TRILL Working Group Weiguo Hao INTERNET-DRAFT Donald Eastlake Intended status: Proposed Standard Yizhou Li Huawei Mohammed Umair Cisco Expires: September 13, 2018 March 14, 2018 TRILL (TRansparent Interconnection of Lots of Links): Address Flush Message Abstract The TRILL (TRansparent Interconnection of Lots of Links) protocol, by default, learns end station addresses from observing the data plane. In particular, it learns local MAC addresses and edge switch port of attachment from the receipt of local data frames and learns remote MAC addresses and edge switch of attachment from the decapsulation of remotely sourced TRILL Data packets. This document specifies a message by which a TRILL switch can explicitly request other TRILL switches to flush certain MAC reachability learned through the decapsulation of TRILL Data packets. This is a supplement to the TRILL automatic address forgetting and can assist in achieving more rapid convergence in case of topology or configuration change. 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: trill@ietf.org. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." W. Hao, et al [Page 1] INTERNET-DRAFT Address Flush Message 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. W. Hao, et al [Page 2] INTERNET-DRAFT Address Flush Message Table of Contents 1. Introduction............................................4 1.1 Terminology and Acronyms...............................4 2. Address Flush Message Details...........................6 2.1 VLAN Block Only Case...................................7 2.2 Extensible Case........................................9 2.2.1 Blocks of VLANs.....................................12 2.2.2 Bit Map of VLANs....................................12 2.2.3 Blocks of FGLs......................................13 2.2.4 list of FGLs........................................13 2.2.5 Big Map of FGLs.....................................14 2.2.6 All Data Labels.....................................14 2.2.7 MAC Address List....................................15 2.2.8 MAC Address Blocks..................................15 3. IANA Considerations....................................17 3.1 Address Flush RBridge Channel Protocol Number.........17 3.2 TRILL Address Flush TLV Types.........................17 4. Security Considerations................................18 Normative References......................................19 Informative References....................................19 Acknowledgements..........................................19 Authors' Addresses........................................21 W. Hao, et al [Page 3] INTERNET-DRAFT Address Flush Message 1. Introduction Edge TRILL (Transparent Interconnection of Lots of Links) switches [RFC6325] [RFC7780], also called edge RBridges, by default learn end station MAC address reachability from observing the data plane. On receipt of a native frame from an end station, they would learn the local MAC address attachment of the source end station. And on egressing (decapsulating) a remotely originated TRILL Data packet, they learn the remote MAC address and remote attachment TRILL switch. Such learning is all scoped by data label (VLAN or Fine Grained Label [RFC7172]). TRILL has mechanisms for timing out such learning and appropriately clearing it based on some network connectivity and configuration changes; however, there are circumstances under which it would be helpful for a TRILL switch to be able to explicitly flush (purge) certain learned end station reachability information in remote RBridges to achieve more rapid convergence. Section 6.2 of [RFC4762] is an example of the use of such a mechanism. Another example, based on Appendix A.3 of [RFC6325] ("Wiring Closet Topology"), presents a bridged LAN connected to a TRILL network via multiple RBridge ports. For optimum paths, Appendix A.3.3 suggests configuring the RBridge ports to be like one Spanning Tree Protocol (STP) tree root in the bridged LAN. The address flush message in this document could also be triggered in this case when one of the edge RBridges receives topology change information (e.g., TC (Topology Change) in STP, TCN (Topology Change Notification) in MSTP (Multiple Spanning Tree Protocol) in order to rapidly flush the MAC addresses for specific VLANs learned at the other edge RBridge ports. A TRILL switch can easily flush any locally learned addresses it wants. This document specifies an RBridge Channel protocol [RFC7178] message to request flushing address information for specific VLANs or FGLs (Fine Grained Labels [RFC7172]) learned from decapsulating TRILL Data packets. 