issue with cbs 220

[lvfranz]

Hi all,

I'm having a problem with several CBS 220 connected each other by a fiber loop.

On all uplink port I see a lot of input packet with error. I try to exchange sfp, fiber patch, fiber port but nothing change.

I'm quite sure that are traffic related since on a couple of switch, connected by 1mt cable length, I try to exchange sfp and also fiber patch but the error rate was the same.

Configuration of the port are very easy and consistent between switch (switchport mode trunk, switchport trunk allowed vlan all).

On both interface I see input error without any detail

GigabitEthernet28 is up
Hardware is Gigabit Ethernet
Auto-duplex, Auto-speed, media type is Fiber
flow-control is off
back-pressure is enabled
74140339 packets input, 11075289989 bytes, 0 throttles
Received 11007586 broadcasts (18596760 multicasts)
0 runts, 1319662 giants, 0 throttles
12554021 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
18596760 multicast, 0 pause input
0 input packets with dribble condition detected
119118010 packets output, 23841215127 bytes, 0 underrun
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 PAUSE output

GigabitEthernet26 is up
Hardware is Gigabit Ethernet
Auto-duplex, Auto-speed, media type is Fiber
flow-control is off
back-pressure is enabled
33111023 packets input, 3029406673 bytes, 0 throttles
Received 11838017 broadcasts (18620039 multicasts)
0 runts, 436791 giants, 0 throttles
28999437 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
18620039 multicast, 0 pause input
0 input packets with dribble condition detected
6018781 packets output, 1357782931 bytes, 0 underrun
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 PAUSE output

I try to capture traffic with wireshark and find that some device connected was brocasting 0x8899 that is Realtek Remote Control Protocol.

I try to poweroff device that was brocasting this traffic and errors on uplink interface to the other switch fall down.

So appear to be traffic dependent.

Any idea?

[pieterh]

Realtek Remote Control Protocol - Wikipedia says:
The Realtek Remote Control Protocol (RRCP), developed by Realtek, is an application layer protocol, running directly over Ethernet frames. The main idea behind this protocol is to allow direct access to the internal register of an Ethernet switch controller (ASIC) over an Ethernet network itself. 

I  doubt if it is possible to have your Cisco switches ASIC managed this way ? (only works on Realtek switches)
=> the CBS220 will not understand this protocol and cannot process the packets 
=> "unknown protocol drops" may be a better description than "input errors"

you should investigate WHY this Realtek controller tries to manage your Cisco switch
perhaps was it a replacement of a Realtek switch ? -> maybe  this CBS220 can be excluded  in the Realtek controller
else you may try to block this traffic using an ACL

[lvfranz]

I agree that RRCP will not manage cisco switch.

I have always see reference ti input error as something related to lowest layers problem (checksum, frame, ecc..).

Your interpretation to "unknown protocol drops" fall well, the strange is that on the network there's also an old catalyst switch, and this doesn't report any error.

It isn't a realtek controller, the device connected are a industrial cnc. I haven't more information about what's inside CNC.

May be there's a small switch inside with Realtek semiconductor.

I'll try to investigate also with the manufacturer of cnc.

I doubt I can create ACL un cbs for this kind of traffic. I see only acl for ip or mac address