Internet DRAFT - draft-perlman-trill-smart-endnodes
draft-perlman-trill-smart-endnodes
TRILL WG Radia. Perlman
Internet-Draft Intel Labs
Intended status: Standards Track Fangwei. Hu
Expires: April 20, 2015 ZTE Corporation
Donald. Eastlake 3rd
Huawei technology
Kesava. Krupakaran
Dell
Ting. Liao
ZTE Corporation
October 17, 2014
TRILL Smart Endnodes
draft-perlman-trill-smart-endnodes-04.txt
Abstract
This draft addresses the problem of the size and freshness of the
endnode learning table in edge RBridges, by allowing endnodes to
volunteer for endnode learning and encapsulation/decapsulation. Such
an endnode is known as a "smart endnode". Only the attached RBridge
can distinguish a "smart endnode" from a "normal endnode". The smart
endnode uses the nickname of the attached RBridge, so this solution
does not consume extra nicknames. The solution also enables Fine
Grained Label aware endnodes.
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 April 20, 2015.
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Copyright Notice
Copyright (c) 2014 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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Smart-Hello Content . . . . . . . . . . . . . . . . . . . . . 4
3.1. Edge RBridge's Smart-Hello . . . . . . . . . . . . . . . 4
3.2. Smart Endnode's Smart-Hello . . . . . . . . . . . . . . . 5
4. Frame Processing . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Frame Processing for Smart Endnode . . . . . . . . . . . 6
4.2. Frame Processing for Edge RBridge . . . . . . . . . . . . 6
5. Multi-homing . . . . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. Normative References . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The IETF TRILL (Transparent Interconnection of Lots of Links)
protocol [RFC6325] provides optimal pair-wise data frame forwarding
without configuration, safe forwarding even during periods of
temporary loops, and support for multipathing of both unicast and
multicast traffic. TRILL accomplishes this by using IS-IS [IS-IS]
[RFC7176] link state routing and encapsulating traffic using a header
that includes a hop count. Devices that implement TRILL are called
"RBridges" (Routing Bridges) or TRILL Switches.
An RBridge that attaches to endnodes is called an "edge RBridge",
whereas one that exclusively forwards encapsulated frames is known as
a "transit RBridge". An edge RBridge traditionally is the one that
encapsulates a native Ethernet packet with a TRILL header, or that
receives a TRILL-encapsulated packet and decapsulates the TRILL
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header. To encapsulate efficiently, the edge RBridge must keep an
"endnode table" consisting of (MAC,Data Label, TRILL egress switch
nickname) sets, for those remote MAC addresses in Data Labels
currently communicating with endnodes to which the edge RBridge is
attached.
These table entries might be configured, received from ESADI
[RFC7357], looked up in a directory [RFC7067], or learned from
decapsulating received traffic. If the edge RBridge has attached
endnodes communicating with many remote endnodes, this table could
become large. Also, if one of the MAC addresses and Data Labels in
the table has moved to a different remote TRILL switch, it might be
difficult for the edge RBridge to notice this quickly, and because
the edge RBridge is encapsulting to the incorrect egress RBridge, the
traffic will get lost.
For these reasons, it is desirable for an endnode E (whether it is a
server, hypervisor, or VM) to maintain the endnode table for remote
endnodes that E is corresponding with. This eliminates the need for
the edge RBridge RBx, to which E is connected, to know about those
nodes (unless some non-smart endnode attached to RBx is also
corresponding with those nodes), Once D is unreachable for E, which
could be determined through ICMP messages or other techniques, the
smart endnode should delete the entry of (MAC, Data Label, nickname).
If D moves to a new place, E should attempt to acquire a fresh entry
for D by flooding to D, examining updates to the ESADI link state
database,or consulting a directory.
The mechanism in this draft is that E issue a Smart-Hello (even
though E is just an endnode), indicating E's desire to act as a smart
endnode, together with the set of MAC addresses and Data Labels that
E owns, and whether E would like to receive ESADI packets. E learns
from RBx's Smart-Hello, whether RBx is capable of having a smart
endnode neighbor, what RBx's nickname is, and which trees RBx can use
when RBx ingresses multi-destination frames. Although E transmits
Smart-Hellos, E does not transmit or receive LSPs or E-L1FS FS-
LSPs[I-D.eastlake-trill-rfc7180bis].
