Hi, Randy: 

Thanks a bunch for pointing it out! Yup, you are absolutely right. What I 
wanted to say is why not put qg-, qr-, and ns- interfaces in the single 
namespace.

I typed it on my small keyboard on iPhone. Sorry for the confusion. :(

Shixiong




On Dec 19, 2013, at 8:44 PM, Randy Tuttle <[email protected]> wrote:

> Shixiong,
> 
> I know you must have a typo in the 3rd paragraph. I think maybe you mean to 
> include the ns- interface in that list. So why not have qg- qr- and ns- 
> interfaces in the same namespace. Am I right?
> 
> Rnady
> 
> 
> On Thu, Dec 19, 2013 at 8:31 PM, Shixiong Shang 
> <[email protected]> wrote:
> Hi, Ian:
> 
> The use case brought by Comcast team today during the ipv6 sub-team meeting 
> actually proved the point I made here, instead of against it. If I didn’t 
> explain it clearly in my previous email, here it is.
> 
> I was questioning the design with two namespaces and I believe we can use a 
> SINGLE namespace as the common container to host two services, i.e. DHCP and 
> ROUTING. If your use case needs DHCP instance, but not ROUTING, then just 
> launch dnsmasq in THE namespace with qr- interface; If your use case needs 
> default GW, then add qg- interface in THE namespace. Whether it is called 
> qdhcp or qrouter, I don’t care. It is just a label. 
> 
> People follow the routine to use it, simply because this is what OpenStack 
> offers. But my question is, why? And why NOT we design the system in the way 
> that qg- and qr- interface collocate in the same namespace?
> 
> It is because we intentionally separate the service, now the system become 
> clumsy and less efficient. As you can see in IPv6 cases, we are forced to 
> deal with two namespaces now. It just doesn’t make any sense.
> 
> Shixiong
> 
> 
> 
> 
> 
> 
> On Dec 19, 2013, at 7:27 PM, Ian Wells <[email protected]> wrote:
> 
>> Per the discussions this evening, we did identify a reason why you might 
>> need a dhcp namespace for v6 - because networks don't actually have to have 
>> routers.  It's clear you need an agent in the router namespace for RAs and 
>> another one in the DHCP namespace for when the network's not connected to a 
>> router, though.  
>> 
>> We've not pinned down all the API details yet, but the plan is to implement 
>> an RA agent first, responding to subnets that router is attached to (which 
>> is very close to what Randy and Shixiong have already done).
>> -- 
>> Ian.
>> 
>> 
>> On 19 December 2013 14:01, Randy Tuttle <[email protected]> wrote:
>> First, dnsmasq is not being "moved". Instead, it's a different instance for 
>> the attached subnet in the qrouter namespace. If it's not in the qrouter 
>> namespace, the default gateway (the local router interface) will be the 
>> interface of qdhcp namespace interface. That will cause blackhole for 
>> traffic from VM. As you know, routing tables and NAT all occur in qrouter 
>> namespace. So we want the RA to contain the local interface as default 
>> gateway in qrouter namespace
>> 
>> Randy
>> 
>> Sent from my iPhone
>> 
>> On Dec 19, 2013, at 4:05 AM, Xuhan Peng <[email protected]> wrote:
>> 
>>> I am reading through the blueprint created by Randy to bind dnsmasq into 
>>> qrouter- namespace:
>>> 
>>> https://blueprints.launchpad.net/neutron/+spec/dnsmasq-bind-into-qrouter-namespace
>>> 
>>> I don't think I can follow the reason that we need to change the namespace 
>>> which contains dnsmasq process and the device it listens to from qdhcp- to 
>>> qrouter-. Why the original namespace design conflicts with the Router 
>>> Advertisement sending from dnsmasq for SLAAC?
>>> 
>>> From the attached POC result link, the reason is stated as:
>>> 
>>> "Even if the dnsmasq process could send Router Advertisement, the default 
>>> gateway would bind to its own link-local address in the qdhcp- namespace. 
>>> As a result, traffic leaving tenant network will be drawn to DHCP 
>>> interface, instead of gateway port on router. That is not desirable! "
>>> 
>>> Can Randy or Shixiong explain this more? Thanks!
>>> 
>>> Xuhan 
>>> _______________________________________________
>>> 
>>> OpenStack-dev mailing list
>>> [email protected]
>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>> 
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