"Stiliadis, Dimitrios (Dimitri)" <[email protected]> writes:
> I believe that Section 3.1 needs to be significantly revised since it
> has some confusing statements. I cannot support this draft without a
> revision of this Section:
I'll assume that since you didn't comment about the first two
paragraphs (L2 VLAN stuff), you are OK with that text.
> VRF's are a pure routing construct and do not have end-to-end
> significance in the sense that the data plane carries a VRF
> indicator on an end-to-end basis.
You're right. When I wrote this text, I didn't realize that MPLS had
adopted the VRF terminology. What the text refers to is what others
have pointed out is known as VRF lite.
Now I understand why this text produced such a backlash. :-)
Proposed new text:
<t>
In the case of IP networks, many routers provide a Virtual
Routing and Forwarding (VRF) service commonly known as "VRF
Lite". The same router operates multiple instances of
forwarding tables, one for each tenant. Each forwarding
table instance is populated separately via routing
protocols, and adjacent routers encapsulate traffic in a way
that identifies the tenant (e.g., using a VLAN tag). Each
VRF Lite instance provides address and traffic isolation.
The VRF Lite instance for each frame is selected based on
that tenant identification.
</t>
<t>
VRF's are a pure routing construct and in VRF Lite do not
have end-to-end significance in the sense that the data
plane carries a VRF Lite instance selector on an end-to-end
basis. Instead, the VRF Lite instance to be used is
determined at each hop using a combination of incoming
interface and some information in the frame (e.g., local
VLAN tag). Furthermore, the VRF Lite model has typically
assumed that a separate control plane (e.g., based on a
routing protocol) governs the population of each forwarding
table. Thus, the VRF Lite model assumes multiple, logically
independent control plane instances and has no specific tag
within a data frame to identify the VRF Lite instance for
that frame.
</t>
<t>
MPLS VRFs <xref target="RFC4364"></xref> place the VRF
functionality on the CE and PE devices, using MPLS
encapsulation to preserve tenant separation between the CE
and PE devices. Control plane protocols (e.g.,
LDP<xref target="RFC5036"></xref>) are used to set up the
data path between PE and CE.
</t>
Does that work?
Thomas
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