1.1 Terminology and Acronyms 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] [RFC8174] when, and only when, they appear in all capitals, as shown here. This document uses the terms and acronyms defined in [RFC6325] and [RFC7978] as well as the following: Data Label - VLAN or FGL. W. Hao, et al [Page 4] INTERNET-DRAFT Address Flush Message Edge TRILL switch - A TRILL switch attached to one or more links that provide end station service. FCS - Frame Check Sequence. FGL - Fine Grained Label [RFC7172]. Management VLAN - A VLAN in which all TRILL switches in a campus indicate interest so that multi-destination TRILL Data packets, including RBridge Channel messages [RFC7978], sent with that VLAN as the Inner.VLAN will be delivered to all TRILL switches in the campus. Usually no end station service is offered in the Management VLAN. MAC - Media Access Control. RBridge - An alternative name for a TRILL switch. STP - Spanning Tree Protocol. TC - Topology Change message. TCN - Topology Change Notification message. TRILL switch - A device implementing the TRILL protocol [RFC6325] [RFC7780]. W. Hao, et al [Page 5] INTERNET-DRAFT Address Flush Message 2. Address Flush Message Details The Address Flush message is an RBridge Channel protocol message [RFC7178]. The general structure of an RBridge Channel packet on a link between TRILL switches is shown in Figure 1 below. The Protocol field in the RBridge Channel Header gives the type of RBridge Channel packet and indicates how to interpret the Channel Protocol Specific Payload [RFC7178]. +----------------------------------+ | Link Header | +----------------------------------+ | TRILL Header | +----------------------------------+ | Inner Ethernet Addresses | +----------------------------------+ | Data Label (VLAN or FGL) | +----------------------------------+ | RBridge Channel Header | +----------------------------------+ | Channel Protocol Specific Payload| +----------------------------------+ | Link Trailer (FCS if Ethernet)| +----------------------------------+ Figure 1. RBridge Channel Protocol Message Structure An Address Flush RBridge Channel message by default applies to addresses within the Data Label that appears right after the Inner Ethernet Addresses. Address Flush protocol messages are usually sent as multi-destination packets (TRILL Header M bit equal to one) so as to reach all TRILL switches offering end station service in the VLAN or FGL specified by that Data Label. Both multi-destination and unicast Address Flush messages SHOULD be sent at priority 6 since they are important control messages but are lower priority than control messages that establish or maintain adjacency. Nevertheless: - There are provisions for optionally indicating the Data Label(s) to be flushed for cases where the Address Flush message is sent over a Management VLAN or the like. - An Address Flush message can be sent unicast, if it is desired to clear addresses at one TRILL switch only. - An Address Flush message can be sent selectively to the RBridges that have at least one access port configured as one of VLANs or FGLs specified in the Address Flush message payload. Implementations should consider logging address flush messages W. Hao, et al [Page 6] INTERNET-DRAFT Address Flush Message received with appropriate protections against packet storms. 2.1 VLAN Block Only Case Figure 2 below expands the RBridge Channel Header and Channel Protocol Specific Payload from Figure 1 for the case of the VLAN only based Address Flush message. This form of the Address Flush message is optimized for flushing MAC addressed based on nickname and blocks of VLANs. 0x8946 is the Ethertype assigned by IEEE for the RBridge Channel protocol. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 RBridge Channel Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RBridge-Channel (0x8946) | 0x0 | Channel Protocol = TBD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | ERR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Flush Protocol Specific: +-+-+-+-+-+-+-+-+ | K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname 1 | Nickname 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname ... | Nickname K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | K-VLBs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN 1 | RESV | End.VLAN 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN 2 | RESV | End.VLAN 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN ... | RESV | End.VLAN ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN K-VLBs | RESV | End.VLAN K-VLBs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2. Address Flush Message - VLAN Block Case The fields in Figure 2 related to the Address Flush message are as follows: Channel Protocol: The RBridge Channel Protocol value allocated for Address Flush (see Section 3). K-nicks: K-nicks is the number of nicknames listed as an unsigned integer. If this is zero, the ingress nickname in the TRILL W. Hao, et al [Page 7] INTERNET-DRAFT Address Flush Message Header [RFC6325] is considered to be the only nickname to which the message applies. If non-zero, it given the number of nicknames listed right after K-nicks to which the message applies and, in this non-zero case, the flush does not apply to the ingress nickname in the TRILL Header unless it is also listed. The message flushes address learning due to egressing TRILL Data packets that had an ingress nickname to which the message applies. Nickname: A listed nickname to which it is intended that the Address Flush message apply. If an unknown or reserved nickname occurs in the list, it is ignored but the address flush operation is still executed with the