Internet DRAFT - draft-eastlake-trill-channel-tunnel
draft-eastlake-trill-channel-tunnel
INTERNET-DRAFT Donald Eastlake
Updates: RFCchannel Yizhou Li
Intended status: Proposed Standard Huawei
Expires: April 20, 2014 October 21, 2013
TRILL: RBridge Channel Tunnel Protocol
<draft-eastlake-trill-channel-tunnel-00.txt>
Abstract
The IETF TRILL (Transparent Interconnection of Lots of Links)
protocol includes an optional mechanism, called RBridge Channel, for
the transmission of typed messages between TRILL switches in the same
campus and between TRILL switches and end stations on the same link.
This document specifies optional extensions to RBridge Channel that
provides three facilities: (1) A mechanism to send such messages
between a TRILL switch and an end station in either direction, or
between two end stations, when the two devices are in the same campus
but not on the same link; (2) A method to support security facilities
for RBridge Channel messages; and (3) A method to tunnel a variety of
payload types by encapsulating them in an RBridge Channel message.
Status of This Memo
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 authors or the TRILL working group mailing list:
trill@ietf.org
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft
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http://www.ietf.org/shadow.html.
D. Eastlake & Y. Li [Page 1]
INTERNET-DRAFT TRILL: RBridge Channel Tunnel
Table of Contents
1. Introduction............................................3
1.2. Terminology and Acronyms.............................3
2. Channel Tunnel Packet Format............................5
3. Tunnel Payload Types....................................8
3.1 Null Payload...........................................8
3.2 RBridge Channel Message Payload........................8
3.3 TRILL Data Packet......................................9
3.4 TRILL IS-IS Packet....................................10
3.5 Ethernet Frame........................................11
3. Channel Tunnel Scopes..................................13
3.1 End Station to RBridge(s).............................14
4.2 RBridge to End Station................................15
4.3 End Station to End Station............................16
5. Security, Keying, and Algorithms.......................18
5.1 SType None............................................18
5.2 RFC 5310 Based Authentication.........................18
5.3 DTLS Based Security...................................19
6. Channel Tunnel Errors..................................20
6.1 SubERRs under ERR 6...................................20
7. IANA Considerations....................................21
8. Security Considerations................................21
Normative References......................................22
Informative References....................................22
Acknowledgements..........................................23
Authors' Addresses........................................24
D. Eastlake & Y. Li [Page 2]
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1. Introduction
The IETF TRILL protocol [RFC6325] provides efficient least cost
transparent frame routing in multi-hop networks with arbitrary
topologies and link technologies, using link-state routing and a
header with a hop count. End stations are attached to TRILL switches
by Ethernet but links between TRILL switches can be arbitrary
technology. In general, the TRILL way to address or specify a TRILL
switch (RBridge) in a TRILL campus is by the switch's TRILL provided
nickname [RFC6325] [ClearCorrect].
The TRILL protocol includes an optional RBridge Channel facility
[RFCchannel] to support typed message transmission between two
RBridges (for example BFD [RFCbfd]) in the same campus and between
RBridges and end stations on the same link.
This document specifies optional extensions to RBridge Channel that
provides three facilities:
(1) A mechanism to send RBridge Channel messages between a TRILL
switch and an end station in either direction, or between two
end stations, when the two devices are in the same campus but
not on the same link. This mechanism requires the cooperation
of an RBridge that is on the same link as the end station or
stations involved.
(2) A method to support security facilities for RBridge Channel
messages.
(3) A method to tunnel a variety of payload types by encapsulating
them in an RBridge Channel message.
Any one, two, or all three of these facilities can be use in the same
message.
There is no mechanism to stop end stations on the same link, from
sending native RBridge Channel messages to each other; however, such
use is outside the scope of this document.
1.2. Terminology and Acronyms
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 [RFC2119].
