From: Ben Greear <greearb@candelatech•com>
To: Hannes Frederic Sowa <hannes@stressinduktion•org>,
David Ahern <dsahern@gmail•com>,
Sowmini Varadhan <sowmini05@gmail•com>
Cc: "Eric W. Biederman" <ebiederm@xmission•com>,
Nicolas Dichtel <nicolas.dichtel@6wind•com>,
netdev <netdev@vger•kernel.org>
Subject: Re: VRFs and the scalability of namespaces
Date: Mon, 29 Sep 2014 18:15:07 -0700 [thread overview]
Message-ID: <542A041B.3000600@candelatech.com> (raw)
In-Reply-To: <1412034624.2008259.173208057.03BE7CBA@webmail.messagingengine.com>
On 09/29/2014 04:50 PM, Hannes Frederic Sowa wrote:
> On Tue, Sep 30, 2014, at 01:43, David Ahern wrote:
>> On 9/29/14, 11:00 AM, Ben Greear wrote:
>>> On 09/29/2014 09:50 AM, Sowmini Varadhan wrote:
>>>> On Mon, Sep 29, 2014 at 12:40 PM, Ben Greear <greearb@candelatech•com> wrote:
>>>>> On 09/29/2014 06:06 AM, David Ahern wrote:
>>>>
>>>>>
>>>>> We have implemented support for at least most of this (excepting duplicate IPs)
>>>>> using routing tables, rules, and (optionally, xorp as the router).
>>>>>
>>>>
>>>> My undertanding of multiple routing-tables/rules was that they
>>>> are closer in semantics to switch/router ACLs than to VRFs, eg.,
>>>> one big difference is that an interface can belong to exactly one
>>>> VRF at a time, which is not mandated by multiple routing-tables/rules.
>>>>
>>>> Was I mistaken?
>>>
>>> You can effectively force an interface to belong to a particular virtual
>>> router (table). It is not trivial to do, and possibly I have still not
>>> covered every possible case. Some rules grow somewhat exponentially as
>>> interfaces are added to virtual routers (ie, preference 10 rules).
>>
>> An interesting way of doing it; thanks for the reference point.
>>
>> Fundamentally the design should be able to assign interfaces to a single
>> VRF, support duplicate IP addresses on different interfaces in different
>> VRFs and be able to scale to 10,000+ netdevices -- devices representing
>> physical ports as well as logical interfaces built on top of them (e.g.,
>> sub-interfaces).
>
> Duplicate IP addresses don't go well with current linux stack being a
> soft end model by default. Current separation is done on arp level today
> if some kind of strong end model is desired. This calls for some kind of
> namespaces again. ;)
arp is per interface as well if you set arp-filter properly, the main problem with duplicate IPs is that
you can't (easily?) set up routing rules that match them properly...
Thanks,
Ben
>
> Bye,
> Hannes
>
--
Ben Greear <greearb@candelatech•com>
Candela Technologies Inc http://www.candelatech.com
next prev parent reply other threads:[~2014-09-30 1:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-26 22:37 VRFs and the scalability of namespaces David Ahern
2014-09-26 23:52 ` Stephen Hemminger
2014-09-27 0:00 ` David Ahern
2014-09-27 1:25 ` Eric W. Biederman
2014-09-29 12:34 ` David Ahern
2014-09-27 13:29 ` Hannes Frederic Sowa
2014-09-27 14:09 ` Hannes Frederic Sowa
2014-09-29 13:06 ` David Ahern
2014-09-29 16:40 ` Ben Greear
2014-09-29 16:50 ` Sowmini Varadhan
2014-09-29 17:00 ` Ben Greear
2014-09-29 23:43 ` David Ahern
2014-09-29 23:50 ` Hannes Frederic Sowa
2014-09-30 1:15 ` Ben Greear [this message]
2014-09-29 18:05 ` Cong Wang
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