From: "Алексей Болдырев" <devel-net-ne-vlezay80@yandex•ru>
To: Joe Stringer <joe@ovn•org>, David Ahern <dsahern@gmail•com>
Cc: netdev <netdev@vger•kernel.org>
Subject: Re: Maximum MPLS labels on Linux network stack
Date: Thu, 04 May 2017 00:19:52 +0300 [thread overview]
Message-ID: <443301493846392@web51g.yandex.ru> (raw)
In-Reply-To: <CAPWQB7FFwBFL9h7JoJMF4FuK7JXLrHfo5yg4aHJ4iczSdNU_bg@mail.gmail.com>
Is it possible to increase this limit in OpenVswitch?
03.05.2017, 23:21, "Joe Stringer" <joe@ovn•org>:
> On 3 May 2017 at 11:14, David Ahern <dsahern@gmail•com> wrote:
>> On 5/3/17 11:33 AM, Алексей Болдырев wrote:
>>> I watched one forum, there is listed in the properties of one license for Cisco, it says:
>>>
>>> Layer 3 VPN • Multi-VRF CE (VRF-lite); requires IP Services Feature license
>>> • MPLS VPN; requires Advanced IP Feature license
>>> • 26 VRFs
>>
>> There is no direct limit on the number of VRFs the kernel allows you to
>> create. There are indirect ones -- total memory in the system and limits
>> such as /proc/sys/net/ipv6/route/max_size. By increasing the latter I
>> have created 4k VRFs in a system.
>>
>>> • 8192 MPLS labels
>>>
>>> Especially interested in the figure 8192 MPLS Labels.
>>
>> 8192 labels added in one pass is absurd. There is no reason to support
>> such a number. With the latest version of the MPLS stack in the kernel
>> you can add up to 30 labels in a single route. If you want more you have
>> to either recirculate the packet using routes or recompile the kernel
>> and increase the memory limit and the number of labels limit.
>>
>>> As I understand it, is it either a limit on the number of labels on the stack or the total number of labels?
>>>
>>> In Linux, for example, you can specify a common col- lection of labels through /proc/sys/net/mpls/platforms_labels
>>
>> that just allocates the size of an array which dictates the max label
>> number for that namespace. The array needs to be converted to a hash
>> table at some point.
>>
>>> Also I would like to know if the openvswitch has a limit of 3 tags in the stack or the total number of MPLS labels that can send?
>>
>> someone familiar with OVS needs to answer that.
>
> That would be 3 tags in a stack. When we spoke to people involved in
> the design and usage of MPLS in practice, we got the impression that
> it's very rare for anyone to configure a setup where more than that is
> used concurrently on a packet. If you believe the contrary, then I
> imagine it's not hard to bump that limit.
>
> There is no limit on which labels can be used from OVS, it's just a
> number in an action attached to a flow.
next prev parent reply other threads:[~2017-05-03 21:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-03 17:33 Maximum MPLS labels on Linux network stack Алексей Болдырев
2017-05-03 18:14 ` David Ahern
2017-05-03 20:21 ` Joe Stringer
2017-05-03 21:19 ` Алексей Болдырев [this message]
2017-05-03 21:22 ` Joe Stringer
2017-05-03 21:29 ` Алексей Болдырев
2017-05-03 21:46 ` Joe Stringer
2017-05-04 2:22 ` David Ahern
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