One document matched: draft-eastlake-trill-rbridge-isis-02.txt
Differences from draft-eastlake-trill-rbridge-isis-01.txt
Network Working Group Donald Eastlake 3rd
INTERNET-DRAFT Eastlake Enterprises
Intended status: Proposed Standard Radia Perlman
Sun Microsystems
Dinesh Dutt
Cisco
Expires: May 2, 2009 November 3, 2008
RBridges: Use of IS-IS
<draft-eastlake-trill-rbridge-isis-02.txt>
Status of This Document
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Distribution of this document is unlimited. Comments should be sent
to the TRILL Working Group <rbridge@postel.org>.
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Abstract
RBridges implement the TRILL protocol, which in turn makes use of an
extended version of the IS-IS (Intermediate System to Intermediate
System) routing protocol to determine topology and frame forwarding
and for the distribution and synchronization of data. RBridges
provide optimal pair-wise forwarding with zero configuration, safe
forwarding even during periods of temporary loops, and multipathing
for both unicast and multicast traffic. Rbridges also support VLANs.
This document specifies some details of IS-IS PDUs used in TRILL.
D. Eastlake, R. Perlman, & D. Dutt [Page 1]
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Table of Contents
Status of This Document....................................1
Abstract...................................................1
1. Introduction............................................3
1.1 Terminology............................................3
1.2 Ackowledgements........................................3
2. Separation of IS-IS Instances...........................4
3. TRILL IS-IS PDU Details.................................6
3.1 Hello PDUs.............................................6
3.2 LSP PDUs...............................................8
3.2.1 Core TRILL IS-IS LSP.................................8
3.2.2 TRILL ESADI LSP.....................................12
3.3 CSNP/PSNP and MGROUP CSNP/PSNP PDUs...................13
3.4 MGROUP PDUs...........................................13
4. TRILL IS-IS TLVs.......................................14
4.1 Port Capability TLV...................................14
4.2 Area Address..........................................14
4.3 Protocols Supported...................................14
5. Bridged LAN Link Costs.................................15
6. IANA Considerations....................................16
7. Security Considerations................................16
8. Normative References...................................17
9. Informative References.................................17
Disclaimer................................................18
Additional IPR Provisions.................................18
Author's Address..........................................19
Expiration and File Name..................................19
D. Eastlake, R. Perlman, & D. Dutt [Page 2]
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1. Introduction
[RBRIDGE] specifies the TRILL base protocol which provides optimal
pair-wise forwarding with zero configuration, safe forwarding even
during periods of temporary loops, and multipathing for both unicast
and multicast traffic. Rbridges also support VLANs. The TRILL
protocol, in turn, makes use of the IS-IS [ISIS] protocol with
certain extensions. [ISIS-L2] is intended to specify general [ISIS]
facilities to provide true link state routing to any protocol running
directly over Layer-2.
This is a specification of details of TRILL use of IS-IS
concentrating on IS-IS PDU content in TRILL. It makes use of the
Router Capabilities TLV [RFC4971]. It also adds a new Port
Capabilities TLV used only within Hello PDUs.
[RBRIDGE] specifies the TRILL handling and flow of IS-IS PDUs, along
with the determination of the Designated RBridges (DRB, equivalent to
the DIS (Designated Intermediate System)) on a link and the like.
{{Comments in double curly braces relate to version -03 of [ISIS-
L2].}}
1.1 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.
The same acronyms and terminology are used in this document as in
[RBRIDGE].
1.2 Ackowledgements
The comments of Ayan Banerjee are gratefully acknowledged.
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2. Separation of IS-IS Instances
TRILL implements separate IS-IS instances from those used by Layer 3,
that is, different from the one used by IP routers. It is important
that these be distinguishable to avoid possible confusion that would
occur if an IS-IS instance attempted to process IS-IS PDUs intended
for a different instance.
TRILL implements multiple instances of IS-IS for its own use. One
mandatory instance includes information such as basic connectivity
between RBridges, VLAN attachment, location of IP multicast routers,
and the like. RBridges also optionally implement TRILL ESADIs (End
Station Address Distribution Instances) of IS-IS, to carry
information about attached end nodes.