This document uses the acronyms defined in [RFC6325] and [RFCchannel]
supplemented by the following additional acronym:
D. Eastlake & Y. Li [Page 3]
INTERNET-DRAFT TRILL: RBridge Channel Tunnel
Data Label - VLAN or Fine Grained Label [RFCfgl].
Primary Nickname - If a TRILL switch holds two or more nicknames,
the one it holds with the highest priority is the primary
nickname. If two or more are held with the same priority, the
one with the lowest value, considered as a 16-bit unsigned
integer in network byte order, is the primary nickname.
TRILL switch - An alternative term for an RBridge.
D. Eastlake & Y. Li [Page 4]
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2. Channel Tunnel Packet Format
The general structure of an RBridge Channel message on a link between
TRILL switches (RBridges) is shown in Figure 1 below. When a native
RBridge Channel message is sent between an RBridge and an end station
on the same link, in either direction, the TRILL Header (including
the inner Ethernet addresses and Data Label) is omitted as shown in
Figure 2. The type of RBridge Channel message is given by a Protocol
field in the RBridge Channel Header which indicates how to interpret
the Channel Protocol Specific Payload [RFCchannel].
+-----------------------------------+
| Link Header |
+-----------------------------------+
| TRILL Header |
+-----------------------------------+
| Inner Ethernet Addresses |
+-----------------------------------+
| Data Label (VLAN or FGL) |
+-----------------------------------+
| RBridge Channel Header |
+-----------------------------------+
| Channel Protocol Specific Payload |
+-----------------------------------+
| Link Trailer (FCS if Ethernet) |
+-----------------------------------+
Figure 1. RBridge Channel Packet Structure
+-----------------------------------+
| Ethernet Link Header |
+-----------------------------------+
| RBridge Channel Header |
+-----------------------------------+
| Channel Protocol Specific Payload |
+-----------------------------------+
| FCS |
+-----------------------------------+
Figure 2. Native RBridge Channel Frame
The RBridge Channel Header looks like this:
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INTERNET-DRAFT TRILL: RBridge Channel Tunnel
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x8946 | CHV | Channel Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | ERR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Channel Protocol Specific Data
|
Figure 3. RBridge Channel Header
where 0x8946 is the RBridge Channel Ethertype and CHV is the Channel
Header Version, currently zero.
The extensions specified herein are in the form of an RBridge Channel
protocol, the Channel Tunnel Protocol. Figure 4 below expands the
RBridge Channel Header and Protocol Specific Payload above for the
case of the Channel Tunnel Protocol.
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
RBridge Channel Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x8946 | 0x0 | Tunnel Protocol(0x00?)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | ERR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Channel Tunnel Protocol Specific: | SubERR| Scope | SType | PType |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope Information, variable length (0 length if Scope=0)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| Security information, variable length (0 length if SType = 0)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| Tunneled Data, variable length
| ...
Figure 4. Channel Tunnel Header Structure
The RBridge Channel Header field specific to the RBridge Channel
Tunnel Protocol is the Protocol field. Its contents MUST be the value
allocated for this purpose (see Section 7).
The RBridge Tunnel Channel Protocol Specific fields are as follows:
SubERR: This field provides further details when a Tunnel Channel
error is indicated in the RBridge Channel ERR field. If ERR is
zero, then SubERR MUST be sent as zero and ignored on receipt.
See Section 6.
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Scope: This field describes the transport scope of the instance of
Channel Tunnel. See Section 4.
SType: This field describes the type of security information and
features, including keying material, being provided. See
Section 5.
PType: Payload type. The describes the tunneled data. See Section
3 below.
The Channel Tunnel protocol is integrated with the RBridge Channel
facility. Channel Tunnel errors are reported as if they were RBridge
Channel errors, using newly allocated code points in the ERR field of
the RBridge Channel Header supplemented by the SubErr field.
Additional RBridge Channel Header flags are specified and used by
Channel Tunnel.
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3. Tunnel Payload Types
The RBridge Channel Tunnel Protocol can carry a variety of payloads
as indicated by the PType field. Value are shown in the table below
with further explanation after the table.
