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Example: Dynamic IP Demux Subscriber Interfaces over Dynamic VLAN Demux Interfaces

This example describes how to configure dynamic IP demux interfaces over dynamic VLAN demux interfaces.

Requirements

Before you begin, make sure to configure either DHCP Relay or DHCP Local Server. For information about configuring either of these components, see Extended DHCP Relay Agent Overview or Understanding Differences Between Legacy DHCP and Extended DHCP.

Also, before you begin, see the conceptual information about VLAN demux interfaces in:

Overview

You can create a subscriber interface using an IP demux interface stacked on a static or dynamic VLAN demux interface. IP demux interfaces are used to uniquely identify subscribers in an access network based on their IP address.

Configuration

Preparing a Subscriber Access Interface

CLI Quick Configuration

To quickly configure the aggregated Ethernet interface over which subscribers access the router:

Step-by-Step Procedure

You must configure an interface over which clients initially access the router. We recommend that you specify the same VLAN tagging for the interface that you expect from incoming clients. This example uses flexible VLAN tagging to simultaneously support transmission of 802.1Q VLAN single-tag and dual-tag frames on logical interfaces on the same Ethernet port.

If you want it to automatically create dynamic VLANs, the interface must include the VLAN range type (single or stacked) and contain any specific ranges you want the VLANs to use.

To configure an interface for subscriber access:

  1. Configure the number of aggregated Ethernet interfaces on the router.

  2. Access the physical interface over which you want subscribers to initially access the router.

  3. Specify the aggregated Ethernet interface to which the physical interface belongs.

  4. Repeat Step 2 and Step 3 for each interface you want to assign to the aggregated Ethernet bundle.

  5. Access the aggregated Ethernet interface.

  6. Specify the VLAN tagging that you want the aggregated Ethernet interfaces to use.

  7. Edit the auto-configure stanza to automatically configure VLANs.

  8. Edit the vlan-ranges stanza for single-tagged VLANs.

  9. Specify the dynamic VLAN profile that you want the interface to use for dynamically creating single-tagged VLANs.

  10. Specify what VLAN Ethernet packet type the VLAN profile accepts.

  11. Specify the VLAN ranges that you want the dynamic profile to use. The following example specifies a lower VLAN ID limit of 500 and an upper VLAN ID limit of 1000.

  12. (Optional) Activate the transmission of LACP packets on the aggregated Ethernet interfaces.

  13. Specify that the aggregated Ethernet interfaces use link protection.

Preparing the Loopback Interface

CLI Quick Configuration

To quickly configure the required loopback interface for this example:

Step-by-Step Procedure

You must configure a loopback interface for use as the unnumbered address and preferred source address for dynamically created interfaces.

To configure the required loopback interface for this example:

  1. Configure a loopback interface.

  2. Specify that the loopback interface accept inet packets.

  3. Specify the IP address for the loopback interface.

Configuring a Dynamic Profile to Dynamically Create Single-Tagged VLANs

CLI Quick Configuration

To quickly configure the dynamic profile used to dynamically create single-tagged VLANs in the example:

Step-by-Step Procedure

For dynamic IP demux interfaces to reside on a dynamic VLAN demux interface, the VLAN interface must first exist.

A dynamic profile that configures a VLAN demux interface must specify variables for unit, underlying interface name, and VLAN ID. A dynamic VLAN demux interface associates specific subscribers to separate individual circuits by VLAN ID.

To configure a dynamic profile and attach it to a dynamic VLAN demux interface so that it automatically creates VLAN interfaces:

  1. Create a dynamic profile for automatically creating single-tagged VLAN interfaces.

  2. Specify that the dynamic VLAN profile use the demux interface.

  3. Specify that the dynamic profile apply the demux interface unit value to the dynamic VLANs.

  4. (Optional) Specify that the demux source accepts only IPv4 (inet) packets.

  5. (Optional) Specify that each dynamically created interface respond to any ARP request, as long as an active route exists to the target address of the ARP request.

  6. Specify that VLAN IDs are dynamically created.

  7. Specify the logical underlying interface for the dynamic VLANs.

  8. Specify that the VLAN demux interface can accept inet family packets for IPoE/DHCP subscribers.

  9. Specify the loopback address as the unnumbered address and preferred source address for the inet family.

Configuring a Dynamic Profile to Dynamically Create IP Demux Interfaces

CLI Quick Configuration

To quickly configure the dynamic profile used to dynamically create IP demux interfaces in the example:

Step-by-Step Procedure

A dynamic profile that configures an IP demux interface must specify variables for unit, underlying interface name, and IP address. A dynamic IP demux interface associates specific subscribers to separate individual circuits by IP address.

To configure a dynamic profile and attach it to an interface so that it automatically creates IP demux interfaces:

  1. Create a dynamic profile for dynamically creating IP demux interfaces.

  2. Specify that the dynamic profile use the demux0 interface.

  3. Specify that the dynamic profile apply the interface unit value to the dynamic IP demux interfaces.

  4. (Optional) Configure the router to respond to any ARP request, as long as the router has an active route to the target address of the ARP request.

  5. Specify the logical underlying interface for the dynamic IP demux interfaces.

  6. Specify the protocol family information for the dynamic IP demux interfaces.

  7. Specify the demux source address is obtained from the incoming subscriber IP address.

  8. Specify the loopback interface as the unnumbered address and the demux interface IP address as the preferred source address for the dynamic IP demux interfaces.

Verification

Subscriber Verification

Purpose

View subscriber information on the router.

Action

  • To display dynamic subscriber information:

Interface Verification

Purpose

View interface-specific information on the router.

Action

  • To display interface-specific output: