Internet DRAFT - draft-ietf-mpls-sr-over-ip
draft-ietf-mpls-sr-over-ip
Network Working Group X. Xu
Internet-Draft Alibaba, Inc
Intended status: Standards Track S. Bryant
Expires: December 18, 2019 Huawei
A. Farrel
Old Dog Consulting
S. Hassan
Cisco
W. Henderickx
Nokia
Z. Li
Huawei
June 16, 2019
SR-MPLS over IP
draft-ietf-mpls-sr-over-ip-07
Abstract
MPLS Segment Routing (SR-MPLS) is an MPLS data plane-based source
routing paradigm in which the sender of a packet is allowed to
partially or completely specify the route the packet takes through
the network by imposing stacked MPLS labels on the packet. SR-MPLS
can be leveraged to realize a source routing mechanism across MPLS,
IPv4, and IPv6 data planes by using an MPLS label stack as a source
routing instruction set while making no changes to SR-MPLS
specifications and interworking with SR-MPLS implementations.
This document describes how SR-MPLS capable routers and IP-only
routers can seamlessly co-exist and interoperate through the use of
SR-MPLS label stacks and IP encapsulation/tunneling such as MPLS-in-
UDP as defined in RFC 7510.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
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This Internet-Draft will expire on December 18, 2019.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Procedures of SR-MPLS over IP . . . . . . . . . . . . . . . . 5
3.1. Forwarding Entry Construction . . . . . . . . . . . . . . 5
3.1.1. FIB Construction Example . . . . . . . . . . . . . . 6
3.2. Packet Forwarding Procedures . . . . . . . . . . . . . . 8
3.2.1. Packet Forwarding with Penultimate Hop Popping . . . 9
3.2.2. Packet Forwarding without Penultimate Hop Popping . . 10
3.2.3. Additional Forwarding Procedures . . . . . . . . . . 11
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
5. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
MPLS Segment Routing (SR-MPLS) [I-D.ietf-spring-segment-routing-mpls]
is an MPLS data plane-based source routing paradigm in which the
sender of a packet is allowed to partially or completely specify the
route the packet takes through the network by imposing stacked MPLS
labels on the packet. SR-MPLS uses an MPLS label stack to encode a
source routing instruction set. This can be used to realize a source
routing mechanism that can operate across MPLS, IPv4, and IPv6 data
planes. This approach makes no changes to SR-MPLS specifications and
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allows interworking with SR-MPLS implementations. More specifically,
the source routing instruction set information contained in a source
routed packet could be uniformly encoded as an MPLS label stack no
matter whether the underlay is IPv4, IPv6 (including Segment Routing
for IPv6 (SRv6) [RFC8354]), or MPLS.
This document describes how SR-MPLS capable routers and IP-only
routers can seamlessly co-exist and interoperate through the use of
SR-MPLS label stacks and IP encapsulation/tunneling such as MPLS-in-
UDP [RFC7510].
Section 2 describes various use cases for the tunneling SR-MPLS over
IP. Section 3 describes a typical application scenario and how the
packet forwarding happens.
1.1. Terminology
This memo makes use of the terms defined in [RFC3031] and
[I-D.ietf-spring-segment-routing-mpls].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Use Cases
Tunneling SR-MPLS using IPv4 and/or IPv6 (including SRv6) tunnels is
useful at least in the use cases listed below. In all cases, this
can be enabled using an IP tunneling mechanism such as MPLS-in-UDP as
described in [RFC7510]. The tunnel selected MUST have its remote end
point (destination) address equal to the address of the next SR-MPLS
capable node identified as being on the SR path (i.e., the egress of
the active segment). The local end point (source) address is set to
an address of the encapsulating node. [RFC7510] gives further advice
on how to set the source address if the UDP zero-checksum mode is
used with MPLS-in-UDP. Using UDP as the encapsulation may be
particularly beneficial because it is agnostic of the underlying
transport.
o Incremental deployment of the SR-MPLS technology may be
facilitated by tunneling SR-MPLS packets across parts of a network
that are not SR-MPLS as shown in Figure 1. This demonstrates how
islands of SR-MPLS may be connected across a legacy network. It
may be particularly useful for joining sites (such as data
centers).
