I have already read a ton of literature about "size MTU at EX switches".
Like:
https://lists.gt.net/nsp/juniper/25466
https://packet-expert.org/2016/09/23/junos-mtu-handling-on-access-trunk-ports/
In all source say:
"
Obviously its creating confusion, if trunk interface is showing MTU value of 1514 then how it will receive packet with 1500 bytes payload + 18 bytes header . But the matter of the fact is , this interface will receive payload size of 1500 bytes and header size of 18 bytes even with MTU value displayed in CLI as 1514 .
Conclusion
- Trunk ports- Even though MTU size displayed in CLI is 1514 bytes but at hardware level 1518 bytes are handled for 802.1Q packets.
"
On the other hand, I have a other connection from this MX480 to the switch QFX1002:
admin@QFX10002-nl-1> show interfaces ae1
Physical interface: ae1 (MC-AE-1, active), Enabled, Physical link is Up
Interface index: 149, SNMP ifIndex: 531
Description: uplink to MX480
Link-level type: Ethernet, MTU: 1514, Speed: 100Gbps, BPDU Error: None, Ethernet-Switching Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Disabled, Minimum links needed: 1,
Minimum bandwidth needed: 1bps
Device flags : Present Running
No issue.
I have other POP. Other MX480 connected to QFX5100-VC. No issue.
admin@P23> show interfaces ae0
Physical interface: ae0, Enabled, Physical link is Up
Interface index: 695, SNMP ifIndex: 607
Description: to MX480
Link-level type: Ethernet, MTU: 1514, Speed: 180Gbps, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Disabled, Minimum links needed: 1, Minimum bandwidth needed: 1bps
Device flags : Present Running
P.S. Of course I try at EX4550:
admin# set interfaces ae1 mtu 1518
{master:2}[edit]
admin# commit synchronize
fpc2:
configuration check succeeds
fpc3:
commit complete
fpc2:
commit complete
{master:2}[edit]
Not solved.
root@ubuntu:~# wget -O /dev/null https://mirror.leaseweb.com/speedtest/10000mb.bin
--2019-10-11 06:01:46-- https://mirror.leaseweb.com/speedtest/10000mb.bin
Resolving mirror.leaseweb.com (mirror.leaseweb.com)... 37.58.58.140, 2a00:c98:2030:a034::21
Connecting to mirror.leaseweb.com (mirror.leaseweb.com)|37.58.58.140|:443... connected.
P.P.S.
admin# run show ethernet-switching interfaces ae1 detail
Interface: ae1.0, Index: 126, State: up, Port mode: Trunk
Native vlan: native
Ether type for the interface: 0x8100
VLAN membership:
native, 802.1Q Tag: 1, untagged, msti-id: 0, unblocked
vlan_300, 802.1Q Tag: 300, tagged, msti-id: 0, unblocked
vlan_350, 802.1Q Tag: 350, tagged, msti-id: 0, unblocked
vlan_400, 802.1Q Tag: 400, tagged, msti-id: 0, unblocked
vlan_450, 802.1Q Tag: 450, tagged, msti-id: 0, unblocked
vlan_500, 802.1Q Tag: 500, tagged, msti-id: 0, unblocked
vlan_550, 802.1Q Tag: 550, tagged, msti-id: 0, unblocked
vlan_800, 802.1Q Tag: 800, tagged, msti-id: 0, unblocked
Number of MACs learned on IFL: 24
{master:2}[edit]
admin# show interfaces xe-2/0/13
unit 0 {
family ethernet-switching {
vlan {
members vlan_550;
}
filter {
input 2g;
}
}
}