This section explains how TRILL encodes IS-IS frames for its
instances to ensure that there is no confusion between TRILL
instances of IS-IS and Layer-3 instances of IS-IS or between the
mandatory core instance of TRILL IS-IS and TRILL ESADIs.
The first level of discrimination is based on the destination address
of IS-IS frames as follows:
1. Layer 3 IS-IS frames have a destination multicast MAC address of
AllL1ISs or AllL2ISs. (Proposals are under consideration which
would add other multicast addresses to this list but they would
not in duplicate
2. TRILL IS-IS frames are used for the core instance which all
RBridges MUST participate in. The have the multicast destination
address All-IS-IS-RBridges.
3. TRILL ESADI frames are used for the optional per VLAN instances.
An RBridge which is an appointed forwarder for a link in VLAN-x
MAY participate in the ESADI for VLAN-x if the ESADI feature is
implemented in that RBridge and it is configured to so
participate. TRILL ESADI frames will never have the outer MAC
destination addresses listed in items 1 and 2 above. They look
just like TRILL data frames and have an outer TRILL Ethertype, but
the encapsulated IS-IS PDU has a destination MAC multicast address
of All-ESADI-RBridges. Thus TRILL ESADI frames are transparently
tunneled thorough non-participating RBridges exactly as if they
were TRILL data frames. The VLAN to which they apply is indicated
by the encapsulated frames VLAN tag.
In addition, TRILL uses a distinct, constant IS-IS Area Address that
would not appear as a real Layer-3 IS-IS area address. This Area
Address is the value zero. (See Section 4.2.)
The multiple instance mechanism described in [ISIS-MI] is not used to
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distinguish these TRILL IS-IS instances, although TRILL IS-IS PDUs
for the mandatory core instance MAY include the MI TLV with the
instance number of zero. In order to facilitate the optional RBridge
VLAN mapping feature, TRILL ESADI frames MUST NOT contain an instance
identifier. The instance identifier TLV is type #7.
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3. TRILL IS-IS PDU Details
[ISIS], as extended by [ISIS-L2], supports 7 types of PDUs: Hello,
LSP, CSNP, PSNP, MGROUP, MGROUP CSNP, and MGROUP PSNP. TRILL aspects
of the contents of each of the PDU types are specified in this
Section. Some individual TLVs types are discussed in Section 4 below.
All RBridges have a 6-octet System ID that is conveyed in the header
of every TRILL IS-IS PDU they produce, just as in Layer-3 IS-IS. The
Maximum Area Addresses octet in the common fixed header is set to
0x01. An RBridge campus is always a single Level 1 IS-IS Area.
Where some IS-IS TLVs assume a unique 32-bit Router ID, in TRILL IS-
IS this field is zero
All TRILL IS-IS PDUs MAY contain an Authentication TLV (Type #10)
[RFC5304].
3.1 Hello PDUs
Hellos are only used in the core instance of TRILL IS-IS. (The core
instance link state contains enough information that the DRB,
adjacencies, and holding time for any ESADI can be determined without
Hellos. See Section 4.2.4.1 of [RBRIDGE].)
All TRILL Hello PDUs contain the TRILL Area Address TLV (see Section
4.2). The Circuit Type two bit field of TRILL IS-IS Hello PDUs MUST
be set to 0b01 indicating Level 1 only.
An IS Neighbor TLV (Type #6) MUST be included in a TRILL Hello if the
Hello is sent on the Designated VLAN and MAY be included if it is
sent on any other VLAN. (See Section 4.2.3 of [RBRIDGE].)
Core IS-IS instance Hello PDUs MUST include one or more Port
Capability TLVs (Type #<tbd4.1>). The following TRILL related subTLVs
can appear within a Port Capability TLV:
1. Special VLANs and Flags (subTLV Type #10). This subTLV MUST appear
excatly once in a Port Information TLV in every TRILL Hello PDU.
The length of the value is four octets.
0 1 2 3 4 - 15 16 - 19 20 - 31
+----+----+----+----+------------+----------+------------+
| AF | AC | VM | R | Outer.VLAN | Reserved | Desig.VLAN |
+----+----+----+----+------------+----------+------------+
The first and second octets have a copy of the Outer.VLAN ID
associated with the Hello frame when it was sent. The lower 4
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bits of the first octet give the upper ID bits of the VLAN ID and
the second octet gives the lower VLAN ID bits.
