TRILL Working Group Donald Eastlake INTERNET-DRAFT Mingui Zhang Intended status: Proposed Standard Huawei Updates: 6325 Puneet Agarwal Broadcom Dinesh Dutt Cisco Radia Perlman Intel Labs Expires: June 7, 2012 December 8, 2011 TRILL: Fine-Grained Labeling Abstract The IETF has standardized TRILL (TRansparent Interconnection of Lots of Links), a protocol for least cost transparent frame routing in multi-hop networks with arbitrary topologies and link technologies, using link-state routing and encapsulation with a hop count. The TRILL base protocol standard supports labeling of TRILL data with up to 4K IDs. However, there are applications that require more fine- grained labeling of data. This document updates RFC 6325 by specifying extensions to the TRILL base protocol to accomplish this. 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. 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. 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 D. Eastlake, et al [Page 1] INTERNET-DRAFT TRILL: Fine-Grained Labeling Table of Contents 1. Introduction............................................3 1.1 Terminology............................................3 2. Fine-Grained Labeling...................................4 2.1 Requirements...........................................4 2.2 Base Protocol TRILL Data Labeling......................5 2.3 Fine-Grained Labeling (FGL)............................5 3. Campus Wide VL versus FGL Semantic Differences..........7 4. Coexistence with VL TRILL Switches......................8 4.1 VL Specifiable Data Labels.............................8 5. Fine-Grained Labeling Details..........................10 5.1 Ingress Processing....................................10 5.2 Transit Processing....................................11 5.2.1 Unicast Transit Processing..........................11 5.2.2 Multi-Destination Transit Processing................11 5.3 Egress Processing.....................................12 5.4 Appointed Forwarders and the DRB......................13 5.5 Address Learning......................................13 5.6 ESADI Extensions......................................13 6. IS-IS Extensions.......................................14 7. Comparison to Requirements.............................15 8. Allocation Considerations..............................16 8.1 IEEE Allocation Considerations........................16 8.2 IANA Considerations...................................16 9. Security Considerations................................17 Acknowledgements..........................................17 Normative References......................................18 Informative References....................................18 D. Eastlake, et al [Page 2] INTERNET-DRAFT TRILL: Fine-Grained Labeling 1. Introduction The IETF has standardized the TRILL (TRansparent Interconnection of Lots of Links) protocol [RFC6325]. TRILL switches provide a solution for least cost transparent frame routing in multi-hop networks with arbitrary topologies and link technologies, using [IS-IS] [RFC6165] [RFC6326bis] link-state routing and encapsulation with a hop count. They address the problems outlined in [RFC5556]. TRILL switches are sometimes called RBridges (Routing Bridges). The TRILL base protocol standard supports labeling of TRILL data with up to 4K IDs. However, there are applications that require more fine- grained labeling of data for configurable isolation based on different service instances, tenants, or the like. This document updates [RFC6325] by specifying extensions to the TRILL base protocol to accomplish this. Familiarity with [RFC6325] and [RFC6326bis] is assumed in this document. 1.1 Terminology The terminology and acronyms of [RFC6325] are used in this document with the additions listed below. DEI - Drop Eligibility Indicator [802.1Q] FGL - Fine-Grained Labeling or Fine-Grained Labeled or Fine- Grained Label FGL RBridge - A TRILL switch that support both FGL and VL Edge RBridge - A TRILL switch announcing VL or FGL connectivity in its LSP TRILL Switch - Alternative name for an RBridge VL - VLAN Labeling or VLAN Labeled or VLAN Label VL RBridge - A TRILL switch that support VL but does not support FGL 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]. D. Eastlake, et al [Page 3] INTERNET-DRAFT TRILL: Fine-Grained Labeling 2. Fine-Grained Labeling The essence of Fine-Grained Labeling (FGL) is that (a) when TRILL Data frames are ingressed or created they may incorporate a label from a set of significantly more than 4K labels, (b) TRILL switch ports can be labeled with a set of such labels, and (c) an FGL TRILL Data frame cannot be egressed through a TRILL switch port unless its fine-grained label (FGL) matches one of the labels of the port. Section 2.1 lists FGL requirements. Section 2.2 briefly outlines the more coarse TRILL base protocol standard [RFC6325] data labeling. And Section 2.3 outlines a method of FGL of TRILL Data frames. 