[j-nsp] CoS buffer size

[Dan Peachey]

On 23 June 2015 at 17:43, Saku Ytti <saku at ytti.fi> wrote:

> I don't have access to any JNPR box right now, so can't give exact command.
>
> But as you're using QX for scheduling, you'll need the chipID, and
> L2/L3 index, and taildrop index, then you can use 'show qx ..' to
> fetch the size of the tail, which will effectively tell the buffer
> size in bytes.
>
> I usually decide how many buffer I want in queue, then solve X in:
>
> shaper_rate * queue_percent * X = n bytes
>
> Then I'll just configure queue temporal queue with value X.



I must be missing something, but it seems that regardless of what I set as
a temporal buffer, the byte buffer value assigned doesn't appear to change.

I set all 5 queues with temporal buffer values:


xe-0/0/1                       164        0       0       0       0
  xe-0/0/1.2000                329    10000       0       0       0
    q 1 - pri 0/0            37272        0     24%  165000      0%
    q 2 - pri 0/0            37272        0      2%  500000      0%
    q 3 - pri 2/0            37272        0      1%  500000      0%
    q 4 - pri 0/0            37272        0     24%  165000      0%
    q 5 - pri 3/0            37272        0     24%   20000      0% exact


The byte values don't make any sense to me:

NPC0(pe1-RE0 vty)# show qxchip 0 tail-rule 33 0 0
Tail drop rule configuration   : 33
        ref_count    : 0
     Drop Engine 0   :
       Tail drop rule ram address   : 00000840
                       threshold    : 2686976 bytes

NPC0(pe1-RE0 vty)# show qxchip 0 tail-rule 34 0 0
Tail drop rule configuration   : 34
        ref_count    : 0
     Drop Engine 0   :
       Tail drop rule ram address   : 00000880
                       threshold    : 2801664 bytes

NPC0(pe1-RE0 vty)# show qxchip 0 tail-rule 35 0 0
Tail drop rule configuration   : 35
        ref_count    : 0
     Drop Engine 0   :
       Tail drop rule ram address   : 000008c0
                       threshold    : 2932736 bytes

NPC0(pe1-RE0 vty)# show qxchip 0 tail-rule 36 0 0
Tail drop rule configuration   : 36
        ref_count    : 0
     Drop Engine 0   :
       Tail drop rule ram address   : 00000900
                       threshold    : 3063808 bytes
                            shift   : 14
                         mantissa   : 187

NPC0(pe1-RE0 vty)# show qxchip 0 tail-rule 37 0 0
Tail drop rule configuration   : 37
        ref_count    : 0
     Drop Engine 0   :
       Tail drop rule ram address   : 00000940
                       threshold    : 3194880 bytes


The two queues that have the same transmit-percent and buffer-size (33 &
36) even have different byte sizes.

What am I missing?

Thanks,

Dan