topic Re: S-Series Packet-Loss in ExtremeSwitching (EOS)

S-Series Packet-Loss

Eisi1 — Tue, 26 Jan 2021 22:14:16 GMT

Hello,

I have some problems with Packet-Loss at a S-Series switch/router. Every day I get "SNMP Contact Lost" in Netsight for some switches. I have found a device, which is dropping the SNMP-packets (requests). With “debug packet” at this device I get this:

Jan 26 13:41:00 X.X.5.91 DbgIpPkt[2][424], RECEIVE: ingress on port lag.0.1, vr global, vlan.0.1, Matched ipv4 acl 110, rule[1: permit ip host X.X.4.8 host X.X.5.237], FATE: Forwarding discontinued, cause: NTP_DEFER, vlan.0.4, vr global, nexthop X.X.5.237, flow disallowed, PKT-ORIG: InPort(lag.0.1) LEN(114) DA(20:B3:99:9B:67:33) SA(00:0C:29:A9:14:87) C-TAG(8100:0001) ETYPE(0800) SIP(X.X.4.8) DIP(X.X.5.237) VER(4) HLEN(5) TOTALLEN(92) PROTO(17) TOS(0) TTL(64) UDP_DST(161) UDP_SRC(59214)

Now I need to know what “Forwarding discontinued, cause: NTP_DEFER” means in detail and what is the reason for it?

I was not able to find any time-related error in Netsight-server and S-Series switch/router.

Re: S-Series Packet-Loss

SamPirok — Tue, 26 Jan 2021 22:45:05 GMT

Hi Eisi, that message is letting you know the packet wasn’t forwarded, and it wasn’t forwarded because it’s a CPU packet for NTP and didn’t need to be forwarded. The most likely cause for that message is high CPU, but that likely isn’t impacting your packet loss issue.

Re: S-Series Packet-Loss

Eisi1 — Wed, 27 Jan 2021 00:08:29 GMT

Hi Sam,

thanks for the fast answer. What do you mean with “CPU packet for NTP “? The dst-Ip-adress and port show me it’s a snmp-packet which needs to be forwarded to the switch. CPU-Load is at ~ 25 %.

Re: S-Series Packet-Loss

SamPirok — Wed, 27 Jan 2021 22:03:56 GMT

Hi Eisi, thanks for clarifying for me. I ran this past an EOS tech for guidance and they asked that we open a case to troubleshoot this further since the CPU load doesn’t seem to be the issue here.

Re: S-Series Packet-Loss

Eisi1 — Thu, 28 Jan 2021 21:30:05 GMT

Hi Sam,

thanks. I can open a case, but the hardware is old S150 (EOSL). Is it possible to get some support for this?

Re: S-Series Packet-Loss

SamPirok — Fri, 29 Jan 2021 20:12:19 GMT

Thanks for letting me know Eisi, yes that would likely prohibit a case. I ran this past our EOS engineers again and they were only able to suggest general troubleshooting, tracing the SNMP packets to see where they fail. I’m sorry I couldn’t be more helpful here.