IPTV multicast dropping packets

[welisson]

Hi guys,I have been working with IPTV for one year, so, all switch involved in this topology are x460, in this network I have mpls and vr created, nonetheless the multicast traffic is going through a specific VR with pim enabled.Everything is working properly, where on the main switch I have 2x460 in stack and two 10g ports going to other switch and 6 gigabit port going to another x460, in both case I have LACP enabled.
So, the curious situation that sometimes I can see some channels get a little bit checkered for some seconds, once it means that some dropped packed happened, but it just happens over traffic that is going through gigabit ports.In order for trying to solve this issue, we changed the SFP, optical patch cords, added more giga ports, increase the buffer ports to 100%, and with these stuff we could improve the transmission but not eliminated it in definitive.what we could notice that, sometime is still being logged some drop packets in these gigabit interfaces, where is causing this bad experience.I have tried to do a lot of thing to finished this dropped packets off. I could decrease the number of this incidents but not eliminated.I've been thinking that it could be the cpu process when using a gigaport where these are shared with the main cpu, different of 10g modules where they have a specific module to process all over the traffic.
Would someone get the same experience using x460 (not G2)? how would you solve this issue?
Tks

[welisson]

yep, I have. looking at the output below, we can see the packets dropped
Port Congestion Monitor
Port Link Packet
State Drop
================================================================================
1:24 A 20187
1:28 A 50409
2:24 A 17767
2:28 A 17588

this is the biggest problem, where once this drop starts happening automatically we can see some fail on the video stream.
" Having any mcast video stream going into buffers is a bad thing as the buffers cause the packets to arrive at edge out of order. Out of order packets in a constant mcast stream will be dropped ..."
What would you suggest with it?"

Tks

[EtherMan-Dupe]

Lets not go down the path of speed of packets going across copper vs fiber or a DAC cable vs SFP fiber module... Both will deliver the same amount of packets... A few micro-seconds will not cause a stream of packets to drop frames. A buffer filling up due to micro bursts on your one gig interface could be your issue,,

[welisson]

it would be, however I have had increased the buffer to 100% as you can see below in all giga interface which belongs on this sharing/lacp

Packet Buffer Allocation for ports in range 1:1-30
Total Packet Buffer Size: 3145728 bytes, Not Overcommitted
Total Shared Buffer Size: 2934400
Port 1:24 Max Shared Buffer Usage: 1467136 bytes (50%)
QP1: Reserved Buffer: 1536 bytes
QP8: Reserved Buffer: 1536 bytes
Port 1:28 Max Shared Buffer Usage: 1467136 bytes (50%)
QP1: Reserved Buffer: 1536 bytes
QP8: Reserved Buffer: 1536 bytes
Packet Buffer Allocation for ports in range 2:1-30
Total Packet Buffer Size: 3145728 bytes, Not Overcommitted
Total Shared Buffer Size: 2934400
Port 2:24 Max Shared Buffer Usage: 1467136 bytes (50%)
QP1: Reserved Buffer: 1536 bytes
QP8: Reserved Buffer: 1536 bytes
Port 2:28 Max Shared Buffer Usage: 1467136 bytes (50%)
QP1: Reserved Buffer: 1536 bytes
QP8: Reserved Buffer: 1536 bytes

It is a default configuration
Port 2:27 Max Shared Buffer Usage: 586880 bytes (20%)
QP1: Reserved Buffer: 1536 bytes
QP8: Reserved Buffer: 1536 bytes

[Eric_Burke]

Like I said, it was out of left field. Still interesting that there's an almost 7x increase in timing across a fiber module or BaseT port, even if it is minuscule. I'd not expected that.

[Eric_Burke]

For what it's worth, I think this site confirms the SFP+/DAC in an SFP port.

https://community.fs.com/blog/sfp-dac-twinax-cable-deploy-guide.html

Can I Use SFP+ DAC Twinax Cable in SFP Ports? Yes, SFP+ cables are backward compatible to SFP ports and will work fine. But SFP cables are not compatible to SFP+ ports. SFP cables can be plugged into SFP+ ports but they are not designed for 10Gb/s data rates.