BESS WG A. Dolganow
Internet-Draft J. Kotalwar
Updates: 6625 (if approved) Nokia
Intended status: Standards Track E. Rosen, Ed.
Expires: December 7, 2017 Z. Zhang
Juniper Networks, Inc.
June 5, 2017
Explicit Tracking with Wild Card Routes in Multicast VPN
draft-ietf-bess-mvpn-expl-track-02
Abstract
The MVPN specifications provide procedures to allow a multicast
ingress node to invoke "explicit tracking" for a multicast flow or
set of flows, thus learning the egress nodes for that flow or set of
flows. However, the specifications are not completely clear about
how the explicit tracking procedures work in certain scenarios. This
document provides the necessary clarifications. It also specifies a
new, optimized explicit tracking procedure. This new procedure
allows an ingress node, by sending a single message, to request
explicit tracking of each of a set of flows, where the set of flows
is specified using a wildcard mechanism. This document updates
RFC6625.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 7, 2017.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. The Explicit Tracking Flags . . . . . . . . . . . . . . . . . 5
3. Match for Tracking vs. Match for Reception . . . . . . . . . 5
4. Ingress Node Initiation of Tracking . . . . . . . . . . . . . 7
5. Egress Node Response to the Match for Tracking . . . . . . . 8
5.1. General Egress Node Procedures . . . . . . . . . . . . . 8
5.2. Responding to the LIR-pF Flag . . . . . . . . . . . . . . 9
5.3. When the Egress Node is an ABR or ASBR . . . . . . . . . 12
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
[RFC6513] and [RFC6514] define the "Selective Provider Multicast
Service Interface Auto-Discovery route" (S-PMSI A-D route). By
originating one of these BGP routes, an ingress node advertises that
it is transmitting a particular multicast flow. In the terminology
of those RFCs, each flow is denoted by (C-S,C-G), where C-S is an IP
source address and C-G is an IP multicast address, both in the
address space of a VPN customer. The (C-S,C-G) of the multicast flow
is encoded into the Network Layer Reachability Information (NLRI) of
the S-PMSI A-D route.
Additionally, each S-PMSI A-D route contains a PMSI Tunnel attribute
(PTA), which identifies a tunnel through the provider backbone
network (a "P-tunnel"). If a P-tunnel is identified in the PTA of a
given S-PMSI A-D route, the originator of that route is advertising
that it will transmit the flow identified in the NLRI through the
tunnel identified in the PTA.
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[RFC6513] and [RFC6514] also define a procedure that allows an
ingress node to determine the set of egress nodes that have requested
to receive a particular flow from that ingress node. The ability of
an ingress node to identify the egress nodes for a particular flow is
known as "explicit tracking". An ingress node requests explicit
tracking by setting a flag (the "Leaf Information Required" flag, or
LIR) in the PTA. When an egress node receives an S-PMSI A-D route
with LIR set, the egress node originates a Leaf A-D route whose NLRI
contains the NLRI from the corresponding S-PMSI A-D route. In this
way, the egress node advertises that it has requested to receive the
particular flow identified in the NLRI of that S-PMSI A-D route.
[RFC6513] and [RFC6514] also allow an ingress node to originate an
S-PMSI A-D route whose PTA has LIR set, but which does not identify
any P-tunnel. This mechanism can be used when it is desired to do
explicit tracking of a flow without at the same time binding that
flow to a particular P-tunnel.
[RFC6625] (and other RFCs that update it) extends the specification
of S-PMSI A-D routes, and allows an S-PMSI A-D route to encode a
wildcard in its NLRI. Either the C-S or the C-G or both can be
replaced by wildcards. These routes are known as (C-*,C-S) S-PMSI
A-D routes, or as (C-S,C-*) S-PMSI A-D routes, or as (C-*,C-*) S-PMSI
A-D routes, depending on whether the C-S or C-G or both have been
replaced by wildcards. These routes are known jointly as "wildcard
S-PMSI A-D routes".
One purpose of this document is to clarify the way that the explicit
tracking procedures of [RFC6513] and [RFC6514] are applied when
wildcard S-PMSI A-D routes are used.
In addition, this document addresses the following scenario, which is
not addressed in [RFC6513], [RFC6514], or [RFC6625]. Suppose an
ingress node originates an S-PMSI A-D route whose NLRI specifies, for
example, (C-*,C-*) (i.e., both C-S and C-G are replaced by
wildcards), and whose PTA identifies a particular P-tunnel. Now
suppose that the ingress node wants explicit tracking for each
individual flow that it transmits (following the procedures of
[RFC6625] on that P-tunnel.
