[c-nsp] Cisco ME3600 and ME3800 Policy-map Issues with EMC's Recovery Point

[Darwin L.]

Good Afternoon all, I hope you are fine.

We currently have a customer using EMC Recovery Point (for troubleshooting
purposes we put both services in the same switch with a local VLAN
communicating both sites) and as soon as we apply Rate-limits based on
policy maps we start getting what appears to be packet loss. E.g. Customer
sends 6Mbps and gets between 2Mbps and 3Mbps. As soon as we remove the
filters (which are configured at 15Mbps) communication gets balanced.

I have sites A and B and it’s using EMC’s Recovery Point application in
order to do DB replication from site A to site B. We applied under the
service instance configuration of each interface the corresponding
policy-map in order to limit the traffic to 15Mbps in(policing) and
out(shaping) and, as soon as we do this, traffic drops abruptly on site B.
We tried several scenarios with the same topology and the results were the
following:



·         No policy-map applied: Transmission Successful.

·         Policy-map(in and out) applied on Site A (sender): Transmission
Successful.

·         Policy-map(in and out) applied on both Sides: High amount of
packet drops.

·         Policy-map(only out) applied on both sides: High amount of packet
drops.



We used the *show policy-map interface <if name> service instance <ID>* to
verify and there was a high amount of Tail Packet Drop on the B site
(receiver). Below you can see the configured policy-maps and  corresponding
output to the show policy-map command:



DOM-CNHER-ME3603#show runn policy-map

Building configuration...



Current configuration : 850 bytes

!

**********Output deprecated**************

policy-map RATE-LIMIT_15M_in

class class-default

  police cir 15728500 bc 1966080

   conform-action transmit

   exceed-action drop

**********Output deprecated**************

policy-map RATE-LIMIT_15M_out

class class-default

  shape average 15728640

!

end





DOM-CNHER-ME3603#show policy-map interface gi0/19 service instance 2546

  GigabitEthernet0/19: EFP 2546



  Service-policy input: RATE-LIMIT_15M_in



    Class-map: class-default (match-any)

      29339 packets, 4900333 bytes

      5 minute offered rate 107000 bps, drop rate 0000 bps

      Match: any

      police:

        cir 15728500 bps, bc 1966080 bytes

       conform-action transmit

        exceed-action drop

      conform: 29629 (packets) 5024477 (bytes)

      exceed: 0 (packets) 0 (bytes)

      conform: 99000 bps, exceed: 0 bps

      Input Policer:

        Policer Packets Drop: 0

        Policer Bytes Drop: 0



  Service-policy output: RATE-LIMIT_15M_out



    Class-map: class-default (match-any)

      91214 packets, 110777628 bytes

      5 minute offered rate 2305000 bps, drop rate 1189000 bps

      Match: any

  Traffic Shaping

    Average Rate Traffic Shaping

    Shape 15728 (kbps)

      Output Queue:

        Default Queue-limit 49152 bytes

*        Tail Packets Drop: 47993 *

*        Tail Bytes Drop: 62132028 *

DOM-CNHER-ME3603#show policy-map interface gi0/3 service instance 2750

  GigabitEthernet0/3: EFP 2750



  Service-policy input: RATE-LIMIT_15M_in



    Class-map: class-default (match-any)

      94494 packets, 114201810 bytes

      5 minute offered rate 2498000 bps, drop rate 0000 bps

      Match: any

      police:

        cir 15728500 bps, bc 1966080 bytes

        conform-action transmit

        exceed-action drop

      conform: 96277 (packets) 116243689 (bytes)

      exceed: 0 (packets) 0 (bytes)

      conform: 2292000 bps, exceed: 0 bps

      Input Policer:

        Policer Packets Drop: 0

        Policer Bytes Drop: 0



  Service-policy output: RATE-LIMIT_15M_out



    Class-map: class-default (match-any)

      30398 packets, 5096650 bytes

      5 minute offered rate 116000 bps, drop rate 0000 bps

      Match: any

  Traffic Shaping

    Average Rate Traffic Shaping

    Shape 15728 (kbps)

      Output Queue:

        Default Queue-limit 49152 bytes

        Tail Packets Drop: 0

        Tail Bytes Drop: 0


Only behavior happen when the customer start traffic with this application,
if they using another application and load the link issue is not appear.