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Use the commands in this chapter to configure the Switched Multimegabit Data Service (SMDS), a wide-area networking service offered by some Regional Bell Operating Companies (RBOCs) and MCI.
For SMDS configuration information and examples, refer to the "Configuring SMDS" chapter in the Router Products Configuration Guide.
To enable ARP entries for static routing over the SMDS network, use the following variation of the arp global configuration command. Use the no form of this command to disable this capability.
arp ip-address smds-address smds| ip-address | IP address of the remote router. |
| smds-address | 48-bit E.164 SMDS address in the dotted notation Cnnn.nnnn.nnnn or Ennn.nnnn.nnnn. |
| smds | Enables ARP for SMDS. |
Disabled
Global configuration
This command requires a 48-bit dotted-format SMDS address (C or E followed by 11 digits). It does not support 15-digit SMDS addresses.
The following example creates a static ARP entry that maps the IP address 131.108.173.28 to the SMDS address C141.5797.1313 on interface serial 0:
interface serial 0
arp 131.108.173.28 C141.5797.1313 smds
smds enable-arp
smds static-map
Use the encapsulation smds interface configuration command to enable SMDS service on the desired interface.
encapsulation smdsThis command has no arguments or keywords.
Disabled
Interface configuration
The interface to which this command applies must be a serial interface. All subsequent SMDS configuration commands only apply to an interface with encapsulation SMDS.
The following example shows how to configure the SMDS service on serial interface 0:
interface serial 0
encapsulation smds
A dagger (+) indicates that the command is documented in another chapter.
mtu+
Use the show arp privileged EXEC command to display the entries in the ARP table for the router.
show arpThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show arp command:
Router# show arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 131.108.42.112 120 0000.a710.4baf ARPA Ethernet3
AppleTalk 4028.5 29 0000.0c01.0e56 SNAP Ethernet2
Internet 131.108.42.114 105 0000.a710.859b ARPA Ethernet3
AppleTalk 4028.9 - 0000.0c02.a03c SNAP Ethernet2
Internet 131.108.42.121 42 0000.a710.68cd ARPA Ethernet3
Internet 131.108.36.9 - 0000.3080.6fd4 SNAP TokenRing0
AppleTalk 4036.9 - 0000.3080.6fd4 SNAP TokenRing0
Internet 131.108.33.9 - c222.2222.2222 SMDS Serial0
Table 10-1 describes significant fields shown in the first line of output in the display.
Use the show smds addresses privileged EXEC command to display the individual addresses and the interface that they are associated with.
show smds addressesThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show smds addresses command:
Router# show smds addresses
SMDS address - Serial0 c141.5555.1212.FFFF
Table 10-2 describes the fields shown in the display.
| Field | Description |
|---|---|
| Serial0 | Interface to which this SMDS address has been assigned. |
| c141.5555.1212 | SMDS address that has been assigned to the interface. |
Use the show smds map privileged EXEC command to display all SMDS addresses that are mapped to higher-level protocol addresses.
show smds mapThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show smds map command:
Router# show smds map
Serial0: ARP maps to e180.0999.9999.FFFF multicast
Serial0: IP maps to e180.0999.9999.FFFF 150.108.42.112 255.255.255.0 multicast
Serial0: XNS 1006.AA00.0400.0C55 maps to c141.5688.1212.FFFF static [broadcast]
Table 10-3 describes the fields shown in the output.
| Field | Description |
|---|---|
| Serial0 | Name of interface on which SMDS has been enabled. |
| ARP maps to | Higher-level protocol address that maps to this particular SMDS address. |
| e180.0999.9999.FFFF | SMDS address. Includes all SMDS addresses entered with either the smds static-map command (static) and smds multicast command (multicast). |
| 150.108.21.112 | IP address. |
| 255.255.255.0 | Subnet mask for the IP address. |
Use the show smds traffic privileged EXEC command to display statistics on bad SMDS packets the router has received.
show smds trafficThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show smds traffic command:
Router# show smds traffic
624363 Input packets
759695 Output packets
2 DXI heartbeat sent
0 DXI heartbeat received
0 DXI DSU polls received
0 DXI DSU polls sent
0 DXI invalid test frames
0 Bad BA size errors
0 Bad Header extension errors
65 Invalid address errors
1 Bad tag errors
Table 10-4 describes the fields shown in the output.