In this example, if the ingress node sets LIR in the PTA of the
wildcard S-PMSI A-D route, each egress node that needs to receive a
flow from the ingress node will respond with a Leaf A-D route whose
NLRI specifies contains the (C-*,C-*) wildcard. This allows the
ingress node to determine the set of egress nodes that are receiving
flows from the ingress node. However, it does not allow the ingress
node to determine which flows are being received by which egress
nodes.
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If the ingress node needs to determine which egress nodes are
receiving which flows, it needs to originate an S-PMSI A-D route for
each individual (C-S,C-G) flow that it is transmitting, and it needs
to set LIR in the PTA of each such route. However, since all the
flows are being sent through the tunnel identified in the (C-*,C-*)
S-PMSI A-D route, there is no need to identify a tunnel in the PTA of
each (C-S,C-G) S-PMSI A-D route. Per [RFC6514], the PTA of the
(C-S,C-G) S-PMSI A-D routes can specify "no tunnel information".
This procedure allows explicit tracking of individual flows, even
though all those flows are assigned to tunnels in widlcard S-PMSI A-D
routes.
Howver, this procedure requires several clarifications:
o The procedures of [RFC6625] do not clearly state how to handle an
S-PMSI A-D route if its NLRI contains wild cards, but its PTA
specifies "no tunnel info".
o If it is desired to send a set of flows through the same tunnel
(where that tunnel is advertised in a wildcard S-PMSI A-D route),
but it is also desired to explicitly track each individual flow
transmitted over that tunnel, one has to send an S-PMSI A-D route
(with LIR set in the PTA) for each individual flow. It would be
more optimal if the ingress node could just send a single wildcard
S-PMSI A-D route binding the set of flows to a particular tunnel,
and have the egress nodes respond with Leaf A-D routes for each
individual flow.
o [RFC6513] and [RFC6514] support the notion of "segmented
P-tunnels", where "segmentation" occurs at ASBRs; [RFC7524]
extends the notion segmented P-tunnels so that segmentation can
occur at ABRs. One can think of a segmented P-tunnel as passing
through a number of "segmentation domains". In each segmentation
domain, a given P-tunnel has an ingress node and a set of egress
nodes. The explicit tracking procedures allow an ingress node of
a particular segmentation domain to determine, for a particular
flow or set of flows, the egress nodes of that segmentation
domain. This has given rise to two further problems:
* The explicit tracking procedures do not allow an ingress node
to "see" past the boundaries of the segmentation domain.
This particular problem is not further addressed in this
revision of this document.
* The prior specifications do not make it very clear whether an
egress node, upon receiving an S-PMSI A-D route whose PTA
specifies "no tunnel information", is expected to forward the
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S-PMSI A-D route, with the same PTA, to the next segmentation
domain. This document provides the necessary clarifications.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL", when and only when appearing in all capital letters, are
to be interpreted as described in [RFC2119].
2. The Explicit Tracking Flags
Prior specifications define one flag in the PTA, the "Leaf Info
Required" (LIR) flag, that is used for explicit tracking.
This document defines a new flag in the flags field of the PMSI
Tunnel attribute. This new flag is known as the "Leaf Info Required
per Flow" bit (LIR-pF). This flag MAY be set in the PTA of a
(C-*,C-*), (C-*,C-G), or (C-S,C-*) S-PMSI A-D route. (Use of this
flag in a PTA carried by other routes is outside the scope of this
document.) Support for this flag is OPTIONAL.
The action taken by an egress node when the LIR-pF bit is set is
detailed in Section 5.
If the LIR-pF flag is set in a given PTA, the LIR flag of that PTA
SHOULD also be set. (By setting LIR as well as LIR-pF, one forces a
a response to be sent an egress node that does not support LIR-pF,
and it is possible to tell from that response that the egress node
does not support LIR-pF.)
3. Match for Tracking vs. Match for Reception
RFC6625 (and other RFCs or RFCs-to-be that update RFC6625) specify a
set of rules for finding the S-PMSI A-D route that is the "match for
reception" for a given (C-S,C-G) or (C-*,C-G) state. These rules do
not take into account the fact that some S-PMSI A-D routes may not be
carrying PTAs at all, or may be carrying PTAs that do not identify
any P-tunnel. (A PTA that does not identify any P-tunnel is one
whose "tunnel type" field has been set to "no tunnel information", as
specified in Section 5 of [RFC6514].)
