INTERNET-DRAFT Margaret Cullen
Intended Status: Proposed Standard Painless Security
Updates: 7177, 7178 Donald Eastlake
Mingui Zhang
Huawei
Dacheng Zhang
Alibaba
Expires: April 18, 2016 October 19, 2015
Transparent Interconnection of Lots of Links (TRILL) over IP
<draft-ietf-trill-over-ip-05.txt>
Abstract
The Transparent Interconnection of Lots of Links (TRILL) protocol
supports both point-to-point and multi-access links and is designed
so that a variety of link protocols can be used between TRILL switch
ports. This document standardizes methods for encapsulating TRILL in
IP (v4 or v6) so as to use IP as a TRILL link protocol in a unified
TRILL campus. It updates RFC 7177 and updates RFC 7178.
Status of This Document
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Distribution of this document is unlimited. Comments should be sent
to the author or the DNSEXT mailing list <dnsext@ietf.org>.
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Table of Contents
1. Introduction............................................4
2. Terminology.............................................5
3. Use Cases for TRILL over IP.............................6
3.1 Remote Office Scenario.................................6
3.2 IP Backbone Scenario...................................6
3.3 Important Properties of the Scenarios..................6
3.3.1 Security Requirements................................7
3.3.2 Multicast Handling...................................7
3.3.3 Neighbor Discovery...................................8
4. TRILL Packet Formats....................................9
4.1 General Packet Formats.................................9
4.2 General TRILL Over IP Packet Formats..................10
4.2.1 Without Security....................................10
4.2.2 With Security.......................................10
4.3 QoS Considerations....................................11
4.4 Broadcast Links and Multicast Packets.................12
4.5 TRILL Over IP IS-IS SubNetwork Point of Attachment....13
5. TRILL over IP Encapsulation Formats....................14
5.1 Encapsulation Considerations..........................14
5.2 Encapsulation Agreement...............................15
5.3 Broadcast Link Encapsulation Considerations...........16
5.4 Native Encapsulation..................................16
5.5 VXLAN Encapsulation...................................17
5.6 Other Encapulsations..................................18
6. Handling Multicast.....................................19
7. Use of IPsec and IKEv2.................................20
7.1 Keying................................................20
7.1.1 Pairwise Keying.....................................20
7.1.2 Group Keying........................................21
7.2 Mandatory-to-Implement Algorithms.....................21
8. Transport Considerations...............................22
8.1 Congestion Considerations.............................22
8.2 Recursive Ingress.....................................23
8.3 Fat Flows.............................................24
8.4 MTU Considerations....................................25
8.5 Middlebox Considerations..............................25
9. TRILL over IP Port Configuration.......................27
9.1 Per IP Port Configuration.............................27
9.2 Additional per IP Address Configuration...............27
9.2.1 Native Multicast Configuration......................27
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Table of Contents (continued)
9.2.2 Serial Unicast Configuration........................28
9.2.3 Encapsulation Specific Configuration................28
9.2.3.1 VXLAN Configuration...............................28
9.2.3.2 Other Encapsulation Configuration.................29
9.2.4 Security Configuration..............................29
10. Security Considerations...............................30
10.1 IPsec................................................30
10.2 IS-IS Security.......................................31
11. IANA Considerations...................................32
11.1 Port Assignments.....................................32
11.2 Multicast Address Assignments........................32
11.3 Encapsulation Method Support Indication..............32
Normative References......................................34
Informative References....................................36
Acknowledgements..........................................38
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1. Introduction
TRILL switches (RBridges) are devices that implement the IETF TRILL
protocol [RFC6325] [RFC7177] [rfc7180bis]. TRILL provides
transparent forwarding of frames within an arbitrary network
topology, using least cost paths for unicast traffic. It supports
VLANs and Fine Grained Labels [RFC7172] as well as multipathing of
unicast and multi-destination traffic. It uses IS-IS [RFC7176] link
state routing and encapsulation with a hop count.
RBridges ports can communicate with each other over various
protocols, such as Ethernet [RFC6325], pseudowires [RFC7173], or PPP
[RFC6361].
This document defines a method for RBridge ports to communicate over
IP (v4 or v6). TRILL over IP allows Internet-connected RBridges to
form a single TRILL campus, or multiple TRILL over IP networks within
a campus to be connected as a single TRILL campus via a TRILL over IP
backbone.
TRILL over IP connects RBridge ports using IPv4 or IPv6 as a
transport in such a way that the ports appear to TRILL to be
connected by a single multi-access link. If more than two RBridge
ports are connected via a single TRILL over IP link, any pair of them
can communicate.
To support the scenarios where RBridges are connected via IP paths
(such as over the public Internet) that are not under the same
administrative control as the TRILL campus and/or not physically
secure, this document specifies the use of IPsec [RFC4301]
Encapsulating Security Protocol (ESP) [RFC4303] to secure such paths.
To dynamically select a mutually supported TRILL over IP
encapsulation, normally one with good fast path hardware support, a
method is provided for agreement between adjacent TRILL switch ports
as to what encapsulation to use. This document updates [RFC7177] and
[RFC7178] as described in Section 5 by making adjacency between TRILL
over IP ports dependent on having a method of encapsulation in common
and by redefining an interval of RBridge Channel protocol numbers to
indicate encapsulation method support for TRILL over IP.
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2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
The following terms and acronyms have the meaning indicated:
DRB - Designated RBridge. The RBridge (TRILL switch) elected to be in
charge of certain aspects of a TRILL link that is not
configured as a point-to-point link [RFC6325] [RFC7177].
ENCAP Hdr - Encapsulation headers in use between the IP Header and
the TRILL Header. See Section 5.
ESP - IPsec Encapsulating Security Protocol [RFC4303].
FGL - Fine Grained Label [RFC7172].
Hdr - Used herein as an abbreviation for "Header".
HKDF - Hash based Key Derivation Function [RFC5869].
MTU - Maximum Transmission Unit.
RBridge - Routing Bridge. An alternative term for a TRILL switch.
TRILL - Transparent Internconnection of Lots of Links or Tunneled
Routing in the Link Layer. The protocol specified in [RFC6325],
[RFC7177], [rfc7180bis], and related RFCs.
TRILL switch - A device implementing the TRILL protocol.
VNI - Virtual Network Identifier. In VXLAN [RFC7348], the VXLAN
Network Identifier.
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3. Use Cases for TRILL over IP
This section introduces two application scenarios (a remote office
scenario and an IP backbone scenario) which cover typical situations
where network administrators may choose to use TRILL over an IP
network to connect TRILL switches.
3.1 Remote Office Scenario
In the Remote Office Scenario, a remote TRILL network is connected to
a TRILL campus across a multihop IP network, such as the public
Internet. The TRILL network in the remote office becomes a part of
TRILL campus, and nodes in the remote office can be attached to the
same VLANs or Fine Grained Labels [RFC7172] as local campus nodes. In
many cases, a remote office may be attached to the TRILL campus by a
single pair of RBridges, one on the campus end, and the other in the
remote office. In this use case, the TRILL over IP link will often
cross logical and physical IP networks that do not support TRILL, and
are not under the same administrative control as the TRILL campus.
3.2 IP Backbone Scenario
In the IP Backbone Scenario, TRILL over IP is used to connect a
number of TRILL networks to form a single TRILL campus. For example,
a TRILL over IP backbone could be used to connect multiple TRILL
networks on different floors of a large building, or to connect TRILL
networks in separate buildings of a multi-building site. In this use
case, there may often be several TRILL switches on a single TRILL
over IP link, and the IP link(s) used by TRILL over IP are typically
under the same administrative control as the rest of the TRILL
campus.