other nicknames. If an incorrect nickname occurs in the list, so some address learning is flushed that should not have been flush, the network will still operate correctly but will be less efficient as the incorrectly flushed learning is re-learned. K-VLBs: K-VLBs is the number of VLAN blocks present as an unsigned integer. If this byte is zero, the message is the more general format specified in Section 2.2. If it is non-zero, it gives the number of blocks of VLANs present. Thus, in the VLAN Block address flush case, K-VLBs will be at least one. RESV: 4 reserved bits. MUST be sent as zero and ignored on receipt. Start.VLAN, End.VLAN: These 12-bit fields give the beginning and ending VLAN IDs of a block of VLANs. The block includes both the starting and ending values so a block of size one is indicated by setting End.VLAN equal to Start.VLAN. If Start.VLAN is 0x000, it is treated as if it was 0x001. If End.VLAN is 0xFFF, it is treated as if it was 0xFFE. If End.VLAN is smaller than Start.VLAN, considering both as unsigned integers, that VLAN block is ignored but the address flush operation is still executed with other VLAN blocks in the message. VLAN blocks may overlap, in which case the address flush operation is applicable to a VLAN covered by any one or more of the blocks in the message. This message flushes all addresses in an applicable VLAN learned from egressing TRILL Data packets with an applicable nickname as ingress. To flush addresses for all VLANs, it is easy to specify a block covering all valid VLAN IDs, this is, from 0x001 to 0xFFE. W. Hao, et al [Page 8] INTERNET-DRAFT Address Flush Message 2.2 Extensible Case A more general form of the Address Flush message is provided to support flushing by FGL and more efficient encodings of VLANs and FGLs where using a set of contiguous blocks is cumbersome. It also supports optionally specifying the MAC addresses to clear. This form is extensible. The extensible case is indicated by a zero in the byte shown in Figure 2 as "K-VLBs" followed by other information encoded as TLVs. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 RBridge Channel Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RBridge-Channel (0x8946) | 0x0 | Channel Protocol = TBD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | ERR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Flush Protocol Specific: +-+-+-+-+-+-+-+-+ | K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname 1 | Nickname 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname ... | Nickname K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0 | TLVs ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+... Figure 3. Address Flush Message - Extensible Case Channel Protocol, K-nicks, Nickname: These fields are as specified in Section 2.1. TLVs: If the byte immediately before the TLVs field, which is the byte labeled "K-VLBs" in Figure 2, is zero, as shown in Figure 3, the remainder of the message consists of TLVs encoded as shown in Figure 4. 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- | Type | Length | Value +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Figure 4. Type, Length, Value Type: The 8-bit TLV type as shown in the table below. See subsections of this Section 2.2 for details on each type assigned below. If the type is reserved or not known by a W. Hao, et al [Page 9] INTERNET-DRAFT Address Flush Message receiving RBridge, that receiving RBridge ignores the value and skips to the next TLV by use of the Length byte. There is no provision for a list of VLAN IDs TLV as there are few enough of them that an arbitrary subset of VLAN IDs can be represented as a bit map. Type Description Reference ------ ------------------ ----------------- 0 Reserved [this document] 1 Blocks of VLANs [this document] 2 Bit Map of VLANs [this document] 3 Blocks of FGLs [this document] 4 List of FGLs [this document] 5 Bit Map of FGLs [this document] 6 All Data Labels [this document] 7 MAC Address List [this document] 8 MAC Address Blocks [this document] 9-254 Unassigned 255 Reserved [this document] Length: The 8-bit unsigned integer length in bytes of the remaining information in the TLV after the length byte. The length MUST NOT imply that the value extends beyond the end of RBridge Channel Protocol Specific Payload area. If it does, the Address Flush message is corrupt and MUST be ignored. Value: Depends on the TLV type. In an extensible Address Flush message, when the TLVs are parsed those TLVs having unknown types are ignored by the receiving RBridge. There may be multiple instances of TLVs with the same Type in the same address flush message and TLVs are not required to be in any particular order. o All RBridges implementing the Address Flush RBridge Channel message MUST implement types 1 and 2, the VLAN types, and type 6, which indicates addresses are to be flushed for all Data Labels. o RBridges that implement the Address Flush message and implement FGL ingress/egress MUST implement types 3, 4, and 5, the FGL types. (An RBridge that is merely FGL safe [RFC7172], but cannot egress FGL TRILL Data packets, SHOULD ignore the FGL types as it will not