One document matched: draft-hu-trill-rbridge-esadi-01.txt
Differences from draft-hu-trill-rbridge-esadi-00.txt
TRILL Working Group Hongjun Zhai
INTERNET-DRAFT Fangwei Hu
Intended status: Proposed Standard ZTE
Updates: 6325 Radia Perlman
Intel Labs
Donald Eastlake
Huawei
Expires: Jun 30, 2012 December 31, 2011
RBridges: The ESADI Protocol
<draft-hu-trill-rbridge-esadi-01.txt>
Abstract
The IETF TRILL (TRansparent Interconnection of Lots of Links)
protocol provides least cost pair-wise data forwarding without
configuration in multi-hop networks with arbitrary topologies and
safe forwarding even during periods of temporary loops. TRILL
supports the multi-pathing of both unicast and multicast traffic.
TRILL accomplishes this by using IS-IS (Intermediate System to
Intermediate System) link state routing and encapsulating traffic
using a header that includes a hop count.
The ESADI (End System Address Distribution Information) protocol is a
VLAN (Virtual Local Area Network) scoped way that RBridge can
communicate end station addresses to each other. An RBridge
announcing VLAN-x connectivity (normally a VLAN-x forwarder) and
running the TRILL ESADI protocol can receive remote address
information and/or transmit local address information for VLAN-x to
other such RBridges. The purpose of this document is to improve and
update the documentation of the ESADI protocol. It updates RFC 6325.
The ESADI RBridge instance states, DRB (Designated RBridge) election
procedure, and ESADI sub-TLV are specified in this document.
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 TRILL working group mailing list: <rbridge@postel.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-
Drafts.
H. Zhai, et al [Page 1]
INTERNET-DRAFT RBridges: ESADI
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 Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
Acknowledgements
TBD
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Table of Contents
1. Introduction............................................4
1.1 Content and Precedence.................................5
1.2 Terminology............................................5
2. ESADI Protocol Overview.................................6
3. ESADI Control State.....................................8
3.1 ESADI DRB..............................................8
3.2 ESADI RBridge Instance States..........................8
3.3 ESADI DRB election events..............................9
3.4 Timers.................................................9
3.5 ESADI Neighbor List...................................10
3.6 State Table and Diagram...............................11
4. ESADI PDU processing...................................13
4.1 Sending of ESASI PDUs.................................13
4.2 Receipt of PDUs.......................................14
5. ESADI LSP Contents.....................................16
5.1 ESADI Participation Data..............................16
5.2 ESADI MAC Address sub-TLV.............................17
6. IANA Considerations....................................18
7. Security Considerations................................18
8. References.............................................19
8.1 Normative references..................................19
8.2 Informative References................................20
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1. Introduction
The IETF TRILL (TRansparent Interconnection of Lots of Links)
protocol [RFC6325] provides least cost pair-wise data forwarding
without configuration in multi-hop networks with arbitrary
topologies, safe forwarding even during periods of temporary loops,
and support for multi-pathing of both unicast and multicast traffic.
TRILL accomplishes this by using IS-IS (Intermediate System to
Intermediate System) [IS-IS] [RFC1195] [RFC6326] link state routing
and encapsulating traffic using a header that includes a hop count.
The design supports VLANs (Virtual Local Area Networks) and
optimization of the distribution of multi-destination frames based on
VLANs and IP derived multicast groups. Devices that implement TRILL
are called RBridges (Routing Bridges) or TRILL switches.
There are five ways an RBridge can learn end station addresses as
described in Section 4.8 of [RFC6325]. The ESADI (End Station
Address Distribution Information) protocol is an optional VLAN scoped
way RBridges can communicate end station addresses with each other.
An RBridge that is announcing connectivity to VLAN-x (normally a
VLAN-x appointed forwarder) MAY use the (ESADI) protocol to announce
the MAC address of some or all of its attached VLAN-x end nodes to
other RBridges that are running ESADI for VLAN-x.