PType Section Description
----- ------- -----------
0 Reserved
1 3.1 Null
2 3.2 RBridge Channel message
3 3.3 TRILL Data packet
4 3.4 TRILL IS-IS packet
5 3.5 Ethernet Frame
6-14 (Available for assignment by IETF Review)
15 Reserved
Table 1. Payload Type Values
While implementation of the Channel Tunnel protocol is optional, if
it is implemented PTypes 1 (Null) and 2 (RBridge Channel message)
MUST be implemented. PTypes 3, 4, and 5 MAY be implemented. The
processing of any particular Channel Protocol message and its payload
depends on meeting local security and other policy at the destination
TRILL switch or end station.
3.1 Null Payload
The Null payload type is intended to be used for messages such as key
negotiation or the like. It indicates that there is no payload. Any
data after the possible Scope Information and Security Information
fields is ignored.
3.2 RBridge Channel Message Payload
A PType of 2 indicates that the payload of the Channel Tunnel message
is an encapsulated RBridge Channel message without the initial
RBridge Channel Ethertype. Typical reasons for sending an RBridge
Channel message inside a Channel Tunnel message are to provide
security services, such as authentication or encryption, or to
forward it through a cooperating border TRILL switch in either
direction between an end station and a TRILL switch not on the same
link.
This looks like the following:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RBridge-Channel (0x8946) | 0x0 | Tunnel Protocol(tbd) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | ERR | SubERR| Scope | SType | 0x2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible Scope Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| Possible Security information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x0 | Channel Protocol | Flags | ERR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Channel Protocol Specific Data ... |
|
Figure 5. Tunneled Channel Message Channel Tunnel Structure
3.3 TRILL Data Packet
A PType of 3 indicates that the payload of the Tunnel protocol
message is an encapsulated TRILL Data packet without the initial
TRILL Ethertype as shown in the figure below. If this PType is
implemented, the tunneled TRILL Data packet is handled as if it had
been received by the destination TRILL switch on the port where the
Channel Tunnel message was received.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RBridge-Channel (0x8946) | 0x0 | Tunnel Protocol(tbd) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | ERR | SubERR| Scope | SType | 0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible Scope Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| Possible Security information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| V | R |M|Op-Length| Hop Count | Egress Nickname |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress Nickname | Inner.MacDA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner.MacDA continued |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner.MacSA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner.MacSA (cont.) | Inner Data Label ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| TRILL Data Packet payload
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
Figure 6. Nested TRILL Data Packet Channel Tunnel Structure
3.4 TRILL IS-IS Packet
A PType of 4 indicates that the payload of the Tunnel protocol
message is an encapsulated TRILL IS-IS packet without the initial
L2-IS-IS Ethertype as shown in the figure below. If this PType is
implemented, the tunneled TRILL IS-IS packet is processed by the
destination RBridge if it meets local policy. The intended use is to
expedite the receipt of a link state PDU by some TRILL switch with an
immediate requirement for the enclosed link state data. It is
RECOMMENDED that any link local IS-IS PDU (Hello, xSNP, MTU-x)
received via this channel tunnel payload type be discarded.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RBridge-Channel (0x8946) | 0x0 | Tunnel Protocol(tbd) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | ERR | SubERR|| Scope | SType | 0x4
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible Scope Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| Possible Security information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| 0x83 | rest of IS-IS PDU
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
Figure 7. Tunneled TRILL IS-IS Packet Structure
3.5 Ethernet Frame
If PType is 5, the Tunnel Protocol payload is an Ethernet frame as
might be received from or sent to an end station except that the
tunneled Ethernet frame's FCS is omitted, as shown in Figure 8.
(There is still an overall FCS if the RBridge Channel message is
being sent on an Ethernet link.) If this PType is implemented, the
tunneled frame is handled as if it had been received on the port on
which the Tunnel Protocol message was received.