RBx will accept already-encapsulated TRILL Data packets from E
(perhaps verifying that the source MAC and Data Label is indeed one
of the ones that E owns, that the ingress RBridge field is RBx's, and
if the packet is an encapsulated multi-destination frame, the tree
selected is one of the ones that RBx has claimed it will choose).
When RBx receives (from the campus) a TRILL Data packet with RBx's
nickname as egress, RBx checks whether the destination MAC address
and Data Label in the inner packet is one of the MAC addresses and
Data Labels that E owns, and if so, RBx forwards the packet onto E's
port, keeping it encapsulated.
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Since a smart endnode can encapsulate TRILL Data frames, it can cause
the Inner.Lable to be a Fine Grained Label [RFC7172], thus this
method supports FGL aware endnodes.
2. Terminology
Edge RBridge: An RBridge providing endnode service on at least one of
its ports.
Data Label: VLAN or FGL.
ESADI: End Station Address Distribution Information [RFC7357].
FGL: Fine Grained Label [RFC7172].
IS-IS: Intermediate System to Intermediate System [IS-IS].
RBridge: Routing Bridge, an alternative name for a TRILL switch.
Smart endnode: An endnode that has the capability specified in this
document including learning and maintaining(MAC, Data Lable,
Nickname) entries and encapsulating/decapsulating TRILL frame.
Transit RBridge: An RBridge exclusively forwards encapsulated frames.
TRILL: Transparent Interconnection of Lots of Links [RFC6325].
TRILL switch: a device the implements the TRILL protocol; an
alternative term for an RBridge.
3. Smart-Hello Content
Suppose endnode E is attached to RBridge RBx. In order for E to act
as a smart endnode, both E and RBx have to be signaled. The logical
choice of frame to do this is Smart-Hello.
3.1. Edge RBridge's Smart-Hello
For smart endnode operation, RBx's Smart-Hello must contain the
following information:
o RBridge's nickname. The nickname sub-TLV (Specified in section
2.3.2 in [RFC7176])could be reused here, and TLV 242 (IS-IS router
capability) should be updated to be carried in Smart-Hello frame.
o Tree that RBx can use when ingressing multi-destination frames.
The Tree Identifiers Sub-TLV (Specified in section 2.3.4 in
[RFC7176]) could be reused here.
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o Smart endnode neighbor list. The TRILL Neighbor TLV (Specified in
section 2.5 in [RFC7176]) could be reused.
3.2. Smart Endnode's Smart-Hello
A new TLV (S-MAC TLV)is defined for smart endnode. If there are
several VLANs for that smart endnode, the TLV could be filled several
times in smart endnode's Smart-Hello.
+-+-+-+-+-+-+-+-+
| Type= S-MAC | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|E|F|RESV| VLAN/FGL Data Label | (2 bytes or 4 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (1) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (N) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 S-MAC TLV
o Type: S-MAC, the value is TBD.
o Length: Total number of bytes contained in the value field.
o E: one bit. If it sets to 1, which indicates that the endnode
should receive ESADI frames.
o F: one bit. If it sets to 1, which indicates that the endnode
supports FGL data label, otherwise, the VLAN/FGL Data Label
[RFC7172] field is the VLAN ID.
o RESV: 2 bits or 6 bits, is reserved for the future use. If VLAN/
FGL Data Label indicates the VLAN ID(or F flag sets to 0), the
RESV field is 2 bits length, otherwise it is 6 bits.
o VLAN/FGL Data Label: This carries a 12-bits VLAN identifier or
24-bits FGL Data Label that is valid for all subsequent MAC
addresses in this TLV, or the value zero if no VLAN/FGL data label
is specified.
o MAC(i): This is the 48-bit MAC address reachable in the Data Label
given from the IS that is announcing this TLV.