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________________________
_______ ( ) _______
( ) ( IP Network ) ( )
( SR-MPLS ) ( ) ( SR-MPLS )
( Network ) ( ) ( Network )
( -------- -------- )
( | Border | SR-in-UDP Tunnel | Border | )
( | Router |========================| Router | )
( | R1 | | R2 | )
( -------- -------- )
( ) ( ) ( )
( ) ( ) ( )
(_______) ( ) (_______)
(________________________)
Figure 1: SR-MPLS in UDP to Tunnel Between SR-MPLS Sites
o If encoding of entropy ([RFC6790] is desired, IP tunneling
mechanisms that allow encoding of entropy, such as MPLS-in-UDP
encapsulation [RFC7510] where the source port of the UDP header is
used as an entropy field, may be used to maximize the utilization
of ECMP and/or LAG, especially when it is difficult to make use of
the entropy label mechanism. This is to be contrasted with
[RFC4023] where MPLS-in-IP does not provide for an entropy
mechanism. Refer to [I-D.ietf-mpls-spring-entropy-label]) for
more discussion about using entropy labels in SR-MPLS.
o Tunneling MPLS over IP provides a technology that enables SR in an
IPv4 and/or IPv6 network where the routers do not support SRv6
capabilities [I-D.ietf-6man-segment-routing-header] and where MPLS
forwarding is not an option. This is shown in Figure 2.
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__________________________________
__( IP Network )__
__( )__
( -- -- -- )
-------- -- -- |SR| -- |SR| -- |SR| -- --------
| Ingress| |IR| |IR| | | |IR| | | |IR| | | |IR| | Egress |
--->| Router |===========| |======| |======| |======| Router |--->
| SR | | | | | | | | | | | | | | | | | | SR |
-------- -- -- | | -- | | -- | | -- --------
(__ -- -- -- __)
(__ __)
(__________________________________)
Key:
IR : IP-only Router
SR : SR-MPLS-capable Router
== : SR-MPLS in UDP Tunnel
Figure 2: SR-MPLS Enabled Within an IP Network
3. Procedures of SR-MPLS over IP
This section describes the construction of forwarding information
base (FIB) entries and the forwarding behavior that allow the
deployment of SR-MPLS when some routers in the network are IP only
(i.e., do not support SR-MPLS). Note that the examples in
Section 3.1.1 and Section 3.2 assume that OSPF or ISIS is enabled: in
fact, other mechanisms of discovery and advertisement could be used
including other routing protocols (such as BGP) or a central
controller.
3.1. Forwarding Entry Construction
This sub-section describes the how to construct the forwarding
information base (FIB) entry on an SR-MPLS-capable router when some
or all of the next-hops along the shortest path towards a prefix
Segment Identifier (prefix-SID) are IP-only routers. Section 3.1.1
provides a concrete example of how the process applies when using
OSPF or ISIS.
Consider router A that receives a labeled packet with top label L(E)
that corresponds to the prefix-SID SID(E) of prefix P(E) advertised
by router E. Suppose the i-th next-hop router (termed NHi) along the
shortest path from router A toward SID(E) is not SR-MPLS capable
while both routers A and E are SR-MPLS capable. The following
processing steps apply:
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o Router E is SR-MPLS capable, so it advertises a Segment Routing
Global Block (SRGB). The SRGB is defined in [RFC8402]. There are
a number of ways that the advertisement can be achieved including
IGPs, BGP, configuration/management protocols. For example, see
[I-D.ietf-bess-datacenter-gateway].
o When Router E advertises the prefix-SID SID(E) of prefix P(E) it
MUST also advertise the encapsulation endpoint and the tunnel type
of any tunnel used to reach E. This information is flooded domain
wide.
o If A and E are in different routing domains then the information
MUST be flooded into both domains. How this is achieved depends
on the advertisement mechanism being used. The objective is that
router A knows the characteristics of router E that originated the
advertisement of SID(E).
o Router A programs the FIB entry for prefix P(E) corresponding to
the SID(E) according to whether a pop or swap action is advertised
for the prefix. The resulting action may be:
* pop the top label
* swap the top label to a value equal to SID(E) plus the lower
bound of the SRGB of E
Once constructed, the FIB can be used by a router to tell it how to
process packets. It encapsulates the packets according to the
appropriate encapsulation advertised for the segment and then it
sends the packets towards the next hop NHi.
