I am on WB-II lab 1 task 8.1 and a little confused about the question and solution.
We have two DLCIs applied to the same physical interface and shaping needs to be applied.
The solution says to apply the below parameters:
Tc = 50ms
1) DLCI 504: CIR = 512000, Bc = 25600, Be = 51200, MinCIR = 384000
2) DLCI 513: CIR = 128000, Bc = 6400, Be = 0, MinCIR = 96000
My math came up to
1) DLCI 504: CIR = 512000, Bc = 25600, Be = 44800, MinCIR = 384000
2) DLCI 513: CIR = 128000, Bc = 6400, Be = 0, MinCIR = 96000
The discrepency is in the Be on DLCI 504. It was my understanding that you should never exceed the interface AIR which is 1536K. The solution calculates Be as
(25600 + Be)= 1536000*50/1000 and therefore Be = 51200.
This will cause oversubscription if DLCI 513 is using 128K.
I calculated Be as
(25600 + Be)= (1536000-128000)*50/1000 and therefore Be = 44800.
I subtracted DLCI513's CIR to eliminate the possibility of oversubscription.
Any help clearing this up would be greatly appriciated.
Thanks,
Dan