The upper 4 bits of the first octet are flag bits as shown. The AF
bit, if one, indicates that the sending RBridge believes it is
Appointed Forwarder for the VLAN and port on which the Hellos was
sent. The AC bit, if one, indicates that the sending port is
configured as an access port. The VM flag, if a one, indicates
that the sending RBridge has detected VLAN mapping within the
link. The R bit is reserved and MUST be sent as zero and ignored
on receipt.
The third and forth octets give the Designated VLAN for the link.
The lower 4 bits of the third octet give the upper ID bits of the
Designated VLAN and the forth octet gives the lower VLAN ID bits.
The upper 4 bits of the third octet are reserved and MUST be sent
as zero and ignored on receipt.
2. Enabled VLANs (subTLV Type #11). Specifies the VLANs enabled for
end station service at the port on which the Hello was sent. The
minimum size of the value is 3 octets. The third and subsequent
octets provide a bit map of enabled VLANs starting at the VLAN ID
indicated in the first two octets. The lower order four bits of
the first octet give the upper bits of the starting VLAN ID and
the second octet gives the lower bits of that VLAN ID. The upper
four bits of the first octet are reserved and MUST be sent as zero
and ignored on receipt. The highest order bit of the third octet
indicates the VLAN equal to the starting ID while the lowest order
bit of the third octet indicated that ID plus 7. For example,
VLANs 1 and 14 being enabled for end station service could be
encoded in 4-octets value 0x00 0x01 0x80 0x04 or, alternatively,
as 0x00 0x00 0x40 0x02.
This subTLV may occur more than once in a TRILL Hello and a VLAN
is enabled for end station service on the port where the Hellos
was sent if this is indicated by any occurrence in the Hello. For
example, a receiver could allocate a 512-octet buffer and, with
appropriate shifting operations, OR in the enabled bits for each
subTLV of this type it finds in a Hello to derive the complete bit
map of these VLANs.
3. Appointed Forwarders (subTLV Type #12). This subTLV provides the
mechanism by which the DRB can inform other RBridges on the link
that they are the designated VLAN-x forwarder for that link for
one or more ranges of VLAN IDs. The size of the value is 6*n
octets where there are n appointments. Each 6 octet part of the
value is formatted as follows:
D. Eastlake, R. Perlman, & D. Dutt [Page 7]
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| octet 1 - 2 | octet 3 | octet 4 | octet 5 | octet 6 |
+----------------+-----+-----+---------+-----+----+---------+
| Appointee Nick | Res | Start VLAN ID | Res | End VLAN ID |
+----------------+-----+-----+---------+-----+----+---------+
The appointed forwarder RBridge is specified by its nickname in
the first two octets.
The "Res" fields of 4 bits each are reserved and MUST be sent as
zero and ignored on reciept.
The VLAN range give is inclusive. To specify a single VLAN, that
VLAN ID appears as both the start and end VLAN. The RBridge whose
nickname is given is appointed forwarder for those VLANs for which
it has end station service enabled (see item 2 above) in the
inclusive range. For example, assume an RBridge with end station
service enabled on VLANs 100, 101, 199, and 200 (and possibly
other VLANs less than 100 or greater than 200), but not enabled
for VLANS 102 through 198. It could be appointed forwarder for
these four VLANs through either (1) a single 6-octet value
sequence with start and end VLAN IDs of 100 and 200, or (2) a
12-octet value sequence with start and end VLAN IDs of 100 and 101
in the first part and 199 and 200 in the second part.
An RBridge's nickname may occur as appointed forwarder for
multiple VLAN ranges within the same or different Port Capability
TLVs within a DRB's Hello. In the absence of appointed forwarder
subTLVs referring to a VLAN, the DRB acts as the appointed
forwarder for that VLAN if end station service is enabled.
3.2 LSP PDUs
The TLVs to be included in TRILL LSP PDUs are different for the
mandatory core TRILL IS-IS instance of a campus, discussed in Section
3.2.1 below, and in the optional TRILL ESADIs, discussed in section
3.2.2 below.
