[j-nsp] JUNIPER POLICER and CoS Shaping Rate

[GIULIANO (WZTECH)]

People,

Some topics where questioned today about how to limit traffic for vlan 
subscribers using MX5 routers.

The main question is related to system architecture related to the main 
gear (internal machine) to control and limiting packets.

Using policers (input or output) or shaping-rate we have quite the same 
result: miscalculating or error.

If we create a rule like the following:


set class-of-service interfaces ge-0/0/1 unit 530 shaping-rate 20m


The output traffic rates 19.2~ Mbps only (using MRTG and SNMP statistics 
and graphics).

We ever needs to allocate more bandwidth for the subscriber like.

set class-of-service interfaces ge-0/0/1 unit 530 shaping-rate 22m

To get the correct result ...

Using policers generate almost the same result for output traffic.

Is this because of system architecture or this is a graphic's mistake ?

The burst size limit influence this result ? It must be calculated using 
what kind of parameter ?

For example (same physical interface, same MTU, etc):

Interface ge-0/0/0 unit 10 - VLAN 10 - 30 Mbps What is the correct burst ?

Interface ge-0/0/0 unit 20 - VLAN 20 - 50 Mbps What is the correct burst ?

Interface ge-0/0/0 unit 30 - VLAN 30 - 150 Mbps What is the correct burst ?

Interface ge-0/0/0 unit 30 - VLAN 30 - 4 Mbps What is the correct burst ?

Does anyone has solved this problems ?

Is it possible to get a correct parameter and points to a correct limit 
for the contracted bandwidth ?

Thanks a lot,

Giuliano