3.3 Important Properties of the Scenarios
There are a number of differences between the above two application
scenarios, some of which drive features of this specification. These
differences are especially pertinent to the security requirements of
the solution, how multicast data frames are handled, and how the
TRILL switch ports discover each other.
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3.3.1 Security Requirements
In the IP Backbone Scenario, TRILL over IP is used between a number
of RBridge ports, on a network link that is in the same
administrative control as the remainder of the TRILL campus. While it
is desirable in this scenario to prevent the association of
unauthorized RBridges, this can be accomplished using existing IS-IS
security mechanisms. There may be no need to protect the data
traffic, beyond any protections that are already in place on the
local network.
In the Remote Office Scenario, TRILL over IP may run over a network
that is not under the same administrative control as the TRILL
network. Nodes on the network may think that they are sending traffic
locally, while that traffic is actually being sent, in an IP tunnel,
over the public Internet. It is necessary in this scenario to protect
the integrity and confidentiality of user traffic, as well as
ensuring that no unauthorized RBridges can gain access to the RBridge
campus. The issues of protecting integrity and confidentiality of
user traffic are addressed by using IPsec for both TRILL IS-IS and
TRILL Data packets between RBridges in this scenario.
3.3.2 Multicast Handling
In the IP Backbone scenario, native IP multicast may be supported on
the TRILL over IP link. If so, it can be used to send TRILL IS-IS and
multicast data packets, as discussed later in this document.
Alternatively, multi-destination packets can be transmitted serially
by IP unicast to the intended recipients.
In the Remote Office Scenario there will often be only one pair of
RBridges connecting a given site and, even when multiple RBridges are
used to connect a Remote Office to the TRILL campus, the intervening
network may not provide reliable (or any) multicast connectivity.
Issues such as complex key management also make it difficult to
provide strong data integrity and confidentiality protections for
multicast traffic. For all of these reasons, the connections between
local and remote RBridges will commonly be treated like point-to-
point links, and all TRILL IS-IS control messages and multicast data
packets that are transmitted between the Remote Office and the TRILL
campus will be serially transmitted by IP unicast, as discussed later
in this document.
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3.3.3 Neighbor Discovery
In the IP Backbone Scenario, TRILL switches that use TRILL over IP
can use the normal TRILL IS-IS Hello mechanisms to discover the
existence of other TRILL switches on the link [RFC7177], and to
establish authenticated communication with them.
In the Remote Office Scenario, an IPsec session will need to be
established before TRILL IS-IS traffic can be exchanged, as discussed
below. In this case, one end will need to be configured to establish
a IPSEC session with the other. This will typically be accomplished
by configuring the TRILL switch or a border device at a Remote Office
to initiate an IPsec session and subsequent TRILL exchanges with a
TRILL over IP-enabled RBridge attached to the TRILL campus.
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4. TRILL Packet Formats
To support the TRILL protocol [RFC6325], two types of TRILL packets
are transmitted between TRILL switches: TRILL Data packets and TRILL
IS-IS packets.
Section 4.1 describes general TRILL packet formats for data and IS-IS
independent of link technology. Section 4.2 specifies general TRILL
over IP packet formats including IPsec ESP encapsulation. Section 4.3
provides QoS Considerations. Section 4.4 discusses broadcast links
and multicast packets. And Section 4.5 provides TRILL IS-IS Hello
SubNetwork Point of Attachment (SNPA) considerations for TRILL over
IP.
4.1 General Packet Formats
The on-the-wire form of a TRILL Data packet in transit between two
neighboring TRILL switch ports is as shown below:
+----------------+----------+----------------+-----------+
| Link Header | TRILL | Native Frame | Link |
| for TRILL Data | Header | Payload | Trailer |
+----------------+----------+----------------+-----------+
The encapsulated Native Frame Payload is similar to an Ethernet frame
with a VLAN tag or Fine Grained Label [RFC7172] but with no trailing
Frame Check Sequence (FCS).
TRILL IS-IS packets are formatted on-the-wire as follows:
+-----------------+---------------+-----------+
| Link Header | TRILL IS-IS | Link |
| for TRILL IS-IS | Payload | Trailer |
+-----------------+---------------+-----------+
The Link Header and Link Trailer in these formats depend on the
specific link technology. The Link Header contains one or more fields
that distinguish TRILL Data from TRILL IS-IS. For example, over
Ethernet, the Link Header for TRILL Data ends with the TRILL
Ethertype while the Link Header for TRILL IS-IS ends with the L2-IS-
IS Ethertype; on the other hand, over PPP, there are no Ethertypes in
the Link Header but PPP protocol code points are included that
distinguish TRILL Data from TRILL IS-IS.
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4.2 General TRILL Over IP Packet Formats
In TRILL over IP, we will use an IP (v4 or v6) header as the link
header. (On the wire, the IP header will normally be preceded by the
lower layer header of a protocol that is carrying IP; however, this
does not concern us at the level of this document.)
There are multiple IP based encapsulations usable for TRILL over IP
that differ in exactly what appears after the IP header and before
the TRILL Header or the TRILL IS-IS Payload. These encapsulations are
further detailed in Section 5. In the general specification below,
those encapsulation fields will be represented as "ENCAP Hdr". See
Section 5 for details.
4.2.1 Without Security
When TRILL over IP link security is not being used, a TRILL over IP
packet on the wire looks like the following:
TRILL Data Packet
+---------+------------+---------+---------------+
| IP | ENCAP Hdr | TRILL | Native frame |
| Header | for Data | Header | Payload |
+---------+------------+---------+---------------+
TRILL IS-IS
+---------+------------+--------------+
| IP | ENCAP Hdr | TRILL IS-IS |
| Header | for IS-IS | Payload |
+---------+------------+--------------+
As discussed above and further specified in Section 5, the ENCAP Hdr
indicates whether the packet is TRILL Data or IS-IS.
4.2.2 With Security
TRILL over IP link security uses IPsec Encapsulating Security
Protocol (ESP) in tunnel mode [RFC4303]. Since TRILL over IP always
starts with an IP Header (on the wire this appears right after any
lower layer header that might be required), the modifications for
IPsec are independent of the TRILL over IP ENCAP Hdr that occurs
after that IP Header. The resulting packet formats are as follows for
IPv4 and IPv6:
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IPv4
+-------------+-----+--------------+-----------+-----------+
| new IP Hdr | ESP | TRILL IP Hdr | ENCAP Hdr | ESP |ESP|
|(any options)| Hdr | (any options)| + payload |Trailer|ICV|
+-------------+-----+--------------+-----------+-----------+
|<---------- encryption ---------->|
|<-------------- integrity ------------->|
IPv6
+------+-------+-----+------+--------+-----------+-------+---+
| new |new ext| ESP | orig |orig ext| ENCAP Hdr | ESP |ESP|
|IP Hdr| Hdrs | Hdr |IP Hdr| Hdrs | + payload |Trailer|ICV|
+------+-------+-----+------+--------+-----------+-------+---+
|<----------- encryption ---------->|
|<--------------- integrity ------------->|
As shown above, IP Header options are considered part of the IPv4
Header but are extensions ("ext") of the IPv6 Header. For further
information on the IPsec ESP Hdr, Trailer, and ICV, see [RFC4303] and
Section 7. "ENCAP Hdr + payload" is the encapsulation header (Section
5) and TRILL data or IS-is payload, that is, the material after the
IP Header in the diagram in Section 4.2.1.
