I have picked up the task of shepherding this draft, and
have a number of comments which I think that you should
address before we send this text to the IESG.
As the text contains both LDP and BGP control information
I am copying the BESS WG and their chairs.
- Stewart
========
SB> The document fails I-D nits with
Summary: 2 errors (**), 0 flaws (~~), 9 warnings (==), 1 comment (--).
Please fix this.
======
SB> Number of authors. The guideline is five but it is not
a hard limit provided that all authors made significant contribution.
If asked by the IESG can all authors point to specific
text that they wrote?
Ethernet-Tree (E-Tree) Support in Virtual Private LAN Service (VPLS)
draft-ietf-l2vpn-vpls-pe-etree-04.tx
=====
Abstract
A generic Virtual Private LAN Service (VPLS) solution is proposed for
Ethernet-Tree (E-Tree) services which uses VLANs to indicate root or
leaf traffic. A VPLS Provider Edge (PE) model is illustrated as an
example for the solution. In the solution, E-Tree VPLS PEs are
interconnected by PWs which carry the VLAN indicating the E-Tree
attribute, the MAC address based Ethernet forwarding engine and the
PW work in the same way as before. A signaling mechanism for E-Tree
capability and VLAN mapping negotiation is further described.
======
2. Terminology
E-Tree: Ethernet Tree, a Rooted-Multipoint EVC service as defined in
MEF 6.1
EVC: Ethernet Virtual Connection, as defined in MEF 4.0
FIB: Forwarding Information Base, or forwarding table
T-VSI: Tree VSI, a VSI with E-Tree support
Root AC, an AC attached with a root
Leaf AC, an AC attached with a leaf
C-VLAN, Customer VLAN
S-VLAN, Service VLAN
B-VLAN, Backbone VLAN
Root VLAN, a VLAN ID used to indicate all the frames that are
originated at a root AC
Leaf VLAN, a VLAN ID used to indicate all the frames that are
originated at a leaf AC
I-SID, Backbone Service Instance Identifier, as defined in IEEE
802.1ah
=======
3. Introduction
Further, an E-Tree service may
include multiple roots and multiple leaves. Although VPMS or P2MP
SB> VPMS, P2MP and in a few line VPLS, VSI and PE need expansion (and ideally a
reference)
========
IEEE 802.1 has incorporated the generic E-Tree solution in the latest
version of 802.1Q [802.1Q-2011], which is just an improvement on the
traditional asymmetric VLAN mechanism (the use of different VLANs to
indicate E-Tree root/leaf attributes and prohibiting leaf-to-leaf
traffic with the help of VLANs was first standardized in IEEE 802.1Q-
2003). In the solution, VLANs are used to indicate root/leaf
SB> In THE solution - which solution is THE solution?
=======
This document introduces how the Ethernet VLAN solution can be used
SB> s/introduces/specifies/ and later s/proposed/specified/
to support generic E-Tree services in VPLS. The solution proposed
=======
here is fully compatible with the IEEE bridge architecture and the
SB> s/the/with/
IETF PWE3 technology, thus it will not change the FIB (such as
SB> please expand FIB
=======
4. PE Model with E-Tree Support
Problem scenario of E-Tree as shown in Fig. 1 of [Etree-req] is a
SB> The problem
=======
4.1. Existing PE Models
SB> In the text that follows it is clear how Fig 1 fits into the picture
but not Fig 2 (which as far as I can see you do not even reference).
I think you are saying that Fig 2 is the existing VPLS model, then
Fig 3 is the obvious mapping to E-tree, but there are problems, but this
needs to be much clearer.
========
4.2. A New PE Model with E-Tree Support
In order to support the E-Tree in a more scalable way, a new VPLS PE
model with a single Tree VSI (T-VSI, a VSI with E-Tree support) is
proposed.
