F3215-HP Load Balancing Module Network Management Configuration Guide-6PW101

Configuring Layer 3 forwarding

This chapter takes LB module as an example to describe Layer 3 forwarding on LB modules.

For the configurations on the switches involved in the configuration examples, see the configuration on

the switch in the Layer 3 subinterface forwarding configuration example.

Layer 3 forwarding can be configured only at the CLI.

Overview

Layer 3 forwarding involves Layer 3 subinterface forwarding and inter-VLAN Layer 3 forwarding.

Layer 3 subinterface forwarding

If the VLAN tag of an incoming packet matches the PVID of a subinterface of the receiving interface on

the LB module, the LB module removes the Layer 2 header and sends the packet to the subinterface.

Layer 3 subinterface forwarding operates as follows:

1. After receiving a packet, the switch adds the VLAN tag of the receiving interface to the packet and

if the packet is not destined to the VLAN the switch tagged, sends the packet to the LB module

through the trunk port in between.

2. If the VLAN tag of the packet matches the PVID of a subinterface, the LB module removes the Layer

2 header and sends the packet to the Layer 3 forwarding engine.

3. The Layer 3 forwarding engine looks up a route entry for the packet and sends it out of the

outgoing Layer 3 subinterface.

Inter-VLAN Layer 3 forwarding

If the destination MAC address of an incoming packet matches the MAC address of a VLAN interface,

the LB module removes the Layer 2 header and delivers the packet to the Layer 3 forwarding engine.

Inter-VLAN Layer 3 forwarding operates as follows:

1. After receiving a packet, the switch adds the VLAN tag of the receiving interface to the packet and

if the packet is destined to another VLAN, sends the packet to the LB module through the trunk port

in between.

2. If the destination MAC address of the packet matches the MAC address of a VLAN interface, the

LB module removes the Layer 2 header and delivers the packet to the Layer 3 forwarding engine.

3. The Layer 3 forwarding engine looks up a route entry for the packet and sends it out of the

outgoing VLAN interface.

Configuring Layer 3 subinterface forwarding

NOTE:

For more information about Layer 3 subinterface forwarding configuration commands, see

Network

Management Command Reference