In the case of a non-Ethernet link, such as a PPP link [RFC6361], the
ports on the link are considered to have link local synthetic 48-bit
MAC addresses constructed by concatenating three 16-bit quantities:
0xFEFF, the primary nickname of the TRILL switch (see Section 1.2),
and the Port ID that the RBridge has assigned to that port, as shown
in Figure 9. The resulting MAC address has the Local bit on and the
Group bit off [RFC5342bis]. Since end stations are connected to TRILL
switches only over Ethernet, there can be no end stations on a non-
Ethernet link in a TRILL campus. Thus such synthetic MAC addresses
cannot conflict on the link with an end station address.
D. Eastlake & Y. Li [Page 11]
INTERNET-DRAFT TRILL: RBridge Channel Tunnel
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RBridge-Channel (0x8946) | 0x0 | Tunnel Protocol(tbd) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | ERR | SubERR| Scope | SType | 0x5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible Scope Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
| Possible Security information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MacDA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MacDA (cont.) | MacSA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner.MacSA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MacSA (cont.) | Any Ethernet frame tagging...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
| Ethernet frame payload
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
Figure 8. Ethernet Frame Channel Tunnel Structure
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0xFEFF | Primary Nickname |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9. Synthetic MAC Address
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3. Channel Tunnel Scopes
The Channel Tunnel protocol extends the RBridge Channel facility to
optionally support typed messages between an end station and a TRILL
switch, in either direction, or between two end stations, when these
devices are part of the same TRILL campus but not on the same link.
The scopes specified in this document are as follows:
Scope Symbol Section From-To
----- ------ ------- -------
0 NORM Normal
1 ESRB 3.1 End Station to RBridge
2 RBES 3.2 RBridge to End Station
3 ESES 3.3 End Station to End Station
4-14 Available for assignment by IETF Review
15 Reserved
Table 2. Scope Values
If the Channel Tunnel protocol is supported, then the NORM scope MUST
be supported. All other scopes MAY be supported. In cases where a
sequence of steps is given, other processing sequences producing the
same result are, as always, allowed. The detail are given below.
NORM: This is the normal scope of an RBridge Channel message. The
base RBridge Channel mechanisms apply [RFCchannel]. The scope
dependent addressing information is of zero length. This scope is
typically used when just the security or payload type features of
the Tunnel Protocol are desired. If a TRILL switch supports the
Channel Tunnel facility, it MUST support NORM scope.
ESRB: From end station to RBridge(s) not on the same link. The scope
dependent address information is eight bytes long. See Section 4.1
for further details. This scope MAY be supported.
RBES: From RBridge to end station not on the same link. The scope
dependent address information is eight bytes long. See Section 4.2
for further details. This scope MAY be supported.
ESES: From end station to en station not on the same link. The scope
information is twelve bytes long. See Section 4.3 for further
details. This scope MAY be supported.
It is an implementation option and may depend on local policy whether
or not an edge TRILL switch that has been requested to forward a
Channel Tunnel protocol message due to a non-NORM Scope examines the
SType and, if it does examine the SType, whether it verifies any
authentication.
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3.1 End Station to RBridge(s)
The ESRB scope additional information is as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope Destination Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
| Scope Source MAC Address | (6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
Figure 10. ESRB Scope Information
To support the case where an end station originates a multi-
destination RBridge Channel message to all the TRILL switches
advertising interest in a Data Label, the BR (Broadcast) bit is the
RBridge Channel Header Flags field is used (see Section 7).
Steps by the source end station:
If the RBridge Channel message is intended to a single destination
RBridge, the source end station sets the Scope Destination
Nickname to the nickname of that RBridge and ensures that the BR
bit is zero. If the message is intended to be broadcast to the
RBridges indicating interest in a Data Label, the end stations
sets the BR bit, uses that Data Label as part of the TRILL Header
information, and the contents of the Scope Destination Nickname
field is ignored.
