Configuring SMDS

This section shows how to set up ERX system B in the sample configuration in Figure 12-6. In the example, the GRE tunnel runs over an OC3 ATM interface.

Figure 12-6 Sample SMDS configuration

ATM Interface

To configure an ATM interface:

1. Specify an ATM interface, and set the clock source.

host1(config)#interface atm 10/0 

host1(config-if)#atm clock internal 

2. Configure a subinterface on the ATM interface.

host1(config)#interface atm 10/0.1 

3. Configure a PVC on the subinterface by specifying the virtual circuit descriptor (VCD), the virtual path identifier (VPI), the virtual channel identifier (VCI), and the encapsulation type.

host1(config-subif)#atm pvc 1 0 1 aal5snap

4. Assign an IP address to the subinterface.

host1(config-subif)#ip address 160.1.0.1

GRE Tunnel and CBF Interface

To configure a GRE tunnel and CBF interface:

1. Create and configure a GRE tunnel interface called newport1.

host1(config)#interface tunnel gre:newport1 

2. Assign a source address for the GRE tunnel. The tunnel source address must match an address configured on the system where the GRE tunnel originates.

host1(config-if)#tunnel source 160.1.0.1 

3. Assign a destination address for the GRE tunnel. The tunnel destination address must match an address configured on the system where the tunnel terminates.

host1(config-if)#tunnel destination 160.1.0.2

4. Add SMDS trunk encapsulation over the GRE tunnel interface.

host1(config-if)#encapsulation smds-trunk

5. Create a CBF interface over the GRE tunnel interface.

host1(config-if)#cbf

HSSI and CBF Interface

To configure a HSSI and a CBF interface:

1. Specify a HSSI.

host1(config)#interface hssi 1/0

2. Set the HSSI to CRC-32 mode.

host1(config-if)#crc 32

3. Specify the HSSI DCE clock rate of 34 MHz.

host1(config-if)#clock rate 34

4. Set the HSSI to DCE mode by setting clocking to internal.

host1(config-if)#hssi internal-clock 

Note: If the SMDS switch acts as the DTE, you must set up the ERX system to be the DCE.

5. Add SMDS trunk encapsulation over the HSSI.

host1config-if)#encapsulation smds-trunk

6. Create a CBF interface over the HSSI.

host1(config-if)#cbf

Note: For information on HSSI commands, see ERX Physical Layer Configuration Guide, Chapter 7, Configuring HSSIs.

CBF Connection

Create a CBF connection between the HSSI in slot 1, port 0 and the GRE tunnel, newport1. All SMDS traffic received on a HSSI must be mapped one-to-one with a specific GRE tunnel. The CBF connection provides that mapping.

host1(config)#cbf connection hssi 1/0 tunnel gre:newport1 

    atm clock internal

• Use to cause the ATM interface to generate the transmit clock internally.
• You can add one of the following keywords:

• module - internal clock is from the line module
• chassis - internal clock is from the configured system clock

• Example

host1(config-if)#atm clock internal 

• Use the no version to cause ATM interfaces to recover the clock from the received signal.

    atm pvc

• Use to configure a PVC on the ATM interface.
• You must include each of the following parameters:

• vcd - unique number that you assign to identify a virtual circuit. The range is 1-4294967293.
• vpi - 8-bit field in the ATM cell header. The VPI value must match the value of the VPI on the switch. You cannot set both the VPI and VCI to 0; if one is 0, the other cannot be 0.
• vci - 16-bit field in the ATM cell header. You cannot set both the VPI and VCI to 0; if one is 0, the other cannot be 0.
• encapsulation type:

• aal5snap - specifies a logical link control (LLC) encapsulated circuit. An LLC/Subnetwork Access Protocol (LLC/SNAP) precedes the protocol datagram.
• aal5mux ip - specifies a multiplexed circuit used for IP only.
• aal5autoconfig - enables the autodetection of a 1483 encapsulation (LLC/SNAP or VC multiplexed). See Chapter 13, Configuring Dynamic Interfaces for more explanation.

• Example

host1(config-subif)#atm pvc 1 0 1 aal5snap

• Use the no version to remove the specified PVC

    cbf

• Use to create a CBF interface over the SMDS interface that you are configuring.
• Example

host1(config-if)#cbf

• Use the no version to remove the CBF interface.

    cbf connection

• Use to create a bidirectional CBF connection between two CBF interfaces.
• Note that the bidirectional connection consists of a symmetrical pair of unidirectional connections, one from interface1 to interface2 and a second from interface2 to interface1.
• Example - the following example creates a CBF connection between the HSSI in slot 1, port 0 and the GRE tunnel newport1.

host1config)#cbf connection hssi 1/0 tunnel gre:newport1 

• Use the no version to remove an existing connection.

    cbf shutdown

• Use to administratively disable a CBF interface.
• Example

host1(config-if)#cbf shutdown

• Use the no version to enable a CBF interface. (Newly created CBF interfaces are enabled by default.)

    encapsulation smds-trunk

• Use to configure SMDS as the encapsulation method on an interface.
• Example

host1(config-if)#encapsulation smds-trunk

• Use the no version to disable SMDS encapsulation on an interface.

    interface atm

• Use to configure an ATM interface or subinterface type in the slot/port.subinterface format:

• slot - number of the slot in which the line module resides
• port - port number on the I/O module
• subinterface - number of the subinterface in the range 1-4294967293

• Example

host1(config)#interface atm 10/0 

• Use the no version to remove the subinterface or the logical interface.

    interface tunnel

• Use to create a GRE IP tunnel interface.
• Specify the type of tunnel as gre, and assign a name to the tunnel.
• Example

host1(config)#interface tunnel gre:boston-tunnel-1

• Use the no version to remove the tunnel.

    tunnel destination

• Use to configure the remote end of the tunnel.
• Specify either the IP address of an interface on the remote system or the hostname of the remote system.

• The IP address is the address for the destination interface.
• The hostname is the name of the destination interface.

• Example 1

host1(config)#interface tunnel gre:tunnel2

host1(config-if)#tunnel destination 192.13.7.1

• Example 2

host1(config)#interface tunnel gre:tunnel2

host1(config-if)#tunnel destination remoteHost

• Use the no version to remove the destination of a tunnel.

    tunnel source

• Use to configure the source of the tunnel.
• Specify either the primary IP address or the type and number of a new interface.
• Do not specify an unnumbered interface.
• Example 1

host1(config)#interface tunnel gre:boston-tunnel-1

host1(config-if)#tunnel source 192.10.2.1

• Example 2

host1(config)#interface tunnel gre:boston-tunnel-1

host1(config-if)#tunnel source atm 5/0.12

• Use the no version to remove the source of a tunnel.