Beta Draft Confidential
13-2
1/19/05
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
Configuring Layer 2 VPNs
About Layer 2 VPNs
About Layer 2 VPNs
The Layer 2 VPN feature allows you to create multiple private networks from a single
public network. After you create a Layer 2 VPN name and ID, you associate one or
more customer names and IDs with the VPN. When all VPNs and customers are
created in the database, you assign UNI/NNI logical ports to the specific
VPN/customer association. In addition, you need to dedicate selected public network
trunks to specific VPNs.
You must configure all PVCs that you create on the UNI/NNI logical ports for selected
Layer 2 VPN/customer associations. SVCs, however, inherit the VPN/customer
associations of the host logical port.
When you configure the logical port or PVC, you also set the Net Overflow attribute.
This attribute specifies whether PVCs or SVCs are restricted to trunks of their own
Layer 2 VPN or can use public (shared) trunks during outages. Customers that operate
in restrictive mode need to purchase redundant trunks.
provides a
restrictive mode example.
Figure 13-1.
Layer 2 VPN Restrictive Mode Example
Action
Action
Customer A
Customer B
Customer A
Customer B
Customer D
Customer D
Customer C
Customer C
Customer B
Customer A
Create VPN-D and associate Customer D.
Configure PVC for VPN-D and Private Net Overflow to Restrict.
Under ALL conditions, PVC will use only trunk(s) assigned to VPN-D.
During overflow or trunk failure, public trunks will not be used.
In this example, if VPN-D fails, the PVC will fail until the trunk comes back up.
VP
N-
D
Public
Summary of Contents for CBX 3500
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