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Transmit-rate limit in scheduler with VLAN interface

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There is an upper limit in the transmit-rate of the scheduler when it is defined under the VLAN interface.

Scheduler cannot be applied to an interface when transmit-rate is above a certain bandwidth.

For example, the customer defines two VLAN interfaces under the reth interface with the scheduler using a 501M transmit-rate:

set interfaces ge-0/0/7 per-unit-scheduler 
set interfaces ge-0/0/7 vlan-tagging /
set interfaces ge-0/0/7 unit 150 vlan-id 150 
set interfaces ge-0/0/7 unit 150 family inet address 10.168.0.254/24 
set interfaces ge-0/0/7 unit 160 vlan-id 160 
set interfaces ge-0/0/7 unit 160 family inet address 10.168.3.254/24 
set class-of-service forwarding-classes queue 4 voice 
set class-of-service forwarding-classes queue 0 internet 
set class-of-service interfaces ge-0/0/7 unit 150 scheduler-map customer-map 
set class-of-service scheduler-maps customer-map forwarding-class voice scheduler voice-scheduler 
set class-of-service scheduler-maps customer-map forwarding-class internet scheduler internet-scheduler 
set class-of-service schedulers voice-scheduler transmit-rate 501m exact 
set class-of-service schedulers voice-scheduler priority low 
set class-of-service schedulers internet-scheduler transmit-rate remainder 
set class-of-service schedulers internet-scheduler buffer-size remainder 
set class-of-service schedulers internet-scheduler priority low

The following error is printed out in the message file and the scheduler fails to apply to the interface, noting no such error with transmit-rate 500M:

Apr 7 17:45:38 R2 R2 COSMAN: queue 4 got tx_rate = 501000 kbps which is too high for ge-0/0/7
Apr 7 17:45:38 R2 R2 cosman_compute_install_sched_params: Failed to compute scheduler params for ge-0/0/7.Hence retaining defaults

Another example with 10 VLANs defined, the transmit rate of each VLAN can define up to 100M:

set interfaces ge-0/0/15 per-unit-scheduler 
set interfaces ge-0/0/15 vlan-tagging 
set interfaces ge-0/0/15 unit 150 vlan-id 150 
set interfaces ge-0/0/15 unit 150 family inet address 10.168.10.254/24 
set interfaces ge-0/0/15 unit 160 vlan-id 160 
set interfaces ge-0/0/15 unit 160 family inet address 10.168.16.254/24 
set interfaces ge-0/0/15 unit 170 vlan-id 170 
set interfaces ge-0/0/15 unit 170 family inet address 10.168.17.254/24 
set interfaces ge-0/0/15 unit 180 vlan-id 180 
set interfaces ge-0/0/15 unit 180 family inet address 10.168.18.254/24 
set interfaces ge-0/0/15 unit 190 vlan-id 190 
set interfaces ge-0/0/15 unit 190 family inet address 10.168.19.254/24 
set interfaces ge-0/0/15 unit 200 vlan-id 200 
set interfaces ge-0/0/15 unit 200 family inet address 10.168.20.254/24 
set interfaces ge-0/0/15 unit 210 vlan-id 210 
set interfaces ge-0/0/15 unit 210 family inet address 10.168.21.254/24 
set interfaces ge-0/0/15 unit 220 vlan-id 220 
set interfaces ge-0/0/15 unit 220 family inet address 10.168.22.254/24 
set interfaces ge-0/0/15 unit 230 vlan-id 230 
set interfaces ge-0/0/15 unit 230 family inet address 10.168.23.254/24 
set interfaces ge-0/0/15 unit 240 vlan-id 240 
set interfaces ge-0/0/15 unit 240 family inet address 10.168.24.254/24 
set class-of-service forwarding-classes queue 4 voice set class-of-service forwarding-classes queue 0 internet 
set class-of-service scheduler-maps customer-map forwarding-class voice scheduler voice-scheduler 
set class-of-service scheduler-maps customer-map forwarding-class internet scheduler internet-scheduler 
set class-of-service schedulers voice-scheduler transmit-rate 101m exact 
set class-of-service schedulers voice-scheduler priority low 
set class-of-service schedulers internet-scheduler transmit-rate remainder 
set class-of-service schedulers internet-scheduler buffer-size remainder 
set class-of-service schedulers internet-scheduler priority low

In the following error, note that there is no such error if transmit-rate is 100M:

May 13 08:14:25 R2 R2 COSMAN: queue 4 got tx_rate = 101000 kbps which is too high for ge-0/0/15 
May 13 08:14:25 R2 R2 cosman_compute_install_sched_params: Failed to compute scheduler params for ge-0/0/15.Hence retaining defaults

Note: The above test was done on SRX240 running 12.1X44-D45.

Scheduler cannot be applied to an interface when transmit-rate is above a certain bandwidth.

For Branch SRX, if there are two VLANs and the physical interface is 1G bandwidth, then each VLAN’s bandwidth is 500M. This is current behavior. Note that this behavior is not applicable to high-end SRX devices (i.e., SRX 1K/3K/5K) as class of service is done by the hardware, which is different from Branch SRX.

Generally speaking, per-unit-scheduler divides the bandwidth of the Gigabit Ethernet (GE) interface equally based on the number of VLAN interfaces defined.