3.1.1. FIB Construction Example
This section is non-normative and provides a worked example of how a
FIB might be constructed using OSPF and ISIS extensions. It is based
on the process described in Section 3.1.
o Router E is SR-MPLS capable, so it advertises a Segment Routing
Global Block (SRGB) using
[I-D.ietf-ospf-segment-routing-extensions] or
[I-D.ietf-isis-segment-routing-extensions].
o When Router E advertises the prefix-SID SID(E) of prefix P(E) it
also advertises the encapsulation endpoint and the tunnel type of
any tunnel used to reach E using [I-D.ietf-isis-encapsulation-cap]
or [I-D.ietf-ospf-encapsulation-cap].
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o If A and E are in different domains then the information is
flooded into both domains and any intervening domains.
* The OSPF Tunnel Encapsulation TLV
[I-D.ietf-ospf-encapsulation-cap] or the ISIS Tunnel
Encapsulation sub-TLV [I-D.ietf-isis-encapsulation-cap] is
flooded domain-wide.
* The OSPF SID/label range TLV
[I-D.ietf-ospf-segment-routing-extensions] or the ISIS SR-
Capabilities Sub-TLV [I-D.ietf-isis-segment-routing-extensions]
is advertised domain-wide so that router A knows the
characteristics of router E.
* When router E advertises the prefix P(E):
+ If router E is running ISIS it uses the extended
reachability TLV (TLVs 135, 235, 236, 237) and associates
the IPv4/IPv6 or IPv4/IPv6 source router ID sub-TLV(s)
[RFC7794].
+ If router E is running OSPF it uses the OSPFv2 Extended
Prefix Opaque LSA [RFC7684] and sets the flooding scope to
AS-wide.
* If router E is running ISIS and advertises the ISIS capability
TLV (TLV 242) [RFC7981], it sets the "router-ID" field to a
valid value or includes an IPV6 TE router-ID sub-TLV (TLV 12),
or does both. The "S" bit (flooding scope) of the ISIS
capability TLV (TLV 242) is set to "1" .
o Router A programs the FIB entry for prefix P(E) corresponding to
the SID(E) according to whether a pop or swap action is advertised
for the prefix as follows:
* If the NP flag in OSPF or the P flag in ISIS is clear:
pop the top label
* If the NP flag in OSPF or the P flag in ISIS is set:
swap the top label to a value equal to SID(E) plus the lower
bound of the SRGB of E
When forwarding the packet according to the constructed FIB entry the
router encapsulates the packet according to the encapsulation as
advertised using the mechanisms described in
[I-D.ietf-isis-encapsulation-cap] or
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[I-D.ietf-ospf-encapsulation-cap]). It then sends the packets
towards the next hop NHi.
Note that [RFC7510] specifies the use of port number 6635 to indicate
that the payload of a UDP packet is MPLS, and port number 6636 for
MPLS-in-UDP utilizing DTLS. However,
[I-D.ietf-isis-encapsulation-cap] and
[I-D.ietf-ospf-encapsulation-cap] provide dynamic protocol mechanisms
to configure the use any Dynamic Port for a tunnel that uses UDP
encapsulation. Nothing in this document prevents the use of an IGP
or any other mechanism to negotiate the use of a Dynamic Port when
UDP encapsulation is used for SR-MPLS, but if no such mechanism is
used then the port numbers specified in [RFC7510] are used.
3.2. Packet Forwarding Procedures
[RFC7510] specifies an IP-based encapsulation for MPLS, i.e., MPLS-
in-UDP. This approach is applicable where IP-based encapsulation for
MPLS is required and further fine-grained load balancing of MPLS
packets over IP networks over Equal-Cost Multipath (ECMP) and/or Link
Aggregation Groups (LAGs) is also required. This section provides
details about the forwarding procedure when UDP encapsulation is
adopted for SR-MPLS over IP. Other encapsulation and tunnelling
mechanisms can be applied using similar techniques, but for clarity
this section uses UDP encapsulation as the exemplar.
