Table of Contents

1 Service Loopback Group Configuration· 1-1

Overview· 1-1

Functions of Service Loopback Groups· 1-1

Port Configuration Prerequisites of Service Loopback Groups· 1-1

States of the Ports in a Service Loopback Group· 1-2

Configuring a Service Loopback Group· 1-2

Displaying and Maintaining Service Loopback Groups· 1-3

Configuration Example· 1-3

 

When configuring a service loopback group, go to these sections for information you are interested in:

l          Overview

l          Configuring a Service Loopback Group

l          Displaying and Maintaining Service Loopback Groups

l          Configuration Example

Overview

Functions of Service Loopback Groups

If a device that supports service board intermixing is present in a distributed system, service loopback enables you to redirect services between these boards. Thus, when a service board receives traffic not intended for it, the board can redirect the traffic to the intended destination. For example, when an IPv4 service board receives IPv6 traffic, the service loopback port can send the IPv6 traffic to the IPv6 service board of the device.

To increase service redirecting throughput, you can bundle multiple service loopback ports into a logical link, called a service loopback group. Similar to link aggregation, a service loopback group can increase bandwidth and implement load sharing.

Service loopback groups fall into five types:

l          IPv6, supporting IPv6 unicast traffic

l          IPv6mc, supporting IPv6 multicast traffic

l          Tunnel, supporting unicast tunnel traffic

l          Multicast tunnel, supporting multicast tunnel traffic

l          MPLS, supporting MPLS traffic

 

 

Port Configuration Prerequisites of Service Loopback Groups

Before assigning a port to a service loopback group, ensure that:

l          The port supports the services type or types of the service loopback group.

l          The port is configured with only physical configurations such as rate and duplex mode, QoS and ACL configurations.

l          The port is not configured with MSTP, uplink/downlink port of an isolation group, 802.1x, MAC address authentication, port security mode, or IP source guard. Additionally, the member port of a service loopback group cannot be configured with any of the above-mentioned configurations.

l          The port belongs to VLAN 1.

l          The port is not a member of any aggregation group or service loopback group.

States of the Ports in a Service Loopback Group

A member port in a service loopback group can be in one of the following two states:

l          Selected: a selected port can forward user traffic.

l          Unselected: an unselected port cannot forward user traffic.

The system sets the state of each port in a service loopback group to selected or unselected as follows:

l          Select the full-duplex port with the highest rate as the reference port. If two ports with the same duplex mode/speed pair are present, the one with the lower port number wins out.

l          Consider the ports the same as the reference port in rate, duplex mode, and hardware restrictions as candidate selected ports, and set the rest ports to unselected state.

l          The number of selected ports is limited in a service loopback group. If the number of candidate ports exceeds the limit, those with smaller port IDs are set to selected state and the others are set to unselected state.

 

 

Configuring a Service Loopback Group

Follow these steps to configure a service loopback group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a service loopback group	service-loopback group number type { multicast-tunnel | tunnel } *	Required
Enter Layer-2 Ethernet interface view	interface interface-type interface-number	Required Repeat the two steps to assign multiple Ethernet interfaces to the service loopback group.
Assign the Ethernet interface to the specified service loopback group	port service-loopback group number

 

 

Displaying and Maintaining Service Loopback Groups

To do…	Use the command…	Remarks
Display information about the specified service loopback group or all service loopback groups	display service-loopback group [ number ]	Available in any view

 

Configuration Example

Network requirements

Ports of Device A support the tunnel service. Assign Ethernet 2/0/1 through Ethernet 2/0/3 to a service loopback group to increase bandwidth and achieve load sharing.

Configuration procedure

# Create service loopback group 1 for the tunnel service.

<DeviceA> system-view

[DeviceA] service-loopback group 1 type tunnel

# Assign Ethernet 2/0/1 through Ethernet 2/0/3 to service loopback group 1.

[DeviceA] interface ethernet 2/0/1

[DeviceA-Ethernet2/0/1] undo stp

[DeviceA-Ethernet2/0/1] port service-loopback group 1

[DeviceA-Ethernet2/0/1] interface ethernet 2/0/2

[DeviceA-Ethernet2/0/2] undo stp

[DeviceA-Ethernet2/0/2] port service-loopback group 1

[DeviceA-Ethernet2/0/2] interface ethernet 2/0/3

[DeviceA-Ethernet2/0/3] undo stp

[DeviceA-Ethernet2/0/3] port service-loopback group 1

[DeviceA-Ethernet2/0/3] quit

# Create a logical interface Tunnel and reference service loopback group 1 on Tunnel 1.

[DeviceA] interface tunnel 3/0/1

[DeviceA-Tunnel3/0/1] service-loopback-group 1