[ovs-discuss] How to increase mtu on gre_sys interface ?

[Jean-mathieu CHANTREIN]

Hello. 

It's work if I add a post-up instruction on the OVSBridge 

iface vmbr1 inet manual 
ovs_type OVSBridge 
ovs_ports gre1 gre2 gre3 
mtu 9000 
post-up ( ovs-vsctl set Bridge vmbr1 rstp_enable=true && sleep 10 && ip link set gre_sys mtu 8872 ) 

But I'm not sure it's the best way ... 

Regards. 

Jean-Mathieu 

> De: "Jean-mathieu CHANTREIN" <jean-mathieu.chantrein at univ-angers.fr>
> À: "ovs-discuss" <ovs-discuss at openvswitch.org>
> Envoyé: Lundi 10 Septembre 2018 13:13:59
> Objet: [ovs-discuss] How to increase mtu on gre_sys interface ?

> Hello.

> I use OVS on a Proxmox cluster and I configure GRE Tunnel like this:
> http://docs.openvswitch.org/en/latest/howto/tunneling/

> I activated the jumbo frame (mtu 9000) on physical switch, physical and virtual
> interfaces (OVSBridge and OVSTunnel gre). By default, the gre_sys mtu is set to
> 1472 (I suppose to prevent the overhead of 28 bytes of GRE(8 bytes) and new IP
> header(20 bytes)) .

> I can modify it manually with:
> ip link set gre_sys mtu 8872 #(9000-28)

> So, 2VM on 2 hosts can communicate correctly with a 1500 mtu

> user at VM1:$ ping -M do -s 1472 $IP_VM2 # 1500 - (ICMP(8 bytes) + IPV4(20
> bytes))=1472
> PING IP_VM2 1472(1500) bytes of data.
> 1480 bytes from IP_VM2: icmp_seq=1 ttl=64 time=0.227 ms
> ...

> I would like to know what is the best practice to make it persistent in
> /etc/network/interfaces file ?

> Best regards.

> Jean-Mathieu



> _______________________________________________
> discuss mailing list
> discuss at openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openvswitch.org/pipermail/ovs-discuss/attachments/20180911/e8cf5592/attachment.html>