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4. Frame Processing
4.1. Frame Processing for Smart Endnode
Smart endnode E does not issue or receive LSPs or E-L1FS FS-LSPs or
calculate topology. E does the following:
o E maintains an endnode table of (MAC, Data Label, nickname)
entries of end nodes with which the smart endnode is
communicating. Entries in this table are populated the same way
that an edge RBridge populates the entries in its table:
* learning from (source, ingress) on packets it decapsulates.
* from ESADI[RFC7357].
* by querying a directory [RFC7067].
* by having some entries configured.
o When E wishes to transmit to unicast destination D, if (D,
nickname) is in E's endnode table, E encapsulates with ingress
nickname=RBx, egress nickname as indicated in D's table entry. If
D is unknown, D either queries a directory or encapsulates the
packet as a multi-destination frame, using one of the trees that
RBx has specified in RBx's Smart-Hello.
o When E wishes to transmit to a multicast or broadcast destination,
E encapsulates the packet using one of the trees that RBx has
specified.
The smart endnode E need not send Smart-Hellos as frequently as
normal RBridges. These Smart-Hellos could be periodically unicast to
the Appointed Forwarder RBx. In case RBx crashes and restarts, or
the DRB changes, and E receives the Smart-Hello without mentioning E,
then E SHOULD send a Smart-Hello immediately. If RBx is AF for any
of the VLANs that E claims, RBx MUST list E in its Smart-Hellos as a
smart endnode neighbor.
4.2. Frame Processing for Edge RBridge
The attached RBridge RBx does the following:
o If receiving an encapsulated unicast data frame from a port with a
smart endnode, with RBx's nickname as ingress, RBx forwards the
frame to the specified egress nickname, as with any encapsulated
frame. However, RBx MAY filter the encapsulation frame based on
the inner source MAC and Data Label as specified for the smart
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endnode. If the MAC (or Data Label) are not among the expected
set of the smart endnode, the frame would be dropped by the edge
RBridge.
o If receiving an mulit-destination TRILL Data packet from a port
with smart endnode, RBridge RBx forwards the TRILL encapsulation
to the TRILL campus based on the distribution tree. If there are
some normal endnodes (i.e, non-smart endnode) attached to RBridge
RBx, RBx should decapsulates the frame and sends the native frame
to these ports.
o When RBx receives a multicast frame from a remote RBridge, and the
exit ports includes hybrid endnodes, it should send two copies of
mulicast frames, one as native and the other as TRILL encapsulated
frame. When smart endnode receives the encapsulated frame, it
learns the remote (MAC, Data Label, Nickname) set, A smart
endnodes ignores any native data frames. The normal endnode
receives the native frame and learns the remote MAC address and
ignore the native frame. This transit solution may bring some
complex for the edge RBridge and waste network bandwidth, so it is
recommended to avoid the hybrid endnodes scenario by attaching the
smart endnodes and non-smart endnodes to different ports when
deployed. Another solution is that if there are one or more
endnodes on a link, the non-smart endnodes are ignored on a link;
but we can configure a port to support mixed links. The RBx only
sends TRILL encapsulated frame to the link in this situation.
5. Multi-homing
Now suppose E is attached to the TRILL campus in two places: to
RBridges RB1 and RB2. There are two ways for this to work:
(1) E can choose either RB1 or RB2's nickname, when encapsulating a
frame, whether the encapsulated frame is sent via RB1 or RB2.
If E wants to do active-active load splitting, and uses RB1's
nickname when forwarding through RB1, and RB2's nickname when
forwarding through RB2, which will cause the flip-floping of the
endnode table entry in the remote RBridges (or smart endnodes).
One solution is to set a multi-homing bit in the RESV field of
the TRILL data Frame. When remote RBs or smart endnodes receive
the data frame with the multi-homed bit set, the MAC entry (E,
RB1's nickname) and (E, RB2's nickname) will be coexist as two
entries for that MAC address. Another solution is to extend the
ESADI protocol to distribute multiple attachments of a MAC
address of a multi-homing group.(Please refer to the option C in
section 4 of [I-D.ietf-trill-aa-multi-attach] for details).