By default, RBridges with connected end stations learn addresses from
the data plane when ingressing and egressing native frames. The ESADI
protocol's potential advantages over data plane learning include the
following:
1. Security advantages: The EDADI protocol can be used to announce
end stations with an authenticated enrollment (for example
enrollment authenticated by cryptographically based EAP
(Extensible Authentication Protocol [RFC3748]) methods via
[802.1X]). In addition, the ESADI protocol supports cryptographic
authentication of its message payloads for more secure
transmission.
2. Fast update advantages: ESADI protocol provides a fast update of
end nodes MAC (Media Access Control) addresses. If an end station
is unplugged from one RBridge RB1 and plugged into RB2, frames
addressed to that older RBridge can be black holed. They can be
sent just to the older RBridge that the end station was connected
to until cached address information at some remote RBridge times
out, possibly for tens of seconds [RFC6325].
MAC address reachability information and some ESADI parameters are
carried in ESADI frames rather than in the core TRILL IS-IS protocol.
As described below, ESADI is, for each VLAN, a virtual logical
topology overlay in the TRILL topology. An advantage of using ESADI
is that the end station attachment information is not flooded to all
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RBridges through the core IS-IS instance but only to participating
RBridges advertising ESADI support for the VLAN in which those end
stations occur.
1.1 Content and Precedence
This document clarifies and updates the description of the ESADI
protocol in the TRILL basic specification, especially the ESADI DRB
(Designated RBridge) election procedure, ESADI instance state
specification, and ESADI parameter announcement.
Section 2 is the ESADI protocol overview. Section 3 specifics ESADI
DRB principles, ESADI instance state and DRB election. Section 4
discusses the processing of ESADI PDUs. Section 5 describes two ESADI
sub-TLVs: the one with ESADI participation information and the MAC
Address sub-TLV.
This document updates [RFC6325] and prevails over [RFC6325] in the
case of conflicts.
1.2 Terminology
This document uses the acronyms defined in [RFC6325].
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].
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2. ESADI Protocol Overview
ESADI is a VLAN scoped way that RBridges can announce and learn end
station addresses rapidly and securely. An RBridge that is
announcing itself as connected to one or more VLANs (usually because
it is an Appointed Forwarder) and participates in the ESADI protocol
is called an ESADI RBridge.
ESADI is a separate protocol from the core IS-IS instance implemented
by all RBridges in a campus. There is a separate ESADI instance for
each VLAN. In essence, for each VLAN, there is an instance of the IS-
IS reliable flooding mechanism in which ESADI RBridges may choose to
participate. (These are not the instances being specified in
[MultiInstance].) It is an implementation decision how independent
the implementations of multiple ESADI instances at an RBridge are.
For example, the ESADI link state could be in a single database with
a field in each record indicating the VLAN to which it applies or
could be a separate database per VLAN. But the update processes
operate separately for each ESADI instance.
After the TRILL header, ESADI frames have an inner Ethernet header
with the Inner.MacDA of "All-Egress-RBridges" (formerly called "All-
ESADI-RBridges"), an Inner.VLAN tag specifying the VLAN of interest,
and the "L2-IS-IS" Ethertype followed by the ESADI payload as shown
in Figure 1. For more detail see Section 4.2.5 in the TRILL base
protocol specification [RFC6325].
TRILL ESADI frame Structure
+--------------------------------+
| Link Header |
+--------------------------------+
| TRILL Data Header |
+--------------------------------+
| Inner Ethernet Header |
+--------------------------------+
| ESADI Payload |
+--------------------------------+
| Link Trailer |
+--------------------------------+
Figure 1
All transit RBridges forward ESADI frames as if they were ordinary
multicast TRILL Data frames. Because of this forwarding, it appears
to the ESADI protocol at an RBridge that it is directly connected by
a multi-access virtual link to all other RBridges in the campus
running ESADI for that VLAN. Thus no "routing" computation or
decisions ever have to be made by ESADI. A participating RBridge
merely transmits the ESADI frames it originates on this virtual link
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as described in [RFC6325] for any multicast frame. RBridges that do
not implement the ESADI protocol, do not have it enabled, or are not
announcing connectivity for the Inner.VLAN of an ESADI frame do not
decapsulate or locally process any TRILL ESADI frames they receive.