learn any FGL scoped MAC addresses from the data plane.) o RBridges that implement the Address Flush message SHOULD implement types 7 and 8 so that specific MAC addresses can be flushed. If they do not, the effect will be to flush all MAC addresses for the indicated Data Labels, which may be inefficient as any MAC addresses not intended to be flushed will have to be re-learned. The parsing of the TLVs by a receiving RBridge results in three items of information: 1. a flag indicating whether one or more Type 6 TLVs (All Data W. Hao, et al [Page 10] INTERNET-DRAFT Address Flush Message Labels) were encountered; 2. a set of Data Labels accumulated from VLAN and/or FGL specifying TLVs in the message; and, 3. if the MAC address TLV types are implemented, and a set of MAC addresses accumulated from MAC address specifying TLVs in the message. VLANs/FGLs might be indicated more than once due to overlapping blocks or the like and a VLAN/FGL is included in the above set of VLANs/FGLs if it occurs in any TLV in the address flush message. A MAC address might be indicated more than once due to overlapping blocks or the like and a MAC address is included in the above set of MAC addresses if it occurs in any TLV in the address flush message. After the above information has been accumulated by parsing the TLVs, three sets are derived as described below: a set of nicknames, a set of Data Labels, and a set of MAC addresses. The address flush operation at the receiver applies to the cross product of these derived sets. That is, a { Data Label, MAC address, nickname } triple is flushed if and only if the Data Label matches an element in the derived set of Data Labels, the MAC address matches an element in the derived set of MAC address, and the nickname matches an element in the derived set of nicknames. In the case of Data Labels and MAC addresses, a special value of the set, {ALL}, is permitted which matches all values. The sets are derived as follows: Data Labels set: If the Type 6 TLV has been encountered, the set is {ALL}, else, if any Data Labels have been accumulated by processing Data Label TLVs (Types 1, 2, 3, 4, and 5), the set is those accumulated Data Labels, else, the Data Labels set is null and the address flush message does nothing. MAC Addresses set: In the receiver does not implement the MAC address types (Types 7 and 8) or it does implement those types but no MAC addresses are accumulated in parsing the TLVs, then the MAC Address set is {ALL}, else, the MAC Addresses set is the set of MAC addresses accumulated in processing the TLVs. Nicknames set: If the K-nicks field in the Address Flush message was zero, then the ingress nickname in the TRILL Header of the message is the sole nickname set member, else, the nicknames set members are the K-nicks nicknames listed in the Address Flush message. W. Hao, et al [Page 11] INTERNET-DRAFT Address Flush Message The various formats below are provided for encoding efficiency. A block of values is most efficient when there are a number of consecutive values. A bit map is most efficient if there are scattered values within a limited range. And a list of single values is most efficient if there are widely scattered values. 2.2.1 Blocks of VLANs If the TLV Type is 1, the value is a list of blocks of VLANs as follows: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN 1 | RESV | End.VLAN 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN 2 | RESV | End.VLAN 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN ... | RESV | End.VLAN ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The meaning of Start.VLAN and End.VLAN is as specified in Section 2.1. Length MUST be a multiple of 4. If Length is not a multiple of 4, the TLV is corrupt and the Address Flush message MUST be discarded. 2.2.2 Bit Map of VLANs If the TLV Type is 2, the value is a bit map of VLANs as follows: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 2 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- | RESV | Start.VLAN | Bits... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- The value portion of the TLV begins with two bytes having the 12-bit starting VLAN ID right justified (the top 4 bits are as specified in Section 2.1 RESV). This is followed by bytes with one bit per VLAN ID. The high order bit of the first byte is for VLAN N, the next to the highest order bit is for VLAN N+1, the low order bit of the first byte is for VLAN N+7, the high order bit of the second byte, if there is a second byte, is for VLAN N+8, and so on. If that bit is a one, the Address Flush message applies to that VLAN. If that bit is a zero, then addresses that have been learned in that VLAN are not flushed. Note that Length MUST be at least 2. If Length is 0 or 1 W. Hao, et al [Page 12] INTERNET-DRAFT Address Flush Message the TLV is corrupt and the Address Flush message MUST be discarded. VLAN IDs do not wrap around. If there are enough bytes so that some bits correspond to VLAN ID 0xFFF or higher, those bits are ignored but the message is still processed for bits corresponding to valid VLAN IDs. 2.2.3 Blocks of FGLs If the TLV Type is 3, the value is a list