The definition of "match for reception" in [RFC6625] is hereby
modified as follows:
When finding the "match for reception" for a given (C-S,C-G) or
(C-*,C-G), ignore any S-PMSI A-D route that has no PTA, or whose
PTA specifying "no tunnel information".
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We also introduce a new notion: the "match for tracking". This
differs from the "match for reception" as follows:
For a given C-flow ((C-S,C-G) or (C-*,C-G)) the "match for
tracking" is chosen as follows. Ignore any S-PMSI A-D route that
has no PTA. Also ignore any S-PMSI A-D route whose PTA specifies
"no tunnel information", but does not have either LIR or LIR-pF
set. (In particular, DO NOT ignore an S-PMSI A-D route that has a
PTA specifying "no tunnel information", but whose LIR or LIR-pF
bits are set). Then apply the rules (from [RFC6625] and other
documents that that update it) for finding the "match for
reception". The result (if any) is the match for tracking".
We will clarify this with a few examples. In these examples, we
assume that there is only one segmentation domain. In this case, the
ingress and egress nodes are Provider Edge (PE) routers.
Suppose a given PE router, PE1, has chosen PE2 as the "upstream PE"
([RFC6513]) for a given flow (C-S1,C-G1). And suppose PE1 has
installed the following two routes that were originated by PE2:
o Route1: A (C-*,C-*) S-PMSI A-D route, whose PTA specifies a
tunnel.
o Route2: A (C-S1,C-G1) S-PMSI A-D route, whose PTA specifies "no
tunnel info" and has LIR set.
Route1 is (C-S1,C-G1)'s match for reception, and Route2 is
(C-S1,C-G1)'s match for tracking.
Note that if there is no installed S-PMSI A-D route for (C-S2,C-G2),
then Route1 would be (C-S2,C-G2)'s match for reception and also its
match for tracking. Also note that if a match for tracking does not
have the LIR flag or the LIR-pF flag set, no explicit tracking
information will be generated. See Section 5.
As another example, suppose PE1 has installed the following two
routes that were originated by PE2:
o Route1: A (C-*,C-*) S-PMSI A-D route (irrespective of whether the
PTA specifies a tunnel)
o Route2: A (C-S1,C-G1) S-PMSI A-D route whose PTA specifies a
tunnel.
Then Route2 is both the "match for reception" and the "match for
tracking" for (C-S1,C-G1).
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Note that for a particular C-flow, PE1's match for reception might be
the same route as its match for tracking, or its match for reception
might be a "less specific" route than its match for tracking. But
its match for reception can never be a "more specific" route than its
match for tracking.
4. Ingress Node Initiation of Tracking
An ingress node that needs to initiate explicit tracking for a
particular flow or set of flows can do so by performing one of the
following procedures:
1. An ingress node can initiate explicit tracking for (C-S1,C-G1) by
originating an S-PMSI A-D route that identifies (C-S1,C-G1) in
its NLRI, including a PTA in that route, and setting the LIR flag
in that PTA. The PTA may specify a particular tunnel, or may
specify "no tunnel info".
However, the PTA of the (C-S1,C-G1) S-PMSI A-D route SHOULD NOT
specify "no tunnel info" unless the ingress node also originates
an A-D route carrying a PTA that specifies the tunnel to be used
for carrying (C-S1,C-G1) traffic. Such a route could be an
I-PMSI A-D route, a (C-*,C-G1) S-PMSI A-D route, a (C-S1,C-*)
S-PMSI A-D route, or a (C-*,C-*) S-PMSI A-D route. (There is no
point in requesting explicit tracking for a given flow if there
is no tunnel on which the flow is being carried.)
Further, if the ingress node originates a wildcard S-PMSI A-D
route carrying a PTA specifying the tunnel to be used for
carrying (C-S1,C-G1) traffic, and if that PTA has the LIR-pF bit
set, then explicit tracking for (C-S1,C-G1) is requested by that
S-PMSI A-D route. Thus the ingress node SHOULD NOT originate a
(C-S1,C-G1) S-PMSI A-D route whose PTA specifies "no tunnel
info"; such a route would not provide any additional
functionality.
To terminate explicit tracking that has been initiated by an
S-PMSI A-D route whose PTA specifies "no tunnel info", the
ingress node withdraws the route.
To terminate explicit tracking that has been initiated by an
S-PMSI A-D route whose PTA specifies a tunnel, the ingress node
re-originates the route without the LIR flag set.
