Cisco Application Visibility and Control User Guide

Unsupported Logical Interfaces

Logical interfaces not supported by Cisco AVC in the current release:

• Dialer interfaces

Supported on Cisco IOS platforms. Support was added for Cisco IOS XE platforms beginning with Cisco IOS XE 3.16.3, 15.5(3)S3; not supported in prior releases.

• Multiprotocol Label Switching (MPLS)
• Overlay Transport Virtualization (OTV) overlay interfaces
• IPv6 tunnels that terminate on the device

Also see Pass-through Tunneled IPv6 Traffic: Classification and Reporting.

Partially Supported Logical Interfaces

Logical interfaces partially supported by Cisco AVC in the current release:

• Virtual template interface

Only ezPM monitors can be configured on the virtual template. Static performance monitors (non-ezPM monitors) cannot be configured on the virtual template.

• Example of supported configuration:

• Example of an unsupported configuration:

VPN Support

AVC support for VPN modes in the current release:

• FLEXVPN

Supports spoke-to-spoke and hub-to-spoke topologies.

FLEXVPN does not support IPv6.

Only ezPM monitors can be configured for FLEXVPN. Static performance monitors (non-ezPM monitors) cannot be configured for FLEXVPN.

• EzVPN

Only ezPM monitors can be configured for ezVPN. Static performance monitors (non-ezPM monitors) cannot be configured for EzVPN.

AVC Compatibility with Layer 2 Transparent Mode

Background

A router operating in layer 2 transparent mode (also called local switching) bridges two interfaces, transparently forwarding packets directly from one interface to the other. The device does not provide typical router functionality; it is sometimes referred to as operating as a “bump in the wire.”

For more information, see Layer 2 Local Switching.

AVC Support

AVC supports Layer 2 transparent mode scenarios, providing full AVC functionality.

Configuration

Bridging the Interfaces

To bridge the interfaces:

connect connection-name interface1 interface2

Example:

For detailed information, see the configuration guide for your device.

Configure AVC

In the following example, an AVC performance monitor is configured on a device operating in Layer 2 transparent mode. The monitor operates on the bridged traffic.

Use Cases

Case 1: Evaluating AVC Before Full Deployment

Layer 2 transparent mode (local switching) can be used to bypass a router by bridging two interfaces in the network, diverting traffic through a device operating with Cisco AVC. This enables isolation and testing of AVC functionality in the network to evaluate before wider deployment.

Case 2: Standalone AVC-Only Device

Layer 2 transparent mode (local switching) can be used to configure a router to act as a dedicated AVC device, used without routing. A router, such as the comparatively low-cost Cisco ASR1002-X, can serve as the platform for the standalone AVC-enabled device.

Limitations

When operating AVC on a device in Layer 2 transparent mode, the following limitations apply:

• The following MAC addresses are reported as 00:00:00:00:00:00:

– fields datalink mac source address output

– datalink mac destination address output

• The per-packet time-to-live (TTL) value may be reported as 1 higher than the actual value.