Steps by the ingress TRILL switch on receiving the native RBridge
Channel message from the end station:
0. As with any RBridge Channel message, determine, as a matter of
local policy, whether the native RBridge Channel message is
acceptable and discard it if it is not. This test might take
into account, for example, whether the message is authenticated
(see Section 5), whether or not the BR flag is set, and whether
or not the original native destination MAC address is All-Edge-
RBridges.
1. Store the native RBridge Channel message's source MAC address
into the Scope Source MAC Address field.
2. Clear the NA bit and set the MH bit in the RBridge Channel
Header flags.
3. Set the native RBridge Channel message's MAC destination
address to All-Egress-RBridges.
4. Set the native RBridge Channel message's MAC source address to
the MAC address that the ingress RBridge normally uses as the
Inner.MacSA for RBridge Channel messages it originates.
5.a. If the BR flag is zero, ingress the modified native frame as
a unicast TRILL RBridge Channel message with egress nickname
set from the Scope Destination Nickname. If that Scope
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Destination Nickname is unknown, the appropriate error SHOULD
be returned (see Section 6).
5.b If the BR flag is one, select a distribution tree and ingress
the modified native frame as a multi-destination TRILL RBridge
Channel message.
5.c Regardless of the BR flag value, the Inner.VLAN is the VLAN ID
reported by the ingress port or, if that port is configured for
FGL, the Inner.Lable is the FGL that VLAN maps to.
6. Process the resulting RBridge Channel message. Note that if it
is unicast to the ingress RBridge as egress, it is then
egressed. And if it is multi-destination and the ingress
RBridge qualifies, a copy is egressed as well as a copy being
sent on the selected distribution tree.
4.2 RBridge to End Station
The RBES scope additional addressing information is as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
| Scope Destination MAC Address | (6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
| Scope Source Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11. RBES Scope Information
Steps by the source TRILL switch:
The source RBridge must set the Scope Destination MAC Address
field. It creates an RBridge Channel message, either unicast or
multi-destination, based on that MAC address. (The Inner.MacDA
cannot be used for this because it must be the All-Egress-RBridges
MAC address.) The created RBridge Channel message is unicast if
the Scope Destination MAC address is unicast and the creating
RBridge knows the egress to which that MAC address is connect. The
created RBridge channel message is multi-destination if the Scope
Destination MAC Address is broadcast, multicast, or unknown
unicast. The source RBridge sets the Inner.MacSA to the MAC
address it usually uses for RBridge Channel messages and also
selects the Inner VLAN or FGL.
Steps by the egress TRILL switch(es):
The egress TRILL switch stores the ingress nickname into the Scope
Source Nickname and sets the NA bit in the RBridge Channel Header
flags. It then egresses the frame as a native RBridge Channel
message, setting the native frame's outer destination and source
MAC addresses to the Scope Destination MAC Address and the egress
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RBridge port's MAC address, respectively.
If the original RBridge Channel message was multi-destination it
might be egressed by more than one TRILL switch, each of which
would perform the above transform. Whether such a multi-
destination RBridge Channel Tunnel Protocol message would be
accepted by any particular egress TRILL switch is a matter of
local policy.
4.3 End Station to End Station
The ESES scope additional addressing information is as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
| Scope Destination MAC Address | (6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
| Scope Source MAC Address | (6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
Figure 12. ESES Scope Information
Steps by the source end stations:
If the RBridge Channel message is intended for a single
destination end station, the source end station sets the Scope
Destination MAC address to the MAC address of that end station and
ensures that the BR bit is zero. If the message is intended to be
broadcast to a set of end stations via a multicast MAC address or
the broadcast MAC address, the end station sets the Scope
Destination MAC address to that multicast or broadcast address and
sets the BR bit. All of this is within the VLAN of the native
RBridge Channel message or its Fine Grained Label (FGL) if the
ingress port is configured to map to an FGL.
