vxlan code is missing max_frame_size callback which is now mandatory if you
want to be able to do the change.
If vxlan code doesn’t care about that change, it can be as simple as:
vxlan_set_max_frame_size (vnet_main_t *vnm, vnet_hw_interface_t *hw, u32
frame_size)
{
return 0;
}
and:
eir.cb.set_max_frame_size = vxlan_set_max_frame_size;
right before call to vnet_eth_register_interface (vnm, &eir);
However right solution will be to allow/disallow change based on underlying
MTU…..
—
Damjan
> On 17.02.2022., at 12:11, Pim van Pelt <[email protected]> wrote:
>
> Hoi Artyom,
>
> Not an authoritative answer, although perhaps Damjan can confirm:
> Is the semantic difference between max frame size (==device will reject
> frames larger than that on Rx, and never Tx frames larger than that) and mtu
> (L3 IP/IP6/MPLS packets will not be larger than that) with an implication
> that MTU can bever be larger than max_frame_size.
>
> Regardless, Artyom, here's how I manipulate the MTU of VXLAN tunnels - the
> trick is to use the 'mtu packet' rather than 'mtu' option (see the CLI call
> in bold):
>
> create vxlan tunnel instance 10 src $A dst $B vni 320501 decap-next l2
> set interface state vxlan_tunnel10 up
> set interface mtu packet 1522 vxlan_tunnel10
> set interface l2 xconnect TenGigabitEthernet5/0/0.50 vxlan_tunnel10
> set interface l2 xconnect vxlan_tunnel10 TenGigabitEthernet5/0/0.50
>
> pim@ddln1:~$ vppctl show ver
> vpp v22.06-rc0~93-g360aee3e0 built by pim on dellr610 at 2022-02-13T11:56:07
>
> pim@ddln1:~$ vppctl show int vxlan_tunnel10
> Name Idx State MTU (L3/IP4/IP6/MPLS)
> Counter Count
> vxlan_tunnel10 17 up 1522/0/0/0 rx
> packets 209408
> rx bytes
> 81834552
> tx
> packets 1616124
> tx bytes
> 2471872228
>
> Does that help for you? I actually noticed that it doesn't prevent
> vxlan_tunnel10 from emitting larger frames, so I'm not quite sure what
> benefit it brings.
>
> On Thu, Feb 17, 2022 at 11:38 AM Artyom Glazychev
> <[email protected]> wrote:
> Hello,
>
> There is a problem with setting MTU for VxLAN. I see, that there was a change
> related to MTU and Max_frame_size - https://gerrit.fd.io/r/c/vpp/+/34928
>
> I don't know, what VxLAN configuration is right (I've asked about it here
> https://lists.fd.io/g/vpp-dev/topic/vxlan_l3_mode/89205942?p=,,,20,0,0,0::recentpostdate/sticky,,,20,2,0,89205942,previd=1645090589967474984,nextid=1643993575016104745&previd=1645090589967474984&nextid=1643993575016104745)
>
> But neither this:
> DBGvpp# create vxlan tunnel src 10.0.3.1 dst 10.0.3.3 vni 55 l3
> vxlan_tunnel0
> DBGvpp# set interface mtu 1400 vxlan_tunnel0
> set interface mtu: Unsupported (underlying driver doesn't support changing
> Max Frame Size)
>
> Nor this:
> DBGvpp# create vxlan tunnel src 10.0.3.1 dst 10.0.3.3 vni 55
> vxlan_tunnel0
> DBGvpp# set interface mtu 1400 vxlan_tunnel0
> set interface mtu: not supported
> is not working.
>
> So, my final question is how to configure the VxLAN L2-tunnel and set MTU?
> Thank you.
>
>
>
>
>
>
> --
> Pim van Pelt <[email protected]>
> PBVP1-RIPE - http://www.ipng.nl/
>
>
>
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