Specifications

Multilayer Switching Overview
Introduction to IPX MLS
14
IPX MLS Operation
Figure 68 shows a simple IPX MLS network topology:
• Host A is on the Sales VLAN (IPX address 01.Aa).
• Host B is on the Marketing VLAN (IPX address 03.Bb).
• Host C is on the Engineering VLAN (IPX address 02.Cc).
When Host A initiates a file transfer to Host B, an IPX MLS entry for this flow is created (see the first
item in Figure 68’s table). When the MLS-RP forwards the first packet from Host A through the switch
to Host B, the MLS-SE stores the MAC addresses of the MLS-RP and Host B in the IPX MLS entry. The
MLS-SE uses this information to rewrite subsequent packets from Host A to Host B.
Similarly, a separate IPX MLS entry is created in the MLS cache for the traffic from Host A to Host C,
and for the traffic from Host C to Host A. The destination VLAN is stored as part of each IPX MLS entry
so that the correct VLAN identifier is used for encapsulating traffic on trunk links.
Table 41 Layer 3-Switched Packet with Rewrite from the MLS-RP
Frame Header Encap IPX Header Payload
Destination Source Length Checksum/
IPX
Length/
Transport
Control
Packet
Type
Destination
Net/Node/
Socket
Source
Net/Node/
Socket
Data PAD/FCS
Host B MAC MLS-RP
MAC
Host B IPX Host A IPX