of blocks of FGLs as follows: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 3 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Start.FGL 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | End.FGL 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Start.FGL 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | End.FGL 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Start.FGL ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | End.FGL ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The TLV value consists of sets of Start.FGL and End.FGL numbers. The Address Flush information applies to the FGLs in that range, inclusive. A single FGL is indicated by setting both Start.FGL and End.FGL to the same value. If End.FGL is less than Start.FGL, considering them as unsigned integers, that block is ignored but the Address Flush message is still processed for any other blocks present. For this Type, Length MUST be a multiple of 6; if it is not, the TLV is corrupt and the Address Flush message MUST be discarded if the receiving RBridge implements Type 3. 2.2.4 list of FGLs If the TLV Type is 4, the value is a list of FGLs as follows: W. Hao, et al [Page 13] INTERNET-DRAFT Address Flush Message +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 4 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FGL 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FGL 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FGL ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The TLV value consists of FGL numbers each in 3 bytes. The Address Flush message applies to those FGLs. For this Type, Length MUST be a multiple of 3; if it is not, the TLV is corrupt and the address flush Message MUST be discarded if the receiving RBridge implements Type 4. 2.2.5 Big Map of FGLs If the TLV Type is 5, the value is a bit map of FGLs as follows: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 5 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Start.FGL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bits... +-+-+-+-+-+-+-+- The TLV value consists of three bytes with the 24-bit starting FGL value N. This is followed by bytes with one bit per FGL. The high order bit of the first byte is for FGL N, the next to the highest order bit is for FGL N+1, the low order bit of the first byte is for FGL N+7, the high order bit of the second byte, if there is a second byte, is for FGL N+8, and so on. If that bit is a one, the Address Flush message applies to that FGL. If that bit is a zero, then addresses that have been learned in that FGL are not flushed. Note that Length MUST be at least 3. If Length is 0, 1, or 2 for a Type 5 TLV, the TLV is corrupt and the Address Flush message MUST be discarded if type 5 is implemented. FGLs do not wrap around. If there are enough bytes so that some bits correspond to an FGL higher than 0xFFFFFF, those bits are ignored but the message is still processed for bits corresponding to valid FGLs. 2.2.6 All Data Labels If the TLV Type is 6, the value is null as follows: W. Hao, et al [Page 14] INTERNET-DRAFT Address Flush Message +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 6 | Length = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ This type is used when a RBridge wants to withdraw all addresses for all the Data Labels (all VLANs and FGLs). Length MUST be zero. If Length is any other value, the TLV is corrupt and the Address Flush message MUST be discarded. 2.2.7 MAC Address List If the TLV Type is 7, the value is a list of MAC addresses as follows: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 7 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC 1 upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC 1 lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC 2 upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC 2 lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC ... upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC ... lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The TLV value consists of a list of 48-bit MAC addresses. Length MUST be a multiple of 6. If it is not, the TLV is corrupt and the Address Flush message MUST be discarded if the receiving RBridge implements Type 7. 2.2.8 MAC Address Blocks If the TLV Type is 8, the value is a list of blocks of MAC addresses as follows: W. Hao, et al [Page 15] INTERNET-DRAFT Address Flush Message +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 8 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.start 1 upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.start 1 lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.end 1 upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.end 1 lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.start 2 upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.start 2 lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.end 2 upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.end 2 lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.start ... upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.start ... lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.end ... upper