SB> s/proposed/specified/
=======
For an S-VLAN tagged port, the S-VLAN tag in the Ethernet frames
received from the root ACs SHOULD be translated to the root S-VLAN in
the VPLS network domain. Alternatively, the PBB VPLS PE model (where
SB> PBB needs expansion
=======
In all cases, the outermost VLAN in the resulted Ethernet header is
used to indicate the E-Tree attribute of an Ethernet frame; this
document will use VLAN to refer to this outermost VLAN for simplicity
SB> S/will use/uses/
5. PW for E-Tree Support
5.1. PW Encapsulation
To support an E-Tree service, T-VSIs in a VPLS must be interconnected
with a bidirectional Ethernet PW. The Ethernet PW may work in the
tagged mode (PW type 0x0004) as described in [RFC4448], and a VLAN
tag must be carried in each frame in the PW to indicate the frame
SB>s/and a VLAN tag must be carried in each frame/
in which case a VLAN tag MUST be carried in each frame/
originated from either root or leaf (the VLAN tag indicating the
frame originated from either root or leaf can be translated by a
bridge module in the PE or added by an outside Ethernet edge device,
even by a customer device). In the tagged PW mode, two service
delimiting VLANs must be allocated in the VPLS domain for an E-Tree.
s/must/MUST/
=======
Raw PW (PW type 0x0005 in [RFC4448]) may be used to carry E-Tree
service for a PW in Compatible mode as shown in Section 5.3.2.
SB> I think this needs to be :
Raw PW (PW type 0x0005 in [RFC4448]) MAY also be used
========
6. Signaling for E-Tree Support
6.1. LDP Extensions for E-Tree Support
In addition to the signaling procedures as specified in [RFC4447],
this document proposes a new interface parameter sub-TLV to provision
an E-Tree service and negotiate the VLAN mapping function, as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| E-Tree | Length=8 | Reserved |P|V|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Root VLAN ID | Leaf VLAN ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8 E-Tree Sub-TLV
Where:
o E-Tree is the sub-TLV identifier to be assigned by IANA.
SB> You have an assigned value. I think it would be clearer to all
to say that and include the value in this text
========
A PE that receives a PW label mapping message with an E-Tree Sub-TLV
from its peer PE, after saving the VLAN information for the PW, must
SB> must or MUST? The latter I think.
=========
SB> Does what follows need to be proceeded by Else or Otherwise?
PW processing as described in [RFC4448] proceeds as usual for all
cases.
6.2. BGP Extensions for E-Tree Support
A PE which does not recognize this attribute shall ignore it silently.
SB> I think that should be SHALL or MUST.
======
7. OAM Considerations
Ethernet OAM for E-Tree including both service OAM and segment OAM
frames shall undergo the same VLAN mapping as the data traffic; and
root VLAN SHOULD be applied to segment OAM frames so that they are
not filtered.
SB> I think s/shall/SHALL/
=======
8. Applicability
The solution is applicable to both LDP VPLS [RFC4762] and BGP VPLS
SB> s/The/This/ or s/The solution specified in this document/
======
10. IANA Considerations
IANA is requested to allocate a value for E-Tree in the registry of
Pseudowire Interface Parameters Sub-TLV type.
Parameter ID Length Description
=======================================
TBD 8 E-Tree
SB> Update to show you have the assignment
=======
IANA is requested to allocate two new LDP status codes from the
registry of name "STATUS CODE NAME SPACE". The following values are
suggested:
Range/Value E Description
------------- ----- ----------------------
TBD 1 E-Tree VLAN mapping not supported
TBD 0 Leaf to Leaf PW released
SB> Update to show you have the assignment
======
IANA is requested to allocate a value for E-Tree in the registry of
BGP Extended Community.
Type Value Name
=======================================
TBD E-Tree Info
SB> Update to show you have the assignment
=======
Appendix A. Other PE Models for E-Tree
A.1. A PE Model With a VSI and No bridge
This PE model may be used by an MTU-s in an H-VPLS network, or an N-
PE in an H-VPLS network with non-bridging edge devices, wherein a
spoke PW can be treated as an AC in this model.
SB> Please check that all of the above abbreviations have been
previously expanded.
=======
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