Erik,
Good point. L2 service provides a broadcast domain. Whether the
broadcast/multicast packet should be sent to another VN is depend on inter VN
policy. It is possible. When the broadcast/multicast packet deliver to the L3
router too. If the policy allows the broadcast/multicast to broadcast to
another VN, L3 router will forward the packet to another VN with the same DMAC.
If the policy does not allow, L3 router will drop the packet.
You are right, if dMAC is broadcast/multicast address, it should send to L3
router for the further process. I change the text to following.
A tenant network may require both L2 and L3
services, i.e. the packets from a tenant may get L2 and/or L3
treatment.
An NVE receiving packets from a TS determines the type of service to
be applied to
the packet on a per-packet basis and as indicated by the
destination MAC address on the packet. If
the MAC address corresponds to that of an L3 router (as
determined by the NVE) traffic is given L3
semantics with inter-VN policy. When an NVE receives a
broadcast/multicast packet,
it should be processed by the L3 router. Depending on the inter-VN
policy,
the broadcast/multicast may be allowed or prohibited. Otherwise, the
packet is given L2
semantics. Thus the packet from a tenant must contain IP header (as
well
as Ethernet header) . A combined L2/L3 service presents no special
considerations for NVO3, other than packets received from a
tenant must be classified as to what type of service they
are to be given before they can be processed.
Thanks,
Lucy
-----Original Message-----
From: Erik Nordmark [mailto:[email protected]]
Sent: Tuesday, November 19, 2013 6:56 PM
To: Lucy yong; Thomas Narten
Cc: [email protected]; Linda Dunbar
Subject: Re: [nvo3] Fwd: Arch: proposed text for Combined L2/L3 Service
Lucy,
What would the rules be for multicast packets?
Such packets are not addressed to a router's MAC address but instead the router
receives all of them and processes them based on the L3 multicast FIB.
(For products which implement both L2 and L3 the processing of multicast
depends on whether the input port is L2 or L3, and in some cases that will
result in both bridging the packet out other L2 ports, and forwarding the
packet out other L3 (virtual) ports.)
Thus AFAICT the multicast rules can't depend on the destination MAC address to
determine whether L2 or L3 service should be applied.
Erik
On 11/19/13 4:20 PM, Lucy yong wrote:
> Hi Thomas,
>
> How about the following text:
>
> A tenant network may require both L2 and L3
> services, i.e. the packets from a tenant may get L2 and/or
> L3 treatment.
>
> An NVE receiving packets from a TS determines the type of
> service to be applied to
> the packet on a per-packet basis and as indicated by the
> destination MAC address on the packet. If
> the MAC address corresponds to that of an L3 router (as
> determined by the NVE), traffic is given L3
> semantics. Otherwise, the packet is given L2
> semantics. Thus the packet from a tenant must contain IP
> header (as well
>
> as Ethernet header) . A combined L2/L3 service presents no
> special
> considerations for NVO3, other than packets received from a
> tenant must be classified as to what type of service they
> are to be given before they can be processed.
>
> Comment: should we use a tenant system (TS) or a tenant in the text to
> make consistency?
>
> Regards,
>
> Lucy
>
> ---------- Forwarded message ----------
> From: *Thomas Narten* <[email protected] <mailto:[email protected]>>
> Date: Mon, Nov 18, 2013 at 3:25 PM
> Subject: [nvo3] Arch: proposed text for Combined L2/L3 Service
> To: [email protected] <mailto:[email protected]>
>
>
> There has been some discussion on the list about whether or not to
> have a combined L2/L3 service. Here is proposed text for the
> architecture document:
>
> <t>
> A virtual network can also provide a combined L2 and L3
> service to tenants. In such cases, a tenant sends and
> receives both L2 and L3 packets. An NVE recieving packets
> from a TS determines the type of service to be applied to
> the packet on a per-packet basis as indicated by the
> packet's destination MAC address as provided by the TS. If
> the MAC address corresponds to that of an L3 router (as
> determined by the NVE), traffic is given L3
> semantics. Otherwise, the packet is given L2 service
> semantics. A combined L2/L3 service presents no special
> considerations for NVO3, other than packets received from a
> tenant must be classified as to what type of service they
> are to be given before they can be processed.
> </t>
>
> This text would go at the end of Section 3.1 "VN Service (L2 and L3)".
>
> Make sense?
>
> Additional thinking behind this (taken from mail within the DT):
>
> > FWIW, I think that there are separate issues here. One is simply >
> describing what we mean by a combined L2/L3 service. That is what my
> > text was trying to do. The thinking is if the service definition is
> > clear and simple, supporting it in NVO3 is not a problem. I.e., it's
> > not really much different to provide a combined service than if you
> > offer an L2 or L3 service. And the service semantics for combined >
> L2/L3 are easy to understand and explain. That is goodness. :-) > >
> Whether and how it makes sense to have distributed gateways in a >
> combined service is a separate matter. What I'd like to be able to do
> > here (if we need to say anything at all) is be able to say that if a
> > distributed GW makes sense for L2 service, then having an L2 >
> distributed GW for the L2 traffic would make sense in the combined >
> service case too. Ditto for L3 service.
> >
> > A key point is that having a combined service is pretty much the
> same > as taking the two separate L2 and L3 services and combining
> them into > one implementation. There is nothing really "special"
> about this that > would complicate the overall architecture. Where
> we can easily get > into trouble is if we start defining a combined
> service as has special > cases that have to be dealt with that don't
> appear when you have only > L2 or only L3 service semantics.
>
> Thomas
>
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