		 
          
                
Defines a logical subinterface for each IP network.
                

          
                
          
                

         
      
                

                Step 2
Router(config-if)# ip address ip-address mask 
       
          
                
Configures the subinterface as an IP network.
                

         
      
                

                Step 3
Router(config-if)# smds address  smds-address 
       
          
                
Assigns unicast SMDS E.164 address to the subinterface.
                

         
      
                

                Step 4
Router(config-if)# smds multicast protocol smds-address 
       
          
                
Assigns multicast SMDS E.164 address for each protocol supported on the subinterface.
                

         
      
                

                Step 5
Router(config-if)# smds enable-arp 
       
          
                
Enables ARP on the subinterface, if required by the protocol.
                

         
      
                

                1  Beginning in Cisco IOS Release 11.3, all commands supported on the Cisco 7500 series are also supported on the Cisco 7000 series.
                

                

                

                Reenabling Data Exchange Interface Version 3.2 with Heartbeat Support
                

                
To reenable the DXI heartbeat, use the following command in interface configuration mode:
                


                
              
                
Command
                

                            		

              
                
Purpose
                

                            		

                
                

                
              
                Router(config-if)# smds dxi
                

            
                
                		

              
                
Enables DXI 3.2.
                

                            		

                
                

                

                

                

                

                Configuring Pseudobroadcasting
                

                
To configure pseudobroadcasting, use the following command in interface configuration mode:
                


                
              
                
Command
                

                            		

              
                
Purpose
                

                            		

                
                

                
              
                Router(config-if)# smds static-map  protocol protocol-address smds-address broadcast
                

            
                
                		

              
                
Configures pseudobroadcasting.
                

                            		

                
                

                

                

                
For an example of how to configure pseudobroadcasting, see the section "Pseudobroadcasting Example" later in this chapter.
                

                

                

                Enabling Fast Switching
                

                
      
                
To re-enable fast switching, use the following commands beginning in global configuration mode: 
                

    
                
SUMMARY STEPS
                  1.   
      
Router(config)# interface type number
                  

                  2.   
      
Router(config-if)# encapsulation smds
                  

                  3.   
      
Router(config-if)# ip route-cache
                  

                  4.   
      
Router(config-if)# ipx route-cache
                  

                  5.   
      
Router(config-if)# appletalk route-cache
                  


                DETAILED STEPS
                   Command or ActionPurpose
                  Step 1
Router(config)# interface type number 
       
          
                  
Defines and enters interface configuration mode.
                  

         
      
                  

                  Step 2
Router(config-if)# encapsulation smds 
       
          
                  
Sets SMDS encapsulation.
                  

         
      
                  

                  Step 3
Router(config-if)# ip route-cache 
       
          
                  
Enables the interface for IP fast switching.
                  

         
      
                  

                  Step 4
Router(config-if)# ipx route-cache 
       
          
                  
Enables the interface for IPX fast switching.
                  

         
      
                  

                  Step 5
Router(config-if)# appletalk route-cache 
       
          
                  
Enables the interface for AppleTalk fast switching.
                  

         
      
                  

                  

                  

                  

                  

                  Monitoring the SMDS Connection
                  

                  
To monitor the SMDS connection, use one or more of the following commands in EXEC mode:
                  


                  
              
                  
Command
                  

                              		

              
                  
Purpose
                  

                              		

                  
                  

                  
              
                  Router# show arp
                  

            
                  
                  		

              
                  
Monitors ARP activity.
                  

                              		

                  

                  
              
                  Router# show smds addresses
                  

            
                  
                  		

              
                  
Displays the individual addresses and the interface with which they are associated.
                  

                              		

                  

                  
              
                  Router# show smds map
                  

            
                  
                  		

              
                  
Displays all SMDS addresses that are mapped to higher-level protocol addresses.
                  

                              		

                  

                  
              
                  Router# show smds traffic
                  

            
                  
                  		

              
                  
Displays packet traffic activity.
                  