2.1 Requirements There are several requirements that should be met by FGL in TRILL. They are briefly described in the list below in approximate order by priority with the most important first. 1. Fine-Grained Some networks have a large number of entities that need configurable isolation, whether those entities are independent customers, applications, or branches of a single endeavor or some combination of these or other entities. The labeling supported by [RFC6325] provides for only ( 2**12 - 2 ) valid identifiers or labels. A substantially larger number is required. 2. Silicon Considerations Fine-grained labeling (FGL) should, to the extent practical, use existing features, processing, and fields that are already supported in at least some TRILL fast path silicon implementations. 3. Base RBridge Compatibility To support some incremental conversion scenarios, it is desirable that not all RBridges in a campus using FGL be required to be FGL aware. That is, it is desirable that RBridges not implementing the FGL feature and performing at least the transit forwarding function can usefully process TRILL Data frames that incorporate FGL. 4. Alternate Priority It would be desirable for an ingress TRILL Switch to be able to assign a different priority to an FGL TRILL Data frame for its D. Eastlake, et al [Page 4] INTERNET-DRAFT TRILL: Fine-Grained Labeling ingress-to-egress propagation from the priority of the original native frame. The original priority should be restored on egress. 2.2 Base Protocol TRILL Data Labeling This section provides a brief review of the [RFC6325] TRILL Data frame internal VL Labeling and changes the description of the TRILL Header by moving its end point. This description change does not involve any change in the bits on the wire or in the behavior of existing [RFC6325] RBridges. Currently TRILL Data frames have the VL structure shown below: +-------------------------------------------+ | Link Header (depends on link technology) | | (may include VLAN tag if an Ethernet link)| +-------------------------------------------+ | TRILL Header | | +---------------------------------------+ | | | Initial Fields and Options | | | +---------------------------------------+ | | | Inner.MacDA | (6 bytes) | | +-----------------------------+ | | | Inner.MacSA | (6 bytes) | | +-----------------------------+ | | | EtherType 0x8100 | (2 bytes) | | +-------------------------+ | | | Inner.VLAN Label | (2 bytes) | | +-------------------------+ | +-------------------------------------------+ | Native Payload | +-------------------------------------------+ | Link Trailer (depends on link technology) | +-------------------------------------------+ As specified in [RFC6325] the 0x8100 value is always present and is followed by the Inner.VLAN field which includes the 12-bit VLAN label. 2.3 Fine-Grained Labeling (FGL) FGL expands the data label available under the TRILL base protocol standard to a 24-bit fine-grained label. In this document, FGLs are usually denoted as "(X.Y)" where X is the high order half and Y is the low order half of the FGL. The FGL information appears in the TRILL Header as shown below. D. Eastlake, et al [Page 5] INTERNET-DRAFT TRILL: Fine-Grained Labeling +-------------------------------------------+ | Link Header (depends on link technology) | | (may include VLAN tag if an Ethernet link)| +-------------------------------------------+ | TRILL Header | | +---------------------------------------+ | | | Initial Fields and Options | | | +---------------------------------------+ | | | Inner.MacDA | (6 bytes) | | +-----------------------------+ | | | Inner.MacSA | (6 bytes) | | +-----------------------------+ | | | EtherType 0x8100 | (2 bytes) | | +-------------------------+ | | | Inner.Label First Part | (2 bytes) | | +-------------------------+ | | | EtherType 0x893B | (2 bytes) | | +-------------------------+ | | | Inner.Label Second Part | (2 bytes) | | +-------------------------+ | +-------------------------------------------+ | Native Payload | +-------------------------------------------+ | Link Trailer (depends on link