UDP Drop in 2960

[Mahdi.ka]

Hi ....

I have a Cisco switch 2960 24-port with 20 camera connected it
Sometimes camera images are displayed in black. (in NVR)

While the Ping connection is in place
What causes this problem?
There is a way to see the drop packets? (without using monitoring equipment)

Thank you for help and guidance

[balaji.bandi]

Do you have any QoS in Place, how far the recorder and Camera in the network, what are the devices in the Path ?

post all the configuration to have look. ?

[Mahdi.ka]

Unused Qos in Network Implementation

[Georg Pauwen]

Hello,

in addition to Balaji's post, what brand/model are the cameras ?

[Mark Malone]

Just to add to your original question , this is how i have tested packets drops on specific voice video systems when no monitoring tools in place

QOS may fix it anyway as it should provide some protection to the traffic but if it doesn't it will allow you to test further

apply L2 auto qos then ping via TOS value under an extended ping and see if the counters are dropping in the qos policys
You would need to know the DSCP value (maybe AF41 video ) that the system is using then convert it to TOS you could run the ping check then specific to that value based against the DSCP value , its a bit more complicated than looking at a monitoring system but it should work

Type ping hit return to get to extended mode

DSCP to TOS chart
https://irfansalam.wordpress.com/2013/07/17/tos-values-calculator/

so this below would test for Voice packet drops based on DSCP EF matching TOS value 184

Target IP address: 10.1.1.1
Repeat count [5]: 100
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: 10.1.1.1
Type of service [0]: 184

[Mahdi.ka]

AVtech

[Mahdi.ka]

AVtech

[Georg Pauwen]

Hello,

from what I can find in the manuals, it looks like the cameras use port 80 by default. You could try and use a less common port, since 80 is used for a lot of Internet browsing traffic...

[Mahdi.ka]

There are no traffic on the network, and only the camera is there

[balaji.bandi]

coming back to my question i have asked, provide configuration and port information ?

[Mahdi.ka]

I have one vlan for cctv (vlan = 40)
all port is access-vlan 40
one interface connect to NVR and other interfaces connect to cameras.
network is 10.40.1.0/24
and three are no other traffic in switch(all interface is 1G)
camera brand is AVtech and 2MP

[Joseph W. Doherty]

So, all the video streams would egress out the NVR port? If so, what's that port's stats?

[Joseph W. Doherty]

"What causes this problem?"

Possibly due to dropped packets.

"There is a way to see the drop packets? (without using monitoring equipment)"

Yes, might require a command to show stats at the ASIC level. (Sorry, off-the-top-of-my-head, don't recall actual commands, but they do exist.)

BTW, the 2960's series have a somewhat small buffer RAM shared by all its ports, so if any port is busting above its capacity, it often will drop packets. If this is only happening on one or a few ports, it's possible to configure the 2960 to "better" share its buffer RAM (decreasing such drops).

[Mahdi.ka]

What solution do you have for solving this problem?

[Mark Malone]

As a quick fix to protect the UDP if only the cameras are on these switches i would try basic auto qos
You can use this under the camera interface and the uplinks see if it makes a difference , it shouldnt break anything and can be removed if it doesnt work

All our video switches or anything running real time traffic has qos to ensure its protected at some level and not dropped

mls qos trust dscp
auto qos trust dscp