Nodes that are SR-MPLS capable can process SR-MPLS packets. Not all
of the nodes in an SR-MPLS domain are SR-MPLS capable. Some nodes
may be "legacy routers" that cannot handle SR-MPLS packets but can
forward IP packets. An SR-MPLS-capable node MAY advertise its
capabilities using the IGP as described in Section 3. There are six
types of node in an SR-MPLS domain:
o Domain ingress nodes that receive packets and encapsulate them for
transmission across the domain. Those packets may be any payload
protocol including native IP packets or packets that are already
MPLS encapsulated.
o Legacy transit nodes that are IP routers but that are not SR-MPLS
capable (i.e., are not able to perform segment routing).
o Transit nodes that are SR-MPLS capable but that are not identified
by a SID in the SID stack.
o Transit nodes that are SR-MPLS capable and need to perform SR-MPLS
routing because they are identified by a SID in the SID stack.
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o The penultimate SR-MPLS capable node on the path that processes
the last SID on the stack on behalf of the domain egress node.
o The domain egress node that forwards the payload packet for
ultimate delivery.
3.2.1. Packet Forwarding with Penultimate Hop Popping
The description in this section assumes that the label associated
with each prefix-SID is advertised by the owner of the prefix-SID as
a Penultimate Hop Popping (PHP) label. That is, if one of the IGP
flooding mechanisms is used, the NP flag in OSPF or the P flag in
ISIS associated with the prefix-SID is not set.
+-----+ +-----+ +-----+ +-----+ +-----+
| A +-------+ B +-------+ C +-------+ D +-------+ H |
+-----+ +--+--+ +--+--+ +--+--+ +-----+
| | |
| | |
+--+--+ +--+--+ +--+--+
| E +-------+ F +-------+ G |
+-----+ +-----+ +-----+
+--------+
|IP(A->E)|
+--------+ +--------+ +--------+
| UDP | |IP(E->G)| |IP(G->H)|
+--------+ +--------+ +--------+
| L(G) | | UDP | | UDP |
+--------+ +--------+ +--------+
| L(H) | | L(H) | |Exp Null|
+--------+ +--------+ +--------+
| Packet | ---> | Packet | ---> | Packet |
+--------+ +--------+ +--------+
Figure 3: Packet Forwarding Example with PHP
In the example shown in Figure 3, assume that routers A, E, G and H
are SR-MPLS-capable while the remaining routers (B, C, D and F) are
only capable of forwarding IP packets. Routers A, E, G, and H
advertise their Segment Routing related information, such as via IS-
IS or OSPF.
Now assume that router A (the Domain ingress) wants to send a packet
to router H (the Domain egress) via the explicit path {E->G->H}.
Router A will impose an MPLS label stack on the packet that
corresponds to that explicit path. Since the next hop toward router
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E is only IP-capable (B is a legacy transit node), router A replaces
the top label (that indicated router E) with a UDP-based tunnel for
MPLS (i.e., MPLS-over-UDP [RFC7510]) to router E and then sends the
packet. In other words, router A pops the top label and then
encapsulates the MPLS packet in a UDP tunnel to router E.
When the IP-encapsulated MPLS packet arrives at router E (which is an
SR-MPLS-capable transit node), router E strips the IP-based tunnel
header and then processes the decapsulated MPLS packet. The top
label indicates that the packet must be forwarded toward router G.
Since the next hop toward router G is only IP-capable, router E
replaces the current top label with an MPLS-over-UDP tunnel toward
router G and sends it out. That is, router E pops the top label and
then encapsulates the MPLS packet in a UDP tunnel to router G.
When the packet arrives at router G, router G will strip the IP-based
tunnel header and then process the decapsulated MPLS packet. The top
label indicates that the packet must be forwarded toward router H.
Since the next hop toward router H is only IP-capable (D is a legacy
transit router), router G would replace the current top label with an
MPLS-over-UDP tunnel toward router H and send it out. However, since
router G reaches the bottom of the label stack (G is the penultimate
SR-MPLS capable node on the path) this would leave the original
packet that router A wanted to send to router H encapsulated in UDP
as if it was MPLS (i.e., with a UDP header and destination port
indicating MPLS) even though the original packet could have been any
protocol. That is, the final SR-MPLS has been popped exposing the
payload packet.
