nanog mailing list archives

Re: Latency/Packet Loss on ASR1006


From: Blake Hudson <blake () ispn net>
Date: Tue, 7 Dec 2021 09:32:55 -0600


On 11/26/2021 1:09 PM, Colin Legendre wrote:
Hi,

We have ...

ASR1006  that has following cards...
1 x ESP40
1 x SIP40
4 x SPA-1x10GE-L-V2
1 x 6TGE
1 x RP2

We've been having latency and packet loss during peak periods...

We notice all is good until we reach 50% utilization on output of...

'show platform hardware qfp active datapath utilization summary'

Literally ... 47% good... 48% good... 49% latency to next hop goes from 1ms to 15-20ms... 50% we see 1-2% packet-loss and 30-40ms latency... 53% we see 60-70ms latency and 8-10% packet loss.

Is this expected... the ESP40 can only really push 20G and then starts to have performance issues?



I haven't experienced that across about a dozen ASR 1ks. Though I just checked and we are not pushing any of our ESP's over 50% currently (the closest we have is an ESP 40 doing 18Gbps). However, I'm pretty sure we've pushed older ESPs (5, 10's, and 20's) to ~75% or so in the past.

Given the components you have, I would have expected your router to handle 40Gbps input and 40Gbps output. That could either be 40Gbps into the 6 port card [and 40Gbps out of the four 1 port cards] or it could be 40Gbps input that is spread across the 6 port and 1 port cards [that is then output across both cards as well].

Despite other comments, I think your components are well matched. The only non-obvious thing here is that the 6 port card only has a ~40Gbps connection to the backplane so you cannot use all 6 ports at full bandwidth. I think this router is well suited to handle 20-30Gbps of customer demand doing standard destination based routing (if you're doing traffic shaping, NAT, tunnelling, or something else more involved than extended ACLs you may need something beefier at those traffic levels).


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