Steps by the ingress TRILL switch:
0. As with any RBridge Channel message, determine, as a matter of
local policy, whether the native RBridge Channel message is
acceptable and discard it if it is not. This test might take
into account, for example, whether the message is authenticated
(see Section 5), whether or not the BR flag is set, and whether
or not the original Outer.MacDA is All-Edge-RBridges.
1. Store the native RBridge Channel message's source MAC address
into the Scope Source MAC Address.
2. Clear the NA bit and set the MH bit in the RBridge Channel
Header flags.
3. Set the native RBridge Channel message's MAC destination
address to All-Egress-RBridges.
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4. Set the native RBridge Channel message's MAC source address to
the MAC address that the ingress RBridge normally uses as the
Inner.MacSA for RBridge Channel messages it originates.
5.a. If the BR flag is zero, lookup the Scope Destination MAC
Address and ingress the modified native frame as if it were a
unicast native frame with that destination MAC address. This
will result in either a unicast TRILL Data packet to the Scope
Destination MAC Address or in unknown MAC flooding.
5.b If the BR flag is one, select a distribution tree and ingress
the modified native frame as a multi-destination TRILL RBridge
Channel message.
5.c Regardless of the BR flag value, the Inner.VLAN is the VLAN ID
reported by the ingress port or, if that port is configured for
FGL, the Inner.Lable is the FGL that VLAN maps to.
6. Process the resulting RBridge Channel message. Note that if it
is unicast to the ingress RBridge as egress, it is then
egressed. And if it is multi-destination and the ingress
RBridge qualifies, a copy is egressed as well as a copy being
sent on the selected distribution tree. It is possible that the
Scope Destination MAC is actually out a different or even the
same port of the ingress TRILL switch as the port on which the
native RBridge Channel message was received.
Steps by the egress TRILL switch(es):
The egress RBridge sets the NA bit in the RBridge Channel Header
flags. It then egresses the frame as a native RBridge Channel
message, setting the native frame's outer destination and source
MAC addresses to the Scope Destination MAC Address and the egress
RBridge port's MAC address, respectively.
If the original RBridge Channel message was multi-destination it
might be egressed by more than one RBridge, each of which would
perform the above transform. Whether such a multi-destination
RBridge Channel Tunnel Protocol message would be accepted by
egress RBridges is a matter of local policy.
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5. Security, Keying, and Algorithms
The following table gives the assigned values of the SType field and
their meaning.
SType Section Meaning
----- ------- -------
0 5.1 None
1 5.2 RFC 5310 Based Authentication
2 5.3 DTLS Based Security
3-14 Available for assignment on IETF Review
15 Reserved
Table 3. SType Values
For all SType values except zero, the Security Information starts
with a byte of flag bits and a byte of remaining length as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
|A|E| RESV | Size | Info
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
Figure 12. Security Information Format
The fields are as follows:
A: Zero if authentication is not being provided. One if it is.
E: Zero if encryption is not being provided. One if it is.
RESV: Six reserved bits that MUST be sent as zero and ignored on
receipt.
Size: The number of byte of Info as an unsigned byte.
Info: Variable length Security Information.
5.1 SType None
No security services are being invoked. The length of the Security
Information field (see Figure 6) is zero.
5.2 RFC 5310 Based Authentication
The security information is the same as the value of the
Authentication TLV as specified in [RFC5310]. See figure below.
D. Eastlake & Y. Li [Page 18]
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1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|0| RESV | Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Key ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| Authentication Data (Variable)|
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13. SType 1 Security Information
The Key ID normally specifies a keying value and algorithm.
5.3 DTLS Based Security
TBD - permits key negotiation, provides both encryption and
authentication [RFC6347]...
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6. Channel Tunnel Errors
RBridge Channel Tunnel Protocol errors are reported like RBridge
Channel level errors. The ERR field is set to one of the following
error codes:
ERR Meaning
--- ---------
6 Unknown or unsupported field value
7 Authentication failure
(more TBD)
Table 4. Additional ERR Values
6.1 SubERRs under ERR 6
If the ERR field is 6, the SubERR field indicates
SubERR Meaning (for ERR = 6)
------ ---------------------
0 Unsupported Scope
1 Unsupported SType
2 Unsupported PType
3 Unknown or reserved Scope Egress Nickname in an
ESRB scope Tunnel Channel message.
