Use PPPoE Virtual-Template on L2 VPLS Pseudowire

[Michael Schumann]

Hello community,

We would like to use PPPoE services via L2 VPLS pseudowire.

A Catalyst C8500-12X4QC is connected to other IOS XR routers via L2 pseudowire. The connection is created via MPLS LDP on the loopback interface.

How can I bind a virtual template to the L2 pseudowire?
The users should later start a session via PPPoE.

Catalyst PPPoE Server (BRAS): C8500-12X4QC (Version 17.09.04a) with Loopback 10.0.25.7
Acces-Router 1 (PE-Router): NCS 540 (Version 7.8.1 LNT) with Loopback 10.0.25.11
Acces-Router 2 (PE-Router): NCS 540 (Version 7.8.1 LNT) with Loopback 10.0.25.12

AUE-SHM-BRAS#sh l2vpn atom vc
Interface Peer ID         VC ID      Type   Name                     Status
--------- --------------- ---------- ------ ------------------------ ----------
pw100005  10.0.25.11      61         vfi    vfi61                    UP
pw100004  10.0.25.12      61         vfi    vfi61                    UP

AUE-SHM-BRAS#sh mpls l2transport vc
Local intf     Local circuit              Dest address    VC ID      Status
-------------  -------------------------- --------------- ---------- ----------
VFI vfi61      vfi                        10.0.25.11      61         UP
VFI vfi61      vfi                        10.0.25.12      61         UP

AUE-SHM-BRAS#sh bridge-domain
Bridge-domain 61 (2 ports in all)
State: UP                    Mac learning: Enabled
Aging-Timer: 300 second(s)
Unknown Unicast Flooding Suppression: Disabled
Maximum address limit: 65536
    vfi vfi61 neighbor 10.0.25.12 61
    vfi vfi61 neighbor 10.0.25.11 61
   AED MAC address    Policy  Tag       Age  Pseudoport
   0   E028.6DDC.9128 forward dynamic   286  vfi61.420015

AUE-SHM-BRAS#sh run int virtual-template 61
interface Virtual-Template61
 mtu 1492
 ip unnumbered Loopback0
 peer default ip address pool IP-Test-Pool
 ppp ipcp dns 8.8.8.8 1.1.1.1
 ppp ipcp address required
 ppp ipcp address unique
end

Does anyone have an idea how I can proceed?

Thanks Michael

[AshSe]

Hello @Michael Schumann 

To bind a Virtual-Template to an L2 pseudowire for PPPoE services on the Catalyst C8500-12X4QC, you need to configure the pseudowire to terminate in a way that allows PPPoE sessions to be initiated and processed. This involves using a BBA Group (Broadband Access Group) to associate the Virtual-Template with the incoming PPPoE sessions. Below is a step-by-step guide to achieve this:

---

1. Verify the Current Setup

From your output, the L2 pseudowire is already established and operational between the Catalyst C8500 and the NCS 540 routers. The bridge domain (vfi61) is up, and the Virtual-Template61 is configured. This is a good starting point.

---

2. Configure a BBA Group

The BBA Group is used to handle PPPoE sessions and bind them to the Virtual-Template. You need to configure a BBA Group and associate it with the Virtual-Template61.

bba-group pppoe BBA-PPPOE

    virtual-template 61

    sessions per-mac limit 1

• bba-group pppoe BBA-PPPOE: Creates a PPPoE BBA Group named BBA-PPPOE.
• virtual-template 61: Associates the Virtual-Template61 with the BBA Group.
• sessions per-mac limit 1: Limits the number of PPPoE sessions per MAC address to 1 (optional, but recommended).

---

3. Bind the BBA Group to the Bridge Domain

To allow PPPoE sessions to be processed on the L2 pseudowire, you need to bind the BBA Group to the bridge domain (vfi61). This is done by enabling PPPoE on the bridge domain interface.

interface BDI61

    bba-group pppoe BBA-PPPOE

    mtu 1492

    ip unnumbered Loopback0

    no shutdown

• interface BDI61: Creates a Bridge Domain Interface (BDI) for the bridge domain vfi61.
• bba-group pppoe BBA-PPPOE: Associates the BBA Group with the BDI.
• mtu 1492: Sets the MTU for PPPoE traffic.
• ip unnumbered Loopback0: Uses the IP address of Loopback0 for the BDI interface.

---

4. Verify the Configuration

After completing the configuration, verify that the PPPoE sessions are being processed correctly.

Check the BBA Group:

show bba-group

Check PPPoE Sessions:

show pppoe session

Check the Bridge Domain Interface:

show ip interface brief | include BDI61

Check the Virtual Template:

show run interface virtual-template 61

 

5. Test PPPoE Sessions

Once the configuration is complete, test the setup by initiating PPPoE sessions from the access routers (NCS 540). Ensure that the sessions are established successfully and that IP addresses are assigned from the IP-Test-Pool.

---

Notes:

1. MTU Considerations: Ensure that the MTU is set correctly across the entire path to avoid fragmentation issues. For PPPoE, the MTU is typically set to 1492 bytes.
2. QoS for PPPoE Traffic: If you are handling real-time traffic (e.g., voice or video) over PPPoE, configure QoS to prioritize this traffic.
3. Debugging: If the sessions do not come up, use the following debug commands to troubleshoot:
   • debug pppoe events
   • debug pppoe errors
   • debug ppp negotiation

---

By following these steps, you should be able to bind the Virtual-Template61 to the L2 pseudowire and enable PPPoE services on the Catalyst C8500-12X4QC. Let me know if you encounter any issues or need further assistance!

Hope This Helps!!!

AshSe

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