Error 676 Occasionally Occurs in PPPoE Dialup

How to troubleshoot the fault when error 676 occasionally occurs in Point-to-Point Protocol over Ethernet (PPPoE) dialup. Here is the solution:

Fault Description

Network topology: ONU -> optical line terminal (Huawei OLT) -> switch -> broadband remote access server (BRAS)
An ONU user occasionally encounters error 676 in PPPoE dialup. In addition, the fault duration varies.

Possible Causes

• An ONU user forges the MAC address of the BRAS.
• An OLT user forges the MAC address of the BRAS.
• The configuration of the BRAS or remote authentication dial in user service (RADIUS) is incorrect.
• A VLAN conflict occurs.

Procedure

1. Run the security mac-filter command to configure MAC address filtering on the ONU, which prevents the MAC address of the BRAS from being forged. The fault persists.
2. Run the security mac-filter command to configure MAC address filtering on the OLT. The fault persists.
3. Check the configurations of the BRAS and RADIUS. The configurations are correct. Check the VLAN configurations on the upper-layer aggregation switch and OLT. The VLAN configurations are correct.
4. When an ONU user in VLAN A encounters error 676, another user in the same VLAN is already online on the BRAS. Therefore, it is determined that a VLAN conflict occurs on the BRAS. The maximum number of concurrent online users configured on the BRAS is 1 in PPPoE dialup. Therefore, if a user is online in the VLAN with conflicts, error 676 occurs with other users of the same VLAN in PPPoE dialup.
5. Query the configurations of all ONUs connected to the OLT. It is found that VLANs have the same outer VLAN tags and the same inner VLAN tags. Modify the VLAN settings so that they have different outer tags and different inner tags. Then, the fault is rectified.

Suggestions and Summary

Properly plan VLANs for the PON ports on an OLT. It is suggested to configure an outer VLAN tag for each PON port. In such a manner, the fault location scope is minimized even when an inner VLAN conflict occurs.

The more information about technical support you can consult with our technician - Bill, and his e-mail address is as below:  

bill@huanetwork.com

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How to Configure IS-IS IPv6 for Huawei Routers

Applicability

This example applies to all Huawei AR routers of V200R002C00 and later versions.

Networking Requirements

As shown in Figure 1:

• RouterA, RouterB, RouterC, and RouterD belong to the same AS. The four routers need to run IS-IS to implement IPv6 interworking.
• RouterA, RouterB, and RouterC belong to Area 10, and RouterD belongs to Area 20.
• RouterA and RouterB are Level-1 routers, RouterC is a Level-1-2 router, and RouterD is a Level-2 router.

Figure 1 Networking diagram of configuring IS-IS IPv6
 

Procedure

1. Configure RouterA.

#

 sysname RouterA

#

 ipv6  //Enable IPv6 unicast forwarding.

#

isis 1  //Enable IS-IS process 1.

 is-level level-1  //Set the router as a Level-1 router.

 network-entity 10.0000.0000.0001.00  //Set the NET for IS-IS process 1.

 #

 ipv6 enable topology standard  //Enable the IPv6 capability for IS-IS process 1.

 #

#

interface GigabitEthernet1/0/0

 ipv6 enable  //Enable IPv6 on the interface.

 ipv6 address 10:1::2/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1  //Enable the IPv6 capability for IS-IS process 1 on the interface.

#

Return

2. Configure RouterB.

#

 sysname RouterB

#

 ipv6

#

isis 1

 is-level level-1

 network-entity 10.0000.0000.0002.00  //Set the NET for IS-IS process 1.

 #

 ipv6 enable topology standard

 #

#

interface GigabitEthernet1/0/0

 ipv6 enable

 ipv6 address 10:2::2/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1

#

return

3. Configure RouterC.

#

 sysname RouterC

#

 ipv6

#

isis 1

 network-entity 10.0000.0000.0003.00  //Set the NET for IS-IS process 1.

 #

 ipv6 enable topology standard

 #

#

interface GigabitEthernet0/0/0

 ipv6 enable

 ipv6 address 30::1/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1

 isis circuit-level level-2  //Set the circuit type as Level-2, allowing only Level-2 adjacencies to be established on the interface.

#

interface GigabitEthernet1/0/0

 ipv6 enable

 ipv6 address 10:1::1/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1

#

interface GigabitEthernet2/0/0

 ipv6 enable

 ipv6 address 10:2::1/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1

#

return

4. Configure RouterD.

#

 sysname RouterD

#

 ipv6

#

isis 1

 is-level level-2  //Set the router as a Level-2 router.

 network-entity 20.0000.0000.0004.00  //Set the NET for IS-IS process 1.

 #

 ipv6 enable topology standard

 #

#

interface GigabitEthernet1/0/0

 ipv6 enable

 ipv6 address 30::2/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1

#

interface GigabitEthernet2/0/0

 ipv6 enable

 ipv6 address 20::1/64  //Configure a global unicast IPv6 address for the interface.

 isis ipv6 enable 1

#

return

5. Verify the configuration.

Run the display isis route command on each router to view IS-IS routes.

Interfaces on RouterA, RouterB, RouterC, and RouterD can successfully ping each other.

Configuration Notes

• IPv6 must be enabled in the system view and interface view.
• The IPv6 capability must be enabled for IS-IS on interfaces.
• When using the network-entity command to set a NET for an IS-IS process, configure the same area ID for routers in an area.

The more information about technical support you can consult with our technician - Bill, and his e-mail address is as below:  

bill@huanetwork.com

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