Setting up an npc access ring with two n-pes, Using, Using n-pe – Cisco OL-21636-01 User Manual
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Cisco IP Solution Center L2VPN and Carrier Ethernet User Guide, 6.0
OL-21636-01
Appendix D Terminating an Access Ring on Two N-PEs
Setting Up an NPC Access Ring with Two N-PEs
•
For the Cisco ASR 9000 platform, IOS XR version 3.7.3 and 3.9.0 are supported.
Note
Check the on-line version of
for the most
current information on device and platform support, in case updates have occurred since the
publication of this guide.
The implementation of this feature is covered in more detail in the following sections.
Setting Up an NPC Access Ring with Two N-PEs
Terminating an NPC access ring on two N-PEs is achieved by using the standard method of setting up
an NPC ring in ISC. The basic steps for doing this are described the
Additional information is provided in this guide in the section
Named Physical Circuits, page 2-8
.
In normal cases, a ring would be closed by connecting the devices via physical interfaces. When
terminating an access ring on two different N-PEs, there is no need for a physical connection between
the N-PEs. However, ISC requires that a virtual link must be created between the N-PEs, in order to close
the ring. The virtual link is set up through the use of loopback interfaces.
shows the creation
of an NPC ring with loopback interfaces.
Figure D-3
NPC Ring with Loopback Interfaces Between N-PEs
In order to use loopback interfaces in a ring in this manner, you must enable the DCPL property
allowLoopbackIntfInNPC, which is accessed in the Host Configuration window under the folder
/repository/mlshare. When this DCPL property is set to true, ISC allows the use of loopback interfaces
in a ring.
Note
Note that ISC does not generate any configlets onto the loopback interfaces during deployment of the
service request.
Using N-PE Redundancy in FlexUNI/EVC Service Requests
Using a dual-homed access ring in a FlexUNI/EVC service request does not require any change in the
usual workflow in the ISC GUI. During creation of the FlexUNI/EVC service request, you select the
NPC which is associated with an NPC access ring terminating on two N-PEs, as shown