Thus the ESADI frames are transparently tunneled through transit
RBridges.
TRILL ESADI frame payloads are structured like IS-IS frames but are
always TRILL encapsulated on the wire as if they were TRILL Data
frames.
The ESADI instance for VLAN-x at an RBridge RB1 acquires a neighbor
when it first receives ESADI-LSP number zero from that neighbor and
that neighbor is an existing RBridge in the core IS-IS instance link
state database that is data and IS-IS reachable from RB1 (see Section
2 of [ClearCorrect]). When an RBridge RB2 becomes IS-IS or data
unreachable from RB1 or the entry for RB1 is purged from the core IS-
IS link state database, it is lost as a neighbor and also purged from
any ESADI instances.
The information distributed with the ESADI protocol is a list of
local end station MAC addresses known to the originating RBridge and,
for each such address, a one octet unsigned "confidence" rating in
the range 0-254 (see Section 5.2). It is entirely up to the
originating RBridge which locally connected MAC addresses it wishes
to advertise via ESADI. It MAY advertise all, some, or none of such
addresses it has. Future uses of ESADI may use it to distribute
additional information.
TRILL ESADI LSPs MUST NOT contain a VLAN ID in their payload. The
VLAN ID to which the ESADI data applies is the Inner.VLAN of the
TRILL Data frame enclosing the ESADI payload. If a VLAN ID could
occur within the payload, it might conflict with the Inner.VLAN and
could conflict with any future VLAN mapping scheme that may be
adopted [VLANmapping]. If a VLAN ID field in an ESADI frame payload
does include a VLAN ID, its contents is ignored.
(In the future, TRILL may be extended to provide more fine-grained
labeling of data and ports [FineGrained]. If so, it is expected that
ESADI will be extended by allowing such fineegrained labeling of
ESADI frames, as an alternative to the currently allowed Inner.VLAN
labeling. As with the current ESADI specification, it would generally
be prohibited for such fine-grained labeling information to appear
inside such extended ESADI frames.)
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3. ESADI Control State
This Section discusses ESADI control state in terms of DRB,
neighbors, and instance states.
3.1 ESADI DRB
It is necessary to elect one ESADI RBridge for each VLAN scoped
virtual link where ESADI is being used. The ESADI DRB is responsible
for Link State Database synchronization with other RBridges by
issuing ESADI-CSNP PDUs periodically and responding to PSNPs on the
virtual link.
3.2 ESADI RBridge Instance States
There are four states for the ESADI instance at each RBridge for each
VLAN: Down, Initial, Not-DRB and DRB. The state descriptions are as
following:
Down: This is a virtual state for convenience in creating state
diagrams and tables. It indicates that the ESADI instance is
operationally down.
Initial: This state indicates that an ESADI instance is up but does
not know of any ESADI neighbors (i.e., the only entry in its
neighbor list is itself). Once ESADI enters this state, it
should start the Holding Timer, and multicast self-originated
number zero LSPs on the virtual link. If a valid ESADI neighbor
is found by receiving an ESADI-LSP number zero, the ESADI
instance will leave this state and enter into "Not-DRB" state.
In this state, the Holding Timer will be recycled if the timer
is expired or the found neighbor has a higher priority than the
local priority.
Not-DRB: This state indicates that the ESADI instance has found at
least one valid ESADI neighbor and is not DRB yet. If there is
no Holding Timer running, the timer will be started. If an
ESADI-LSP or an ESADI-CSNP PDU is received from a higher
priority ESADI RBridge, the Holding Timer will be recycled. If
the Holding Timer expires, the ESADI instance will enter into
"DRB" state.
