# Tunnel-Service Interface Considerations

To configure a tunnel-server port, you assign the maximum number of tunnel-service interfaces to run on the specified tunnel-server port. This process is referred to as provisioning. Conversely, the process of reducing the maximum number of tunnel-service interfaces on a tunnel-server port to zero is referred to as unprovisioning the port.

This section describes the considerations for provisioning and unprovisioning tunnel-service interfaces on dedicated and shared tunnel-server ports.

For instructions on how to provision and unprovision tunnel-service interfaces, see Configuring Tunnel-Server Ports and Tunnel-Service Interfaces .

## Provisioning Tunnel-Service Interfaces

By default, dedicated tunnel-server ports are configured to have the maximum number of tunnel-service interfaces that the dedicated tunnel-server module supports. You can reduce the maximum number of interfaces or completely unprovision the port by issuing the max-interfaces command.

By default, shared tunnel-server ports are configured to have no tunnel-service interfaces. To provision tunnel-service interfaces on shared tunnel-server ports, you must provision the port by assigning a nonzero maximum number of tunnel-service interfaces to run on the port by issuing the max-interfaces command.

### Bandwidth Limitations of Shared Tunnel-Server Ports

Bandwidth limitations for shared tunnel-server ports and tunnel-service interfaces depend on bandwidth restrictions, if any, that are in effect for the module on which the shared tunnel-server port resides.

For the ES2 10G ADV LMs shared tunnel-server ports, you can reserve a percentage of the total bandwidth available for forwarding using the reserve-bandwidth command. The reserve-bandwidth command is not supported for other line modules that support tunnel-server configuration.

| Note: When you direct the router to reserve a percentage of the total bandwidth for forwarding, you may not always obtain the exact percentage of bandwidth specified. Because of the overhead involved with identifying and assigning incoming traffic to the appropriate resources, you may obtain a value less than the configured value. For instance, if you reserve 50 percent of the total bandwidth for forwarding, you will not obtain an actual bandwidth of 5 Gbps for forwarding and 5 Gbps for tunnel processing.

## Exchanging Tunnel-Server Modules

Tunnel-server modules are available in different hardware revisions that support varying numbers of tunnel-service interfaces. For more information about determining the hardware revision on a module, see ERX Module Guide, Table 1, Module Combinations, or E120 and E320 Module Guide, Table 1, Modules and IOAs.

When you exchange a tunnel-server module with a lower capacity for tunnel-service interfaces with a module that supports a higher capacity, the tunnel-server port maintains the original number of provisioned tunnel-service interfaces. By using the all-available keyword with the max-interfaces command, you can configure the tunnel-server port to automatically adjust the number of provisioned tunnel-service interfaces to the maximum value supported by the new module.

When you exchange a tunnel-server module that has a higher number of provisioned interfaces than the new module’s capacity, the module adjusts the provisioned number of interfaces to the maximum value that the module supports.

Table 25 displays sample capacity, configuration, and utilization values for exchanging tunnel-server modules with different capacities.

Table 25: Sample Capacity, Configuration, and Utilization Values for Tunnel-Service Interfaces

Old Capacity | Old Provisioned Interfaces (max-interfaces command) | Old Utilization | New Capacity | New Provisioned Interfaces (max-interfaces command) | New Utilization
--- | --- | --- | --- | --- | ---
8000 | 5000 | 5000 | 16,000 | 5000 | 5000
8000 | 8000 | 8000 | 16,000 | 8000 | 8000
8000 | all-available | 8000 | 16,000 | all-available | 16,000
16,000 | 5000 | 5000 | 8000 | 5000 | 5000
16,000 | 16,000 | 16,000 | 8000 | 8000 | 8000
16,000 | all-available | 16,000 | 8000 | all-available | 8000

## Unprovisioned Tunnel-Service Interfaces

Tunnel-server ports exist whether or not they have been configured. This means that you cannot delete a tunnel-server port from a module. However, you can unprovision all of the tunnel-service interfaces on a tunnel-server port by issuing the no max-interfaces command or the no tunnel-server command.

You can also restore the default configuration by issuing the default max-interfaces command. On dedicated tunnel-server ports, the default configuration is the maximum number of interfaces that the port supports. On shared tunnel-server ports, the default configuration is zero tunnel-service interfaces.

| Note: If the module on which the tunnel-server port resides supports IP reassembly or NAT services, these services become enabled when you provision tunnel-service interfaces on the port. However, when you unprovision tunnel-service interfaces to zero, only IP reassembly is disabled and NAT remains configured in the current release.