4 Unsupported crypto algorithm
(more TBD)
Table 5. SubERR values under ERR 6
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7. IANA Considerations
IANA is requested to allocate a new RBridge Channel protocol number
from the range based on Standards Action for the "Channel Tunnel"
protocol.
IANA is requested to allocate a new RBridge Channel Header flag bit
for the Broadcast (BR) flag with this document as reference.
8. Security Considerations
The RBridge Channel tunnel facility has potentially positive and
negative effects on security.
On the positive side, it provides optional security that can be used
to authenticate and/or encrypt channel messages. Some RBridge Channel
message payloads provide their own security [RFCbfd] but where this
is not true, careful consideration should be give to requiring use of
the security features of the Tunnel Protocol.
On the negative side, the ability to tunnel various payload types and
to tunnel them not just between TRILL switches but to and from end
stations can increase risk unless precautions are taking. The
processing of decapsulated Tunnel Protocol payloads is not a good
place to be liberal in what you accept as the tunneling facility
makes it easier for unexpected messages to pop up in unexpected
places in a TRILL campus due to accidents or the actions of an
adversary. Local policies should generally be strict and only process
payload types required and then only with adequate authentication for
the particular circumstances.
See [RFCchannel] for general RBridge Channel Security Considerations.
See [RFC6325] for general TRILL Security Considerations.
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Normative References
[RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5310] - Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic Authentication", RFC
5310, February 2009.
[RFC6325] - Perlman, R., D. Eastlake, D. Dutt, S. Gai, and A.
Ghanwani, "RBridges: Base Protocol Specification", RFC 6325,
July 2011.
[RFC6347] - Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, January 2012.
[ClearCorrect] - Eastlake, D., M. Zhang, A. Ghanwani, V. Manral, A.
Banerjee, "TRILL: Clarifications, Corrections, and Updates",
draft-ietf-trill-clear-correct, in RFC Editor's queue.
[RFCchannel] - D. Eastlake, V. Manral, Y. Li, S. Aldrin, D. Ward,
"TRILL: RBridge Channel Support", draft-ietf-trill-rbridge-
channel-08.txt, in RFC Editor's queue.
[RFCfgl] - D. Eastlake, M. Zhang, P. Agarwal, R Perlman, D. Dutt,
"TRILL: Fine-Grained Labeling", draft-ietf-trill-fine-labeling,
in RFC Editor's queue.
Informative References
[RFC6361] - Carlson, J. and D. Eastlake 3rd, "PPP Transparent
Interconnection of Lots of Links (TRILL) Protocol Control
Protocol", RFC 6361, August 2011
[RFC5342bis] - D. Eastlake, J. Abley, " IANA Considerations and IETF
Protocol and Documentation Usage for IEEE 802 Parameters",
draft-eastlake-rfc5342bis, work in progress.
[RFCbfd] - Manral, V., D. Eastlake, D. Ward, A. Banerjee, "TRILL
(Transparent Interconnetion of Lots of Links): Bidirectional
Forwarding Detection (BFD) Support", draft-ietf-trill-rbridge-
bfd, in RFC Editor's queue.
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Acknowledgements
The contributions of the following are hereby acknowledged:
TBD
The document was prepared in raw nroff. All macros used were defined
within the source file.
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Authors' Addresses
Donald E. Eastlake, 3rd
Huawei Technologies
155 Beaver Street
Milford, MA 01757 USA
Phone: +1-508-333-2270
EMail: d3e3e3@gmail.com
Yizhou Li
Huawei Technologies
101 Software Avenue,
Nanjing 210012, China
Phone: +86-25-56622310
Email: liyizhou@huawei.com
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D. Eastlake & Y. Li [Page 25]
