Queue size pfifo

RouterOS General
1

Hello,

I’m wondering is there a way to calculate how big should be the queue size of pfifo in RouterOS.

My scenario is that, I have 1.2 Gbps (12,000 clients) of traffic traveling through a RouterOS bandwidth management platform (dell server running RouterOS in bridge mode), which is connected in between two Cisco switches with etherchannel enabled to aggregate two external GigabitEthernet interfaces (sw1) and two internal GigabiEthernet interfaces (sw2).
The issue with this setup is, that I see lot of packet drops in both external gig interfaces but not in internal gig interfaces, and the parents of queue trees are applied on internal interfaces. I was checking on both Cisco switches for errors and there is no issue with that, I have increased the pfifo queue size from 50 to 4000 packets but still there are drops, on pcq I know the formula of calculating queue size but here I’m not sure how to proceed.

Thanks in advance for the reply.

Best regards.

Faton.

2

Hi,

Any idea ?

Regards.

Faton

3

someone up

4

Hi

The packets from external interfaces being dropped, isn’t that a consequence of the queue on the internal (egress) interface(s) shaping the download traffic. Whatever can’t squeeze into internal, and can’t be buffered would be dropped indeed.

Regarding the queue, i would worry that it would become bottleneck → point of serialisation. Best to use hardware only (or at least multi-queue).