SMTP traffic -- should it be policied or shaped

Unanswered Question
May 11th, 2007

I see a lot of exchange/SMTP traffic on my MPLS network and hence it was planned to restrict this traffic

I shaped the exchange traffic but i am receiving a lot of complaints about slow mail delivery. Woud policing be a better option with SMTP/exchange type of traffic than shaping

below is the config

policy-map QoS-to-MPLS

class voice

priority 1024

set ip dscp ef

class ftp

shape average 512000

class exchange

shape average 1024000

class class-default


class-map match-any exchange

match access-group name exchange

class-map match-all ftp

match access-group name ftp

class-map match-all voice

match ip rtp 16384 16383

Extended IP access list exchange

10 permit ip host any

20 permit ip host any

Extended IP access list ftp

10 permit tcp any any eq ftp-data


I have this problem too.
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Paolo Bevilacqua Fri, 05/11/2007 - 04:20


I think policing would be worst than shaping as it can have very adverse traffic on TCP traffic.

Perhaps what could help a little, would be fair queuing in the shaped classes.

On the other hand, when traffic exceeds capacity, someone will always complain.

Good luck!

royalblues Fri, 05/11/2007 - 04:56

I used shaping as policing would have caused TCP to retransmit again causing more traffic in one sense..

Perhaps i should just try to tune the bandwidth under the shape till it becomes better:-)



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