This architecture permits the ESP tunnel end point to be separated
from the TRILL over IP RBridge port (see, for example, Section 1.1.3
of [RFC7296]).
4.3 QoS Considerations
In IP, QoS handling is indicated by the Differential Services Code
Point (DSCP [RFC2474] [RFC3168]) in the TRILL Header. The former
Type of Service (TOS) octet in the IPv4 Header and the Traffic Class
octet in the IPv6 Header has been divided as shown in the following
diagram adapted from [RFC3168]. (TRILL support of ECN is beyond the
scope of this document.)
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| DSCP FIELD | ECN FIELD |
+-----+-----+-----+-----+-----+-----+-----+-----+
DSCP: Differentiated Services Codepoint
ECN: Explicit Congestion Notification
Within a TRILL switch, priority is indicated by configuration for
TRILL IS-IS packets and for TRILL Data packets by a three bit (0
through 7) priority field and a Drop Eligibility Indicator bit (see
Sections 8.2 and 7 of [rfc7180bis]). (Typically TRILL IS-IS is
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configured to use the highest priority or, alternatively, the highest
two priorities depending on the IS-IS PDU.) The priority affects
queuing behavior at TRILL switch ports and may be encoded into the
link header, particularly if there could be priority sensitive
devices within the link. For example, if the link is a bridged LAN,
it is commonly encoded into an Outer.VLAN tag's priority and DEI
fields.
TRILL over IP implementations MUST support setting the DSCP value in
the outer IP Header of TRILL packets they send by mapping the TRILL
priority and DEI to the DSCP. They MAY support, for a TRILL Data
packet where the native frame payload is an IP packet, copying the
DSCP in this inner IP packet to the outer IP Header.
The default TRILL priority and DEI to DSCP mapping, which may be
configured per TRILL over IP port, is an follows. Note that the DEI
value does not affect the default mapping and, to provide a
potentially lower priority service than the default 0, priority 1 is
considered lower priority than 0. So the priority sequence from lower
to higher priority is 1, 0, 2, 3, 4, 5, 6, 7.
TRILL Priority DEI DSCP Field (Binary/decimal)
-------------- --- -----------------------------
0 0/1 001000 / 8
1 0/1 000000 / 0
2 0/1 010000 / 16
3 0/1 011000 / 24
4 0/1 100000 / 32
5 0/1 101000 / 40
6 0/1 110000 / 48
7 0/1 111000 / 56
4.4 Broadcast Links and Multicast Packets
TRILL supports broadcast links. These are links to which more than
two TRILL switch ports can be attached and where a packet can be
broadcast or multicast from a port to all or a subset of the other
ports on the link as well as unicast to a specific single other port
on the link.
As specified in [RFC6325], TRILL Data packets being forwarded between
TRILL switches can be unicast on a link to a specific TRILL switch
port or multicast on a link to all TRILL switch ports. TRILL IS-IS
packets are always multicast to all other TRILL switches on the link
except for IS-IS MTU PDUs, which may be unicast [RFC7177]. This
distinction is not significant if the link is inherently point-to-
point, such as a PPP link; however, on a broadcast link there will be
a packet outer link address that is unicast or multicast as
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appropriate. For example, over Ethernet links, the Ethernet multicast
addresses All-RBridges and All-IS-IS-RBridges are used for
multicasting TRILL Data and TRILL IS-IS respectively. For details on
TRILL over IP handling of multicast, see Section 6.
4.5 TRILL Over IP IS-IS SubNetwork Point of Attachment
IS-IS routers, such as TRILL switches, establish adjacency through
the exchange of Hello PDUs on a link [IS-IS] [RFC7177]. The Hellos
transmitted out a port indicate what neighbor ports that port can see
on the link by listing what IS-IS refers to as the neighbor port's
SubNetwork Point of Attachment (SNPA). (For an Ethernet link, which
may be a bridged LAN, the SNPA is the port MAC address.)
In TRILL Hello PDUs on a TRILL over IP link, the IP addresses of the
IP ports connected to that link are their actual SNPA (SubNetwork
Point of Attachment [IS-IS]) addresses and, for IPv6, the 16-byte
IPv6 address is used as the SNPA; however, for easy in re-using code
designed for the common case of 48-bit SNPAs, in TRILL over IPv4 a
48-bit synthetic SNPA that looks like a unicast MAC address is
constructed for use in the SNPA field of TRILL Neighbor TLVs
[RFC7176] [RFC7177] in such Hellos. This synthetic SNPA is derived
from the port IPv4 address is as follows:
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0xFE | 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 upper half |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 lower half |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This synthetic SNPA (MAC) address has the local (0x02) bit on in the
first byte and so cannot conflict with any globally unique 48-bit
Ethernet MAC. However, when TRILL operates on an IP link, TRILL sees
only IP stations, not MAC stations, even if the TRILL over IP Link is
being carried over Ethernet. Therefore conflict on the link in TRILL
IS-IS between a real MAC address and the synthetic SNPA (MAC) address
as above would be impossible in any case.
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5. TRILL over IP Encapsulation Formats
There are a variety of TRILL over IP encapsulation formats possible.
By default TRILL over IP adopts a hybrid encapsulation approach.
There is one format, called "native encapsulation" that MUST be
implemented. Although native encapsulation does not typically have
good fast path support, as a lowest common denominator it can be used
by low bandwidth control traffic to determine a preferred
encapsulation with better performance. In particular, by default, all
TRILL IS-IS Hellos are sent using native encapsulation and those
Hellos are used to determine the encapsulation used for all TRILL
Data packets and all other TRILL IS-IS PDUs (with the possible
exception of IS-IS MTU-probe and MTU-ack PDUs).
Alternatively, the network operator can pre-configure a TRILL over IP
port to use a particular encapsulation chosen for their particular
network needs and port capabilities. That encapsulation is then used
for all TRILL Data and IS-IS packets on ports so configured.
Section 5.1 discusses general consideration for the TRILL over IP
encapsulation format. Section 5.2 discusses encapsulation agreement.
Section 5.3 discusses broadcast link encapsulation considerations.
The subsequent subsections discuss particular encapsulations.
5.1 Encapsulation Considerations
In all cases, there must be a method specified to distinguish TRILL
Data packets and TRILL IS-IS packets, or that encapsulation is not
useful for TRILL. In addition, the following criteria can be helpful
is choosing between different encapsulations:
a) Fast path support - For many applications, it is highly desirable
to be able to encapsulate/decpasulate TRILL over IP at line speed
so a format where existing or anticipated fast path hardware can
do that is best. This is commonly a dominant consideration.
b) Ease of multi-pathing - The IP path between TRILL over IP ports
may include equal cost multipath routes internal to the IP link so
a method of encapsulation that provides variable fields available
for existing or anticipated fast path hardware multi-pathing is
better.
c) Robust fragmentation and re-assembly - MTU of the IP link may
require fragmentation in which case an encapsulation with robust
fragmentation and re-assembly is important. There are known
problems with IPv4 fragmentation and re-assembly [RFC6864] which
generally do not apply to IPv6. Some encapsulations can fix these
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problems but the two encapsulations specified in this document do
not. Therefore, if fragmentation is anticipated with the
encapsulations specified in this document, the use of IPv6 is
RECOMMENDED.
d) Checksum strength - Depending on the particular circumstances of
the TRILL over IP link, a checksum provided by the encapsulation
may be an important factor. Use of IPsec can also provide a strong
integrity check.
