Path MTU discovery works on a path - something with an L3 router in the way
- where the outbound interface has a smaller MTU than the inbound one.
You're transmitting across an L2 network - no L3 routers present. You send
a 1500 byte packet, the network fabric (which is not L3, has no address,
The problem is that it is not at the begining to transmit large file. It is
after some packets trasmited, then the connection is choked.
After the connection choked, from the bridge in compute host we can see the
sender send packets, and the receiver can not get the packets.
If it is the pmtud,
lan, you are right, the receiver only receive packet that small than 1450.
Because the sender does not send large packets at the begining, so
tcpdump can catch some small packets.
Another question about the mtu, what if we clear the DF in the ip packets?
Then l2 can split packets into
:* Tuesday, October 28, 2014 11:40 AM
*To:* OpenStack Development Mailing List (not for usage questions)
*Subject:* Re: [openstack-dev] [neutron] vm can not transport large file
under neutron ml2 + linux bridge + vxlan
Path MTU discovery works on a path - something with an L3 router
One more question.
Vxlan use udp, how can vxlan promise reliability.
在 2014-10-28 15:51:02，Ian Wells ijw.ubu...@cack.org.uk 写道：
On 28 October 2014 00:30, Li Tianqing jaze...@163.com wrote:
lan, you are right, the receiver only receive packet that small than 1450.
Because the sender does not
...@cack.org.ukmailto:ijw.ubu...@cack.org.uk]
Sent: Tuesday, October 28, 2014 11:40 AM
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [neutron] vm can not transport large file under
neutron ml2 + linux bridge + vxlan
Path MTU discovery works on a path - something
On Tue, Oct 28, 2014 at 08:32:11, Li Tianqing wrote:
One more question.
Vxlan use udp, how can vxlan promise reliability.
It can't, but that doesn't matter.
VXLAN emulates a single layer 2 broadcast domain: conceptually, a series of
machines all plugged into the same Ethernet switch. This
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On 27/10/14 02:18, Li Tianqing wrote:
Hello, Right now, we test neutron under havana release. We
configured network_device_mtu=1450 in neutron.conf, After create
vm, we found the vm interface's mtu is 1500, the ping, ssh, is ok.
But if we scp
On Mon, Oct 27, 2014 at 4:42 AM, Ihar Hrachyshka ihrac...@redhat.com wrote:
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On 27/10/14 02:18, Li Tianqing wrote:
Hello, Right now, we test neutron under havana release. We
configured network_device_mtu=1450 in neutron.conf, After create
vm,
--
Best
Li Tianqing
At 2014-10-27 17:42:41, Ihar Hrachyshka ihrac...@redhat.com wrote:
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On 27/10/14 02:18, Li Tianqing wrote:
Hello, Right now, we test neutron under havana release. We
configured network_device_mtu=1450 in
Hi Tangqing,
This is a well-known problem, it is because GRE/VxLan 's packet header use
some bytes, length of data packet should reduced.
You can get refer to bellow pages:
http://www.chriscowley.me.uk/blog/2014/03/31/openstack-neutron-performance-problems/
Thanks, it helps a lot. But i want to know, why the mtu discovery can not find
the appropriate mtu to send?
In
http://www.chriscowley.me.uk/blog/2014/03/31/openstack-neutron-performance-problems/,
it says that
Everything matches, however I was using GRE tunnels, which add a header to
each
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