Traffic shaping on SRX340

[Chris Lee]

Hi,

We're running an SRX340 in packet mode as a router for customer internet
access on campus, generally providing smaller speed links around
5/10/20/50Mbps symmetric.

We apply a filter to the customers interface on the input and output, with
a policer policy to discard traffic when exceeding the defined
bandwidth limit.

So in the example configuration below, I find that when running a speed
test on the customers IP that the download traffic to them is shaped
nicely, spot on 22Mbps as in the example below, however on the upload test
it's as if the filter as no impact whatsoever and they get 60-70Mbps.

Anyone have any ideas on what I might be doing wrong? JunOS is 18.2R3-S3 in
this case, however this router was previously running a 15 release and we
had the same issue with the filters only seeming to work on the download
and not the upload traffic.

set interfaces ge-0/0/4 unit 3623 description "CUST-INTERNET-ZZZ Internet"
set interfaces ge-0/0/4 unit 3623 vlan-id 3623
set interfaces ge-0/0/4 unit 3623 family inet filter input customer-ZZZ-in
set interfaces ge-0/0/4 unit 3623 family inet filter output customer-ZZZ-out
set interfaces ge-0/0/4 unit 3623 family inet address 192.0.2.133/30

set firewall family inet filter customer-ZZZ-in term allow-icmp from
protocol icmp
set firewall family inet filter customer-ZZZ-in term allow-icmp then accept
set firewall family inet filter customer-ZZZ-in term default then policer
policer-20m
set firewall family inet filter customer-ZZZ-in term default then accept

set firewall family inet filter customer-ZZZ-out term allow-icmp from
protocol icmp
set firewall family inet filter customer-ZZZ-out term allow-icmp then accept
set firewall family inet filter customer-ZZZ-out term default then policer
policer-20m
set firewall family inet filter customer-ZZZ-out term default then accept

set firewall policer policer-20m if-exceeding bandwidth-limit 22m
set firewall policer policer-20m if-exceeding burst-size-limit 625k
set firewall policer policer-20m then discard

Thanks,
Chris