DRB: In this state, the ESADI instance multicasts the ESADI-CSNP PDUs
periodically to keep Link State Database synchronization with
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its neighbors on virtual link, and responds to ESADI-PSNP PDUs
with ESADI-LSPs. If an EDADI PDU (i.e., LSP, CSNP and PSNP) is
received from a neighbor with a higher priority than its own,
the ESADI instance will move to the "Not-DRB" state.
3.3 ESADI DRB election events
The following events can change the ESADI state. These are all events
for a particular RBridge's ESADI VLAN-x instance.
E1 ESADI instance is operationally up;
E2 Finding the first ESADI neighbor;
E3 Holding Timer expired;
E4 Receiving an ESADI PDU from an ESADI neighbor with higher
priority;
E5 Losing the last ESADI neighbor;
E6 ESADI instance goes operationally down;
(Receiving an ESADI PDU from an ESADI neighbor with lower priority
has no effect on the ESADI instance state.)
Priority is determined by the seven-bit priority field in the ESADI
participation data (see Section 5.1), with the System ID as a tie
breaker, both considered as unsigned integers with the larger
quantity indicating higher priority.
3.4 Timers
There are two timers for ESADI DRB election: one the Holding Timer,
the other the Waiting Timer. The Holding Timer is a cyclic timer, and
is used in connection with ESADI-CSNP PDUs. If this timer expires,
the local ESADI instance will start multicasting its own ESADI-CSNP
PDUs and, if it was in the Non-DRB state, it decides that the DRB is
being non-responsive and moves to the DRB state.
The Waiting Timer is a non-cyclic timer. This timer is started by the
change of neighbor's DRB status and killed by its expiration. It is
used to alleviate the PDU storm stirred by Link State Database
synchronization in the case of current DRB being preempted by a new
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ESADI neighbor with higher priority. If this timer expires, the new
DRB is confirmed and its ESADI parameters, such as intervals of
holding timer and waiting timer, are accepted to overwrite the local
parameters.
3.5 ESADI Neighbor List
In order to be able to access key information about ESADI neighbors
easily, an ESADI neighbor list is maintained for each ESADI VLAN-x
instance. Each entry in this list represents an ESADI neighbor for
VLAN-x.
For each neighbor, there will be a number zero LSP from that neighbor
in the ESADI instance link state. A list entry is created when such
a number zero LSP is first received on the ESADI virtual link from
some RBridge that exists in the core IS-IS instance link state
database and is both data and IS-IS reachable (see Section 2 of
[ClearCorrect]). A neighbor entry for an RBridge is deleted when that
RBridge if that RBridge becomes data or IS-IS unreachable or if it is
purged from the core IS-IS instance link state database. For each
neighbor, the parameters of System-ID/nickname, priority, holding
timer interval, waiting timer interval and the DRB flag, are stored
in its respective entry in this list.
The DRB flag indicates whether a neighbor is regarded as DRB or not.
If this flag is 1, the associated neighbor is considered as DRB,
otherwise, not DRB. At any moment, there is no more than one entry
that is flagged as DRB in this list. The DRB status of a neighbor can
be changed by the receipt of ESADI-CSNP PDUs coupled with the
priorities of the originators of the PDUs, together with the priority
of the local ESADI instance (see Section 4.2 for more details). When
the DRB flag of one entry, such as the entry of the local ESADI
instance, is changed in this list, the Waiting Timer will be started
if it is not running. When the timer is expired, the neighbor, whose
DRB flag is 1, will be confirmed as real DRB, and its CSNP PDUs will
be used to accomplish Link State Database synchronization with other
ESADI RBridges.
If the ESADI instance is in "Initial" state, there is only one entry
existing in this list, where the parameters of the local ESADI VLAN-x
instance is saved. If a new entry is added to this list and the entry
is the second one, an E2 event will occur, which drives the state of
this ESADI instance into "Not-DRB" from "Initial". When there are
only two entries in this list, if the second entry is removed from
this list, an E5 event is originated, which draws this ESADI instance
back to "Initial" state from "Not-DRB" or "DRB".
