cloudstack-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Hean Seng <heans...@gmail.com>
Subject Re: IPV6 in Isolated/VPC networks
Date Thu, 15 Jul 2021 10:25:22 GMT
Hi Wido,

I think the /48 is at physical router as gateway , and subnet of /64 at VR
of Cloudstack.   Cloudstack only keep which /48 prefix and vlan information
of this /48 to be later split the  /64. to VR.

And the instances is getting singe IPv6 of /64  IP.   The VR is getting
/64.  The default gateway shall goes to /48 of physical router ip .   In
this case ,does not need any BGP router .


Similar concept as IPv4 :

/48 subnet of IPv6 is equivalent to current /24 subnet of IPv4 that created
in Network.
and /64  of IPv6 is equivalent to single IP of IPv4 assign to VM.




On Thu, Jul 15, 2021 at 5:31 PM Wido den Hollander <wido@widodh.nl> wrote:

>
>
> Op 14-07-2021 om 16:44 schreef Hean Seng:
> > Hi
> >
> > I replied in another thread, i think do not need implement BGP or OSPF,
> > that would be complicated .
> >
> > We only need assign  IPv6 's /64 prefix to Virtual Router (VR) in NAT
> > zone, and the VR responsible to deliver single IPv6 to VM via DHCP6.
> >
> > In VR, you need to have Default IPv6 route to  Physical Router's /48. IP
> > as IPv6 Gateway.  Thens should be done .
> >
> > Example :
> > Physical Router Interface
> >   IPv6 IP : 2000:aaaa::1/48
> >
> > Cloudstack  virtual router : 2000:aaaa:200:201::1/64 with default ipv6
> > route to router ip 2000:aaaa::1
> > and Clodustack Virtual router dhcp allocate IP to VM , and  VM will have
> > default route to VR. IPv6 2000:aaaa:200:201::1
> >
> > So in cloudstack need to allow  user to enter ,  IPv6 gwateway , and
> > the  /48 Ipv6 prefix , then it will self allocate the /64 ip to the VR ,
> > and maintain make sure not ovelap allocation
> >
> >
>
> But NAT is truly not the solution with IPv6. IPv6 is supposed to be
> routable. In addition you should avoid DHCPv6 as much as possible as
> that's not really the intended use-case for address allocation with IPv6.
>
> In order to route an /48 IPv6 subnet to the VR you have a few
> possibilities:
>
> - Static route from the upperlying routers which are outside of CloudStack
> - BGP
> - OSPFv3 (broken in most cases!)
> - DHCPv6 Prefix Delegation
>
> BGP and/or Static routes are still the best bet here.
>
> So what you do is that you tell CloudStack that you will route
> 2001:db8::/48 to the VR, the VR can then use that to split it up into
> multiple /64 subnets going towards the instances:
>
> - 2001:db8::/64
> - 2001:db8:1::/64
> - 2001:db8:2::/64
> ...
> - 2001:db8:f::/64
>
> And go on.
>
> In case of BGP you indeed have to tell the VR a few things:
>
> - It's own AS number
> - The peer's address(es)
>
> With FRR you can simply say:
>
> neighbor 2001:db8:4fa::179 remote-as external
>
> The /48 you need to have at the VR anyway in case of either a static
> route or BGP.
>
> We just need to add a NullRoute on the VR for that /48 so that traffic
> will not be routed to the upper gateway in case of the VR can't find a
> route.
>
> Wido
>
> >
> >
> >
> >
> >
> > On Wed, Jul 14, 2021 at 8:55 PM Alex Mattioli
> > <Alex.Mattioli@shapeblue.com <mailto:Alex.Mattioli@shapeblue.com>>
> wrote:
> >
> >     Hi Wido,
> >     That's pretty much in line with our thoughts, thanks for the input.
> >     I believe we agree on the following points then:
> >
> >     - FRR with BGP (no OSPF)
> >     - Route /48 (or/56) down to the VR
> >     - /64 per network