                              		

                  
                  

                  

                  

                  

                  

                  

                  SMDS Configuration Examples
                  

                  

                  Typical Multiprotocol Configuration Example
                  

                  
The following example is a typical interface configured for IP, DECnet, ISO CLNS, Novell IPX, XNS, and AppleTalk. DECnet needs to be configured globally and at the interface level.
                  

                  interface serial 4
 ip address 1.1.1.2 255.0.0.0
 decnet cost 4
 appletalk address 92.1
 appletalk zone smds
 clns router igrp FOO
 ipx net 1a
 xns net 17
 encapsulation SMDS
! SMDS configuration follows
 smds address c120.1580.4721
 smds static-map APPLETALK 92.2 c120.1580.4592
 smds static-map APPLETALK 92.3 c120.1580.4593
 smds static-map APPLETALK 92.4 c120.1580.4594
 smds static-map NOVELL 1a.0c00.0102.23ca c120.1580.4792
 smds static-map XNS 17.0c00.0102.23ca c120.1580.4792
 smds static-map NOVELL 1a.0c00.0102.23dd c120.1580.4728
 smds static-map XNS 17.0c00.0102.23aa c120.1580.4727
 smds multicast NOVELL e180.0999.9999
 smds multicast XNS e180.0999.9999
 smds multicast ARP e180.0999.9999
 smds multicast IP e180.0999.9999
 smds multicast APPLETALK e180.0999.9999
 smds multicast AARP e180.0999.9999
 smds multicast CLNS_IS e180.0999.9990
 smds multicast CLNS_ES e180.0999.9990
 smds multicast DECNET_ROUTER e180.0999.9992
 smds multicast DECNET_NODE e180.0999.9992
 smds multicast DECNET e180.0999.9992
 smds enable-arp
                  

                  

                  

                  Remote Peer on the Same Network Example
                  

                  
The following example illustrates a remote peer on the same SMDS network. DECnet needs to be configured globally and at the interface level.
                  

                  interface serial 0
 ip address 1.1.1.1 255.0.0.0
 decnet cost 4
 appletalk address 92.2
 appletalk zone smds
 clns router igrp FOO
 ipx net 1a
 xns net 17
 encapsulation SMDS
! SMDS configuration follows
 smds address c120.1580.4792
 smds static-map APPLETALK 92.1 c120.1580.4721
 smds static-map APPLETALK 92.3 c120.1580.4593
 smds static-map APPLETALK 92.4 c120.1580.4594
 smds static-map NOVELL 1a.0c00.0102.23cb c120.1580.4721
 smds static-map XNS 17.0c00.0102.23cb c120.1580.4721
 smds static-map NOVELL 1a.0c00.0102.23dd c120.1580.4728
 smds static-map XNS 17.0c00.0102.23aa c120.1580.4727
 smds multicast NOVELL e180.0999.9999
 smds multicast XNS e180.0999.9999
 smds multicast IP e180.0999.9999
 smds multicast APPLETALK e180.0999.9999
 smds multicast AARP e180.0999.9999
 smds multicast CLNS_IS e180.0999.9990
 smds multicast CLNS_ES e180.0999.9990
 smds multicast DECNET_ROUTER e180.0999.9992
 smds multicast DECNET_NODE e180.0999.9992
 smds multicast DECNET e180.0999.9992
 smds enable-arp
                  

                  

                  

                  IPX Dynamic Address Mapping Example
                  

                  
The following example enables dynamic address mapping for IPX on interface serial 0 and sets the time to live (TTL) to 14 minutes.
                  

                  interface serial 0
 encapsulation smds
 smds address c141.5797.1313
 smds multicast ipx e180.0999.9999
 smds glean ipx 14
                  

                  

                  

                  AppleTalk Configuration Examples
                  

                  
The following two sections provide basic examples of configuration for an extended AppleTalk network and for a nonextended AppleTalk network. For more information on AppleTalk commands, refer to the Cisco IOS AppleTalk and Novell IPX Command Reference.
                  

                  

                  Extended AppleTalk Network Example
                  

                  
If all AppleTalk routers on the SMDS cloud are running Cisco IOS Release 10.3(4) or later releases, you can use an AppleTalk extended network. To do so, use the appletalk cable-range interface command.
                  

                  
When SMDS is configured for an extended AppleTalk network, SMDS static maps are not required and not used. Dynamic AARP is supported on the multicast channel. 
                  

                  interface Serial0
 ip address 192.168.200.1 255.255.255.0
 encapsulation smds
 appletalk cable-range 10-10
 appletalk zone SMDS
 smds address c151.0988.1923
 smds static-map ip 192.168.200.2 c151.0988.8770
 smds multicast APPLETALK e151.0988.2232
 smds multicast AARP e151.0988.2232
 smds multicast IP e151.0988.2232
 smds multicast ARP e151.0988.2232
 smds enable-arp
                  

                  

                  

                  Nonextended Appletalk Network Example
                  

                  
The following example configures SMDS for a nonextended AppleTalk network. When SMDS is configured for a nonextended AppleTalk network, SMDS static maps are required and the appletalk address command is used. Dynamic AppleTalk Address Resolution Protocol (AARP) is not supported on the multicast channel. 
                  

