Lost Packets on Switches - Help

Unanswered Question
Jul 1st, 2007


I'm losing packets on my switches between our voip phones when using or when not using and only pinging the phones.

The phones are currently in vlan 2, this vlan has rspan on for voice recording. The source switches have trunk ports and these connect to the phone and the pc's connect to the network via the phones.

All the source ports have the following config:

switchport trunk encapsulation dot1q

switchport mode trunk

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape 10 0 0 0

mls qos trust dscp

auto qos voip trust

no mdix auto

The rspan configuration on the source switches is:

monitor session 1 source vlan 2

monitor session 1 destination remote vlan 50

On the destination switch the config is:

monitor session 1 destination interface Gi1/0/2

monitor session 1 source remote vlan 50

The Gi1/0/2 interface has the following config:

switchport access vlan 21

switchport mode access

no mdix auto

spanning-tree portfast

I can't see why I would lose packets when even just pinging the phones. The destination switch is running eigrp and routing betweent the vlan's. If I ping from another vlan to vlan 2(i.e the phone vlan) I lose packets but if I ping devices between any vlan that doesn't have RSPAN capturing data I don't lose any packets.

Just to let you know the phones are like mini switches and they tag their own traffic into vlan 2 and the pc data into any defined vlan.

Can someone please shed some light on to this and how I can resolve it.

Thanks in advance


I have this problem too.
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dan_track Mon, 07/02/2007 - 01:44


I'm just sending a message again to ask if any one can help me with this issue I've been having?



Pavel Bykov Mon, 07/02/2007 - 03:15

What I have found out, is that new firmware revisions have restricted ICMP in that you cannot ping continuously.

I think it's just some normal security function so it's not that easy to interfere with a call.

Standard sequence is:


I.E. only 5 consecutive replies.

The replies just aren't sent.


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