> >     - SLACC for IP addressing
> >
> >     I believe the next big question is then "on which level of ACS do we
> >     manage AS numbers?".  I see two options:
> >     1) Private AS number on a per-zone basis
> >     2) Root Admin assigned AS number on a domain/account basis
> >     3) End-user driven AS number on a per network basis (for bring your
> >     own AS and IP scenario)
> >
> >     Thoughts?
> >
> >     Cheers
> >     Alex
> >
> >
> >
> >
> >     -----Original Message-----
> >     From: Wido den Hollander <wido@widodh.nl <mailto:wido@widodh.nl>>
> >     Sent: 13 July 2021 15:08
> >     To: dev@cloudstack.apache.org <mailto:dev@cloudstack.apache.org>;
> >     Alex Mattioli <Alex.Mattioli@shapeblue.com
> >     <mailto:Alex.Mattioli@shapeblue.com>>
> >     Cc: Wei Zhou <Wei.Zhou@shapeblue.com
> >     <mailto:Wei.Zhou@shapeblue.com>>; Rohit Yadav
> >     <rohit.yadav@shapeblue.com <mailto:rohit.yadav@shapeblue.com>>;
> >     Gabriel Beims Bräscher <gabriel@pcextreme.nl
> >     <mailto:gabriel@pcextreme.nl>>
> >     Subject: Re: IPV6 in Isolated/VPC networks
> >
> >
> >
> >     On 7/7/21 1:16 PM, Alex Mattioli wrote:
> >      > Hi all,
> >      > @Wei Zhou<mailto:Wei.Zhou@shapeblue.com
> >     <mailto:Wei.Zhou@shapeblue.com>> @Rohit
> >     Yadav<mailto:rohit.yadav@shapeblue.com
> >     <mailto:rohit.yadav@shapeblue.com>> and myself are investigating how
> >     to enable IPV6 support on Isolated and VPC networks and would like
> >     your input on it.
> >      > At the moment we are looking at implementing FRR with BGP (and
> >     possibly OSPF) on the ACS VR.
> >      >
> >      > We are looking for requirements, recommendations, ideas, rants,
> >     etc...etc...
> >      >
> >
> >     Ok! Here we go.
> >
> >     I think that you mean that the VR will actually route the IPv6
> >     traffic and for that you need to have a way of getting a subnet
> >     routed to the VR.
> >
> >     BGP is probably you best bet here. Although OSPFv3 technically
> >     supports this it is very badly implemented in Frr for example.
> >
> >     Now FRR is a very good router and one of the fancy features it
> >     supports is BGP Unnumered. This allows for auto configuration of BGP
> >     over a L2 network when both sides are sending Router Advertisements.
> >     This is very easy for flexible BGP configurations where both sides
> >     have dynamic IPs.
> >
> >     What you want to do is that you get a /56, /48 or something which is
> >      >/64 bits routed to the VR.
> >
> >     Now you can sub-segment this into separate /64 subnets. You don't
> >     want to go smaller then a /64 is that prevents you from using SLAAC
> >     for IPv6 address configuration. This is how it works for Shared
> >     Networks now in Basic and Advanced Zones.
> >
> >     FRR can now also send out the Router Advertisements on the downlinks
> >     sending out:
> >
> >     - DNS servers
> >     - DNS domain
> >     - Prefix (/64) to be used
> >
> >     There is no need for DHCPv6. You can calculate the IPv6 address the
> >     VM will obtain by using the MAC and the prefix.
> >
> >     So in short:
> >
> >     - Using BGP you routed a /48 to the VR
> >     - Now you split this into /64 subnets towards the isolated networks
> >
> >     Wido
> >
> >      > Alex Mattioli
> >      >
> >      >
> >      >
> >      >
> >
> >
> >
> > --
> > Regards,
> > Hean Seng
>


-- 
Regards,
Hean Seng

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message