5.2 Encapsulation Agreement
TRILL Hellos sent out a TRILL over IP port indicate the
encapsulations that port is willing to support through a mechanism
initially specified in [RFC7178] and [RFC7176] that is hereby
extended. Specifically, RBridge Channel Protocol numbers 0xFD0
through 0xFF7 are redefined to be link technology dependent flags
that, for TRILL over IP, indicate support for different
encapsulations, allowing for up to 40 encapsulations to be specified.
Support for an encapsulation is indicated in the Hello PDU in the
same way that support for an RBridge Channel was indicated. (See also
section 11.3.) "Support" indicates willingness to use that
encapsulation for TRILL Data and TRILL IS-IS packets (although TRILL
IS-IS Hellos are still sent in native encapsulation by default).
If, in a TRILL Hello on a TRILL over IP link, support is not
indicated for any encapsulation, then the port from which it was sent
is assumed to support only native encapsulation (see Section 5.4).
An adjacency is formed between two TRILL over IP ports if the
intersection of the sets of encapsulation methods they support is not
null. If that intersection is null, then no adjacency is formed. In
particular, for a TRILL over IP link, the adjacency state machine
MUST NOT advance to the Report state unless the ports share an
encapsulation [RFC7177]. If no encapsulation is shared, the adjacency
state machine remains in the state from which it would otherwise have
transitioned to the Report state.
If any TRILL over IP packet, other than an IS-IS Hello or MTU PDU in
native encapsulation, is received in an encapsulation for which
support is not being indicated, it MUST be discarded (see Section
5.3).
If there are two or more encapsulations in common between two
adjacent ports for unicast or the set of adjacent ports for
multicast, a transmitter is free to choose whichever of the
encapsulations it wishes to use. Thus transmissions between adjacent
ports P1 and P2 could use different encapsulations depending on which
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port is transmitting and which is receiving.
It is expected to be the normal case in a well configured network
that all the TRILL over IP ports connected to an IP link (i.e., an IP
network) that are intended to communicate with each other will
support the same encapsulation(s).
5.3 Broadcast Link Encapsulation Considerations
To properly handle TRILL protocol packets on a TRILL over IP link in
the general case, either native IP multicast mode is used on that
link or multicast must be simulated using serial IP unicast, as
discussed in Section 6. (Of course, if the IP link happens to
actually be point-to-point no special provision is needed for
handling multicast addressed packets.)
It is possible for the Hellos from a TRILL over IP port P1 to
establish adjacency with multiple other TRILL over IP ports (P2, P3,
...) on broadcast link. In a well configured network one would expect
all of the IP ports involved to support the same encapsulation(s);
but, if P1 supports multiple encapsulations, it is possible that P2
and P3, for example, do not have an encapsulation in common that is
supported by P1. IS-IS can handle such non-transitive adjacencies
which are reported as specified in [RFC7177]. If serial IP unicast is
being used by P1, it can use different encapsulations for different
transmissions. If native IP multicast is being used by P1, it will
have to send one transmission per encapsulation method by which it
has an adjacency on the link. (It is for this reason that a TRILL
over IP port MUST discard any packet received with the wrong
encapsulation. Otherwise, packets would be duplicated.)
5.4 Native Encapsulation
The mandatory to implement "native encapsulation" format of a TRILL
over IP packet, when used without security, is TRILL over UDP as
shown below.
+----------+--------+-----------------------+
| IP | UDP | TRILL |
| Header | Header | Payload |
+----------+--------+-----------------------+
Where the UDP Header is as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Port = Entropy | Destination Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TRILL Payload ...
Source Port - see Section 8.3
Destination Port - indicates TRILL Data or IS-IS, see Section 11
UDP Length - as specified in [RFC0768]
UDP Checksum - as specified in [RFC0768]
The TRILL Payload starts with the TRILL Header (not including the
TRILL Ethertype) for TRILL Data packets and starts with the 0x83
Intradomain Routeing Protocol Discriminator byte (thus not including
the L2-IS-IS Ethertype) for TRILL IS-IS packets.
5.5 VXLAN Encapsulation
VXLAN [RFC7348] IP encapsulation of TRILL looks, on the wire, like
TRILL over Ethernet over VXLAN over UDP over IP.
+--------+--------+--------+----------+-----------+
| IP | UDP | VXLAN | Ethernet | TRILL |
| Header | Header | Header | Header | Payload |
+--------+--------+--------+----------+-----------+
The outer UDP uses a destination port number indicating VXLAN and the
outer UDP source port MAY be used for entropy as with native
encapsulation (see Section 5.4). The VXLAN header after the outer UDP
header adds a 24 bit Virtual Network Identifier (VNI). The Ethernet
header after the VXLAN header and before the TRILL header consists of
source MAC address, destination MAC address, and Ethertype. The
Ethertype distinguishes TRILL Data from TRILL IS-IS; however, the
destination and source MAC addresses in this inner Ethernet header
are not used and are 12 wasted bytes.
A TRILL over IP port using VXLAN encapsulation by default uses a VNI
of 1 but can be configured as described in Section 9.2.3.1 to use
some other fixed VNI or to map from VLAN/FGL to VNI.
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5.6 Other Encapulsations
It is anticipated that additional TRILL over IP encapsulations will
be specified in future documents and allocated a bit in the TRILL
Hello as per Section 11.3. A primary consideration for whether it is
worth the effort to specify an encapsulation is good existing or
anticipated fast path support.
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6. Handling Multicast
By default, both TRILL IS-IS packets and multi-destination TRILL Data
packets are sent to an All-RBridges IPv4 or IPv6 IP multicast Address
as appropriate (see Section 11.2); however, a TRILL over IP port may
be configured (see Section 9) to use a different multicast address or
to use serial IP unicast with a list of one or more unicast IP
addresses of other TRILL over IP ports to which multi-destination
packets are sent. In the serial unicast case the outer IP header of
each copy of the packet sent shows an IP unicast destination address
even through the TRILL header has the M bit set to one to indicate
multi-destination. Serial unicast configuration is necessary if the
TRILL over IP port is connected to an IP network that does not
support IP multicast. In any case, unicast TRILL packets are sent by
unicast IP.
Even if a TRILL over IP port is configured to send multi-destination
packets with serial unicast, it MUST be prepared to receive IP
multicast TRILL packets. All TRILL over IP ports default to
periodically transmitting appropriate IGMP (IPv4 [RFC3376] or MLD
(IPv6 [RFC2710]) packets, so that the TRILL multicast IP traffic will
be sent to them, unless they are configured not to do so.
Although TRILL fully supports broadcast links with more than 2
RBridges connected to the link there may be good reasons for
configuring TRILL over IP ports to use serial unicast even where
native IP multicast is available. Use of serial unicast provides the
network manager with more precise control over adjacencies and how
TRILL over IP links will be formed in an IP network. In some
networks, unicast is more reliable than multicast. If multiple point-
to-point TRILL over IP connections between parts of a TRILL campus
are configured, TRILL will in any case spread traffic across them,
treating them as parallel links, and appropriately fail over traffic
if a link fails or incorporate a new link that comes up.