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3.6 State Table and Diagram
The table below shows the transitions between the RBridge ESADI
instance states defined above based on the events defined above:
TRILL ESADI State Table
| Event | Down | Initial | Not-DRB | DRB |
+-------+---------+---------+---------+---------+
| E1 | Initial | N/A | N/A | N/A |
| E2 | N/A | Not-DRB | N/A | N/A |
| E3 | N/A | Initial | DRB | N/A |
| E4 | N/A | Initial | Not-DRB | Not-DRB |
| E5 | N/A | N/A | Initial | Initial |
| E6 | Down | Down | Down | Down |
+-------+---------+---------+---------+---------+
Figure 2
N/A indicates that the event to the left is Not Applicable in the
state at the top of the column.
The first state is "Down". Once an RBridge ESADI instance is
operationally up, it enters into "Initial" state. On transition into
the Initial state, an ESADI instance starts its Holding Timer and
multicasts its self-originated number zero LSP on the virtual link.
When the first valid ESADI neighbor is found on the virtual link, the
ESADI instance enters "Not-DRB" state, otherwise the ESADI instance
remains in "Initial" state. While in Initial state, whenever the
timer expires it recycles the Holding Timer and multicasts its ESADI-
LSP number zero. And if the neighbor's priority is higher than its
own, the Holding Timer will be recycled before the ESADI instance
enters the "Not-DRB" state.
In both the "Non-DRB" and "DRB" states, the ESADI RBridge multicasts
all its self-originated LSP fragments.
In the "Not-DRB" state, if any ESADI PDUs are received from ESADI
neighbors with higher priorities, the Holding Timer will be recycled.
Otherwise, if the timer expires without hearing from a higher
priority neighbor, the ESADI instance will enter "DRB" state. If the
DRB receives an ESADI PDU from a higher priority neighbor, the ESADI
instance will move to "Not-DRB" state. As DRB, an ESADI instance will
multicast ESADI-CSNP PDUs to all neighbors on the virtual link
periodically, and respond to the ESADI-PSNP PDUs with ESADI-LSP PDUs
by multicasting them.
Below is the same information as in the state table above presented
as a diagram.
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TRILL ESADI state diagram
+------------------+
| Down |<--------+
+------------------+ |
| | ^ |
|E1 | E6 | |
V +-----+ |
+------------------+ E6 |
+---->| Initial |---------|
| +------------------+ |
| | ^ | ^ |
| |E2 |E5 |E3,E4 | |
| V | +-------+ |
| +------------------+ E6 |
| | Not-DRB |---------|
| +------------------+ |
| | ^ | ^ |
| |E3 |E4 | E4 | |
| V | +-------+ |
| E5 +------------------+ E6 |
+-----| DRB |---------+
+------------------+
Figure 3
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4. ESADI PDU processing
VLAN-x ESADI neighbors are usually not connected directly by a
physical link, but are always logically connected by a virtual link.
There could be hundreds of ESADI RBridges on the virtual link. There
are only LSP, CSNP and PSNP PDUs used in ESADI. In particular, there
are no Hello or MTU PDUs because ESADI does not build a topology and
does not do any routing.
In IS-IS, multicasting is normally on a local link and no effort is
made to optimize to unicast because under the original conditions
when IS-IS was designed (commonly a piece of multi-access Ethernet
cable), any frame made the entire link busy for that frame time. But
in ESADI what appears to be a simple multi-access link is actually a
multi-hop distribution tree that may or may not be pruned. Thus,
transmitting a multicast frame on such a tree imposes a substantially
greater load than transmitting a unicast frame. This load may be
justified if there are likely to be multiple listeners but may not be
justified if there is only one recipient of interest. For this
reason, under some circumstances, ESADI PDUs MAY be TRILL unicast.
