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NX-OS 3548 transmits periodic non IPV4 packets to active access ports

rehadiri
Beginner
Beginner

We have Cisco nx-os 3548 , the software version is nxos.9.2.2.bin. The switch periodically transmit some unknown 60 byte packets to the Unix machines connected to VLAN 1 access ports. On the unix server when we check the interface with ifconfig we see that gets these packets  dropped because unix doesn't understand these frames. Almost every feature of Cisco switch is disabled, including cdp,lldp,udld etc.. The only active features are ssh-server and interface vlan .

We need ultra low latency lan network and get rid of these unknown packets. How can we disable these packets.

 

By the way Unix machines connected to the switch via 10Gbe fiber connection.

 

Thanks

1 Accepted Solution

Accepted Solutions

I am sorry , you are right

 

I have retested the 1gbe nic with Cisco-sf300 and after some period of time i see the same dropping packets there too.

 

It looks like an Ubuntu problem as you have said

 

Thank you for your help

Best Regards

View solution in original post

10 Replies 10

marce1000
VIP Mentor VIP Mentor
VIP Mentor

 

              >....The switch periodically transmit some unknown 60 byte packets

  How was this observed , which tool did you use , can you provide a screenshot (e.g.) , or other output. (?)

 M.

rehadiri
Beginner
Beginner

Here is what we see from the Ubuntu Server,

 

hftuser@hftsrv1:~$ ifconfig -a enp2s0f0
enp2s0f0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.5.11 netmask 255.255.255.0 broadcast 192.168.5.255
ether 3c:fd:fe:9e:98:30 txqueuelen 1000 (Ethernet)
RX packets 11 bytes 660 (660.0 B)
RX errors 0 dropped 11 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

 

hftuser@hftsrv1:~$ ifconfig -a enp2s0f0
enp2s0f0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.5.11 netmask 255.255.255.0 broadcast 192.168.5.255
ether 3c:fd:fe:9e:98:30 txqueuelen 1000 (Ethernet)
RX packets 12 bytes 720 (720.0 B)
RX errors 0 dropped 12 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

hftuser@hftsrv1:~$

 

Two consecutive ifconfig output is like that . These 60 byte frames comes almost every 1 sec. 

If needed i will try to access the frames and give you the frame in hex format.

 

Thanks a lot

 

                                >If needed i will try to access the frames and give you the frame in hex format.

 - Please do  ,because it is a bit unclear how you correlate to the output in bold to an additional 60 bytes, if possible also check if the Ubuntu server is not bothered by this when connected to another switch type (not the 3548) , because it could be bug on Ubuntu or networking problem on the mentioned Unix server.

 M.

This is the frames in Hex

 

Dumping payload [len = 60]:
0: 01 80 c2 00 00 00 6c 13 d5 2a 15 3e 00 27 42 42 ......l..*.>.'BB
16: 03 00 00 02 02 3c 80 01 6c 13 d5 2a 15 7c 00 00 .....<..l..*.|..
32: 00 00 80 01 6c 13 d5 2a 15 7c 80 17 00 00 14 00 ....l..*.|......
48: 02 00 0f 00 00 00 00 00 00 00 00 00


POLLBODY: Received non-IPv4 packet, showing content below:
Dumping payload [len = 60]:
0: 01 80 c2 00 00 00 6c 13 d5 2a 15 3e 00 27 42 42 ......l..*.>.'BB
16: 03 00 00 02 02 3c 80 01 6c 13 d5 2a 15 7c 00 00 .....<..l..*.|..
32: 00 00 80 01 6c 13 d5 2a 15 7c 80 17 00 00 14 00 ....l..*.|......
48: 02 00 0f 00 00 00 00 00 00 00 00 00

 

Thanks Again

I can't connect 10gbe interface to other switches but i can connect 1 gbe NIC to Cisco-sf300 switch

 

Here is the output of 1 Gbe interface counters connected to sf300 switch

enp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.5.15 netmask 255.255.255.0 broadcast 192.168.5.255
ether 50:eb:f6:22:88:d1 txqueuelen 1000 (Ethernet)
RX packets 3 bytes 180 (180.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

 

We don't see any dropped packets here 

 

But when i connect the same 1 GB interface to the 3548 can see the same dropped packets .

 

 

 

 - Check port counters on the interface-port on the 3548. Check if the problem is not there if the Ubuntu is connected somewhere else , or confirm the problem by connecting another server-type to this nexus-port , (I still think the problem is more with Ubuntu).

 M.

Here is what we see after connecting the enp4s0 1gbe interface to 3548 via 1gb sfp

 

enp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.5.15 netmask 255.255.255.0 broadcast 192.168.5.255
ether 50:eb:f6:22:88:d1 txqueuelen 1000 (Ethernet)
RX packets 44 bytes 2640 (2.6 KB)
RX errors 0 dropped 21 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

 

root@hftsrv1:~# ifconfig enp4s0
enp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.5.15 netmask 255.255.255.0 broadcast 192.168.5.255
ether 50:eb:f6:22:88:d1 txqueuelen 1000 (Ethernet)
RX packets 45 bytes 2700 (2.7 KB)
RX errors 0 dropped 22 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

 

Same behaviour like in 10gbe interfaces

This is 3548 interface counters

 

Ethernet1/21 is up
admin state is up, Dedicated Interface
Hardware: 100/1000/10000/40000 Ethernet, address: 6c13.d52a.153c (bia 6c13.d52a.153c)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is access
full-duplex, 10 Gb/s, media type is 10G
Beacon is turned off
Auto-Negotiation is turned on FEC mode is Auto
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
Last link flapped 00:04:11
Last clearing of "show interface" counters never
1 interface resets
Load-Interval #1: 30 seconds
30 seconds input rate 1808 bits/sec, 1 packets/sec
30 seconds output rate 1216 bits/sec, 1 packets/sec
input rate 1.81 Kbps, 1 pps; output rate 1.22 Kbps, 1 pps
Load-Interval #2: 5 minute (300 seconds)
300 seconds input rate 712 bits/sec, 0 packets/sec
300 seconds output rate 568 bits/sec, 0 packets/sec
input rate 712 bps, 0 pps; output rate 568 bps, 0 pps
RX
103 unicast packets 12 multicast packets 1 broadcast packets
116 input packets 13518 bytes
0 jumbo packets 0 storm suppression packets
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
TX
184 unicast packets 2 multicast packets 0 broadcast packets
186 output packets 19929 bytes
0 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard
0 Tx pause

 

As i can see TX packets keep increasing here

Finally i have connected a laptop with Ubuntu 20.04 to 3548 and dropped packets gone.

 

Now it seems that everything normal.

 

 But i dont understand why the 1Gbe nic worked normally with Cisco-sf300 and not with Cisco3548

 

The Malfunctioning Ubuntu is new Asus mainboard Desktop computer and has a Intel XL710-DA2 NIC . The version is Ubuntu 22.04.

 

Something strange here

I am sorry , you are right

 

I have retested the 1gbe nic with Cisco-sf300 and after some period of time i see the same dropping packets there too.

 

It looks like an Ubuntu problem as you have said

 

Thank you for your help

Best Regards

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