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7. Use of IPsec and IKEv2
All TRILL switches (RBridges) that support TRILL over IP MUST
implement IPsec [RFC4301] and support the use of IPsec Encapsulating
Security Protocol (ESP [RFC4303]) in tunnel mode to secure both TRILL
IS-IS and TRILL data packets. When IPsec is used to secure a TRILL
over IP link and no IS-IS security is enabled, the IPsec session MUST
be fully established before any TRILL IS-IS or data packets are
exchanged. When there is IS-IS security [RFC5310] provided,
implementers SHOULD use IS-IS security to protect TRILL IS-IS
packets. However, in this case, the IPsec session still MUST be fully
established before any data packets transmission since IS-IS security
does not provide any protection to data packets.
All RBridges that support TRILL over IP MUST implement the Internet
Key Exchange Protocol version 2 (IKEv2) for automated key management.
7.1 Keying
The following subsections discuss pairwise and group keying for TRILL
over IP IPsec.
7.1.1 Pairwise Keying
When IS-IS security is in use, IKEv2 will use a pre-shared key that
incorporates the IS-IS shared key in order to bind the TRILL data
session to the IS-IS session. The pre-shared key that will be used
for IKEv2 exchanges for TRILL over IP is determined as follows:
HKDF-Expand-SHA256 ( IS-IS-key,
"TRILL IP" | P1-System-ID | P1-Port | P2-System-ID | P2-Port )
In the above "|" indicates concatenation, HKDF is as in [RFC5869],
SHA256 is as in [RFC6234], and "TRILL IP" is the eight byte US ASCII
[RFC0020] string indicated. "IS-IS-key" is an IS-IS key usable for
IS-IS security of link local IS-IS PDUs such as Hello, CSNP, and
PSNP. This SHOULD be a link scope IS-IS key. With [RFC5310] there
could be multiple keys identified with 16-bit key IDs. In this case,
the Key ID of IS-IS-key is also used to identify the derived key.
P1-System-ID and P2-System ID are the System IDs of the two TRILL
RBridges, and P1-Port and P2-Port are the ports in use on each end.
System IDs are guaranteed to be unique within the TRILL campus. Both
of the RBridges involved treat the larger magnitude System ID,
comparing System IDs as unsigned integers, as P1 and the smaller as
P2 so both will derive the same key.
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When IS-IS security is in use, the IS-IS-shared key from which the
IKEv2 shared secret is derived might expire and be updated as
described in [RFC5310]. The IKEv2 pre-shared keys derived from the
IS-IS shared key MUST expire within the same lifetime as the IS-IS-
shared key from which they were derived. When the IKEv2 pre-shared
key expires, the IKEv2 Security Association must be rekeyed using a
new shared secret derived from the new IS-IS shared key.
When IS-IS security is not in use, IKEv2 will not use a pre-shared
key.
7.1.2 Group Keying
In the case of a TRILL over IP port configured as point-to-point (see
Section 4.2.4.1 of [RFC6325]), there is no group keying and the
pairwise key determined as in Section 7.1.1 is used for IP multicast
traffic.
In the case of a TRILL over IP port configured as broadcast but where
the port is configured to use serial unicast (see Section 8), there
is no group keying and the pairwise keying determined as in Section
7.1.1 is used for IP multicast traffic.
In the case of a TRILL over IP port configured as broadcast and using
native multicast, ... tbd ...
7.2 Mandatory-to-Implement Algorithms
All RBridges that support TRILL over IP MUST implement IPsec ESP
[RFC4303] in tunnel mode. The implementation requirements for ESP
cryptographic algorithms are as specified for IPsec. That
specification is currently [RFC7321].
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8. Transport Considerations
This section discusses a variety of important transport
considerations.
8.1 Congestion Considerations
Section 3.1.3 of [RFC5405] discussed the congestion implications of
UDP tunnels. As discussed in [RFC5405], because other flows can share
the path with one or more UDP tunnels, congestion control [RFC2914]
needs to be considered.
The default initial determination of the TRILL over IP encapsulation
to be used through the exchange of TRILL IS-IS Hellos is a low
bandwidth process. Hellos are not permitted to be sent any more often
than once per second, and so are unlikely to cause congestion.
One motivation for including UDP in a TRILL encapsulation is to
improve the use of multipath (such as ECMP) in cases where traffic is
to traverse routers which are able to hash on UDP Port and IP
address. In many cases this may reduce the occurrence of congestion
and improve usage of available network capacity. However, it is also
necessary to ensure that the network, including applications that use
the network, responds appropriately in more difficult cases, such as
when link or equipment failures have reduced the available capacity.
The impact of congestion must be considered both in terms of the
effect on the rest of the network of a UDP tunnel that is consuming
excessive capacity, and in terms of the effect on the flows using the
UDP tunnels. The potential impact of congestion from a UDP tunnel
depends upon what sort of traffic is carried over the tunnel, as well
as the path of the tunnel.
TRILL is used to carry a wide range of traffic. In many cases TRILL
is used to carry IP traffic. IP traffic is generally assumed to be
congestion controlled, and thus a tunnel carrying general IP traffic
(as might be expected to be carried across the Internet) generally
does not need additional congestion control mechanisms. As specified
in [RFC5405]:
"IP-based traffic is generally assumed to be congestion-
controlled, i.e., it is assumed that the transport protocols
generating IP-based traffic at the sender already employ
mechanisms that are sufficient to address congestion on the path.
Consequently, a tunnel carrying IP-based traffic should already
interact appropriately with other traffic sharing the path, and
specific congestion control mechanisms for the tunnel are not
necessary".
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For this reason, where TRILL is sent using UDP and used to carry IP
traffic that is known to be congestion controlled, the UDP paths MAY
be used across any combination of a single or cooperating service
providers or across the general Internet.
However, TRILL is also used to carry traffic that is not necessarily
congestion controlled. For example, TRILL may be used to carry
traffic where specific bandwidth guarantees are provided.
In such cases congestion may be avoided by careful provisioning of
the network and/or by rate limiting of user data traffic. Where TRILL
is carried, directly or indirectly, over UDP over IP, the identity of
each individual TRILL flow is in general lost.
For this reason, where the TRILL traffic is not congestion
controlled, TRILL over UDP/IP MUST only be used within a single
service provider that utilizes careful provisioning (e.g., rate
limiting at the entries of the network while over-provisioning
network capacity) to ensure against congestion, or within a limited
number of service providers who closely cooperate in order to jointly
provide this same careful provisioning. As such, TRILL over UDP/IP
MUST NOT be used over the general Internet, or over non-cooperating
service providers, to carry traffic that is not congestion-
controlled.
Measures SHOULD be taken to prevent non-congestion-controlled TRILL
over UDP/IP traffic from "escaping" to the general Internet, for
example the following:
a. Physical or logical isolation of the TRILL over IP links from the
general Internet.
b. Deployment of packet filters that block the UDP ports assigned for
TRILL-over-UDP.
c. Imposition of restrictions on TRILL over UDP/IP traffic by
software tools used to set up TRILL over UDP paths between
specific end systems (as might be used within a single data
center).
d. Use of a "Managed Circuit Breaker" for the TRILL traffic as
described in [circuit-breaker].