An undesirable storm of LSP PDUs could be sent to update a new
RBridge participant in VLAN-x ESADI if it has higher priority and
becomes DRB on the virtual link. ESADI has a feature to ameliorate
this.
Section 4.1 describes the sending of ESADI PDUs. Section 4.2 covers
the receipt of ESADI PDUs.
4.1 Sending of ESASI PDUs
When the VLAN-x ESADI instance is in "Not-DRB" or "DRB" state and a
new neighbor is found, its self-originated LSP fragments are
scheduled to be sent and MAY be unicast to that neighbor. The
interval elapsed before sending the LSP(s), depends on the priority
of the local ESADI instance. The higher the priority, the shorter
the interval is.
In the case of receiving an LSP with a smaller sequence number than
the LSP copy stored in local Link State Database, the local ESADI
instance will also schedule to transmit the stored LSP copy and MAY
unicast it to the sender. After the sender receives such a LSP, it
can originate a new LSP, whose sequence number is bigger than the
received sequence number, to refresh the LSP in all the neighbors.
If the ESADI instance is DRB, it multicasts an ESADI-CSNP
periodically to keep the Link State Database synchronized among its
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neighbors on the virtual link. After receiving an ESADI-PSNP PDU, the
DRB will transmit the LSPs requested by the PSNP on the virtual link.
If the ESADI instance is not DRB, it will schedule multicasting only
its self-originated LSP on the virtual link when it finds the DRB
losing some LSPs or having stale LSPs, including the local ESADI
instance's self-originated LSPs, from the ESADI-CSNP PDUs it
receives. The higher the priority, the shorter the interval is.
The format of a unicast ESADI frame is the format of TRILL ESADI
frame, in section 4.2 in [RFC6325], except that, in the TRILL header,
the M bit is set to zero and the Egress Nickname is the nickname of
the destination RBridge.
4.2 Receipt of PDUs
When an ESADI PDU is received, the receiver checks for the
originator's System ID in the receiver's core IS-IS instance link
state database. If the System ID is not present or appears to be data
or IS-IS unreachable, the ESADI PDU is discarded.
After receiving a new ESADI-LSP that passes the above check, the LSP
will be installed into or replaced the older copy of this LSP in the
local ESADI Link State Database. If it is a number zero LSP, the
local ESADI instance will try to find the originator of the LSP in
its neighbor list. If the neighbor is found, any different parameters
of this neighbor will be stored in the associated entry in the
neighbor list. Otherwise, a new neighbor is detected, and an
associated entry is inserted into the list to store this neighbor's
information. If the local ESADI instance is in "Initial" state, the
entry will be the second entry in the neighbor list, an E2 event will
be originated, which will move this ESADI instance into "Not-DRB"
state from "Initial".
On receiving an ESADI-CSNP PDU from an ESADI neighbor list member,
the PDU is used for Link State Database synchronization. If received
from some other RBridge, it is discarded.
If the ESADI-CSNP PDU is not discarded and the local ESADI instance
is in "Not-DRB" or "DRB" state, it will be used to update the DRB
flag in the entries in the neighbor list, i.e., the originator's DRB
flag is set to 1 and other entries' DRB flag is cleared to zero. The
above update may make the potential DRB change from one neighbor to
another; if so, the Waiting Timer will be started if it is not
running. If potential DRB doesn't change from one neighbor to
another, and the Waiting Timer is not running yet, this CSNP PDU is
used for Link State Database synchronization. ESADI-PSNP PDUs will be
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multicast on the virtual link to request fresh copies of lost or
stale LSPs from DRB, if necessary.
When receiving an ESADI-PSNP PDU, if the local ESADI instance is DRB
and the Waiting Timer is not running, LSP PDU requested the PSNP will
be multicast on the virtual link. Otherwise, the PSNP PDU is
discarded.
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5. ESADI LSP Contents
The only PDUs used in ESADI are the Level 1 LSP, CSNP, and PSNP PDUs.