To handle this, when a router (here it is router G) pops the final
SR-MPLS label, it inserts an explicit null label [RFC3032] before
encapsulating the packet in an MPLS-over-UDP tunnel toward router H
and sending it out. That is, router G pops the top label, discovers
it has reached the bottom of stack, pushes an explicit null label,
and then encapsulates the MPLS packet in a UDP tunnel to router H.
3.2.2. Packet Forwarding without Penultimate Hop Popping
Figure 4 demonstrates the packet walk in the case where the label
associated with each prefix-SID advertised by the owner of the
prefix-SID is not a Penultimate Hop Popping (PHP) label (e.g., the
the NP flag in OSPF or the P flag in ISIS associated with the prefix-
SID is set). Apart from the PHP function the roles of the routers is
unchanged from Section 3.2.1.
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+-----+ +-----+ +-----+ +-----+ +-----+
| A +-------+ B +-------+ C +--------+ D +--------+ H |
+-----+ +--+--+ +--+--+ +--+--+ +-----+
| | |
| | |
+--+--+ +--+--+ +--+--+
| E +-------+ F +--------+ G |
+-----+ +-----+ +-----+
+--------+
|IP(A->E)|
+--------+ +--------+
| UDP | |IP(E->G)|
+--------+ +--------+ +--------+
| L(E) | | UDP | |IP(G->H)|
+--------+ +--------+ +--------+
| L(G) | | L(G) | | UDP |
+--------+ +--------+ +--------+
| L(H) | | L(H) | | L(H) |
+--------+ +--------+ +--------+
| Packet | ---> | Packet | ---> | Packet |
+--------+ +--------+ +--------+
Figure 4: Packet Forwarding Example without PHP
As can be seen from the figure, the SR-MPLS label for each segment is
left in place until the end of the segment where it is popped and the
next instruction is processed.
3.2.3. Additional Forwarding Procedures
Non-MPLS Interfaces: Although the description in the previous two
sections is based on the use of prefix-SIDs, tunneling SR-MPLS
packets is useful when the top label of a received SR-MPLS packet
indicates an adjacency-SID and the corresponding adjacent node to
that adjacency-SID is not capable of MPLS forwarding but can still
process SR-MPLS packets. In this scenario the top label would be
replaced by an IP tunnel toward that adjacent node and then
forwarded over the corresponding link indicated by the adjacency-
SID.
When to use IP-based Tunnels: The description in the previous two
sections is based on the assumption that MPLS-over-UDP tunnel is
used when the nexthop towards the next segment is not MPLS-
enabled. However, even in the case where the nexthop towards the
next segment is MPLS-capable, an MPLS-over-UDP tunnel towards the
next segment could still be used instead due to local policies.
For instance, in the example as described in Figure 4, assume F is
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now an SR-MPLS-capable transit node while all the other
assumptions remain unchanged: since F is not identified by a SID
in the stack and an MPLS-over-UDP tunnel is preferred to an MPLS
LSP according to local policies, router E replaces the current top
label with an MPLS-over-UDP tunnel toward router G and send it
out. (Note that if an MPLS LSP was preferred, the packet would be
forwarded as native SR-MPLS.)
IP Header Fields: When encapsulating an MPLS packet in UDP, the
resulting packet is further encapsulated in IP for transmission.
IPv4 or IPv6 may be used according to the capabilities of the
network. The address fields are set as described in Section 2.
The other IP header fields (such as the ECN field [RFC6040], the
DSCP code point [RFC2983], or IPv6 Flow Label) on each UDP-
encapsulated segment SHOULD be configurable according to the
operator's policy: they may be copied from the header of the
incoming packet; they may be promoted from the header of the
payload packet; they may be set according to instructions
programmed to be associated with the SID; or they may be
configured dependent on the outgoing interface and payload. The
TTL field setting in the encapsulating packet header is handled as
described in [RFC7510] which refers to [RFC4023].
Entropy and ECMP: When encapsulating an MPLS packet with an IP
tunnel header that is capable of encoding entropy (such as
[RFC7510]), the corresponding entropy field (the source port in
the case of a UDP tunnel) MAY be filled with an entropy value that
is generated by the encapsulator to uniquely identify a flow.