8.2 Recursive Ingress
TRILL is specified to transport data to and from end stations over
Ethernet and IP is frequently transported over Ethernet. Thus, an end
station native data Ethernet frame EF might get TRILL ingressed to
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TRILL(EF) that was then sent out a TRILL over IP over Ethernet port
resulting in a packet on the wire of the form
Ethernet(IP(TRILL(EF))). There is a risk of such a packet being re-
ingressed by the same TRILL campus, due to physical or logical
misconfiguration, looping round, being further re-ingressed, and so
on. The packet might get discarded if it got too large but if
fragmentation is enabled, it would just keep getting split into
fragments that would continue to loop and grow and re-fragment until
the path was saturated with junk and packets were being discarded due
to queue overflow. The TRILL Header TTL would provide no protection
because each TRILL ingress adds a new TRILL header with a new TTL.
To protect against this scenario, a TRILL over IP port MUST by,
default, test whether a TRILL packet it is about to transmit appears
to be a TRILL ingress of a TRILL over IP over Ethernet packet. That
is, is it of the form TRILL(Ethernet(IP(TRILL(...)))? If so, the
default action of the TRILL over IP output port is to discard the
packet rather than transmit it. However, there are cases where some
level of nested ingress is desired so it MUST be possible to
configure the port to allow such packets.
8.3 Fat Flows
For the purpose of load balancing, it is worthwhile to consider how
to transport the TRILL packets over the Equal Cost Multiple Paths
(ECMPs) existing internal to the IP path between TRILL over IP ports.
The ECMP election for the IP traffic could be based, at least for
IPv4, on the quintuple of the outer IP header { Source IP,
Destination IP, Source Port, Destination Port, and IP protocol }.
Such tuples, however, could be exactly the same for all TRILL Data
packets between two RBridge ports, even if there is a huge amount of
data being sent between a variety of ingress and egress RBridges. On
solution to this is to use the Source Port in as an entropy field.
(This idea is also introduced in [gre-in-udp].) For example, for
TRILL Data this entropy field could be based on some hash of the
Inner.MacDA, Inner.MacSA, and Inner.VLAN or Inner.FGL. Unfortunately,
this can conflict with middleboxes inside the TRILL over IP link (see
8.5). Therefore, in order to better support ECMP, a RBridge SHOULD
set the Source Port to a range of values as an entropy field for ECMP
decisions. However, if there are middleboxes in the path, the range
of different Source Port values used MUST be restricted sufficiently
to avoid disrupting connectivity.
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8.4 MTU Considerations
In TRILL each TRILL switch advertises in its LSP number zero the
largest LSP frame it can accept (but not less than 1,470 bytes) on
any of its interfaces (at least those interfaces with adjacencies to
other TRILL switches in the campus) through the
originatingLSPBufferSize TLV [RFC6325] [RFC7177]. The campus minimum
MTU (Maximum Transmission Unit), denoted Sz, is then established by
taking the minimum of this advertised MTU for all RBridges in the
campus. Links that do not meet the Sz MTU are not included in the
routing topology. This protects the operation of IS-IS from links
that would be unable to accommodate some LSPs.
A method of determining originatingLSPBufferSize for an RBridge with
one or more TRILL over IP ports is described in [rfc7180bis].
However, if an IP link either can accommodate jumbo frames or is a
link on which IP fragmentation is enabled and acceptable, then it is
unlikely that the IP link will be a constraint on the
originatingLSPBufferSize of an RBridge using the link. On the other
hand, if the IP link can only handle smaller frames and fragmentation
is to be avoided when possible, a TRILL over IP port might constrain
the RBridge's originatingLSPBufferSize. Because TRILL sets the
minimum values of Sz at 1,470 bytes, there may be links that meet the
minimum MTU for the IP protocol (1,280 bytes for IPv6, 576 bytes for
IPv4) on which it would be necessary to enable fragmentation for
TRILL use.
The use of TRILL IS-IS MTU PDUs, as specified in [RFC6325] and
[RFC7177] can provide added assurance of the actual MTU of a link.
8.5 Middlebox Considerations
This section gives some middlebox considerations for the IP
encapsulations covered by this document, namely native and VXLAN
encapsulation.
The requirements on the usage of the zero UDP Checksum in a UDP
tunnel protocol are detailed in [RFC6936]. These requirements apply
to TRILL over IP the encapsulations specified herein (native and
VXLAN), which are applications of UDP tunnel.
Besides the Checksum, the Source Port number of the UDP header is
also pertinent to the middlebox behavior. Network Address/Port
Translator (NAPT) is the most commonly deployed Network Address
Translation (NAT) device [RFC4787]. For a UDP tunnel protocol, the
NAPT device establishes a NAT session to translate the {private IP
address, private source port number} tuple to a {public IP address,
public source port number} tuple, and vice versa, for the duration of
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the UDP session. This provides the UDP tunnel protocol application
with the "NAT-pass-through" function. NAPT allows multiple internal
hosts to share a single public IP address. The port number, i.e., the
UDP Source Port number, is used as the demultiplexer of the multiple
internal hosts.
However, the above NAPT behavior conflicts with the behavior that the
UDP Source Port number is used as an entropy (See Section 8.3).
Hence, the tunnel operator MUST ensure the TRILL switch ports sending
through local or remote NAPT middleboxes disable the entropy usage of
the UDP Source Port number.
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9. TRILL over IP Port Configuration
This section specifies the configuration information needed at a
TRILL over IP port beyond that needed for a general RBridge port.
9.1 Per IP Port Configuration
Each RBridge port used for a TRILL over IP link should have at least
one IP (v4 or v6) address. If no IP address is associated with the
port, perhaps as a transient condition during re-configuration, the
port is disabled. Implementations MAY allow a single port to operate
as multiple IPv4 and/or IPv6 logical ports. Each IP address
constitutes a different logical port and the RBridge with those ports
MUST associate a different Port ID (see Section 4.4.2 of [RFC6325])
with each logical port.
By default a TRILL over IP port discards output packets that fail the
possible recursive ingress test (see Section 10.1) unless configured
to disable that test.
9.2 Additional per IP Address Configuration
The configuration information specified below is per TRILL over IP
port IP address.
The mapping from TRILL packet priority to Differentiated Services
Code Point (DSCP [RFC2474]) can be configured (see Section 10.5).
Each TRILL over IP port has a list of acceptable encapsulations it
will use. By default this list consists of one entry for native
encapsulation (see Section 7). Additional encapsulations MAY be
configured. Additional configuration can be required or possible for
specific encapsulations as described in Section 9.2.3.
Each IP address at a TRILL over IP port uses native IP multicast by
default but may be configured whether to use serial IP unicast
(Section 9.2.2) or native IP multicast (Section 9.2.1). Each IP
address at a TRILL over IP is configured whether or not to use IPsec
(Section 9.2.4).
9.2.1 Native Multicast Configuration
If a TRILL over IP port address is using native IP multicast for
multi-destination TRILL packets (IS-IS and data), by default
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transmissions from that IP address use the IP multicast address (IPv4
or IPv6) specified in Section 11.2. The TRILL over IP port may be
configured to use a different IP address to multicast packets.
9.2.2 Serial Unicast Configuration
If a TRILL over IP port address has been configured to use serial
unicast for multi-destination packets (IS-IS and data), it should
have associated with it a non-empty list of unicast IP destination
addresses with the same IP version as the version of the port's IP
address (IPv4 or IPv6). Multi-destination TRILL packets are serially
unicast to the addresses in this list. Such a TRILL over IP port will
only be able to form adjacencies [RFC7177] with the RBridges at the
addresses in this list as those are the only RBridges to which it
will send TRILL Hellos.
