MTU issues
-
Hello,
I'm running 2 TNSR in VMWARE and have set the vswitch to MTU9000.
After this, I've created a network in this vswitch to connect the 2 TNSR hosts between them.
For this interfaces in the hosts, I've also set the MTU to 9000.so all good, I can ping.
[toor@labtnsr1 ~]$ ping 192.168.255.11 -s 8972 -M do PING 192.168.255.11 (192.168.255.11) 8972(9000) bytes of data. 8980 bytes from 192.168.255.11: icmp_seq=1 ttl=64 time=0.227 ms 8980 bytes from 192.168.255.11: icmp_seq=2 ttl=64 time=0.261 ms ^C --- 192.168.255.11 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 57ms rtt min/avg/max/mdev = 0.227/0.244/0.261/0.017 ms [toor@labtnsr1 ~]$I've the TNSR dataplane network card also connected to this vswitch, but inside the TNSR, I can't ping over mtu 1512.
labtnsr1 tnsr# dataplane ping 10.0.0.2 packet-size 1484 PING 10.0.0.2 (10.0.0.2) 1484(1512) bytes of data. 1492 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=0.259 ms 1492 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=0.201 ms 1492 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=0.248 ms ^C --- 10.0.0.2 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 57ms rtt min/avg/max/mdev = 0.201/0.236/0.259/0.025 ms labtnsr1 tnsr# dataplane ping 10.0.0.2 packet-size 1485 PING 10.0.0.2 (10.0.0.2) 1485(1513) bytes of data. ^C --- 10.0.0.2 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 84ms labtnsr1 tnsr#The link MTU was correct to all interfaces, all are 9000, but IPv4 MTU was at 0.
To test, I've also changed this MTU to 8000 (lower then the link MTU) and no good also.I've also put this command:
labtnsr1 tnsr(config)# dataplane ethernet default-mtu 9000but nothing seems to work.
Interfaces:
labtnsr1 tnsr# show interface Interface: ipip0 Admin status: up Link up, unknown duplex Link MTU: 9000 bytes IPv4 MTU: 8000 bytes IPv4 Route Table: ipv4-VRF:0 IPv4 addresses: 172.20.0.1/30 IPv6 MTU: 0 bytes IPv6 Route Table: ipv6-VRF:0 IPv6 addresses: fe80::7266:2fb0:9ce5:b003/64 VLAN tag rewrite: disable counters: received: 19880 bytes, 165 packets, 0 errors transmitted: 23480 bytes, 168 packets, 0 errors protocols: 159 IPv4, 6 IPv6 6 drops, 0 punts, 0 rx miss, 0 rx no buffer Interface: loop0 Admin status: up Link up, unknown duplex Link MTU: 9000 bytes MAC address: de:ad:00:00:00:00 IPv4 MTU: 0 bytes IPv4 Route Table: ipv4-VRF:0 IPv4 addresses: 172.21.0.1/32 IPv6 MTU: 0 bytes IPv6 Route Table: ipv6-VRF:0 IPv6 addresses: fe80::dcad:ff:fe00:0/64 VLAN tag rewrite: disable counters: received: 0 bytes, 0 packets, 0 errors transmitted: 5852 bytes, 70 packets, 0 errors protocols: 0 IPv4, 35 IPv6 26 drops, 0 punts, 0 rx miss, 0 rx no buffer Interface: trunk0 Admin status: up Link up, link-speed 10 Gbps, full duplex Link MTU: 9000 bytes MAC address: 00:50:56:ba:ed:31 IPv4 MTU: 8000 bytes IPv4 Route Table: ipv4-VRF:0 IPv6 MTU: 0 bytes IPv6 Route Table: ipv6-VRF:0 IPv6 addresses: fe80::250:56ff:feba:ed31/64 VLAN tag rewrite: disable Rx-queues queue-id 0 : cpu-id 1 counters: received: 55776 bytes, 300 packets, 0 errors transmitted: 94201 bytes, 275 packets, 5 errors protocols: 2 IPv4, 30 IPv6 75 drops, 26 punts, 0 rx miss, 0 rx no buffer Interface: trunk0.50 Description: VPLS Admin status: up Link up, link-speed 10 Gbps, full duplex Link MTU: 9000 bytes IPv4 MTU: 8500 bytes IPv4 Route Table: ipv4-VRF:0 IPv4 addresses: 10.0.0.1/28 IPv6 MTU: 0 bytes IPv6 Route Table: ipv6-VRF:0 IPv6 addresses: fe80::250:56ff:feba:ed31/64 VLAN tag rewrite: disable detailed counters: received: 50084 bytes, 216 packets, 0 errors received unicast: 0 bytes, 0 packets received multicast: 0 bytes, 0 packets received broadcast: 0 bytes, 0 packets transmitted: 28050 bytes, 186 packets, 0 errors transmitted unicast: 0 bytes, 0 packets transmitted multicast: 0 bytes, 0 packets transmitted broadcast: 0 bytes, 0 packets protocols: 182 IPv4, 24 IPv6 25 drops, 0 punts, 0 rx miss, 0 rx no buffer labtnsr1 tnsr#Dataplane shell shows 9000 also.
labtnsr1 tnsr# dataplane shell bash-4.4$ ifconfig lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 1 bytes 396 (396.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1 bytes 396 (396.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 vpp1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000 inet6 fe80::250:56ff:feba:ed31 prefixlen 64 scopeid 0x20<link> ether 00:50:56:ba:ed:31 txqueuelen 1000 (Ethernet) RX packets 28 bytes 21918 (21.4 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 71 bytes 64603 (63.0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 vpp3: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 9000 inet 172.20.0.1 netmask 255.255.255.252 destination 172.20.0.1 inet6 fe80::7266:2fb0:9ce5:b003 prefixlen 64 scopeid 0x20<link> unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 500 (UNSPEC) RX packets 192 bytes 13232 (12.9 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 207 bytes 13960 (13.6 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 vpp5: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000 inet 172.21.0.1 netmask 255.255.255.255 broadcast 0.0.0.0 inet6 fe80::dcad:ff:fe00:0 prefixlen 64 scopeid 0x20<link> ether de:ad:00:00:00:00 txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 14 bytes 1076 (1.0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 vpp7: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000 inet 10.0.0.1 netmask 255.255.255.240 broadcast 0.0.0.0 inet6 fe80::250:56ff:feba:ed31 prefixlen 64 scopeid 0x20<link> ether 00:50:56:ba:ed:31 txqueuelen 1000 (Ethernet) RX packets 24 bytes 21246 (20.7 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 61 bytes 63619 (62.1 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 bash-4.4$Any idea how to go over this?
My goal is to have iopsec tunnels allowing traffic with standard 1500 MTU, but I can't even get that ping over the trunk0.50 interface.
Thanks.
-
There is an issue being worked with jumbo frames and vmxnet3 interfaces on the dataplane in VMware.
There is no workaround at the moment except using pass-through NICs or using E1000e for functionality testing purposes.
-
@Derelict
Ok, thank you for the feedback.
Will change the NIC's for now.
Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.