2. The following procedure can be used if (and only if) it is known
that the egress nodes support the optional LIR-pF flag. If the
ingress node originates a wildcard S-PMSI A-D route, it can
initiate explicit tracking for the individual flows that match
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the wildcard route by setting the LIR-pF flag in the PTA of the
wildcard route. If an egress node needs to receive one or more
flows for which that wildcard route is a match for tracking, the
egress node will originate a Leaf A-D route for each such flow,
as specified in Section 5.2).
When following this procedure, the PTA of the S-PMSI A-D route
may specify a tunnel, or may specify "no tunnel info". The
choice between these two options is determined by considerations
that are outside the scope of this document.
To terminate explicit tracking that has been initiated by an
S-PMSI A-D route whose PTA specifies "no tunnel info", the
ingress node withdraws the route.
To terminate explicit tracking that has been initiated by an
S-PMSI A-D route whose PTA specifies a tunnel, the ingress node
re-originates the route without the LIR flag set
5. Egress Node Response to the Match for Tracking
5.1. General Egress Node Procedures
There are four cases to consider:
1. With regard to a particular (C-S,C-G) or (C-*,C-G) multicast
state, the egress node's match for tracking is same as its match
for reception, and neither LIR nor LIR-pF flags are on.
In this case, the egress node does not originate a Leaf A-D route
in response to the match for reception/tracking, and there is no
explicit tracking of the flow. This document specifies no new
procedures for this case.
2. With regard to a particular (C-S,C-G) or (C-*,C-G) multicast
state, the egress node's match for tracking is the same as its
match for reception, LIR is set, but LIR-pF is not set.
In this case, a Leaf A-D route is originated by the egress node,
corresponding to the S-PMSI A-D route that is the match for
reception/tracking. Construction of the Leaf A-D route is as
specified in [RFC6514]; this document specifies no new procedures
for this case.
3. With regard to a particular (C-S,C-G) or (C-*,C-G) multicast
state, the egress node's match for tracking is the same as its
match for reception, and LIR-pF is set. The egress PE MUST
follow whatever procedures are required by other specifications,
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based on the match for reception. If the egress PE supports the
LIR-pF flag, it MUST also follow the procedures of Section 5.2.
4. With regard to a particular (C-S,C-G) or (C-*,C-G) multicast
state, the egress node's match for tracking is not the same as
its match for reception. This can only happen if the match for
tracking has a PTA specifying "no tunnel info", with either LIR
or LIR-pF set. In this case, the egress node must respond,
separately, BOTH to the match for tracking and to the match for
reception.
When responding to the match for reception, the egress node MUST
ignore the LIR-pF flag. However, the LIR flag is processed
normally per the procedures for the match for reception.
If the match for tracking has LIR set and if either (a) the
egress node does not support LIR-pF, or (b) LIR-pF is not set,
then the egress node must respond to the match for tracking,
following procedures specified in other documents for the case
where LIR is set.
If the match for tracking has LIR-pF set, and the egress node
supports the LIR-pF flag, the egress node must originate one or
more Leaf A-D routes, as specified in Section 5.2.
Note that if LIR is set in the PTA of the match for reception,
the egress node may need to originate one or more Leaf A-D routes
corresponding to the match for tracking, as well as originating a
Leaf A-D route corresponding to the match for reception.
5.2. Responding to the LIR-pF Flag
To respond to a match for tracking that has LIR-pF set, an egress
node originates one or more Leaf A-D routes.
Suppose the egress node has multicast state for a (C-S,C-G) or a
(C-*,C-G) flow, and has determined a particular S-PMSI A-D route,
which has the LIR-pF flag set, to be the match for tracking for that
flow. Then if the egress node supports the LIR-pF flag, it MUST
originate a Leaf A-D route whose NLRI identifies that particular
flow. Note that if a single S-PMSI A-D route (with wild cards) is
the match for tracking for multiple flows, the egress PE may need to
originate multiple Leaf A-D routes, one for each such flow. We say
that, from the perspective of a given egress node, a given S-PMSI A-D
route tracks the set of flows for which it is the match for tracking.
Each of the Leaf A-D routes originated in response to that S-PMSI A-D
route tracks a single such flow.