If this list of destination IP addresses is empty, there is no way to
transmit a multi-destination TRILL over IP packet such as a TRILL
Hello. Thus it is impossible to achieve adjacency [RFC7177] or if
adjacency had been achieved (perhaps the list was non-empty and has
just been configured to be empty), no way to maintain such adjacency.
Thus, in the empty list case, TRILL Data multi-destination packets
cannot be sent and TRILL Data unicast packets will not start flowing
or, if they are already flowing, will soon cease, effectively
disabling the port.
9.2.3 Encapsulation Specific Configuration
Specific TRILL over IP encapsulation methods may provide for further
configuration as specified below.
9.2.3.1 VXLAN Configuration
A TRILL over IP port using VXLAN encapsulation can be configured with
a non-default VXLAN Network Identifier (VNI) that is used in that
field of the VXLAN header for all TRILL packets sent using the
encapsulation and required in all TRILL packets received using the
encapsulation. The default VNI is 1. A TRILL packet received with the
wrong VNI is discarded.
A TRILL over IP port using VXLAN encapsulation can also be configured
to map the Inner.VLAN or Inner.FGL of a TRILL Data packet being
transported to the value it places in the VNI field.
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9.2.3.2 Other Encapsulation Configuration
Additional encapsulation methods, beyond the native UDP encapsulation
and VXLAN encapsulation specified in this document, may be specified
in future documents and may require further configuration.
9.2.4 Security Configuration
tbd ...
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10. Security Considerations
TRILL over IP is subject to all of the security considerations for
the base TRILL protocol [RFC6325]. In addition, there are specific
security requirements for different TRILL deployment scenarios, as
discussed in the "Use Cases for TRILL over IP" section above.
For communication between end stations in a TRILL campus, security is
possible at three levels: end-to-end security between those end
stations, edge-to-edge security between ingress and egress RBridges
[LinkSec], and link security to protect a TRILL hop. Any combination
of these can be used, including all three.
TRILL over IP link security protects the contents of TRILL Data and
IS-IS packets, including the identities of the end stations for data
and the identities of the edge RBridges, from observers of the link
and transit devices within the link such as IP routers, but does not
encrypt the link local IP addresses used in a packet and does not
protect against observation by the sending and receiving RBridges on
the link. Edge-to-edge TRILL security protects the contents of TRILL
data packets including the identities of the end stations for data
from transit RBridges but does not encrypt the identities of the edge
RBridges involved and does not protect against observation by those
edge RBridges. End-to-end security does not protect the identities of
the end stations or edge RBridge involved but does protect the
content of TRILL data packets from observation by all RBridges or
other intervening devices between the end stations involved. End-to-
end security should always be considered as an added layer of
security and to protect any particularly sensitive information from
unintended disclosure.
If VXLAN encapsulation is used, the unused Ethernet source and
destination MAC addresses mentioned in Section 5.5, provide a 96 bit
per packet covert path.
10.1 IPsec
This document specifies that all RBridges that support TRILL over IP
links MUST implement IPsec for the security of such links, and makes
it clear that it is both wise and good to use IPsec in all cases
where a TRILL over IP link will traverse a network that is not under
the same administrative control as the rest of the TRILL campus or is
not physically secure. IPsec is important, in these cases, to protect
the privacy and integrity of data traffic. However, in cases where
IPsec is impractical due to lack of fast path support, use of TRILL
edge-to-edge security or use by the end stations of end-to-end
security can provide significant security.
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Further Security Considerations for IPsec ESP and for the
cryptographic algorithms used with IPsec can be found in the RFCs
referenced by this document.
10.2 IS-IS Security
TRILL over IP is compatible with the use of IS-IS Security [RFC5310],
which can be used to authenticate TRILL switches before allowing them
to join a TRILL campus. This is sufficient to protect against rogue
devices impersonating TRILL switches, but is not sufficient to
protect data packets that may be sent in TRILL over IP outside of the
local network or across the public Internet. To protect the privacy
and integrity of that traffic, use IPsec.
In cases were IPsec is used, the use of IS-IS security may not be
necessary, but there is nothing about this specification that would
prevent using both IPsec and IS-IS security together.
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11. IANA Considerations
IANA considerations are given below.
11.1 Port Assignments
IANA is requested to assign destination UDP Ports for the TRILL IS-IS
and Data channels:
UDP Port Protocol
---------- ---------------------
(TBD1) TRILL IS-IS Channel
(TBD2) TRILL Data Channel
11.2 Multicast Address Assignments
IANA is requested to one IPv4 and one IPv6 multicast address, as
shown below, which correspond to the All-RBridges and All-IS-IS-
RBridges multicast MAC addresses that the IEEE Registration Authority
has assigned for TRILL. Because the low level hardware MAC address
dispatch considerations for TRILL over Ethernet do not apply to TRILL
over IP, one IP multicast address for each version of IP is
sufficient.
(Values recommended to IANA in square brackets)
Name IPv4 IPv6
------------ ------------------ --------------------------
All-RBridges TBD3[233.252.14.0] TBD4[FF0X:0:0:0:0:0:0:205]
The hex digit "X" in the IPv6 address indicates the scope and
defaults to 8. The IPv6 All-RBridges IP address may be used with
other values of X.
11.3 Encapsulation Method Support Indication
The existing "RBridge Channel Protocols" registry is re-named and a
new sub-registry under that registry added as follows:
The TRILL Parameters registry for "RBridge Channel Protocols" is
renamed the "RBridge Channel Protocols and Link Technology Specific
Flags" registry. [this document] is added as a second reference for
this registry. The first part of the table is changed to the
following:
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Range Registration Note
----------- ---------------- ----------------------------
0x002-0x0FF Standards Action
0x100-0xFCF RFC Required allocation of a single value
0x100-0xFCF IESG Approval allocation of multiple values
0xFD0 0xFF7 see Note link technology dependent,
see subregistry
In the existing table of RBridge Channel Protocols, the following
line is changed to two lines as shown:
OLD
0x004-0xFF7 Unassigned
NEW
0x004-0xFCF Unassigned
0xFD0-0xFF7 (link technology dependent, see subregistry)
A new subregistry under the re-named "RBridge Channel Protocols and
Link Technology Specific Flags" registry is added as follows:
Name: TRILL over IP Link Flags
Registration Procedure: IETF Review
Reference: [this document]
Flag Meaning Reference
----------- ------------------------------ ---------
0xFD0 Native encapsulation supported [this document]
0xFD1 VXLAN encapsulation supported [this document]
0xFD2-0xFF7 Unassigned
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Normative References
[IS-IS] - "Intermediate system to Intermediate system routeing
information exchange protocol for use in conjunction with the
Protocol for providing the Connectionless-mode Network Service
(ISO 8473)", ISO/IEC 10589:2002, 2002".
[RFC0020] - Cerf, V., "ASCII format for network interchange", STD 80,
RFC 20, DOI 10.17487/RFC0020, October 1969, <http://www.rfc-
editor.org/info/rfc20>.
[RFC0768] - Postel, J., "User Datagram Protocol", STD 6, RFC 768, DOI
10.17487/RFC0768, August 1980, <http://www.rfc-
editor.org/info/rfc768>.
[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>.
[RFC2474] - Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS Field) in
the IPv4 and IPv6 Headers", RFC 2474, DOI 10.17487/RFC2474,
December 1998, <http://www.rfc-editor.org/info/rfc2474>.
[RFC2710] - Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710, DOI
10.17487/RFC2710, October 1999, <http://www.rfc-
editor.org/info/rfc2710>.