| Field | Description |
|---|---|
| 0 Input packets | Number of input packets. |
| 0 Output packets | Number of output packets. |
| 0 DXI heartbeat sent | Number of DXI heartbeat polls transmitted. |
| 0 DXI heartbeat received | Number of DXI heartbeat polls received. |
| 0 DXI DSU polls sent | Number of DXI DSU polls sent. |
| 0 DXI DSU polls received | Number of DXI DSU polls received. |
| 0 DXI invalid test frames | Number of invalid test frames seen. |
| 0 Bad BA size errors | Number of packets that have a size less than 32 bytes or greater than 9188 bytes. |
| 0 DXI Header extension errors | Number of extended SIP L3 header errors. |
| 0 DXI Invalid address errors | Number of address errors |
| 0 Bad tag errors | Status indicating the number of errors that occur when there is a mismatch between the BeTag values in the header and trailer of a SMDS frame. This usually indicates that there is a misconfiguration (that is, a DXI is connected to a non-DXI) or that the SDSU is scrambling the L2 PDUs. |
Use the smds address interface configuration command to specify the SMDS individual address for a particular interface. Use the no smds address command to remove the address from the configuration file.
smds address smds-address| smds-address | Individual address provided by the SMDS service provider. This address is protocol independent. For more information, see the "Usage Guidelines" section. |
No address is specified.
Interface configuration
All addresses for SMDS service are assigned by the service provider, and can be assigned to individuals and groups.
Addresses are entered in the Cisco SMDS configuration software using an E prefix for Multicast addresses and a C prefix for Unicast addresses. Our software expects the addresses to be entered in E.164 format, which is 64 bits. 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 when broadcasting 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.
The following example specifies an individual address in Ethernet-style notation:
interface serial 0
smds address c141.5797.1313.FFFF
Use the smds dxi interface configuration command to enable the DXI 3.2 support. Use the no smds dxi command to disable the DXI 3.2 support.
smds dxiThis command has no arguments or keywords.
Enabled
Interface configuration
Adding this command to the configuration enables the Data Exchange Interface (DXI) version 3.2 mechanism and encapsulates SMDS packets in a DXI frame before they are transmitted. DXI 3.2 adds an additional four bytes to the SMDS packet header to communicate with the SDSU. These bytes specify the frame type. The interface will expect all packets to arrive with DXI encapsulation.
The DXI 3.2 support also includes the heartbeat process as specified in the SIG-TS-001/1991 standard, revision 3.2. The heartbeat (active process) is enabled when both DXI and keepalives are enabled on the interface. The echo (passive process) is enabled when DXI is enabled on the interface. The heartbeat mechanism automatically generates a heartbeat poll frame every 10 seconds. This default value can be changed with the keepalive command. The Interim Local Management Interface (ILMI) is not supported.
Fast switching of DXI frames is also supported as of this software release.
The following example enables DXI 3.2 on interface HSSI 0:
interface hssi 0
encapsulation smds
smds dxi-mode
smds address C120.1111.2222.FFFF
ip address 131.108.1.30 255.255.255.0
smds multicast ip E180.0999.9999
smds enable-arp
A dagger (+) indicates that the command is documented in another chapter.
keepalive +
Use the smds enable-arp interface configuration command to enable the Address Resolution Protocol (ARP). The multicast address for ARP must be set before this command is issued. Once ARP has been enabled, use the no smds enable-arp command to disable the interface.
smds enable-arpThis command has no arguments or keywords.
Disabled
Interface configuration
The following example enables the dynamic ARP routing table:
interface serial 0
ip address 131.108.1.30 255.255.255.0
smds multicast IP E180.0999.9999.2222
smds enable-arp
arp
Use the smds multicast arp interface configuration command to map the SMDS address to a multicast address. Use the no smds multicast arp command to disable this feature.
smds multicast arp smds-address [ip-address mask]| smds-address | SMDS address in E.164 format |
| ip-address | (Optional) IP address |
| mask | (Optional) Subnet mask for the IP address |
None
Interface configuration
This command is only used when an ARP server is present on a network. When broadcast ARPs are sent, SMDS first attempts to send the packet to all multicast ARP SMDS addresses. If none exist in the configuration, they are sent to all multicast IP SMDS multicast addresses. If the optional ARP multicast address is missing, each entered IP multicast command will be used for broadcasting.
The following example configures broadcast ARP messages:
interface serial 0
smds multicast arp E180.0999.9999.2222
smds multicast ip
Use the smds multicast bridge interface configuration command to enable Spanning Tree updates. Use the no smds multicast bridge command to disable this function.
smds multicast bridge smds-address| smds-address | SMDS multicast address in E.164 format |
None
Interface configuration
Transparent bridging of packets across an SMDS network must already be enabled to allow this update function. Enable transparent bridging across an SMDS network by adding an SMDS interface to an active bridge group.
When the smds multicast bridge command is added to the configuration, broadcast packets will be encapsulated using the specified SMDS multicast address configured for bridging. All bridge packets are first encapsulated in an 802.3 MAC header before encapsulating in an SMDS L3 header with LLC/SNAP. The 802.3 header will specify the particular packet enclosed in the bridge datagram in the EtherType field of the header.
Broadcast ARP packets are treated differently. Two packets are sent to the multicast address. One is sent using a standard (SMDS) ARP encapsulation, the other is sent with the ARP packet encapsulated in an 802.3 MAC header. The native ARP is sent as a regular ARP broadcast. Standard bridging commands are necessary to enable bridging on an SMDS interface.