However, what constitutes a flow is locally determined by the
encapsulator. For instance, if the MPLS label stack contains at
least one entropy label and the encapsulator is capable of reading
that entropy label, the entropy label value could be directly
copied to the source port of the UDP header. Otherwise, the
encapsulator may have to perform a hash on the whole label stack
or the five-tuple of the SR-MPLS payload if the payload is
determined as an IP packet. To avoid re-performing the hash or
hunting for the entropy label each time the packet is encapsulated
in a UDP tunnel it MAY be desirable that the entropy value
contained in the incoming packet (i.e., the UDP source port value)
is retained when stripping the UDP header and is re-used as the
entropy value of the outgoing packet.
Congestion Considerations: Section 5 of [RFC7510] provides a
detailed analysis of the implications of congestion in MPLS-over-
UDP systems and builds on section 3.1.3 of [RFC8085] that
describes the congestion implications of UDP tunnels. All of
those considerations apply to SR-MPLS-over-UDP tunnels as
described in this document. In particular, it should be noted
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that the traffic carried in SR-MPLS flows is likely to be IP
traffic.
4. IANA Considerations
This document makes no requests for IANA action.
5. Security Considerations
The security consideration of [RFC8354] (which redirects the reader
to [RFC5095]) and [RFC7510] apply. DTLS [RFC6347] SHOULD be used
where security is needed on an MPLS-SR-over-UDP segment including
when the IP segment crosses the public Internet or some other
untrusted environment. [RFC8402] provides security considerations
for Segment Routing, and Section 8.1 of that document is particularly
applicable to SR-MPLS.
It is difficult for an attacker to pass a raw MPLS encoded packet
into a network and operators have considerable experience at
excluding such packets at the network boundaries, for example by
excluding all packets that are revealed to be carrying an MPLS packet
as the payload of IP tunnels. Further discussion of MPLS security is
found in [RFC5920].
It is easy for a network ingress node to detect any attempt to
smuggle an IP packet into the network since it would see that the UDP
destination port was set to MPLS, and such filtering SHOULD be
applied. If, however, the mechanisms described in
[I-D.ietf-ospf-segment-routing-extensions] or
[I-D.ietf-isis-segment-routing-extensions] are applied, a wider
variety of UDP port numbers might be in use making port filtering
harder.
SR packets not having a destination address terminating in the
network would be transparently carried and would pose no different
security risk to the network under consideration than any other
traffic.
Where control plane techniques are used (as described in Section 3),
it is important that these protocols are adequately secured for the
environment in which they are run as discussed in [RFC6862] and
[RFC5920].
6. Contributors
Ahmed Bashandy
Individual
Email: abashandy.ietf@gmail.com
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Clarence Filsfils
Cisco
Email: cfilsfil@cisco.com
John Drake
Juniper
Email: jdrake@juniper.net
Shaowen Ma
Mellanox Technologies
Email: mashaowen@gmail.com
Mach Chen
Huawei
Email: mach.chen@huawei.com
Hamid Assarpour
Broadcom
Email:hamid.assarpour@broadcom.com
Robert Raszuk
Bloomberg LP
Email: robert@raszuk.net
Uma Chunduri
Huawei
Email: uma.chunduri@gmail.com
Luis M. Contreras
Telefonica I+D
Email: luismiguel.contrerasmurillo@telefonica.com
Luay Jalil
Verizon
Email: luay.jalil@verizon.com
Gunter Van De Velde
Nokia
Email: gunter.van_de_velde@nokia.com
Tal Mizrahi
Marvell
Email: talmi@marvell.com
Jeff Tantsura
Individual
Email: jefftant@gmail.com
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7. Acknowledgements
Thanks to Joel Halpern, Bruno Decraene, Loa Andersson, Ron Bonica,
Eric Rosen, Jim Guichard, Gunter Van De Velde, Andy Malis, Robert
Sparks, and Al Morton for their insightful comments on this draft.
Additional thanks to Mirja Kuehlewind, Alvaro Retana, Spencer
Dawkins, Benjamin Kaduk, Martin Vigoureux, Suresh Krishnan, and Eric
Vyncke for careful reviews and resulting comments.