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The NLRI of each the Leaf A-D route that tracks a particular flow is
constructed as follows. The "route key" field of the NLRI will have
the following format:
+-----------------------------------+
| RD (8 octets) |
+-----------------------------------+
| Multicast Source Length (1 octet) |
+-----------------------------------+
| Multicast Source (Variable) |
+-----------------------------------+
| Multicast Group Length (1 octet) |
+-----------------------------------+
| Multicast Group (Variable) |
+-----------------------------------+
| Ingress PE's IP address |
+-----------------------------------+
Figure 1: NLRI of S-PMSI A-D Route
o The "ingress PE" address is taken from the "originating router"
field of the NLRI of the S-PMSI A-D route that is the match for
tracking.
o The multicast source and group fields specify the S and G of one
of the flow being tracked by this Leaf A-D route. If a (C-*,C-G)
is being tracked by this Leaf A-D route, the source field is
omitted, and its length is set to 0.
o The RD field is constructed as follows:
* Take the RD value from the NLRI of the S-PMSI A-D route.
* Add 16 to the second octet of the RD.
Note that, per RFC4364, every RD begins with a two-octet type field
that is either 0, 1, or 2. By adding 16 to the second octet of the
RD, we force the type field to be 16, 17, or 18. The presence of one
of these values will indicate that the Leaf A-D route was constructed
in response to a less specific S-PMSI A-D route that had the LIR-pF
bit set. (That is, it distinguishes the routes from "ordinary" MVPN
Leaf A-D routes.)
The encoding of these Leaf A-D routes is similar to the encoding of
the Leaf A-D routes described in section 6.2.2 of [RFC7524], which
were designed for the support of "global table multicast". However,
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that document sets the RD to either 0 or -1; following the procedures
of this document, the RD will never be 0 or -1. Therefore Leaf A-D
routes constructed according to the procedures of this section can
always be distinguished from the Leaf A-D routes constructed
according to the procedures of section 6.2.2 of [RFC7524]. Also,
Leaf A-D routes constructed according to the procedures of this
section are VPN-specific routes, and will always carry an IP-address-
specific Route Target, as specified in [RFC6514].
If a Leaf A-D route is originated as a response to a match for
tracking whose PTA specifies "no tunnel info", a PTA SHOULD NOT be
attached to the Leaf A-D route; if a PTA is attached, it MUST specify
"no tunnel info".
In the case where the match for tracking and the match for reception
are the same, the PTA of the match may have both the LIR and the LIR-
pF flags set. This may cause the egress node to originate one Leaf
A-D route in response to the LIR bit, and one or more Leaf A-D routes
in response to the LIR-pF bit. A PTA SHOULD NOT be attached to the
Leaf A-D routes that are originated in response to the LIR-pF bit.
When a Leaf A-D route constructed according to the procedures of this
section is received, it MUST be processed by the node identified in
its IP-address-specific Route Target, even though its "route key"
field does not correspond to the NLRI of any S-PMSI A-D route.
Of course, an egress node that originates such Leaf A-D routes needs
to remember which S-PMSI A-D route caused these Leaf A-D routes to be
originated; if that S-PMSI A-D route is withdrawn, those Leaf A-D
routes MUST be withdrawn.
Similarly, a Leaf A-D route needs to be withdrawn (either implicitly
or explicitly) if the egress node changes its Upstream Multicast Hop
(UMH) ([RFC6513]) for the flow that is identified in the Leaf A-D
route's NLRI, or if the egress node that originated the route no
longer needs to receive the flow identified in the NLRI of the route.
Note that an egress node may acquire (C-S,C-G) state or (C-*,C-G)
state after it has already received the S-PMSI A-D that is the match
for tracking for that state. In this case, a Leaf A-D route needs to
be originated at that time, and the egress node must remember that
the new Leaf A-D route corresponds to that match for tracking.
Note that if a particular S-PMSI A-D route is a match for tracking
but not a match for reception, the LIR bit in its PTA is ignored if
the LIR-pF bit is set.
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5.3. When the Egress Node is an ABR or ASBR
When segmented P-tunnels are used, the ingress and egress nodes may
be ABRs or ASBRs. An egress ABR/ASBR that receives and installs an
S-PMSI A-D route also forwards that route. If the PTA of an
installed S-PMSI A-D route specifies a tunnel, the egress ABR/ASBR
MAY change the PTA to specify a different tunnel type (as discussed
in [RFC6514] and/or [RFC7524]).
However, if the PTA of the installed S-PMSI A-D route specifies "no
tunnel info", the egress ABR/ASBR MUST pass the PTA along unchanged
when it forwards the S-PMSI A-D route. (That is, a PTA specifying
"no tunnel info" MUST NOT be changed into a PTA specifying a tunnel.)
Furthermore, if the PTA specifies "no tunnel info", the LIR and LIR-
pF flags in the PTA MUST be passed along unchanged.