This section specifies the format for ESADI participation data sub-
TLV and gives the reference for the ESADI MAC Reachability TLV.
5.1 ESADI Participation Data
The figure below presents the format of the ESADI participation data.
This APPsub-TLV MUST be included in a TRILL GENAPP TLV in ESADI LSP
number zero. LSP number zero MUST NOT exceed 1470 bytes in length.
Participation Data
+-+-+-+-+-+-+-+-+
| Type | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+
|D| Priority | (1 byte)
+-+-+-+-+-+-+-+-+
| Holding Time | (1 byte)
+-+-+-+-+-+-+-+-+
| Waiting Time | (1 byte)
+-+-+-+-+-+-+-+-+
Figure 4
Type: set to TRILL APPsub-TLV type 1.
Length: Set to 3.
D: If the sub-TLV is originated by an ESADI instance that thinks it
is DRB or an ESADI instance sending CSNPs as DRB, the D field is
set to 1, otherwise, the field is zero.
Priority: The Priority field gives the ESADI instance's priority for
being DRB on the TRILL ESADI virtual link for the VLAN in which
the PDU containing the Participation data was sent. It is a 7-bit
unsigned integer.
Holding Time: Gives the holding time in seconds as an unsigned
integer.
Waiting Time: Gives the waiting time in seconds as an unsigned
integer.
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When an ESADI instance receives a participation data sub-TLV in which
the D field is set to 1 and the originator of this LSP is confirmed
DRB by the local ESADI instance as highest priority, the RBridge sets
the local Holding Timer according to the value of holding time field,
and sets the local Waiting Timer according to the value of waiting
time field.
5.2 ESADI MAC Address sub-TLV
The information in TRILL ESADI-LSP PDUs consists of one or more MAC
Reachability (MAC-RI) TLVs as specified in [RFC6165]. These TLVs
contain one or more unicast MAC addresses of end stations that are
both on a port and in a VLAN for which the originating RBridge is
appointed forwarder, along with the one octet unsigned Confidence in
this information with a value in the range 0-254.
To avoid conflict with the Inner.VLAN ID, the TLVs in TRILL ESADI
PDUs, including the MAC-RI TLV, MUST NOT containing the VLAN ID. If a
VLAN-ID is present in the MAC-RI TLV, it is ignored. The VLAN to
which the ESADI-LSP applies is indicated only by the Inner.VLAN tag
in the encapsulated TRILL ESADI frame.
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6. IANA Considerations
IANA is requested to allocate an IS-IS Application Identifier under
the Generic Information TLV (#251) for TRILL [RFCgenapp] and to
create a subregistry in the TRILL Parameters Registry for "TRILL
APPsub-TLVs under IS-IS TLV #251 Application Identifier #TBD". The
initial contents of this subregistry are as follows:
Type Name Reference
------ -------- -----------
0 Reserved <this RFC>
1 ESADI Parameters <this RFC>
2-254 Available <this RFC>
255 Reserved <this RFC>
TRILL APPsub-TLV Types 2 through 254 are available for allocation by
Standard Action as modified by [RFC4020]. The standards track RFC
causing such an allocation will also include a discussion of security
issues and of the rate of change of the information being advertised.
TRILL APPsub-TLVs MUST NOT alter basic TRILL IS-IS protocol operation
including the establishment of adjacencies, the update process, and
the decision process [IS-IS] [RFC1195] [RFC6327].
The V, I, D, and S flags in the initial flags byte of a TRILL Generic
Information TLV [RFCgenapp] are not used as TRILL operates as a Level
1 IS-IS area and no meaning is hereby assigned to the inclusion of an
IPv4 and/or IPv6 address via the I and V flags. Thus these flags MUST
be zero; however, use of multi-level IS-IS is an obvious extension
for TRILL [MultiLevel] and future IETF Standards Actions may update
or obsolete this specification to provide for the use of any or all
of these flags in the TRILL GENAPP TLV.