                  interface Serial0
 ip address 192.168.200.1 255.255.255.0
 encapsulation smds
 appletalk address 10.1
 appletalk zone SMDS
 smds address c151.0988.1923
 smds static-map ip 192.168.200.2 c151.0988.8770
 smds static-map appletalk 10.2 c151.0988.8770
 smds multicast APPLETALK e151.0988.2232
 smds multicast IP e151.0988.2232
 smds multicast ARP e151.0988.2232
 smds enable-arp
                  

                  

                  

                  

                  Multiple Logical IP Subnetworks over SMDS Example
                  

                   In the following example, routers A, B, and C are connected to an SMDS cloud by means of two logical subnetworks labeled 1 and 2, as shown in the figure below. 
	 
                  

                   Router A recognizes two IP networks and can communicate with Routers B and C directly. Router B can communicate with router A directly, and with router C through router A. Router C can communicate with router A directly and with router B through router A. 
	 
                  

                   Notice that a packet destined to router B from router C must make two hops on the cloud through the same interface on router A. Notice also that this configuration is nonstandard. This issue was considered when the multiple logical IP subnetworks proposal was made, and was deemed not to be critical. 
	 
                  

                  Figure 2. Multiple Logical IP Subnetworks Configuration

                  

                   The following example shows all routers as Cisco 7200 routers, but they can be other platforms. 
	 
                  

                  Configuration for Router A 
                   
		 
		
                  interface serial 2/0 
 encapsulation smds
!
interface serial 2/0.1 multipoint
 smds addr c111.3333.3333
 ip address 2.2.2.1 255.0.0.0
 smds multicast ip e122.2222.2222
 smds enable-arp
 smds multicast ARP e122.2222.2222
                  
 
	 
                  

                  Configuration for Router B
                   
		 
		
                  interface serial 4/0
 encapsulation smds
 smds address c111.2222.2222
 ip address 1.1.1.3 255.0.0.0
 smds multicast ip e180.0999.9999
 smds enable-arp
                  
 
	 
                  

                  Configuration for Router C
                   
		 
		
                  interface serial 1/0
 encapsulation smds
 smds address c111.4444.4444
 ip address 2.2.2.2 255.0.0.0
 smds multicast ip e122.2222.2222
 smds enable-arp
                  
 
	 
                  

                  

                  

                  Pseudobroadcasting Example
                  

                  
In the following example, an ARP broadcast from router A is sent to multicast address E180.0999.9999.FFFF to router B and to unicast address C120.1234.5678.FFFF to router C. The reply from router C uses the unicast address C120.1111.2222.FFFF for the return reply if it is the target of the ARP request. IGRP broadcast updates follow the same rules.
                  

                  Configuration for Router A
                  
      
      
                  interface s 0
 encapsulation smds
 smds address c120.1111.2222
 ip address 172.20.1.30 255.255.255.0
 smds multicast ip e180.0999.9999
 smds static-map ip 172.20.1.10 c120.1234.5678 broadcast
 smds enable-arp
                  

    
                  

                  Configuration for Router B
                  
      
      
                  interface s 4
 smds address c120.9999.8888
 ip address 172.20.1.20
 smds multicast ip e180.0999.9999
 smds enable-arp
                  

    
                  

                  Configuration for Router C
                  
      
      
                  interface serial 2
 smds address c120.1234.5678
 ip address 172.20.1.10
 smds static-map ip 172.20.1.30 c120.1111.2222 broadcast
 smds enable-arp 

                  

    
                  

                  

                  

                  

                  Feature Information for SMDS
                  

                   
		
                  The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature. 
		
                  
 
		
                  Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to 
		  www.cisco.com/​go/​cfn. An account on Cisco.com is not required. 
		
                  
 
	 
                  

                   
		

                  Table 2 Feature Information for Phrase Based on Module Title 
                   
				  
                   Feature Name
				  
                  
 
				                  		
 
				  
                   Releases
				  
                  
 
				                  		
 
				  
                   Feature Information
				  
                  
 
				                  		

                  
                  

                   
				  
                   Switched Multimegabit Data Service (SMDS)
				  
                  
 
				                  		
 
				  
                   11.2(1) 15.0(1)S
				  
                  
 
				                  		
 
				  
                   The Switched Multimegabit Data Service (SMDS) is a WAN service offered by a variety of service providers. 
				  
                  
 
				  
                   The following sections provide information about this feature: