LSP extension for Tree Distribution Optimization across sites
draft-wu-trill-lsp-ext-tree-distr-opt-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Expired".
|
|
|---|---|---|---|
| Authors | Qin Wu , Hao Weiguo | ||
| Last updated | 2012-07-09 | ||
| RFC stream | (None) | ||
| Formats | |||
| Additional resources | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-wu-trill-lsp-ext-tree-distr-opt-00
Transparent Interconnection of Lots of Q. Wu
Links Working Group W. Hao
Internet-Draft Huawei
Updates: 6325 (if approved) July 9, 2012
Intended status: Standards Track
Expires: January 10, 2013
LSP extension for Tree Distribution Optimization across sites
draft-wu-trill-lsp-ext-tree-distr-opt-00
Abstract
This document specifies an extension to LSP for the Rbridge in one
site to advertise Global VLAN scope and associated link attribute to
all the Rbridges both in the site of that Border Rbridge and the
other adjacent sites in the same campus. With this extension,
RBridges can prune the distribution tree of multi-destination frames
according to the scope of the VLAN and link attribute defined in this
document.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on January 10, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
Wu & Hao Expires January 10, 2013 [Page 1]
Internet-Draft LSP extension for Distribution Tree July 2012
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions used in this document . . . . . . . . . . . . . . 4
3. TLV and Sub-TLV Extensions to IS-IS for Inter-site
Distribution Tree . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Global-VLANs Sub-TLV for the Router Capability TLV . . . . 5
3.1.1. Definition of Fields in Sub-TLV . . . . . . . . . . . 5
3.2. Link-Attributes Sub-TLV extension for extended IS
reachability TLV . . . . . . . . . . . . . . . . . . . . . 6
4. Use of TLV and Sub-TLV for Tree Distribution Optimization
within or across sites . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
Wu & Hao Expires January 10, 2013 [Page 2]
Internet-Draft LSP extension for Distribution Tree July 2012
1. Introduction
IS-IS was designed to be multilevel [IS-IS][RFC1195]. A trill Campus
network may also be designed to be multilevel, e.g., partition it
into multiple "sites" in 2-level. Routing between Rbridges within a
site is known as "Level 1 routing". Routing between sites is known
as "Level 2 routing". The Level 2 Trill site network with Level 2
routing support consists of Border Rbridges and links between the
Border Rbridges. Border Rbridges may participate in one or more
sites as Level-1 Rbridges inside each site, in addition to their role
as Level 2 Rbridge across sites.
In case of multiple sites within one Trill campus network, some
subset of traffic on a number of VLANs traverses across sites within
the TRILL campus while some subset of traffic belonging to a number
of other VLANs may be limited to only one site and not allowed to go
to other sites. In order to support scaling and performance of large
TRILL networks in the real deployments, it is more desirable to
forward Multi- destination traffic within the site and reduce the
traffic that is required to span across sites within the entire TRILL
campus.
The scope of global traffic may be identified either through VLAN or
link type that is used between Rbridges. When it is inevitable to
construct trees that have a scope across sites throughout the TRILL
campus, it is necessary to treat traffic based on VLAN scope and
distinct the link between Rbridge in one site and link between two
Border Rbridge in two sites to support large scale multi-tenants
application.
This document specifies an extension to LSP for the Rbridge in one
site to advertise Global VLAN scope and associated link attribute to
all the Rbridges both in the site of that Border Rbridge and the
other adjacent sites in the same campus. With this extension,
RBridges can prune the distribution tree of multi-destination frames
according to the scope of the VLAN and link attribute defined in this
document.
Wu & Hao Expires January 10, 2013 [Page 3]
Internet-Draft LSP extension for Distribution Tree July 2012
2. Conventions used in this document
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 [RFC2119].
Wu & Hao Expires January 10, 2013 [Page 4]
Internet-Draft LSP extension for Distribution Tree July 2012
3. TLV and Sub-TLV Extensions to IS-IS for Inter-site Distribution Tree
This section describes data formats and code points for the TLVs and
sub-TLVs added to IS-IS defined by this specification to support the
multi-level TRILL or re-used from that already contained in the
standard IS-IS extensions defined in [RFC6326].
3.1. Global-VLANs Sub-TLV for the Router Capability TLV
The optional Global-VLANs sub-TLV specifies the VLANs that have
global scope and enable Construction of global multi-destination
trees among different sites. It has the following format:
+-+-+-+-+-+-+-+-+
| Type | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | Start VLAN ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VLAN bit-map....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure
3.1.1. Definition of Fields in Sub-TLV
Type: 8bits
Router Capability sub-TLV type, set to TBD (GLOBAL-VLANs).
Length: 8bits
Variable, minimum 3.
RESV: 4bits
4 reserved bits that MUST be sent as zero and ignored on receipt.
Start VLAN ID:12bits
The 12-bit VLAN ID that is represented by the high order bit of
the first byte of the VLAN bit-map.
Wu & Hao Expires January 10, 2013 [Page 5]
Internet-Draft LSP extension for Distribution Tree July 2012
VLAN bit-map:
The highest order bit indicates the VLAN equal to the start VLAN
ID, the next highest bit indicates the VLAN equal to start VLAN ID
+ 1, continuing to the end of the VLAN bit-map field.
3.2. Link-Attributes Sub-TLV extension for extended IS reachability TLV
The link-attribute sub-TLV is carried within the TLV 22 and has a
format identical to the sub-TLV format used by the Traffic
Engineering Extensions for IS-IS ([RFC3784]): 1 octet of sub-type, 1
octet of length of the value field of the sub-TLV followed by the
value field -- in this case, a 16 bit flags field.
The Link-attribute sub-type is 19 and the link-attribute has a length
of 2 octets.
This sub-TLV is OPTIONAL and MUST appear at most once for a single IS
neighbor. If a received Link State Packet (LSP) contains more than
one Link-Attribute Sub-TLV, an implementation SHOULD decide to
consider only the first encountered instance. The following bit is
defined:
Public Link Type For TRILL(0x03) When set, this indicates that the
link is public link for TRILL sites interconnection.
Wu & Hao Expires January 10, 2013 [Page 6]
Internet-Draft LSP extension for Distribution Tree July 2012
4. Use of TLV and Sub-TLV for Tree Distribution Optimization within or
across sites
When the TRILL campus is divided into multiple sites, each site may
have one or more Border Rbridges used to interconnect other remaining
sites and form the Level 2 IS-IS Trill network which consists of
Level 2 Rbridges and links between the Level 2 Rbridges. Such Level2
IS-IS Trill network can be used to construct global multi-destination
tree spanning across various sites.
TRILL Site 1 TRILL Site 2
+-------------------+ +---------------+ +-------------------+
| | | | | |
| +---+ +----+ | | WAN | |+----+ +---+ |
| |RB1|------+BRB2| |--|L2 Connectivity|---||BRB3|-------|RB4| |
| +---+ +----+ | | | |+----+ +---+ |
| | | | | |
+-------------------+ +---------------+ +-------------------+
|
|
+-------------------+
| +----+ |
| |BRB5| |
| +----+ |
| +---+ | +---+ |
| |RB6|---+---|RB7| |
| +---+ +---+ |
+-------------------+
TRILL Site 3
Figure 1: Example of multiple sites within one Trill Campus
However in order to support scaling and performance of large TRILL
networks in the real deployments, firstly, not all the links between
the level 2 Rbridges need to be used to Construct global multi-
destination trees. If the link between the level 2 Rbridges is
allowed to construct global multi-destination trees, we can set this
link attribute into public interface for global tree construction.
In this document, we reuse Link Attribute sub-TLV for the extended IS
reachability TLV and allocate a new bit value inside link Attribute
Sub-TLV to support indication of public link for global tree
construction. The border Rbridge in one site need to advertise this
link attribute Sub-TLV to all the neighboring Border Rbridges in
other neighboring sites and then this sub-TLV will be further
forwarded to all the Rbridges in the site of each neighboring Border
Rbridge. RBridges in each site can prune the distribution tree of
multi- destination frames according to such link attribute.
Wu & Hao Expires January 10, 2013 [Page 7]
Internet-Draft LSP extension for Distribution Tree July 2012
Secondly, not all traffic should have global scope and need to span
across sites. Since each distribution tree SHOULD be pruned per VLAN
according to [RFC6325], we can use specified Global VLAN to identify
the traffic that has global scope. In this document, we define one
new sub-TLV for the Router Capability TLV, i.e., Global- VLANs Sub-
TLV. This Sub-TLV can be used by Rbriges in one site to determine
whether Construction of global multi-destination trees across sites
is allowed. In order to achieve this, the tree root or highest
priority RBridge in one site configured to know a number of
appropriate VLANs as Global VLANs and announce such information to
the nearest border Rbrige; Then such border Rbridge in this site need
to advertise Global VLAN Sub-TLV to all the neighboring Border
Rbridges in other neighboring sites and then this sub-TLV will be
further forwarded to all the Rbridges in the site of each neighboring
Border Rbridge. When Global VLAN and link attribute Sub-TLV
described above has been distributed to each Rbridges, RBridges can
prune the distribution tree of multi-destination frames according to
the scope of the VLAN and link attribute defined in this document,
eliminating branches that own link type mismatching with Distribution
Tree scope identified by VLAN. If the distribution tree is local
tree and there is a branch including a link with link attribute is
set to public link for global tree construction, such branch should
be eliminated. If the distribution tree is global tree and there is
one branch containing a link with link attribute not set to public
link for global tree construction, such branch also should be
eliminated.