In the case where the egress node is a PE, it will know whether it
needs to receive a given flow by virtue of its having received a PIM
or IGMP Join for that flow from a CE. In the case where the egress
node is not a PE, but rather an ABR or ASBR, it will not know whether
it needs to receive a given flow unless it receives a Leaf A-D route
whose NLRI specifies that flow and whose IP-address-specific RT
specifies an address of the egress node. Therefore an egress ABR/
ASBR MUST NOT originate a Leaf A-D route for a given flow UNLESS it
has an installed Leaf A-D route for that flow, received from further
downstream.
This will ensure that an egress ABR/ASBR only sends a Leaf A-D route
in response to a "match for tracking" if it is on the path to an
egress PE for the flow(s) identified in the corresponding S-PMSI A-D
route.
Then we can establish the following rule for egress ABRs/ASBRs.
Suppose an egress ABR/ASBR receives an S-PMSI A-D route whose NLRI is
X, and whose PTA (a) specifies "no tunnel info" and (b) has LIR set.
The egress ABR/ASBR should not immediately originate a Leaf A-D route
in response. Rather it should wait until it receives a Leaf A-D
route whose NLRI contains X in the "route key" field. If it receives
such a Leaf A-D route, it redistributes that route, but first it
changes that route's RT. The "global administrator" field of the
modified RT will be set to the IP address taken either from the
S-PMSI A-D route's next hop field, or from its Segmented P2MP Next
Hop Extended Community. (This is the same rule that is used for when
the PTA does specify a tunnel type.)
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6. Acknowledgments
The authors wish to thank Robert Kebler for his ideas and comments.
7. IANA Considerations
The LIR-pF flag needs to be added to the "P-Multicast Service
Interface Tunnel (PMSI Tunnel) Attribute Flags" in the "Border
Gateway Protocol (BGP) Parameters" registry. This registry is
defined in [RFC7902]. The requested value is Bit Position 2. This
document should be the reference.
IANA is requested to allocate three new types from the Route
Distinguisher Type Field registry:
o Administrator field is two-byte Autonomous System Number. To be
used only in certain MCAST-VPN Leaf A-D routes.
o Administrator field is four-byte IP Address. To be used only in
certain MCAST-VPN Leaf A-D routes.
o Administrator field is four-byte Autonomous System Number. To be
used only in certain MCAST-VPN Leaf A-D routes.
The requested values are 16, 17, and 18 respectively.
8. Security Considerations
The Security Considerations of [RFC6513] and [RFC6514] apply.
By setting the LIR-pF flag in a single wildcard S-PMSI A-D route, a
large number of Leaf A-D routes can be elicited. If this flag is set
when not desired (through either error or malfeasance), a significant
increase in control plane overhead can result.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <http://www.rfc-editor.org/info/rfc6513>.
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[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
<http://www.rfc-editor.org/info/rfc6514>.
[RFC6625] Rosen, E., Ed., Rekhter, Y., Ed., Hendrickx, W., and R.
Qiu, "Wildcards in Multicast VPN Auto-Discovery Routes",
RFC 6625, DOI 10.17487/RFC6625, May 2012,
<http://www.rfc-editor.org/info/rfc6625>.
[RFC7902] Rosen, E. and T. Morin, "Registry and Extensions for
P-Multicast Service Interface Tunnel Attribute Flags",
RFC 7902, DOI 10.17487/RFC7902, June 2016,
<http://www.rfc-editor.org/info/rfc7902>.
9.2. Informative References
[RFC7524] Rekhter, Y., Rosen, E., Aggarwal, R., Morin, T.,
Grosclaude, I., Leymann, N., and S. Saad, "Inter-Area
Point-to-Multipoint (P2MP) Segmented Label Switched Paths
(LSPs)", RFC 7524, DOI 10.17487/RFC7524, May 2015,
<http://www.rfc-editor.org/info/rfc7524>.
Authors' Addresses
Andrew Dolganow
Nokia
600 March Rd.
Ottawa, Ontario K2K 2E6
Canada
Email: andrew.dolganow@nokia.com
Jayant Kotalwar
Nokia
701 East Middlefield Rd
Mountain View, California 94043
United States
Email: jayant.kotalwar@nokia.com
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Eric C. Rosen (editor)
Juniper Networks, Inc.
10 Technology Park Drive
Westford, Massachusetts 01886
United States
Email: erosen@juniper.net
Zhaohui Zhang
Juniper Networks, Inc.
10 Technology Park Drive
Westford, Massachusetts 01886
United States
Email: zzhang@juniper.net
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