The ESADI Parameters information, for which APPsub-TLV 1 is hereby
assigned, is compact and slow changing (see Section 5.1).
The security implications of each RBridge Channel protocol will be
discussed in the RFC specifying that protocol. For Security
Considerations related to ESADI and the ESADI parameters APPsub-TLV,
see Section 7.
7. Security Considerations
TBD
For general TRILL Security Considerations, see [RFC6325].
H. Zhai, et al [Page 18]
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8. References
Normative and informative references for this document are below.
8.1 Normative references
[IS-IS] - International Organization for Standardization,
"Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in conjunction
with the protocol for providing the connectionless-mode Network
Service (ISO 8473)", ISO/IEC 10589:2002, Second Edition, Nov
2002.
[RFC1195] - Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990.
[RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4020] - Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020, February 2005.
[RFC6165] - Banerjee, A. and D. Ward, "Extensions to IS-IS for
Layer-2 Systems", RFC 6165, April 2011.
[RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
Ghanwani, "Routing Bridges (RBridges): Base Protocol
Specification", RFC 6325, July 2011.
[RFC6326] - Eastlake, D., Banerjee, A., Dutt, D., Perlman, R., and A.
Ghanwani, "Transparent Interconnection of Lots of Links (TRILL)
Use of IS-IS", RFC 6326, July 2011.
[RFC6327] - Eastlake 3rd, D., Perlman, R., Ghanwani, A., Dutt, D.,
and V. Manral, "Routing Bridges (RBridges): Adjacency", RFC
6327, July 2011.
[RFCgenapp] - Ginsberg, L., S. Previdi, M. Shand, "Advertising
Generic Information in IS-IS", draft-ietf-isis-genapp-04.txt,
in RFC Editor's queue.
[ClearCorrect] - draft-eastlake-trill-rbridge-clear-correct, work in
progress.
H. Zhai, et al [Page 19]
INTERNET-DRAFT RBridges: ESADI
8.2 Informative References
[802.1X] - IEEE 802.1, "IEEE Standard for Local and metropolitan area
networks / Port-Based Network Access Control", IEEE Std
802.1X-2010, 5 February 2010.
[FineGrained] - Eastlake, D., M. Zhang, P. Agarwal, D. Dutt, R.
Perlman, "TRILL: Fine-Grained Labeling", draft-ietf-trill-fine-
labeling, work in progres.
[MultiInstance] - Previdi, S., L. Ginsberg, M. Shand, A. Roy, D.
Ward, draft-ietf-isis-mi, work in progrss.
[MultiLevel] - draft-perlman-trill-rbridge-multilevel, work in
progress.
[RFC3748] - Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, Ed., "Extensible Authentication Protocol (EAP)", RFC
3748, June 2004.
[VLANmapping] - Perlman, R., D. Dutt, A. Banerjee, A. Rijhsinghani,
and D. Eastlake, "RBridges: Campus VLAN and Priority Regions",
draft-ietf-trill-rbridge-vlan-mapping, work in process.
H. Zhai, et al [Page 20]
INTERNET-DRAFT RBridges: ESADI
Authors' Addresses
Hongjun Zhai
ZTE Corporation
68 Zijinghua Road
Nanjing 200012 China
Phone: +86-25-52877345
Email: zhai.hongjun@zte.com.cn
Fangwei Hu
ZTE Corporation
889 Bibo Road
Shanghai 201203 China
Phone: +86-21-68896273
Email: hu.fangwei@zte.com.cn
Radia Perlman
Intel Labs
2200 Mission College Blvd.
Santa Clara, CA 95054-1549 USA
Phone: +1-408-765-8080
Email: Radia@alum.mit.edu
Donald Eastlake
Huawei Technologies
155 Beaver Street
Milford, MA 01757 USA
Phone: +1-508-333-2270
Email: d3e3e3@gmail.com
H. Zhai, et al [Page 21]
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H. Zhai, et al [Page 22]
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