We have Cisco 4500-X 32SFP with IOS-XE 03.11.11.E as aggregation switch in small ISP setup for broadband and IPTV services.
At customers side we experience picture freezing for 1-2 seconds (no pixelation). Sound is uninterrupted. TS Reader shows increase of continuity errors every few minutes.
Internet traffic at the switch is is only switched (up to 2,5Gbps). IPTV traffic is UDP multicast with each stream around 10 Mbps and enters the switch through 1Gbit/s SFP port. The switch is doing multicast routing with PIM-SSM. IPTV traffic is <600Mbps in peak. It is mixed multicast and unicast but mostly multicast live channels. IPTV input interface is not saturated and does not show any errors:
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseT
input flow-control is off, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
...
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
273871465 packets output, 41155056998 bytes, 0 underruns
0 output errors, 0 collisions, 3 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Output is to two GPON OLT's connected by TenGig ports. Max traffic at both TenGig ports is up to 2Gpbs, often much less with CC errors still present.
We experience the same behaviour also on 1G test port at this 4500X switch with laptop connected and TSreader running.
We have no QoS deployed. I don't see a point for it and don't know what to prioritize when all related interfaces input or output are by far not saturated. Maybe I am wrong and QoS is the missing part. All the documentation is generic and I dont know what is missing. I can mark UDP packets at input with some DSCP value but how to set-up output policies? Would it help deploying on test 1G interface where there is no output traffic except 1 UDP stream of ~10Mbps?
Btw, Cat7 cable on IPTV input port has been replaced. Measurements on out IPTV supplier's switch have been done (and no CC errors there). ETH interface os supplier's switch also changed. Our switch was also replaced few days ago. Before there was 4948E with exactly the same issues. And before this probles started to occur (about 1 month ago) the setup with 4948E worked for more than 6 years.
Has anybody some idea?