All TRILL LSP PDUs contain the TRILL Area Address TLV (see Section
4.2). In addition, in the LSP header, the P Flag and Att flags MUST
be zero and the IS type two bit field MUST be set to 0b01 indicating
Level 1.
3.2.1 Core TRILL IS-IS LSP
The content of core TRILL IS-IS instance LSP PDUs includes:
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1. Information on reachable RBridge neighbors and the cost of the hop
via the Extended IS Reachability TLV (Type #22) [RFC5305] (wide
metric). TRILL IS-IS does not use the IS Reachability TLV (Type
#2) (narrow metric).
2. The RBridge flags, nickname, VLANs, and other information via one
or more Router Capability TLVs [RFC4971] (Type #242). The D and S
flags in the Router Capability TLV MUST be zero. Other information
is included by instances of the following TRILL related Router
Capability TLV subTLVs:
2.a TRILL Flags (subTLV Type #<tbd3.2.1a>). Exactly one TRILL
Flags subTLV must occur in the link state of every RBridge.
The length of the value of this subTLV is variable with a
minimum size of 1 octet. The top four bits of the first octet
are defined as below. Additional bits may be specified in the
future and those bits may extend into subsequence octets. The
value of all bits in any octets not present is assumed by a
receiver to be zero.
first octet
0 1 2 3 4 - 7
+----+----+----+----+-----------+---
| V0 | V1 | V2 | V3 | reserved |
+----+----+----+----+-----------+---
V0 through V4 indicate support of TRILL Header Versions 0
through 4. The remaining bits of the first octet (and all bits
of subsequent octets if present) are reserved and MUST be zero
when sent and ignored on receipt.
2.b Nickname and Tree Root (subTLV Type #<tbd3.2.1b>). If an
RBridge is to be able to act as an ingress, egress, or tree
root, it must have a nickname. The value is 7 octets in
length. The first octet is the RBridge's nickname priority,
the second and third octets are its nickname. Octets 4 and 5
are the RBridge's priority to be a tree root as an unsigned
16-bit integer. Octets 6 and 7 are an unsigned 16-bit integer
that gives the number of additional trees every RBridge in the
campus is to compute if the RBridge in whose link state this
occurs is the highest priority tree root. (See [RBRIDGE]
Section 4.3.)
{{While the Device ID subTLV in [ISIS-L2] could be used for
Nickname, putting the Nickname priority in 8 of the Options
bits, the Root Priority subTLV and Root Identity subTLV in
[ISIS-L2] does not correspond and never has corresponded whith
how with how TRILL determines distribution tree roots or
multi-path multi-destination frames.}}
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2.c Distribution Tree Roots (subTLV Type #<tbd3.2.1c>). The value
is a variable length array of the nicknames of the RBridges
from which the originating RBridge must pick the root of the
distribution tree for multi-destination traffic for which it
is the ingress RBridge. If the list is empty or this subTLV is
not provided, the originating RBridge can only select the
highest priority tree root (see [RBRIDGE] Section 4.3).
2.d VLANs and Bridge Roots (subTLV Type #<tbd3.2.1d>). The value
of this subTLV consists of a VLAN range, flags, and a variable
length list of spanning tree root bridge IDs. This subTLV may
appear zero, one, or many times. The union of the VLAN ranges
in all occurrences MUST be precisely the set of VLANs for
which the originating RBridge is appointed forwarder on at
least one port and the VLAN ranges in multiple VLANs subTLVs
for an RBridge MUST NOT overlap. That is, the intersection of
the VLAN ranges for any pair of these subTLVs originated by an
RBridge must be null. The value length is 4 + 6*n where n is
the number of root bridge IDs. The initial 4 octets of value
are as follows:
0 1 2 3 4 - 15 16 - 19 20 - 31
+----+----+----+----+------------+----------+------------+--
| M4 | M6 | OM | R | VLAN start | Reserved | VLAN end |
+----+----+----+----+------------+----------+------------+--
The M4 bit indicates that there is an IPv4 multicast router on
a link for which the originating RBridge is appointed
forwarder for every VLAN in the indicated range. The M6 bit
indicates the same for an IPv6 multicast router. The OM bit
indicates that this RBridge requests that all non-IP derived
multicast traffic in the indicated VLAN range be sent to it.