Wu & Hao Expires January 10, 2013 [Page 8]
Internet-Draft LSP extension for Distribution Tree July 2012
+---+
| a |
+---+
L1 \ \ L2
\ \
\ \
+---+ +---+
| b | | c |
+---+ +---+
L3 \ \ L4
VLAN20 \ \
\ \
+---+ +---+
| d | | e |
+---+ +---+
_ _
_ _ \
public link _L5 _L6 \ L7
_ _ \
+---+ +---+ +---+
| f | | g | | h |
+---+ +---+ +---+
VLAN10 VLAN10 VLAN20
Figure 2: Distribution Tree
Take distribution tree in the Figure 2 as an example, Rbridge a is
root node. Rbridge f,g are leaf nodes that have end station on VLAN
10 while Rbridge b,h are another two leaf nodes and that have end
station on VLAN 20. The link between Rbridge d and f is public link
used across sites while the other links in the figure 2 are link owns
by one single site. Assume VLAN 10 are local VLAN and VLAN 20 are
Global VLAN, after distribution tree pruning is done, Rbrige c should
eliminate branch that has Rridge d and f since distribution tree is
pruned based on local VLAN 10 and Link 5 in that branch is public
link, which mismatch with each other.
Wu & Hao Expires January 10, 2013 [Page 9]
Internet-Draft LSP extension for Distribution Tree July 2012
5. IANA Considerations
IANA is requested to assign a new codepoint for the Global-VLANs Sub-
TLV defined in this document and carried within TLV 242.
IANA has created a registry for bit values inside the link-attributes
sub-TLV called "link-attribute bit values for sub-TLV 19 of TLV 22".
This document instructs IANA to add a new bit value in the link-
attribute bit values for sub-TLV 19 of TLV 22 registry as follows:
Value Name Reference
----- ---- ---------
0x3 Public Link Type between sites [This document]
Further values are to be allocated by the Standards Action process
defined in [RFC2434], with Early Allocation (defined in [RFC4020])
permitted.
Wu & Hao Expires January 10, 2013 [Page 10]
Internet-Draft LSP extension for Distribution Tree July 2012
6. Security Considerations
The security considerations documented in [RFC4971][RFC5305] are
applicable for the Sub-TLV extension defined in this document.
Wu & Hao Expires January 10, 2013 [Page 11]
Internet-Draft LSP extension for Distribution Tree July 2012
7. References
7.1. Normative References
[IS-IS] "Intermediate System to Intermediate System Intra-Domain
Routing Exchange Protocol for use in Conjunction with the
Protocol for Providing the Connectionless-mode Network
Service (ISO 8473)", ISO/IEC 10589:2002 Second Edition,
2002.
[RFC1195] Ohta, M., "Use of OSI IS-IS for routing in TCP/IP and dual
environments", December 1990.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 2434,
October 1998.
[RFC3784] Smit, H., "Intermediate System to Intermediate System
(IS-IS) Extensions for Traffic Engineering (TE)",
June 2004.
[RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", RFC 4020, February 2005.
[RFC4971] Vasseur, J., "Intermediate System to Intermediate System
(IS-IS) Extensions for Advertising Router Information",
July 2007.
[RFC5029] Vasseur, J. and S. Previdi, "SDP: Session Description
Protocol", September 2007.
[RFC5305] Li, T. and H. Smit, "S-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC6325] Perlman, R., Eastlake , 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.
Wu & Hao Expires January 10, 2013 [Page 12]
Internet-Draft LSP extension for Distribution Tree July 2012
7.2. Informative References
[TRILL-ML]
Perlman , R., Eastlake, D., Ghanwani, A., and H. Zhai,
"RBridges: Multilevel TRILL",
ID draft-perlman-trill-rbridge-multilevel-03,
October 2011.
Wu & Hao Expires January 10, 2013 [Page 13]
Internet-Draft LSP extension for Distribution Tree July 2012
Authors' Addresses
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Weiguo Hao
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: haoweiguo@huawei.com
Wu & Hao Expires January 10, 2013 [Page 14]