technology) | +-------------------------------------------+ The fixed format area of the TRILL Header with the Inner.Label and EtherType fields 0x8100 and 0x893B is mandatory for FGL frames. It is designed for backward compatibility with IETF standard [RFC6325] conformant RBridges although such RBridges will only be aware of the most significant 12-bits of the FGL. The two bytes following the EX-TAG EtherType 0x893B have, in their low order 12 bits, the low order part of the fine-grained label. The upper 4 bits of those two bytes are used for a 3-bit priority field and one drop eligibility indicator (DEI) bit. The priority field of the Inner.Label First Part is the priority used for frame transport from ingress to egress. The appropriate FGL value for an ingressed native frame is determined by the ingress RBridge port as specified in Section 5.1. Ports of TRILL switches supporting FGL also have capabilities to transmit frames being forwarded or egressed as untagged or VLAN tagged as specified in Section 5.3. D. Eastlake, et al [Page 6] INTERNET-DRAFT TRILL: Fine-Grained Labeling 3. Campus Wide VL versus FGL Semantic Differences There are significant differences between the semantics across a campus for VLs and FGLs of TRILL Data frames. With VL, data label IDs have the same meaning throughout the campus and are from the same label space as the VLAN IDs used on Ethernet links to end stations. With TRILL FGL, many things remain the same. Ports of FGL TRILL switches, at and below the EISS (Extended Internal Sublayer Service) interface, act as they do for VL RBridges: Ethernet links still have C-VLAN tagging on them and the EISS of TRILL switch ports provide a VLAN ID for an incoming frame and accept a VLAN ID for a frame being queued for output. Appointed Forwarders [RFC6439] on a link are still appointed for a C-VLAN. The Designated VLAN for a link is a C-VLAN. The larger FGL space is a different flat space from the VL data label space. For ports configured for FGL, the C-VLAN on an ingressed native frame is mapped to the FGL data label space with a potentially different mapping for each port. A similar FGL to C-VLAN mapping occurs on egress. Thus, for ports configured for FGL, the native frame C-VLAN on one link corresponding to an FGL can be different from the native frame C-VLAN corresponding to that same FGL on a different link elsewhere in the campus or even a different link attached to the same RBridge. The FGL label space is flat and does not hierarchically encode any particular number of native frame C- VLAN bits or the like. FGLs in TRILL Data frames appear only inside the payload after the TRILL EtherType. As a result, they are only seen by TRILL aware devices. FGL RBridge ports can be configured for FGL or VL with VL being the default. As with a base protocol [RFC6325] RBridge, by default an FGL TRILL switch port reports an untagged frame it receives as being in VLAN 1. D. Eastlake, et al [Page 7] INTERNET-DRAFT TRILL: Fine-Grained Labeling 4. Coexistence with VL TRILL Switches Unmodified VL RBridges will operate properly as transit TRILL switches. Transit TRILL switches look at the VL or FGL data labeling only for the filtering of multi-destination frames. If an RBridge does not perform filtering, or filters on only part of the fields in the packet, the only consequence is that multi-destination frames will use more bandwidth than necessary. VL RBridges would only look at the high order X of the (X.Y) FGL, which are in the position where a VL RBridge would expect to find a VL data label. Thus they will not be able to prune as effectively as transit FGL TRILL switches could because they will ignore the lower order half of the FGL. (Transit RBridge that fully support FGL can, of course, prune on the full FGL.) To avoid potential problems with VL RBridges, the high order X of an (X.Y) FGL MUST NOT be zero or 0xFFF. It would be more serious if a VL edge RBridge, RB1, unaware of FGL, forwarded an FGL frame with FGL (X.Y) onto a link through an RB1 port configured as VL VLAN-X. VL RB1 would strip the TRILL Header only through the Inner.Label First Part and forward the packet with the Inner.Label Second Part and preceding 0x893B field still present. This might cause other problems on the link. It would also be problematic if a malicious end station could forge an apparent FGL (X.Y) frame by including extra fields in native frames ingressed by a VL edge RBridge. Therefore, it is highly desirable for all the edge RBridges to be FGL TRILL switches. FGL RBridge will report the FGL capability in LSPs, so FGL RBridges (and any management system with access to the link state database) will be able to detect the existence of VL edge RBridges. 