The R and Reserved bits MUST be sent as zero and are ignored
on receipt.
The VLAN start and end IDs are inclusive. A range of one VLAN
ID is indicated by setting them both to that VLAN ID value.
The list of zero or more spanning tree root bridge IDs is the
set of root bridge IDs seen for all ports for which the
RBridge is appointed forwarder for the VLANs in the range.
This information is learned from BPDUs heard by the RBridge.
If MSTP is in use on a link, the root bridge referred to is
the CIST (common and internal spanning tree) root bridge.
(While, of course, only one spanning tree root should be seen
on any particular port, there may be multiple ports in the
same VLAN connected to differed bridged LANs with different
spanning tree roots.) If no spanning tree roots can be seen on
any of the links in any of the VLANs in the range indicated
for which the RBridge is appointed forwarder (for example all
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such links are point-to-point links to other RBridges or to
end stations so no BPDUs are received) then the listed set of
spanning tree root IDs will be null.
If there are any two VLANs in the range indicated for which
the value of the M4, M6, or OM bits are different, the subTLV
is incorrect and must be split into multiple subTLVs each
indicating only VLANs with the same M4, M6, and OM values. If
there are any two VLANs in the range indicated for which the
set of root bridge IDs see on all links for which the RBridge
is appointed forwarder for the VLAN are not the same, the
subTLV is incorrect and must be split into multiple subTLVs
each indicating only VLANs with the same set of DRB seen root
bridge IDs. It is always safe to use subTLVs with a "range" of
one VLAN ID but this may be too verbose.
2.e ESADI Participation (subTLV Type #<tbd3.2.1e>). The value of
this optional subTLV is 6*N octets where N is the number of
VLAN ranges given. The presence of this subTLV in the LSP for
an RBridge constitutes the ESADI participation flag for the
VLANs in the range or ranges given. An RBridge which does not
implement the ESADI feature may ignore this subTLV. Each 6
octets of value is structured as follows:
0 1-7 | 8-11| 12-23 |24-27| 28-39 | 40-47 |
+-+--------+-----+------------+-----+----------+------------+
|R|Priority| Res | VLAN start | Res | VLAN end |Holding Time|
+-+--------+-----+------------+-----+----------+------------+
The R bit and the two "Res" fields are reserved and MUST be
sent as zero and ignored on receipt. The Priority field gives
the RBridge's priority for being DRB on the TRILL EASDI
virtual links for the VLAN or VLANs indicated while the
Holding Time field gives its holding time if it is DRB. The
VLAN start and end values give the inclusive range of VLAN IDs
for which the RBridge wishes to participate in a TRILL ESADI.
A range of one VLAN is specified by making the start and end
IDs equal.
2.f VLAN Groups (subTLV Type #<tbd3.2.1f>). The value of this
optional subTLV consists of two or more 16-bit fields each of
which has a VLAN ID in the low order 12 bits. The top 4 bits
MUST be sent as zero and ignored on receipt. The first such
VLAN ID is the primary, or may be zero if there is no primary.
Address learning is shared between the listed VLANs at the
originating RBridges as described in Section 4.6.3 of
[RBRIDGE]. This subTLV may appear zero, one, or many times.
2.g VLAN Mapping (subTLV Type #<tbd3.2.1g>). The value of this
optional subTLV consists of 6*N octets where N is the number
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of VLAN mappings occuring at the cut set RBridge originating
the LSP [VLANmapping]. Each 6 octet subpart of the value is
structured as follows:
0-7 |8-11| 12-23 | 24-31 |32-35| 36-47 |
+-+----------+----+----------+------------+-----+----------+
| 1st Domain |Res | 1st VLAN | 2nd Domain | Res | 2nd VLAN |
+-+----------+----+----------+------------+-----+----------+
The numbering of the parts of the IETF compus (Domains)
between which VLAN mapping is occuring must be done
consistently by the administrator. The value indicates that
the 1st VLAN's ID in the 1st domain is being mapped to the 2nd
VLAN's ID in the 2nd domain. Since these mappings must be
symmetric, this implies that the 2nd VLAN's ID in the 2nd
domain is also being mapped to the 1st VLAN's ID in the 1st
domain. In other words, if makes no difference if the first 3
and last 3 octets in each 6-octet substring of the value are
swapped. This subTLV may appear zero, one, or many times.