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(2) RB1 and RB2 might indicate, in their Smart-Hello, a virtual
nickname that attached end nodes may use if they are multihomed
to RB1 and RB2, separate from RB1 and RB2's nicknames (which
they would also list in their Smart-Hello). This would be
useful if there were many end nodes multihomed to the same set
of RBridges. This would be analogous to a pseudonode nickname;
return traffic would go via the shortest path from the source to
the endnode, whether it is RB1 or RB2. If E loses connectivity
to RB2, then E would revert to using RB1's nickname. In order
to avoid RPF check issue for multi-destination frame, the
affinity TLV [I-D.ietf-trill-cmt] is recommended to be used in
this solution.
6. Security Considerations
For general TRILL Security Considerations, see [RFC6325].
7. Acknowledgements
8. IANA Considerations
IANA is requested to allocate a S-MAC TLV identifier. TLV 242(ISIS
router capability) is required to updated to be carried by Smart-
Hello frame.
9. Normative References
[I-D.eastlake-trill-rfc7180bis]
Eastlake, D., Zhang, M., Perlman, R., Banerjee, A.,
Ghanwani, A., and S. Gupta, "TRILL: Clarifications,
Corrections, and Updates", draft-eastlake-trill-
rfc7180bis-00 (work in progress), October 2014.
[I-D.ietf-trill-aa-multi-attach]
Zhang, M., Perlman, R., Corporation, Z., Durrani, D.,
Shaikh, M., and S. Gupta, "TRILL Active-Active Edge Using
Multiple MAC Attachments", draft-ietf-trill-aa-multi-
attach-01 (work in progress), August 2014.
[I-D.ietf-trill-cmt]
Senevirathne, T., Pathangi, J., and J. Hudson,
"Coordinated Multicast Trees (CMT) for TRILL", draft-ietf-
trill-cmt-04 (work in progress), October 2014.
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[IS-IS] ISO/IEC 10589:2002, Second Edition,, "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)", 2002.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6165] Banerjee, A. and D. Ward, "Extensions to IS-IS for Layer-2
Systems", RFC 6165, April 2011.
[RFC6325] Perlman, R., Eastlake, D., Dutt, D., Gai, S., and A.
Ghanwani, "Routing Bridges (RBridges): Base Protocol
Specification", RFC 6325, July 2011.
[RFC7067] Dunbar, L., Eastlake, D., Perlman, R., and I. Gashinsky,
"Directory Assistance Problem and High-Level Design
Proposal", RFC 7067, November 2013.
[RFC7172] Eastlake, D., Zhang, M., Agarwal, P., Perlman, R., and D.
Dutt, "Transparent Interconnection of Lots of Links
(TRILL): Fine-Grained Labeling", RFC 7172, May 2014.
[RFC7176] Eastlake, D., Senevirathne, T., Ghanwani, A., Dutt, D.,
and A. Banerjee, "Transparent Interconnection of Lots of
Links (TRILL) Use of IS-IS", RFC 7176, May 2014.
[RFC7357] Zhai, H., Hu, F., Perlman, R., Eastlake, D., and O.
Stokes, "Transparent Interconnection of Lots of Links
(TRILL): End Station Address Distribution Information
(ESADI) Protocol", RFC 7357, September 2014.
Authors' Addresses
Radia Perlman
Intel Labs
2200 Mission College Blvd.
Santa Clara, CA 95054-1549
USA
Phone: +1-408-765-8080
Email: Radia@alum.mit.edu
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Fangwei Hu
ZTE Corporation
No.889 Bibo Rd
Shanghai 201203
China
Phone: +86 21 68896273
Email: hu.fangwei@zte.com.cn
Donald Eastlake,3rd
Huawei technology
155 Beaver Street
Milford, MA 01757
USA
Phone: +1-508-634-2066
Email: d3e3e3@gmail.com
Kesava Vijaya Krupakaran
Dell
Olympia Technology Park
Guindy Chennai 600 032
India
Phone: +91 44 4220 8496
Email: Kesava_Vijaya_Krupak@Dell.com
Ting Liao
ZTE Corporation
No.50 Ruanjian Ave.
Nanjing, Jiangsu 210012
China
Phone: +86 25 88014227
Email: liao.ting@zte.com.cn
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