File Transfer QoS Configuration

jeetkulkarni · ‎06-06-2017

We recently implemented Twelve-Class (1P7Q1T+DBL) Egress Queuing model on our core 4500 switches in the environment. We have had some significant improvements for VoIP traffic (Skype for Business, EF). We want to have similar benefit to our file transfer between two sites. At the moment the speeds are averaging 700-800 Kbs for a 500Mb link between sites. Does file transfer between sites improved by altering the QoS policy? Can we mark the traffic is AF2 (Transactional Data)? Let me know your thoughts around this.

Georg Pauwen · ‎06-06-2017

Hello,

can you identify the file transfer flows ? With only 700-800Kbps, it sounds like your traffic somehow gets in the scavenger or best effort queues.

Post the config you have so far.

jeetkulkarni · ‎06-07-2017

Yes, i think the traffic is going to the default queue which has 25% bandwidth allocated.

Below is our configuration and interface policy-map output.

Policy Map PoolOutput-Policy
    Class PoolOutput-Priority-Queue
      priority
     police cir percent 30
       conform-action transmit
       exceed-action drop
    Class PoolOutput-Control-Mgmt-Queue
      bandwidth remaining 10 (%)
    Class PoolOutput-Multimedia-Conf-Queue
      bandwidth remaining 10 (%)
      dbl
    Class PoolOutput-Multimedia-Strm-Queue
      bandwidth remaining 10 (%)
      dbl
    Class PoolOutput-Trans-Data-Queue
      bandwidth remaining 10 (%)
      dbl
    Class PoolOutput-Bulk-Data-Queue
      bandwidth remaining 4 (%)
      dbl
    Class PoolOutput-Scavenger-Queue
      bandwidth remaining 1 (%)
    Class class-default
      bandwidth remaining 25 (%)
      dbl

#show policy-map interface t5/12
   TenGigabitEthernet5/12

Service-policy input: PoolTrust-Dscp-Input-Policy

    Class-map: class-default (match-any)
      225027924429 packets
      Match: any
      QoS Set
        dscp dscp table PoolTrust-Dscp-Table

Service-policy output: PoolOutput-Policy

    queue stats for all priority classes:
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/5
      (bytes output) 137869841276

    Class-map: PoolOutput-Priority-Queue (match-any)
      9391962010 packets
      Match: dscp cs4 (32) cs5 (40) ef (46)
        9391962010 packets
      Priority: Strict, b/w exceed drops: 5

      police:
          cir 30 %
          cir 3000000000 bps, bc 93750000 bytes
        conformed 135361482842 bytes; actions:
          transmit
        exceeded 0 bytes; actions:
          drop
        conformed 246000 bps, exceeded 0000 bps

    Class-map: PoolOutput-Control-Mgmt-Queue (match-any)
      313805202 packets
      Match: dscp cs2 (16) cs3 (24) cs6 (48) cs7 (56)
        313805202 packets
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/0
      (bytes output) 294042057
      bandwidth remaining 10%

    Class-map: PoolOutput-Multimedia-Conf-Queue (match-any)
      2548401638 packets
      Match: dscp af41 (34) af42 (36) af43 (38)
        2548401638 packets
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/1
      (bytes output) 25160834390
      bandwidth remaining 10%
      dbl
          Probabilistic Drops: 0 Packets
          Belligerent Flow Drops: 4 Packets

    Class-map: PoolOutput-Multimedia-Strm-Queue (match-any)
      114950200 packets
      Match: dscp af31 (26) af32 (28) af33 (30)
        114950200 packets
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/0
      (bytes output) 13072359153
      bandwidth remaining 10%
      dbl
          Probabilistic Drops: 0 Packets
          Belligerent Flow Drops: 0 Packets

    Class-map: PoolOutput-Trans-Data-Queue (match-any)
      110951001 packets
      Match: dscp af21 (18) af22 (20) af23 (22)
        110951001 packets
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/0
      (bytes output) 22317639635
      bandwidth remaining 10%
      dbl
          Probabilistic Drops: 0 Packets
          Belligerent Flow Drops: 0 Packets

    Class-map: PoolOutput-Bulk-Data-Queue (match-any)
      785709124 packets
      Match: dscp af11 (10) af12 (12) af13 (14)
        785709124 packets
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/0
      (bytes output) 41479401625
      bandwidth remaining 4%
      dbl
          Probabilistic Drops: 0 Packets
          Belligerent Flow Drops: 0 Packets

    Class-map: PoolOutput-Scavenger-Queue (match-any)
      230146 packets
      Match: dscp cs1 (8)
        230146 packets
      Queueing
      queue limit 680 packets
      (queue depth/total drops) 0/0
      (bytes output) 211785
      bandwidth remaining 1%

    Class-map: class-default (match-any)
      214760652709 packets
      Match: any
      Queueing
      queue limit 648 packets
      (queue depth/total drops) 0/0
      (bytes output) 613318368189
      bandwidth remaining 25%
      dbl
          Probabilistic Drops: 0 Packets
          Belligerent Flow Drops: 0 Packets

Georg Pauwen · ‎06-07-2017

Hello,

the default queue has 25% of bandwidth, which still doesn't explain the 700-800kbps. I agree with Joseph that the problem might be elsewhere. Your QoS doesn't show any drops.

What you could do is match a host to host connection and put it in the priority queue. Then transfer a large file between those hosts and check if that makes a difference.

That said, how are the files being transferred ?

Joseph W. Doherty · ‎06-07-2017

It's possible QoS might improve bulk file transfer rate. Insufficient information, though, to know for sure.

Things that QoS can impact include insuring drops aren't prematuring throttling transfer rate or conversely using minimal drops to keep transfer from bursting beyond link capacity.

However, besides QoS, if using TCP, some hosts may have an insufficient sized RWIN to fully utilize high bandwidth WAN links.