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Chapter 9 The VPN Transport Screens
User’s Guide
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9.3 Customer Interface
Customer interfaces connect data coming from your computers to Ethernet
pseudowires, according to the data’s VLAN (Virtual Local Area Network)
information. One customer interface is for traffic that has no tag; this is the
default interface (rule 0) which cannot be deleted in the GUI. All other customer
interfaces are identified by their VLAN ID.
Once the WiMAX Modem has examined a frame’s VLAN tag, it is able to assign the
frame to a specified path. This is done using a customer interface. The customer
interface is simply a set of information that takes frames from a VLAN and put
them on an Ethernet pseudowire, and vice versa.
In this example, the WiMAX Modem takes frames tagged with two different VLAN
IDs (10 and 20) and using the customer interfaces, assigns them to specific
pseudowires (PW1 and PW2).
Figure 36 Pseudowire Mapping
The WiMAX Modem has a default customer interface configured for frames that
arrive at the WiMAX Modem without VLAN tags.
9.3.1 Multi-Protocol Label Switching
The WiMAX Modem uses MPLS VPNs to create virtual private LANs. MPLS stands
for Multi-Protocol Label Switching, and is a packet-switching technology that
allows packets with different VLAN tags to be transported on different paths
(known as LSPs, or Label Switched Paths). Each packet is identified by its VLAN
tag and sent to a specific LSP for transport over the WiMAX network.
Each LSP has a defined start-point and end-point. Since MPLS creates mono-
directional paths (traffic flows in only one direction), each Ethernet pseudowire
uses two LSPs so that traffic can flow both ways. One LSP carries upstream traffic,
and the other carries downstream traffic.
VLAN 10 PW1
VLAN 20 PW2
10
20
PW1
PW2
1
2
WiMAX
R