No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

Broadcast Packets in the VlanIf Failed to Be Sent Because LPUA and LPUB of the NE40E&80E Are Added to the Same Layer 2 Trunk

Publication Date:  2012-07-27 Views:  47 Downloads:  0
Issue Description
1. Software version: V300R002
2. Interface board: LPUA (including LPUG/LPUH, which adopts the 2800 chip) and LPUB (which adopts the 588 chip) are inserted on the same NE40E/NE80E.
3. Configuration: The interfaces of LPUA and LPUB were added to the same Layer 2 Eth-Trunk. A VlanIf interface was created in the VLAN where the Eth-Trunk was added.
4.Symptom of fault:
When the fault occurred, ARP entries could not be learned successfully. Thus, the attached device could not ping the gateway, services failed to be forwarded, and all the upper layer protocols, such as OSPF/BGP, could not be enabled. 
 
Alarm Information
Null
Handling Process
At present, this problem cannot be solved thoroughly, but it can be avoided with the following methods:
1. Do not add the interfaces of LPUA and LPUB to the same Layer 2 Eth-Trunk interface during network planning.
2. If the interfaces of LPUA and LPUB are added to the same Layer 2 Eth-Trunk interface on the existing network, you can:
A. Change the Eth-Trunk into a sub-interface, rather than a VlanIf interface.
B. Take the interface of LPUA or LPUB out of the Eth-Trunk to ensure that only one type of board is in the Eth-Trunk. 
 
Root Cause
The R&D staff confirmed that this problem was caused by the implementation feature of V300R002:
For a broadcast packet to be sent from the Layer 2 port, TM needs to copy the packet on the lower-layer interface for delivery. This process is implemented in the same way on LPUA and LPUB of V300R001, but the process is implemented in different ways on LPUA and LPUB of V300R002.
In V300R001, one mirror flag bit is set in the frame header, and TM copies packets based on this flag bit.
In V300R002, LPUB is not changed, but LPUA is.
If the interfaces of LPUA and LPUB are added to the same Layer 2 Eth-Trunk, the following may occur:
1. When the Eth-Trunk interface selected for outgoing packets through the hash algorism is the LPUA interface, and the Eth-Trunk interface selected for incoming packets through the hash algorism is still the LPUA interface, packets can be delivered normally.
2. When the Eth-Trunk interface selected for outgoing packets through the hash algorism is the LPUB interface, and the Eth-Trunk interface selected for incoming packets through the hash algorism is still the LPUB interface, packets can be delivered normally.
3. When the Eth-Trunk interface selected for outgoing packets through the hash algorism is the LPUA interface, and the Eth-Trunk interface selected for incoming packets through the hash algorism is the LPUB interface, packets fail to be delivered.
4. When the Eth-Trunk interface selected for outgoing packets through the hash algorism is the LPUB interface, and the Eth-Trunk interface selected for incoming packets through the hash algorism is the LPUA interface, packets fail to be delivered. 
 
Suggestions
In the following cases, it is recommended that you plan the network based on the previous analysis to avoid the problem in advance:
1. The site is to be deployed with V300R002 or later versions, and LPUA and LPUB are required to be intermixed on the site.
2. In terms of V300R001 and the NE40E/80E on which LPUA and LPUB are intermixed on the existing network, you shall check whether the previous problem exists before upgrading the software to V300R002 or later versions to avoid the problem. 
 

END