[j-nsp] [ERX] Policy counters not matching L2TP counter

[Guillet, David (David)]

Hi,
	I'm facing a strange behaviour here.

	I have a L2TP interface where I received 100 IP packets of 184
bytes I have an IP policy applied to the L2TP interface and when I take
a look at the bytes counters I have a difference of 600 bytes that makes
6 bytes per IP packet difference. 

	I'm wondering if the ERX adds any overhead to the IP packets or
what is the reason why I have such a difference. Is the ERX also carries
the traffic into 64bytes Jcells internally ?

	Any body have an idea of what's going on here ? 


Here is the output I have (it is truncated for best reading) :

L2TP interface

(config)#run sh ip int TUNNEL l2tp:1/1/58 delta TUNNEL l2tp:1/1/58 line
protocol Ppp is up, ip is up
  Network Protocols: IP
  Unnumbered Interface on loopback0
  Operational MTU = 1492  Administrative MTU = 0
  Operational speed = 100000000  Administrative speed = 0
  Discontinuity Time = 27252140
  Router advertisement = disabled
  Proxy Arp = disabled
  Network Address Translation is disabled
  TCP MSS Adjustment = disabled
  SA-validation Enabled
  Administrative debounce-time = disabled
  Operational debounce-time    = disabled
  Multipath mode = hashed
  Auto Configure = disabled
  Auto Detect = disabled
  Inactivity Timer = disabled

  In Received Packets 100, Bytes 18400	<----------- here
    Unicast Packets 100, Bytes 18400	<----------- here

  IP policy input xxxxxxxxxxxxxxx
    classifier-group aaaaaaaaaaaaaaa entry 1
      100 packets, 19000 bytes		<----------- here
      traffic-class bbbbbbbbbb
      mark 184 mask 252
      rate-limit-profile ccccccccccccc
        committed: 100 packets, 19000 bytes, action: transmit	
        conformed: 0 packets, 0 bytes, action: transmit
        exceeded:  0 packets, 0 bytes, action: drop