08-16-2022 02:27 PM
I have two cisco Nexus3500 C3548P-10GX Chassis connected to one another via L3 port-channel. MTU on the system and interface are both set to 9000, however I am unable to ping over link more that 1478 bytes?
08-16-2022 02:30 PM
there are two MTU
the MTU of interface and MTU of VLAN SVI,
so check each port member of PO MTU
and check the MTU of SVI
08-16-2022 03:16 PM
Thanks for your reply but Its a L3 port-channel not L2 with VLAN.
08-16-2022 03:40 PM
can you share the show interface of one port member of L3 PO?
08-16-2022 04:34 PM
absolutely!
interface port-channel2
no switchport
mtu 9000
ip address 10.51.222.89/30
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.51
ip pim sparse-mode
08-16-2022 04:45 PM
port member not the PO,
i meaning for example g0/0 and g0/1 is bound to form PO-2
PO-2 have MTU 9000 but are g0/0 and g0/1 have same ?
08-16-2022 05:01 PM
its the same (MTU 9000), as once in the Po all config from Po.
08-16-2022 05:21 PM - edited 08-16-2022 05:21 PM
As I know all L3 port (include the L3 PO) for all NSK platform support per-port MTU and you do right
https://www.cisco.com/c/en/us/support/docs/switches/nexus-9000-series-switches/118994-config-nexus-00.html
BUT
still one thing
you config MTU 9000 not 9216
so can you try ping 8700 not 9000 ?
08-16-2022 05:34 PM
anything above 1478 does not ping.
08-17-2022 07:19 AM
Switch#show system internal ethpm info interface eth <PO port member> | egrep -i mtu
can you share this
08-17-2022 07:29 AM
show system internal ethpm info interface Po2 | egrep -i mtu
medium(broadcast), snmp trap(on), MTU(9000),
admin_state(1), admin_layer(1), admin_router_mac(0) admin_mtu(1)
ethpm_ im_get_ifindex_mtu_list 9000
ethpm_ im_get_ifindex_mtu_usr_conf_flag_list 1
ethpm_ im_get_ifindex_vl_mtu_list No function pointer
ethpm_ im_get_ifindex_system_def_class_mtu_list No function pointer
08-17-2022 09:12 AM
show system internal ethpm info interface <port member not PO> | egrep -i mtu
08-17-2022 09:28 AM
show system internal ethpm info interface eth1/23 | egrep -i mtu
medium(broadcast), snmp trap(on), MTU(9000),
admin_state(1), admin_layer(1), admin_router_mac(0) admin_mtu(1)
ethpm_ im_get_ifindex_mtu_list 9000
ethpm_ im_get_ifindex_mtu_usr_conf_flag_list 1
ethpm_ im_get_ifindex_vl_mtu_list No function pointer
ethpm_ im_get_ifindex_system_def_class_mtu_list No function pointer
08-18-2022 01:06 PM
https://www.cisco.com/c/en/us/support/docs/lan-switching/ethernet/215451-padding-and-different-mtu-behavior.html
all your config is right and PO and port member show 9000 as jumbo frame size,
I think may be this is not issue of NSK but issue of other SW connect both side (ping source and ping destination)
if L2 SW interconnect both NSK then even if NSK support 9000 the L2 SW with 1500 will drop the frame.
check above link
08-18-2022 05:45 PM
issue with config, MTU had to be set in QoS policy
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