4.1 VL Specifiable Data Labels It might be useful, in a particular campus with mixed VL and FGL TRILL switches, to have some end station VLANs accessible via VL edge RBridges. This is supported by reserving some number of VLANs (say the first k), to be VL-addressable. These VLANs will be specified with a VL data label, whether or not any of the edge TRILL switches attached to these end station VLANs are FGL-capable. When VL- specifiable VLANs are used in a FGL campus the upper half of an FGL MUST NOT be equal to the value of any VL-specifiable data label. If this rule is violated, the network misconfiguration is detected by the FGL TRILL switches that will then refuse in ingress to or egress from label (X.Y) while end station VLAN X connectivity is VL- specifiable as described below. D. Eastlake, et al [Page 8] INTERNET-DRAFT TRILL: Fine-Grained Labeling To avoid FGL frames getting pruned by VL RBridges, an FGL RBridge that ingresses to or egresses from (X.Y) MUST advertise in its LSP that it is connected to VLAN X. To avoid confusion, it is necessary to distinguish whether a TRILL switch is advertising VL-specifiable connectivity to VLAN X or just advertising such connectivity to avoid incorrect VL RBridge pruning. A VL data label X is VL-specifiable in a campus if either of the following two conditions apply: 1. A VL RBridge advertises connectivity to VLAN-X. 2. An FGL RBridge advertises connectivity to VLAN-X but does not advertise connectivity to FGL (X.Y) for any Y. D. Eastlake, et al [Page 9] INTERNET-DRAFT TRILL: Fine-Grained Labeling 5. Fine-Grained Labeling Details This section specifies ingress, transit, egress, and other processing of TRILL Data frames with regard to Fine-Grained Labels (FGLs). A transit or egress FGL TRILL switch detects FGL TRILL Data frames by noticing that the Inner.Label First Part is not a VL-specifiable data label (see Section 4.1). 5.1 Ingress Processing An FGL RBridge may be configured, on one or more ports, to FGL ingress native frames. There is no change in VL ingress processing, which is the default unless a port has been configured for FGL, and no change in Appointed Forwarder logic (see Section 5.4). FGL TRILL switches MUST support configurable per port mapping from the C-VLAN ID of a native frame, as reported by the ingress port, to a 24-bit fine-grained label. FGL TRILL switches MAY support other methods to determine the FGL of an incoming native frame, such as based on the protocol of the native frame. If the resulting label (X.Y) is such that X is a VL-specifiable data label, the ingressed frame MUST be dropped. The FGL ingress process MUST place the priority and DEI associated with an ingressed native frame in upper 4 bits of the second Inner.Label part. It SHOULD also associate a possibly different mapped priority and DEI with an ingressed frame. The mapped priority is placed in the Inner.Label First Part. If such mapping is not supported then the original priority and DEI MUST be placed in the Inner.Label First Part. An FGL ingress RBridge MAY serially TRILL unicast a multi-destination TRILL Data frame to the relevant egress TRILL switches, if those egress RBridges are all FGL, after encapsulating it as a TRILL known unicast data frame (M=0) and SHOULD so unicast such a multi- destination TRILL Data frame if there is only one relevant egress FGL RBridge. For FGL RBridges, this permits serial unicast of multi- destination frames by the ingress as an alternative to the use of a distribution tree. The relevant egress TRILL switches are determined by starting with those announcing connectivity to the frame's (X.Y) label. That set SHOULD be further filtered based on multicast listener and router connectivity if the native frame was a multicast frame. Use of S-tags is beyond the scope of this document but is an obvious extension. D. Eastlake, et al [Page 10] INTERNET-DRAFT TRILL: Fine-Grained Labeling 5.2 Transit Processing TRILL Data frame transit processing is fairly straightforward as described in Section 5.2.1 for known unicast TRILL Data frames and in Section 5.2.2 for multi-destination TRILL Data frames. 