Note: See Section 3.4 below for multicast groups.
3.2.2 TRILL ESADI LSP
The information in TRILL ESADI LSP PDUs consists of one or more MAC
Reachability (MAC-RI) TLVs [ISIS-L2] (Type #139). 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.
In order to support VLAN mapping, the TRILL EASDI LSP and any TLVs in
it, including theh MAC-RI TLV MUST NOT containg the VLAN ID. The VLAN
to which the TRILL ESADI LSP applies is indicated only by the VLAN
tag in the encapsulated TRILL ESADI IS-IS frame.
{{There is no place in the current MAC-Reachability TLV for the
confidence level. It could go where the VLAN ID currently is as the
VLAN ID is not needed for the TRILL use and, in fact, can't be used
if you want VLAN mapping to be practical. Alternatively, some option
bits and the confidence could be inserted before or after the VLAN ID
and the VLAN ID always set to zero.}}
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3.3 CSNP/PSNP and MGROUP CSNP/PSNP PDUs
CSNP stands for Complete Sequence Number Packet and PSNP for Partial
Sequence Number Packet. These relate to the IS-IS link state flooding
algorithm and link state sequence numbers. There is no change from
typical Layer-3 sequence number IS-IS PDUs except for the addition of
MGROUP CSNP and PSNP PDUs. TRILL IS-IS uses only Level 1 sequence
number packets.
3.4 MGROUP PDUs
MGROUP PDUs [ISIS-L2] are only sent as part of the core TRILL IS-IS
instance. They contain one or more Group Address (GADDR) TLVs each of
which, in turn, contains one or more Group MAC Address (GMAC-ADDR)
sub-TLVs. Those GMAC-ADDR sub-TLVs specify the VLAN involved and list
the IP-derived multicast addresses for which there are listeners on
links for which the originating RBridge is appointed forwarder.
(MGROUP PDUs must be in the core TRILL IS-IS, even if an optional
TRILL ESADI is in use for the relevant VLAN, so that transit RBridges
can properly prune the distribution of multicast frames.)
All TRILL MGROUP PDUs contain the TRILL Area Address TLV (see Section
4.2).
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4. TRILL IS-IS TLVs
This section describes particular TLVs included or not included in
TRILL IS-IS PDUs.
4.1 Port Capability TLV
The Port Capability TLV is used in TRILL IS-IS Hellos to announce a
variety of information specific to the port on which the Hello is
sent. It is TLV Type #tbd4.1. It's content is structured as subTLVs
in the same manner as in [RFC5305].
The Port Capability TLV appears only in IS-IS Hello PDUs
4.2 Area Address
The TRILL zero Area Address TLV is encoded as follows:
+--------------------------+--------------------------+
| 0x01 (Area Address Type | 0x02 (Length of Value) |
+--------------------------+--------------------------+
| 0x01 (Length of Address) | 0x00 (zero Area Address) |
+--------------------------+--------------------------+
4.3 Protocols Supported
Since no NLPID (Network Layer Protocol Identifier) has been allocated
by the ISO/IEC TR 9577 Registry for the Ethernet protocol or MAC-48
address type or TRILL, there is no way to indicate support of IS-IS
routing for these in a Protocols Supported TLV (TLV #129).
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5. Bridged LAN Link Costs
RBridges use IS-IS to support TRILL and may be interconnected by
direct links such as 802.3, or by bridged LANs. If there an
intervening bridge or bridges, the link is really multiple bridged
physical links. RBridges can automatically detect this condition
under some circumstances.
For loop avoidance purposes RBridges listen for BPDUs and keep track
of the most recent announced root bridge on a link [RBRIDGE], if any.
This bridge, or the fact that no BPDUs have been received, is
reported in the link state database as described in Section 3.2.1
above. It is still possible for RBridges to be connected by a
bridged LAN where the bridge ports to which they are connected have
been configured not to emit BPDUs. On the other hand, if any RBridge
connected to a link is seeing BPDUs, it is likely that there are one
or more intervening bridges between it and any RBridge on the link to
which it appears to be adjacent.