8. References
8.1. Normative References
[I-D.ietf-spring-segment-routing-mpls]
Bashandy, A., Filsfils, C., Previdi, S., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-22
(work in progress), May 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>.
[RFC4023] Worster, T., Rekhter, Y., and E. Rosen, Ed.,
"Encapsulating MPLS in IP or Generic Routing Encapsulation
(GRE)", RFC 4023, DOI 10.17487/RFC4023, March 2005,
<https://www.rfc-editor.org/info/rfc4023>.
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095,
DOI 10.17487/RFC5095, December 2007,
<https://www.rfc-editor.org/info/rfc5095>.
[RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion
Notification", RFC 6040, DOI 10.17487/RFC6040, November
2010, <https://www.rfc-editor.org/info/rfc6040>.
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[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC7510] Xu, X., Sheth, N., Yong, L., Callon, R., and D. Black,
"Encapsulating MPLS in UDP", RFC 7510,
DOI 10.17487/RFC7510, April 2015,
<https://www.rfc-editor.org/info/rfc7510>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>.
[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions
for Advertising Router Information", RFC 7981,
DOI 10.17487/RFC7981, October 2016,
<https://www.rfc-editor.org/info/rfc7981>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
8.2. Informative References
[I-D.ietf-6man-segment-routing-header]
Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment
Routing Header (SRH)", draft-ietf-6man-segment-routing-
header-21 (work in progress), June 2019.
[I-D.ietf-bess-datacenter-gateway]
Farrel, A., Drake, J., Rosen, E., Patel, K., and L. Jalil,
"Gateway Auto-Discovery and Route Advertisement for
Segment Routing Enabled Domain Interconnection", draft-
ietf-bess-datacenter-gateway-02 (work in progress),
February 2019.
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[I-D.ietf-isis-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Chunduri, U., Contreras,
L., and L. Jalil, "Advertising Tunnelling Capability in
IS-IS", draft-ietf-isis-encapsulation-cap-01 (work in
progress), April 2017.
[I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Gredler, H., and B. Decraene, "IS-IS Extensions for
Segment Routing", draft-ietf-isis-segment-routing-
extensions-25 (work in progress), May 2019.
[I-D.ietf-mpls-spring-entropy-label]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and J. Tantsura, "Entropy label for SPRING
tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in
progress), July 2018.
[I-D.ietf-ospf-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Contreras, L., and L.
Jalil, "The Tunnel Encapsulations OSPF Router
Information", draft-ietf-ospf-encapsulation-cap-09 (work
in progress), October 2017.
[I-D.ietf-ospf-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", draft-ietf-ospf-segment-
routing-extensions-27 (work in progress), December 2018.
[RFC2983] Black, D., "Differentiated Services and Tunnels",
RFC 2983, DOI 10.17487/RFC2983, October 2000,
<https://www.rfc-editor.org/info/rfc2983>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<https://www.rfc-editor.org/info/rfc5920>.
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, DOI 10.17487/RFC6790, November 2012,
<https://www.rfc-editor.org/info/rfc6790>.
[RFC6862] Lebovitz, G., Bhatia, M., and B. Weis, "Keying and
Authentication for Routing Protocols (KARP) Overview,
Threats, and Requirements", RFC 6862,
DOI 10.17487/RFC6862, March 2013,
<https://www.rfc-editor.org/info/rfc6862>.
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[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[RFC8354] Brzozowski, J., Leddy, J., Filsfils, C., Maglione, R.,
Ed., and M. Townsley, "Use Cases for IPv6 Source Packet
Routing in Networking (SPRING)", RFC 8354,
DOI 10.17487/RFC8354, March 2018,
<https://www.rfc-editor.org/info/rfc8354>.
Authors' Addresses
Xiaohu Xu
Alibaba, Inc
Email: xiaohu.xxh@alibaba-inc.com
Stewart Bryant
Huawei
Email: stewart.bryant@gmail.com
Adrian Farrel
Old Dog Consulting
Email: adrian@olddog.co.uk
Syed Hassan
Cisco
Email: shassan@cisco.com
Wim Henderickx
Nokia
Email: wim.henderickx@nokia.com
Zhenbin Li
Huawei
Email: lizhenbin@huawei.com
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