5.2.1 Unicast Transit Processing There is almost no change in TRILL Data frame unicast transit processing. A transit TRILL switch forwards any unicast TRILL Data frame to the next hop towards the egress RBridge as specified in the TRILL Header. Just as transit RBridges conformant to the TRILL base protocol standard [RFC6325] do not examine the VL of unicast TRILL Data frames, transit FGL RBridges do not examine the FGL of unicast TRILL Data frames. All transit TRILL switches, whether VL or FGL, MUST take the priority and DEI used to forward a frame from the Inner.VLAN label or the FGL Inner.Label First Part. These bits are in the same relative position for VL and FGL frames so VL RBridges will do this automatically even though they do not fully understand FGL frames. 5.2.2 Multi-Destination Transit Processing Multi-destination TRILL Data frames are forwarded on a distribution tree selected by the ingress TRILL switch except that an FGL ingress RBridge MAY choose to TRILL unicast such a frame to all relevant egress TRILL switches if they are all support FGL. The distribution trees for FGL and VL multi-destination frames are the same and are calculated as provided for in the TRILL base protocol standard [RFC6325]. There is no change in the Reverse Path Forwarding Check. An FGL RBridge, say RB1, having an FGL multi-destination frame for label (X.Y) to forward on a distribution tree, SHOULD prune based on whether there are any edge TRILL switches on the tree branch that are connected to label (X.Y). In addition, RB1 SHOULD prune multicast frames based on reported multicast listener and multicast router attachment in (X.Y). Finally, a transit FGL RBridge MAY drop any multi-destination frame for label (X.Y) if X is VL-specifiable (see Section 4.1). "MAY" is chosen in this case to minimize the checking burden on transit TRILL switches. To ensure that a transit VL RBridge does not falsely filter traffic for FGL (X.Y), an FGL edge RBridge attached to FGL (X.Y) MUST report connection to VLAN X in addition to reporting connectivity to label (X.Y). Because of this, VL transit RBridges can safely apply pruning D. Eastlake, et al [Page 11] INTERNET-DRAFT TRILL: Fine-Grained Labeling to all TRILL Data frames, both VL and FGL, based on the reported VLAN-X connectivity of all downstream TRILL switches. To ensure that a transit VL RBridge does not falsely prune traffic for FGL (X.Y) base on multicast filtering, an FGL edge RBridge attached to label (X.Y) MUST also report for VLAN-X either (1) that it is attached to both IPv4 and IPv6 multicast routers or (2) its merged FGL (X.Y) multicast listener and router connectivity for all Y. 5.3 Egress Processing Egress processing is generally the reverse of ingress progressing described in Section 5.1. If X is VL-specifiable (see Section 4.1), an FGL RBridge MUST NOT egress a frame with FGL (X.Y) but MUST drop such a frame. An FGL RBridge MUST be able to configurably convert the 24-bit fine grained label in an FGL TRILL Data frame it is egressing to a C-VLAN ID for the resulting native frame on a per port basis. A port MAY be configured to strip output VLAN tagging. It is the responsibility of the network manager to properly configure the TRILL switches and ports in the campus to obtain the desired mappings. The priority and DEI of the egressed native frame are taken from the Inner.Label Second Part. An FGL RBridge egresses FGL frames similarly to the egressing of VL frames, as follows: 1. A known unicast FGL frame is egressed to the FGL port matching its fine-grained label and Inner.MacDA. If there is no such port, it is flooded out all FGL ports that have its fine-grained label unless the TRILL switch has knowledge that the frames Inner.MacDA cannot be out that port. 2. A multi-destination FGL frame is decapsulated and flooded out all ports with its fine-grained label, subject to multicast pruning. FGL RBridges MUST accept multi-destination encapsulated frames that are sent to them as TRILL unicast frames, that is, frames with a multicast or broadcast Inner.MacDA and the TRILL Header M bit = 0. They locally egress such frames, if appropriate, but MUST NOT forward them (other than egressing them as native frames on their local links). Use of S-tags is beyond the scope of this document but is an obvious D. Eastlake, et al [Page 12] INTERNET-DRAFT TRILL: Fine-Grained Labeling extension. 