Bridging over multiple logical IP subnets (MultiLIS) is not supported in IOS Release 10.0. Bridging of IP packets in a MultiLIS environment is unpredictable.
This implementation of 802.6 bridging only supports the transmission and reception of 802.3 encapsulated bridge packets. Other encapsulations will be supported in a future release.
In the following example, all broadcast bridge packets will be sent to the configured SMDS multicast address:
interface hssi 0
encapsulation smds
smds address C120.1111.2222.FFFF
ip address 131.108.1.30 255.255.255.0
smds multi bridge E180.0999.9999.FFFF
Use the smds multicast ip interface configuration command to map an SMDS group address to a secondary IP address. Use the no smds multicast ip command to remove the address map.
smds multicast ip smds-address [ip-address mask]| smds-address | SMDS address in E.164 format |
| ip-address | (Optional) IP address |
| mask | (Optional) Subnet mask for the IP address |
The IP address and mask will default to the primary address of the interface if they are left out of the configuration.
Interface configuration
This command allows a single SMDS interface to be treated as multiple logical IP subnets (MultiLIS). If taking advantage of the MultiLIS support in SMDS, you can use more than one multicast address on the SMDS interface, that is, multiple commands can be entered. However, each smds multicast ip command entry must be associated with a different IP address on the SMDS interface.
Broadcasts can be sent on the SMDS interface using the multicast address. By sending broadcasts in this manner, the router is not required to replicate broadcasts messages to every remote host.
In addition, the higher-level protocols such as OSPF and IS-IS can use the multicast capability by sending one update packet or routing packet to the multicast address.
If the optional IP address and mask arguments are not present, the SMDS address and multicast address are associated with the primary IP address of the interface. This allows the command to be backward compatible with earlier versions of the software.
If an ARP multicast address is missing, each entered IP multicast command will be used for broadcasting. The ARP multicast command has the same format as the IP multicast command and is typically used only when an ARP server is present in the network.
The following example configures an interface that supports two different subnets with different multicast addresses to each network. The first multicast configuration command associates the multicast address with the primary IP address and mask of the interface.
interface hssi 0
encapsulation smds
smds address C120.1111.2222.FFFF
ip address 131.108.1.30 255.255.255.0
ip address 131.108.5.30 255.255.255.0 secondary
smds multicast ip E180.0999.9999.FFFF
smds multicast ip E180.0333.3333.FFFF 131.108.5.0 255.255.255.0
smds enable-arp
smds multicast arp
Use the smds multicast interface configuration command to map an SMDS group address to a broadcast or multicast address used by higher-level protocols. Use the no smds multicast command with the appropriate address to remove a multicast address.
smds multicast protocol-type smds-address| protocol-type | Protocol type. See Table 10-5 in the "Usage Guidelines" section for a list of supported protocols and their keywords. |
| smds-address | SMDS address. Because SMDS does not incorporate broadcast addressing, a group address for a particular protocol must be defined to serve the broadcast function. |
No mapping is defined.
Interface configuration
When configuring DECnet, all three DEC keywords (decnet, decnet_router, and decnet_node) must be entered in the configuration.
Table 10-5 lists the high-level protocols supported by the smds multicast command.
The following example maps the IP broadcast address to the SMDS group address E180.0999.9999:
interface serial 0
smds multicast IP E180.0999.9999.FFFF
Use the smds static-map interface configuration command to configure a static map between an individual SMDS address and a higher-level protocol address. Use the no smds static-map command with the appropriate arguments to remove the map.
smds static-map protocol-type protocol-address smds-address [broadcast]No mapping is defined.
Interface configuration
The smds static-map command provides pseudo-broadcasting by allowing the use of broadcasts on those hosts that cannot support SMDS multicast addresses.
The following example illustrates how to enable pseudo-broadcasting. In addition to broadcasting IP and ARP requests to E180.0999.9999, the device at address C120.4444.9999 will also receive a copy of the broadcast request. The host at address 131.108.1.15 is incapable of receiving multicast packets. The multicasting is simulated with this feature.
interface hssi 0
encapsulation smds
smds address C120.1111.2222.FFFF
ip address 131.108.1.30 255.255.255.0
smds static-map ip 131.108.1.15 C120.4444.9999.FFFF broadcast
smds enable-arp
The following example illustrates how to enable multicasting. In addition to IP and ARP requests to E180.0999.9999, the device at address C120.4444.9999 will also receive a copy of the multicast request. The host at address 131.108.1.15 is incapable of receiving broadcast packets.
interface hssi 0
encapsulation smds
smds address C120.1111.2222.FFFF
ip address 131.108.1.30 255.255.255.0
smds multicast ip E100.0999.999.FFFF
smds static-map ip 131.108.1.15 C120.4444.9999.FFFF
smds enable-arp
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