When a link is a bridged LAN, transit traffic will experience at
least two bridged physical links and possibly many more. To account
for this, RBridges SHOULD assume, for IS-IS routing purpose, that the
default metric for traversing such a link is 2*C + 1, where C is the
Layer-3 IS-IS default metric (usually auto-configured from port
speed).
More precise link cost can be asserted by management configuration.
D. Eastlake, R. Perlman, & D. Dutt [Page 15]
INTERNET-DRAFT RBridges: Use of IS-IS
6. IANA Considerations
IANA will allocate a TLV number for the new Port Capability TLV and
create a registry for subTLVs under the Port Capabilities TLV.
The Port Capabilities TLV is generally described in Section 4.1. Its
TLV number is <tbd4.1>(suggest 243). IANA Considerations for the
allocation of additional subTLVs under the Port Capability TLV are
Expert Approval except that subTLV Types 0 and 0xFF are Reserved and
require an IETF Standards Action for allocation.
In addition, seven new subTLVs will be allocated under the Router
Capabilities TLV as listed in Section 3.2.1 and listed below.
Port Capaiblities
subTLV Name Value
----------- -----
Special VLANs and Flags 10
Enabled VLANs 11
Appointed Forwarders 12
Router Capaiblities
subTLV Name Value
----------- -----
TRILL Flags <tbd3.2.1a>(suggest 21)
Nickname and Tree Root <tbd3.2.1b>(suggest 22)
Distribution Tree Roots <tbd3.2.1c>(suggest 23)
VLANs <tbd3.2.1d>(suggest 24)
ESADI Participation <tbd3.2.1e>(suggest 25)
VLAN Groups <tbd3.2.1f>(suggest 26)
VLAN Mapping <tbd3.2.1g>(suggest 27)
7. Security Considerations
This document raises no new security issues for IS-IS. IS-IS security
may be used to secure the IS-IS messages discussed here. See
[RFC5304]. See [RBRIDGE] for TRILL Security Considerations.
D. Eastlake, R. Perlman, & D. Dutt [Page 16]
INTERNET-DRAFT RBridges: Use of IS-IS
8. Normative References
[ISIS] "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, ISO/IEC 10589:1992.
[ISIS-L2] D. Ward et. al, "Carrying Attached Addresses in IS-IS",
draft-ward-l2isis-03.txt, work in progress, May 2008.
[RBRIDGE] R. Perlman et. al., "Rbridges: Base Protocol
Specification", draft-ietf-trill-rbridge-protocol-10.txt, work in
progress, July 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[VLANmapping] R. Perlman e.t al., "RBridge VLAN Mapping", draft-
perlman-trill-rbridge-vlan-mapping-00.txt, work in progress,
October 2008.
9. Informative References
[ISIS-MI] S. Previd et. al., "IS-IS Multi-instance", draft-ietf-isis-
mi-01.txt, work in progress, February 2008.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, October 2008..
D. Eastlake, R. Perlman, & D. Dutt [Page 17]
INTERNET-DRAFT RBridges: Use of IS-IS
Disclaimer
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OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
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OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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Copyright (C) The IETF Trust 2008. This document is subject to the
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set forth therein, the authors retain all their rights.
D. Eastlake, R. Perlman, & D. Dutt [Page 18]
INTERNET-DRAFT RBridges: Use of IS-IS
Author's Address
Donald E. Eastlake 3rd
Eastlake Enterprises
155 Beaver Street
Milford, MA 01757 USA
Phone: +1-508-634-2066
email: d3e3e3@gmail.com
Radia Perlman
Sun Microsystems
16 Network Circle
Menlo Park, CA 94025
Phone: +1-650-960-1300
Email: Radia.Perlman@sun.com
Dinesh G. Dutt
Cisco Systems
170 Tasman Drive
San Jose, CA 95134-1706 USA
Phone: +1-408-527-0955
email: ddutt@cisco.com
Expiration and File Name
This draft expires in May 2009.
Its file name is <draft-eastlake-trill-rbridge-isis-02.txt>.
D. Eastlake, R. Perlman, & D. Dutt [Page 19]
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