5.4 Appointed Forwarders and the DRB There is no change in Adjacency [RFC6327] or Appointed Forwarder logic [RFC6439] on a link regardless of whether some or all the ports on the link are for FGL RBridges. However, if it is intended for native frames on a link in some VLAN-X to be ingressed and egressed with FGL, the Appointed Forwarder for VLAN-X for that link obviously MUST be an FGL RBridge. If there are FGL and VL TRILL switches connected to a link, it may be best if the priorities are configured so that the DRB is an FGL RBridge. However, there is no inherent difficulty in a VL DRB RBridge appointing an FGL TRILL switch connected to the link as Appointed Forwarder for whatever VLANs are appropriate. 5.5 Address Learning An FGL RBridge learns addresses on FGL ports based on the fine- grained label rather than the native frame's VLAN. Addresses learned from ingressed native frames on FGL ports are logically represented by { MAC address, fine-grained label, port, confidence, timer } while remote addresses learned from egressing FGL frames are logically represented by { MAC address, fine-grained label, remote TRILL switch nickname, confidence, timer }. 5.6 ESADI Extensions The TRILL ESADI (End Station Address Distribution Information) protocol is specified in [RFC6325] as optionally transmitting MAC address connection information through TRILL Data frames between participating TRILL switches over the virtual link provided by the TRILL multicast frame distribution mechanism. In [RFC6325], the VLAN to which an ESADI frame applies is indicated only by the Inner.VLAN label and no indication of that VLAN is allowed within the ESADI payload. ESADI is extended to support FGL by providing for the indication of the FGL to which an ESADI frame applies only in the Inner.Label of that frame and no indication of that FGL is allowed within the ESADI payload. D. Eastlake, et al [Page 13] INTERNET-DRAFT TRILL: Fine-Grained Labeling 6. IS-IS Extensions Extensions to the TRILL use of IS-IS are required to support the following: 1. An method for a TRILL switch to announce itself in its LSP as supporting FGL. 2. A sub-TLV analogous to Interested VLANs and Spanning Tree Roots sub-TLV of the Router Capabilities TLV but indicating FGLs rather than VLANs. 3. A sub-TLV analogous to the GMAC-ADDR sub-TLV of the Group Address TLV that specifies a FGL rather than a VLAN. See [RFC6326bis] and Section 8.2. D. Eastlake, et al [Page 14] INTERNET-DRAFT TRILL: Fine-Grained Labeling 7. Comparison to Requirements Comparing TRILL fine-grained labeling (FGL), as specified in this document, with the requirements given in Section 2.1, we find they are met as follows: 1. Fine-Grained: FGL provides approaching 2**24 labels, vastly more labels than the 4K inner TRILL data labels provided in [RFC6325]. 2. Silicon Considerations: Existing TRILL fast path silicon chips can, almost by definition, perform base TRILL Header insertion and removal to support ingress and egress. In addition, it is believed that most such silicon chips can also perform the native frame C- VLAN and port to fine-grained label mapping and the encoding of the fine-grained label as specified herein, as well as the inverse decoding and mapping. Some existing silicon can perform only one of these operations on a frame in the fast path and is thus not suitable to implement fast path TRILL FGL processing; however, other existing chips are believed to be able to perform both operations on the same frame in the fast path and are suitable for FGL implementation. 3. Base RBridge Compatibility: As described in Section 3, FGL is compatible with base specification (VL) RBridges [RFC6325] acting as transit TRILL switches and, as described in Section 5.4, there is no particular problem in mixing VL and FGL TRILL switches on the same link. 4. Alternate Priority: The encoding specified in Section 2.3 provides for a new priority and DEI in the Inner.Label First Part and a place to preserve the original user priority and DEI in the Second Part, so it can be restored on egress. D. Eastlake, et al [Page 15] INTERNET-DRAFT TRILL: Fine-Grained Labeling 8. Allocation Considerations Allocations by the IEEE Registration Authority and IANA are listed below. 8.1 IEEE Allocation Considerations The IEEE Registration Authority has assigned EtherType 0x893B for use as the EX-TAG EtherType. 8.2 IANA Considerations IANA is requested to allocate capability bit TBD (0 recommended) in the TRILL-VER sub-TLV capability bits [RFC6326bis] to indicate an RBridge is FGL-capable. D. Eastlake, et al [Page 16] INTERNET-DRAFT TRILL: Fine-Grained Labeling 9. Security Considerations See [RFC6325] for general RBridge Security Considerations. As with any communications system, end-to-end encryption and authentication should be considered for sensitive data. Confusion between a frame with VL X and FGL (X.Y) is a potential problem: 1. A TRILL Data frame with FGL (X.Y) could be egressed to an end station in VLAN-X by a VL RBridge that is Appointed Forwarder for VLAN-X on one of its ports. This is solved by prohibiting FGL RBridges from ingressing to FGL (X.Y) if the campus is configured so that VLAN-X is VL-specifiable (see Section 4.1). 