Specifications

Configuring IPX Multilayer Switching
IPX MLS Configuration Examples
8
Operation Before IPX MLS Example
Before IPX MLS is implemented, when the source host NC1 (on VLAN 10) sends traffic destined for
destination server NS2 (on VLAN 30), Switch B forwards the traffic (based on the Layer 2 forwarding
table) to Switch A over the ISL trunk link. Switch A forwards the packet to the router over the ISL trunk
link.
The router receives the packet on the VLAN 10 subinterface, checks the destination IPX address, and
routes the packet to the VLAN 30 subinterface. Switch A receives the routed packet and forwards it to
Switch C. Switch C receives the packet and forwards it to destination server NS2. This process is
repeated for each packet in the flow between source host NC1 and destination server NS2.
Operation After IPX MLS Example
After IPX MLS is implemented, when the source host NC1 (on VLAN 10) sends traffic destined for
destination server NS2 (on VLAN 30), Switch B forwards the traffic (based on the Layer 2 forwarding
table) to Switch A (the MLS-SE) over the ISL trunk link. When the first packet enters Switch A, a
candidate flow entry is established in the MLS cache. Switch A forwards the packet to the MLS-RP over
the ISL trunk link.
The MLS-RP receives the packet on the VLAN 10 subinterface, checks the destination IPX address, and
routes the packet to the VLAN 30 subinterface. Switch A receives the routed packet (the enabler packet)
and completes the flow entry in the MLS cache for the destination IPX address of NS2. Switch A
forwards the packet to Switch C, where it is forwarded to destination server NS2.
Subsequent packets destined for the IPX address of NS2 are multilayer switched by the MLS-SE based
on the flow entry in the MLS cache. For example, subsequent packets in the flow from source host NC1
are forwarded by Switch B to Switch A (the MLS-SE). The MLS-SE determines that the packets are part
of the established flow, rewrites the packet headers, and switches the packets directly to Switch C,
bypassing the router.
Switch A Configuration
This example shows how to configure Switch A (MLS-SE):
SwitchA> (enable) set vtp domain Corporate mode server
VTP domain Corporate modified
SwitchA> (enable) set vlan 10
Vlan 10 configuration successful
SwitchA> (enable) set vlan 20
Vlan 20 configuration successful
SwitchA> (enable) set vlan 30
Vlan 30 configuration successful
SwitchA> (enable) set port name 1/1 Router Link
Port 1/1 name set.
SwitchA> (enable) set trunk 1/1 on isl
Port(s) 1/1 trunk mode set to on.
Port(s) 1/1 trunk type set to isl.
SwitchA> (enable) set port name 1/2 SwitchB Link
Port 1/2 name set.
SwitchA> (enable) set trunk 1/2 desirable isl
Port(s) 1/2 trunk mode set to desirable.
Port(s) 1/2 trunk type set to isl.
SwitchA> (enable) set port name 1/3 SwitchC Link
Port 1/3 name set.
SwitchA> (enable) set trunk 1/3 desirable isl
Port(s) 1/3 trunk mode set to desirable.
Port(s) 1/3 trunk type set to isl.