[RFC2914] - Floyd, S., "Congestion Control Principles", BCP 41, RFC
2914, DOI 10.17487/RFC2914, September 2000, <http://www.rfc-
editor.org/info/rfc2914>.
[RFC3168] - Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP", RFC 3168, DOI
10.17487/RFC3168, September 2001, <http://www.rfc-
editor.org/info/rfc3168>.
[RFC3376] - Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version 3",
RFC 3376, DOI 10.17487/RFC3376, October 2002, <http://www.rfc-
editor.org/info/rfc3376>.
[RFC4301] - Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, December
2005, <http://www.rfc-editor.org/info/rfc4301>.
[RFC4303] - Kent, S., "IP Encapsulating Security Payload (ESP)", RFC
4303, DOI 10.17487/RFC4303, December 2005, <http://www.rfc-
editor.org/info/rfc4303>.
Margaret Cullen, et al [Page 34]
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[RFC5405] - Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October 2008,
<http://www.rfc-editor.org/info/rfc5304>.
[RFC5310] - Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic Authentication", RFC
5310, DOI 10.17487/RFC5310, February 2009, <http://www.rfc-
editor.org/info/rfc5310>.
[RFC5869] - Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-
Expand Key Derivation Function (HKDF)", RFC 5869, DOI
10.17487/RFC5869, May 2010, <http://www.rfc-
editor.org/info/rfc5869>.
[RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
Ghanwani, "Routing Bridges (RBridges): Base Protocol
Specification", RFC 6325, DOI 10.17487/RFC6325, July 2011,
<http://www.rfc-editor.org/info/rfc6325>.
[RFC7176] - Eastlake 3rd, D., Senevirathne, T., Ghanwani, A., Dutt,
D., and A. Banerjee, "Transparent Interconnection of Lots of
Links (TRILL) Use of IS-IS", RFC 7176, DOI 10.17487/RFC7176,
May 2014, <http://www.rfc-editor.org/info/rfc7176>.
[RFC7177] - Eastlake 3rd, D., Perlman, R., Ghanwani, A., Yang, H.,
and V. Manral, "Transparent Interconnection of Lots of Links
(TRILL): Adjacency", RFC 7177, DOI 10.17487/RFC7177, May 2014,
<http://www.rfc-editor.org/info/rfc7177>.
[RFC7178] - Eastlake 3rd, D., Manral, V., Li, Y., Aldrin, S., and D.
Ward, "Transparent Interconnection of Lots of Links (TRILL):
RBridge Channel Support", RFC 7178, DOI 10.17487/RFC7178, May
2014, <http://www.rfc-editor.org/info/rfc7178>.
[RFC7321] - McGrew, D. and P. Hoffman, "Cryptographic Algorithm
Implementation Requirements and Usage Guidance for
Encapsulating Security Payload (ESP) and Authentication Header
(AH)", RFC 7321, DOI 10.17487/RFC7321, August 2014,
<http://www.rfc-editor.org/info/rfc7321>.
[RFC7348] - Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3 Networks",
RFC 7348, DOI 10.17487/RFC7348, August 2014, <http://www.rfc-
editor.org/info/rfc7348>.
[rfc7180bis] - Eastlake, D., et al, "TRILL: Clarifications,
Corrections, and Updates", draft-ietf-trill-rfc7180bis, work in
progress.
Margaret Cullen, et al [Page 35]
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Informative References
[RFC4787] - Audet, F., Ed., and C. Jennings, "Network Address
Translation (NAT) Behavioral Requirements for Unicast UDP", BCP
127, RFC 4787, DOI 10.17487/RFC4787, January 2007,
<http://www.rfc-editor.org/info/rfc4787>.
[RFC6234] - Eastlake 3rd, D. and T. Hansen, "US Secure Hash
Algorithms (SHA and SHA-based HMAC and HKDF)", RFC 6234, DOI
10.17487/RFC6234, May 2011, <http://www.rfc-
editor.org/info/rfc6234>.
[RFC6361] - Carlson, J. and D. Eastlake 3rd, "PPP Transparent
Interconnection of Lots of Links (TRILL) Protocol Control
Protocol", RFC 6361, DOI 10.17487/RFC6361, August 2011,
<http://www.rfc-editor.org/info/rfc6361>.
[RFC6864] - Touch, J., "Updated Specification of the IPv4 ID Field",
RFC 6864, DOI 10.17487/RFC6864, February 2013, <http://www.rfc-
editor.org/info/rfc6864>.
[RFC6936] - Fairhurst, G. and M. Westerlund, "Applicability Statement
for the Use of IPv6 UDP Datagrams with Zero Checksums", RFC
6936, DOI 10.17487/RFC6936, April 2013, <http://www.rfc-
editor.org/info/rfc6936>.
[RFC7172] - Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R.,
and D. Dutt, "Transparent Interconnection of Lots of Links
(TRILL): Fine-Grained Labeling", RFC 7172, DOI
10.17487/RFC7172, May 2014, <http://www.rfc-
editor.org/info/rfc7172>.
[RFC7173] - Yong, L., Eastlake 3rd, D., Aldrin, S., and J. Hudson,
"Transparent Interconnection of Lots of Links (TRILL) Transport
Using Pseudowires", RFC 7173, DOI 10.17487/RFC7173, May 2014,
<http://www.rfc-editor.org/info/rfc7173>.
[RFC7296] - Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2 (IKEv2)",
STD 79, RFC 7296, DOI 10.17487/RFC7296, October 2014,
<http://www.rfc-editor.org/info/rfc7296>.
[circuit-breaker] - Fairhurst, G., "Network Transport Circuit
Breakers", draft-ietf-tsvwg-circuit-breaker, work in progress.
[gre-in-udp] - Crabbe, E., Yong, L., and X. Xu, "Generic UDP
Encapsulation for IP Tunneling", draft-yong-tsvwg-gre-in-udp-
encap, work in progress.
[LinkSec] - Eastlake, D., D. Zhang, "TRILL: Link Security", draft-
Margaret Cullen, et al [Page 36]
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eastlake-trill-link-security, work in progress.
Margaret Cullen, et al [Page 37]
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Acknowledgements
The following people have provided useful feedback on the contents of
this document: Sam Hartman, Adrian Farrel, and Mohammed Umair.
Some material in Section 10.2 is derived from draft-ietf-mpls-in-udp
by Xiaohu Xu, Nischal Sheth, Lucy Yong, Carlos Pignataro, and
Yongbing Fan.
The document was prepared in raw nroff. All macros used were defined
within the source file.
Margaret Cullen, et al [Page 38]
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Authors' Addresses
Margaret Cullen
Painless Security
356 Abbott Street
North Andover, MA 01845
USA
Phone: +1 781 405-7464
Email: margaret@painless-security.com
URI: http://www.painless-security.com
Donald Eastlake
Huawei Technologies
155 Beaver Street
Milford, MA 01757
USA
Phone: +1 508 333-2270
Email: d3e3e3@gmail.com
Mingui Zhang
Huawei Technologies
No.156 Beiqing Rd. Haidian District,
Beijing 100095 P.R. China
EMail: zhangmingui@huawei.com
Dacheng Zhang
Alibaba
Beijing, Chao yang District
P.R. China
Email: dacheng.zdc@alibaba-inc.com
Copyright, Disclaimer, and Additional IPR Provisions
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
Margaret Cullen, et al [Page 39]
INTERNET-DRAFT TRILL over IP
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Margaret Cullen, et al [Page 40]