2. An end station could try to forge FGL (X.Y) frames by sending frames with an EX-TAG Y at the front to a VL RBridge port where the frame would be input as being in VLAN-X. This is solved by prohibiting egress from FGL (X.Y) while VLAN-X is VL-specifiable (see Section 4.1). Acknowledgements The comments and contributions of the following are gratefully acknowledged: Anoop Ghanwani, Sujay Gupta, Weiguo Hao, Jon Hudson, Yizhou Li, Vishwas Manral, Erik Nordmark, Tissa Senevirathne, and Ilya Varlashkin. The document was prepared in raw nroff. All macros used were defined within the source file. D. Eastlake, et al [Page 17] INTERNET-DRAFT TRILL: Fine-Grained Labeling Normative References [IS-IS] - ISO/IEC 10589:2002, Second Edition, "Intermediate System to Intermediate System Intra-Domain Routeing Exchange Protocol for use in Conjunction with the Protocol for Providing the Connectionless-mode Network Service (ISO 8473)", 2002. [802.1Q] - IEEE 802.1, "IEEE Standard for Local and metropolitan area networks - Virtual Bridged Local Area Networks", IEEE Std 802.1Q-2011, May 2011. [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A. Ghanwani, "Routing Bridges (RBridges): Base Protocol Specification", RFC 6325, July 2011. [RFC6326bis] - Eastlake, D., Banerjee, A., Dutt, D., Perlman, R., and A. Ghanwani, "Transparent Interconnection of Lots of Links (TRILL) Use of IS-IS", draft-eastlake-isis-rfc6326bis-01.txt, work in progress. Informative References [RFC5556] - Touch, J. and R. Perlman, "Transparent Interconnection of Lots of Links (TRILL): Problem and Applicability Statement", RFC 5556, May 2009. [RFC6165] - Banerjee, A. and D. Ward, "Extensions to IS-IS for Layer-2 Systems", RFC 6165, April 2011. [RFC6327] - Eastlake 3rd, D., Perlman, R., Ghanwani, A., Dutt, D., and V. Manral, "Routing Bridges (RBridges): Adjacency", RFC 6327, July 2011 [RFC6439] - Perlman, R., Eastlake, D., Li, Y., Banerjee, A., and F. Hu, "Routing Bridges (RBridges): Appointed Forwarders", RFC 6439, November 2011. D. Eastlake, et al [Page 18] INTERNET-DRAFT TRILL: Fine-Grained Labeling Authors' Addresses Donald Eastlake 3rd Huawei Technologies 155 Beaver Street Milford, MA 01757 USA Phone: +1-508-333-2270 Email: d3e3e3@gmail.com Mingui Zhang Huawei Technologies Co.,Ltd Huawei Building, No.156 Beiqing Rd. Z-park ,Shi-Chuang-Ke-Ji-Shi-Fan-Yuan,Hai-Dian District, Beijing 100095 P.R. China Email: zhangmingui@huawei.com Puneet Agarwal Broadcom Corporation 3151 Zanker Road San Jose, CA 95134 USA Phone: +1-949-926-5000 Email: pagarwal@broadcom.com Dinesh G. Dutt Cisco Systems 170 Tasman Drive San Jose, CA 95134-1706 USA Phone: +1-408-527-0955 Email: ddutt@cisco.com Radia Perlman Intel Labs 2200 Mission College Blvd. Santa Clara, CA 95054 USA Phone: +1-408-765-8080 Email: Radia@alum.mit.edu D. Eastlake, et al [Page 19] INTERNET-DRAFT TRILL: Fine-Grained Labeling Copyright, Disclaimer, and Additional IPR Provisions Copyright (c) 2011 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 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. The definitive version of an IETF Document is that published by, or under the auspices of, the IETF. Versions of IETF Documents that are published by third parties, including those that are translated into other languages, should not be considered to be definitive versions of IETF Documents. The definitive version of these Legal Provisions is that published by, or under the auspices of, the IETF. Versions of these Legal Provisions that are published by third parties, including those that are translated into other languages, should not be considered to be definitive versions of these Legal Provisions. For the avoidance of doubt, each Contributor to the IETF Standards Process licenses each Contribution that he or she makes as part of the IETF Standards Process to the IETF Trust pursuant to the provisions of RFC 5378. No language to the contrary, or terms, conditions or rights that differ from or are inconsistent with the rights and licenses granted under RFC 5378, shall have any effect and shall be null and void, whether published or posted by such Contributor, or included with or in such Contribution. D. Eastlake, et al [Page 20]