SN2700 mgmt0 offline / arp cache ?

Infrastructure & Networking Switches and Gateways Ethernet Switches
1

Hi,

we have 2 brand new SN2700 100G Switches. It shipped with Onyx and since the beginning one of them was acting weird on the Management Interface. Even after upgrading to latest version 8190, the switch is rebooted and not pingable, BUT if i start pinging anything from serial connection, the gateway or the second device, the network connecticity is restored.

I ping 10.0.100.100 -t and get no answer from the switch. If i then go on the serial and ping 10.0.254.254, or 10.0.100.101 and the switch begins to be available from my admin host again. Network guys checked the other switch where the mgmt0 is connected to, and point to maybe ARP problems ? Anything else i can do to make it stable ?

The second switch worked fine out of the box, im not sure whats wrong with that device.

Best regards

Tim

2

Hi,

So, we tried reverting to factory defaults, switched LAN Cables and LAN Ports. Its still faulty.

It is NOT pingable from outside until i start pinging from the switch to other machines (10.0.100.146)

tcpdump ARP is getting more and more AFTER i used ping from console. Before it was rather low. Weird behaviour.

mx4 [standalone: master] # mx4 [standalone: master] # show interfaces mgmt0

Interface mgmt0 status:

Comment :

Admin up : yes

Link up : yes

DHCP running : no

IP address : 10.0.100.145

Netmask : 255.255.0.0

IPv6 enabled : yes

Autoconf enabled: no

Autoconf route : yes

Autoconf privacy: no

DHCPv6 running : yes (but no valid lease)

IPv6 addresses : 1

IPv6 address:

fe80::526b:4bff:fef4:fd30/64

Speed : 1000Mb/s (auto)

Duplex : full (auto)

Interface type : ethernet

Interface source: bridge

MTU : 1500

lines 1-23 HW address : 50:6B:4B:F4:FD:30

Rx:

748655546 bytes

7397224 packets

0 mcast packets

0 discards

0 errors

0 overruns

0 frame

Tx:

3503019 bytes

26117 packets

0 discards

0 errors

0 overruns

0 carrier

0 collisions

0 queue len

lines 22-44/44 (END) mx4 [standalone: master] # sh interfaces mgmt0 configured

Interface mgmt0 configuration:

Comment :

Enabled : yes

DHCP : no

DHCP Hostname : yes

Zeroconf : no

IP address : 10.0.100.145

Netmask : 255.255.0.0

IPv6 enabled : yes

Autoconf enabled: no

Autoconf route : yes

Autoconf privacy: no

DHCPv6 enabled : yes

IPv6 addresses : 0

Speed : auto

Duplex : auto

MTU : 1500

mx4 [standalone: master] # show ip route

Flags:

F: Failed to install in H/W

B: BFD protected (static route)

i: BFD session initializing (static route)

x: protecting BFD session failed (static route)

VRF Name default:

Destination Mask Flag Gateway Interface Source

AD/M

default 0.0.0.0 10.0.254.254 mgmt0 static

1/1

10.0.0.0 255.255.0.0 0.0.0.0 mgmt0 direct

0/0

mx4 [standalone: master] # mx4 [standalone: master] # tcpdump -i mgmt0 arp

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

listening on mgmt0, link-type EN10MB (Ethernet), capture size 262144 bytes

11:42:41.187479 ARP, Request who-has 10.0.40.170 tell 10.0.100.201, length 46

11:42:41.414540 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

11:42:41.423851 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:42:41.911195 ARP, Request who-has 10.0.10.200 tell 10.0.40.135, length 46

11:42:42.414526 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

11:42:42.423809 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:42:43.376184 ARP, Request who-has 10.0.220.222 tell 10.0.220.3, length 46

mx4 [standalone: master] # ping 10.0.254.254

PING 10.0.254.254 (10.0.254.254) 56(84) bytes of data.

— 10.0.254.254 ping statistics —

33 packets transmitted, 0 received, 100% packet loss, time 32000ms

mx4 [standalone: master] # ping 10.0.100.145

PING 10.0.100.145 (10.0.100.145) 56(84) bytes of data.

64 bytes from 10.0.100.145: icmp_seq=1 ttl=64 time=0.045 ms

64 bytes from 10.0.100.145: icmp_seq=2 ttl=64 time=0.047 ms

64 bytes from 10.0.100.145: icmp_seq=3 ttl=64 time=0.046 ms

64 bytes from 10.0.100.145: icmp_seq=4 ttl=64 time=0.047 ms

64 bytes from 10.0.100.145: icmp_seq=5 ttl=64 time=0.045 ms

64 bytes from 10.0.100.145: icmp_seq=6 ttl=64 time=0.045 ms

AFTER pinging itself and the other maschine (10.0.100.146) suddenly ping works from outside remote host and ARP works more.

mx4 [standalone: master] # tcpdump -i mgmt0 arp

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

listening on mgmt0, link-type EN10MB (Ethernet), capture size 262144 bytes

11:45:43.400435 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

11:45:43.415670 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:43.670091 ARP, Request who-has 10.0.10.200 tell 10.0.34.105, length 46

11:45:43.694971 ARP, Request who-has 10.0.10.200 tell 10.0.34.105, length 46

11:45:44.400438 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

11:45:44.415638 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:45.400293 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

11:45:45.415544 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:46.419348 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

11:45:46.438702 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:46.462978 ARP, Request who-has 10.0.10.200 tell 10.0.34.105, length 46

11:45:47.419341 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

11:45:47.431649 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:48.419348 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

11:45:48.431642 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:48.449022 ARP, Request who-has 10.0.115.20 tell 10.0.100.170, length 46

11:45:48.761626 ARP, Request who-has 10.0.254.254 tell 10.0.117.200, length 46

11:45:49.403327 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

11:45:50.403320 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

11:45:50.415558 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:51.403313 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

11:45:51.415546 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:52.415634 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

11:45:52.438487 ARP, Request who-has 10.0.216.184 tell 10.0.110.135, length 46

11:45:53.427496 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

3

Hi Tim,

Can you share the output of:

show interface mgmt0

show interface mgmt0 configured

show ip route

Please recreate the issue and try the following:

Connect to the switch using the console, and run the following command:

tcpdump -i mgmt0 arp or icmp

After this and while tcpdump is on start a ping from the remote host.

Are you seeing the remote host ARP or ICMP echo requests ?