[j-nsp] Multicast flow with "Wrong incoming interface notifications" counter incrementing

[Riccardo S]

Having also a look to Juniper documentation says:

Wrong incoming interface notifications = Number of times that the upstream interface was not available

It doesn't sound as an RPF fail counter, isn't it ?

Tks

> From: nkhambal at juniper.net
> To: dim0sal at hotmail.com
> CC: juniper-nsp at puck.nether.net
> Subject: Re: [j-nsp] Multicast flow with "Wrong incoming interface notifications" counter incrementing
> Date: Mon, 14 Jan 2013 17:14:42 +0000
> 
> Iif mismatch means the multicast traffic received for this (S,G) has a different incoming interface than the one we programmed in the PFE (based on RPF check). 
> 
> Traffic would get discarded in this case and not forwarded. However, a notification is sent to RPD/PIM on the RE to check if the we need to change the iif on this (S,G) to a new iif (for e.g. if this leads to RPT to SPT cutover or if there is a change in the iif due to RPF interface change)
> 
> If the counter increase consistently, then most likely you are not forwarding on that (S,G) if 100% of the incoming traffic on this (S,G) get discarded with iif mismatch. Alternately, you might be getting same (S,G) traffic on 2 different iifs and in this case one coming over correct iif gets forwarded and one over wrong iif gets discarded with iif mismatch counted against that (S,G).
> 
> Thanks,
> Nilesh. 
> 
> --------------------------------
> Sent from my mobile device
> 
> On Jan 14, 2013, at 8:14 AM, "Riccardo S" <dim0sal at hotmail.com> wrote:
> 
> > 
> > 
> > 
> > Hi
> > 
> > What does means incrementing counter
> > “Wrong incoming interface notifications” in the following command ?
> > 
> > Is the following flow forwarded, as expected,
> > towards the receiver ?
> > 
> > 
> > 
> > 
> > 
> > # run show multicast route group
> > 224.12.22.1 extensive    
> > 
> > Instance: master Family: INET
> > 
> > 
> > 
> > Group: 224.12.22.1
> > 
> > 
> > Source: 1.1.1.1/32 
> > 
> > 
> > Upstream interface: vlan.1
> > 
> > 
> > Downstream interface list: 
> > 
> >        vlan.100
> > 
> > 
> > Session description: Unknown
> > 
> > 
> > Statistics: 3 kBps, 30 pps, 43340 packets
> > 
> > 
> > Next-hop ID: 131071
> > 
> > 
> > Upstream protocol: PIM
> > 
> > 
> > Route state: Active
> > 
> > 
> > Forwarding state: Forwarding
> > 
> > 
> > Cache lifetime/timeout: 360 seconds
> > 
> > 
> > Wrong incoming interface notifications: 6960
> > 
> > 
> > Uptime: 00:36:36
> > 
> > 
> > 
> > After 10 seconds:
> > 
> > 
> > 
> > # run show multicast route group
> > 224.12.22.1 extensive    
> > 
> > Instance: master Family: INET
> > 
> > 
> > 
> > Group: 224.12.22.1
> > 
> > 
> > Source: 1.1.1.1/32 
> > 
> > 
> > Upstream interface: vlan.1
> > 
> > 
> > Downstream interface list: 
> > 
> >        vlan.100
> > 
> > 
> > Session description: Unknown
> > 
> > 
> > Statistics: 2 kBps, 30 pps, 43491 packets
> > 
> > 
> > Next-hop ID: 131071
> > 
> > 
> > Upstream protocol: PIM
> > 
> > 
> > Route state: Active
> > 
> > 
> > Forwarding state: Forwarding
> > 
> > 
> > Cache lifetime/timeout: 360 seconds
> > 
> > 
> > Wrong incoming interface notifications: 6974
> > 
> > 
> > Uptime: 00:36:41
> > Tks
> > 
> > 
> >                         
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> > 
>