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NE80E 10G LPUs Fail to Perform Wire-speed Forwarding Because of Insufficient SFUs

Publication Date:  2012-07-27 Views:  45 Downloads:  0
Issue Description

At PM 20:00, the hush hour, the forwarding speed of 10GE LPUs of the NE80E in the MAN can forward traffic is only 7.5 Gbit/s. No more traffic can be added and some MAN users feed that loss of ping DNS packets is very serous.

The NE80E is installed with two SFUs, three 10 x GE LPUs, and one 10 GE LPU.  

      
Alarm Information

Null

      
Handling Process

Add one SFU.

      
Root Cause

The 10G LPUs of the NE80E need three SFUs to implement wire-speed forwarding. With two SFUs, the forwarding speed of the LPUs can reach only about 7.5 Gbit/s. 
Computing formula: 11Gbits/s x 67% = 7.37 Gbits/s (11 Gbit/s is the unidirectional speed of the LPU and a little margin is reserved during the design).
The percent 67% indicates that the router is installed with only two SFUs though three are required. The bidirectional bandwidth of the 10G LPUs of the NE40E/NE80E/NE5000E is 22 Gbit/s. If three SFUs are installed, the LPUs can provide 10 Gbit/s wire-speed forwarding.

      
Suggestions

If the NE40E/NE80E/NE5000 is installed with only the 10G LPUs, it is required to install three or more SFUs to implement wire-speed forwarding even if only one 10G LPU is installed.
When the router fails to provide wire-speed forwarding, check whether the number of SFUs satisfies the requirement or not.

      

END