half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC.end ... lower half | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The TLV value consists of sets of Start.MAC and End.MAC numbers. The Address Flush information applies to the 48-bit MAC Addresses in that range, inclusive. A single MAC Address is indicated by setting both Start.MAC and End.MAC to the same value. If End.MAC is less than Start.MAC, considering them as unsigned integers, that block is ignored but the Address Flush message is still processed for any other blocks present. For this Type, Length MUST be a multiple of 12; if it is not, the TLV is corrupt and the Address Flush message MUST be discarded if the receiving RBridge implements Type 7. W. Hao, et al [Page 16] INTERNET-DRAFT Address Flush Message 3. IANA Considerations Two IANA actions are requested as follows: 3.1 Address Flush RBridge Channel Protocol Number IANA is requested to assign TBD as the Address Flush RBridge Channel Protocol number from the range of RBridge Channel protocols allocated by Standards Action [RFC7178]. The added RBridge Channel protocols registry entry on the TRILL Parameters web page is as follows: Protocol Description Reference -------- -------------- ------------------ TBD Address Flush [this document] 3.2 TRILL Address Flush TLV Types IANA is requested to create a TRILL Address Flush TLV Types registry on the TRILL Parameters web page indented after the RBridge Channel Protocols registry. Registry headers are as below. The initial entries are as in the table in Section 2.2 above. Registry: TRILL Address Flush TLV Types Registration Procedures: IETF Review Reference: [this document] W. Hao, et al [Page 17] INTERNET-DRAFT Address Flush Message 4. Security Considerations The Address Flush RBridge Channel Protocol itself provides no security assurances or features. However, Address Flush protocol messages can be secured by use of the RBridge Channel Header Extension [RFC7978]. It is RECOMMENDED that all RBridges that implement the address flush message be configured to ignore such messages unless they have been secured with an RBridge Channel Header Extension that meets local security policy. If RBridges receiving Address Flush messages do not require them to be at least authenticated, they are relatively easy to forge. In that case, such forged Address Flush messages can reduce network efficiency, by purging useful learned information that will have to be re-learned. This provides a denial of service attack but cannot cause incorrect operation in the sense that it cannot cause a frame to be improperly delivered. See [RFC7178] for general RBridge Channel Security Considerations. See [RFC6325] for general TRILL Security Considerations. W. Hao, et al [Page 18] INTERNET-DRAFT Address Flush Message Normative References [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6325] - Perlman, R., D. Eastlake, D. Dutt, S. Gai, and A. Ghanwani, "RBridges: Base Protocol Specification", RFC 6325, July 2011. [RFC7172] - Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R., and D. Dutt, "Transparent Interconnection of Lots of Links (TRILL): Fine-Grained Labeling", RFC 7172, DOI 10.17487/RFC7172, May 2014, . [RFC7178] - Eastlake 3rd, D., Manral, V., Li, Y., Aldrin, S., and D. Ward, "Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Support", RFC 7178, DOI 10.17487/RFC7178, May 2014, . [RFC7780] - Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee, A., Ghanwani, A., and S. Gupta, "Transparent Interconnection of Lots of Links (TRILL): Clarifications, Corrections, and Updates", RFC 7780, DOI 10.17487/RFC7780, February 2016, . [RFC7978] - Eastlake 3rd, D., Umair, M., and Y. Li, "Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Header Extension", RFC 7978, DOI 10.17487/RFC7978, September 2016, . [RFC8174] - Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, Informative References [RFC4762] - Lasserre, M., Ed., and V. Kompella, Ed., "Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling", RFC 4762, January 2007. Acknowledgements The following are thanked for their contributions: Ramkumar Parameswaran, Henning Rogge W. Hao, et al [Page 19] INTERNET-DRAFT Address Flush Message The document was prepared in raw nroff. All macros used were defined within the source file. W. Hao, et al [Page 20] INTERNET-DRAFT Address Flush Message Authors' Addresses Weiguo Hao Huawei Technologies 101 Software Avenue, Nanjing 210012, China Phone: +86-25-56623144 Email: haoweiguo@huawei.com Donald E. Eastlake, 3rd Huawei Technologies 155 Beaver Street Milford, MA 01757 USA Phone: +1-508-333-2270 EMail: d3e3e3@gmail.com Yizhou Li Huawei Technologies 101 Software Avenue, Nanjing 210012 China Phone: +86-25-56624629 Email: liyizhou@huawei.com Mohammed Umair Cisco Cessna Business Park, Kadubeesanahalli Village, Hobli, Sarjapur, Varthur Main Road, Marathahalli, Bengaluru, Karnataka 560087 India Email: mohammed.umair2@gmail.com W. Hao, et al [Page 21] INTERNET-DRAFT Address Flush Message Copyright, Disclaimer, and Additional IPR Provisions Copyright (c) 2018 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. W. Hao, et al [Page 22]