TRILL (Transparent Interconnection of Lots of Links): ESADI (End Station Address Distribution Information) Protocol
Author(s): fangwei hu, ZTE Corporation, Donald Eastlake, Radia Perlman, Olen Stokes
The IETF TRILL (Transparent Interconnection of Lots of Links) protocol provides least cost pair-wise data forwarding without configuration in multi-hop networks with arbitrary topologies and link technologies. TRILL supports multi-pathing of both unicast and multicast traffic. Devices that...
TRILL Working Group Hongjun Zhai INTERNET-DRAFT Fangwei Hu Intended status: Proposed Standard ZTE Updates: 6325 Radia Perlman Intel Labs Donald Eastlake Huawei Olen Stokes Extreme Networks Expires: August 21, 2013 February 22, 2013 TRILL (Transparent Interconnection of Lots of Links): ESADI (End Station Address Distribution Information) Protocol <draft-ietf-trill-esadi-02.txt> Abstract The IETF TRILL (Transparent Interconnection of Lots of Links) protocol provides least cost pair-wise data forwarding without configuration in multi-hop networks with arbitrary topologies and link technologies. TRILL supports multi-pathing of both unicast and multicast traffic. Devices that implement the TRILL protocol are called RBridges (Routing Bridges) or TRILL Switches. ESADI (End Station Address Distribution Information) is an optional protocol by which a TRILL switch can communicate, in a Data Label (VLAN or Fine Grained Label) scoped way, end station addresses and other information to TRILL switches pariticipating in ESADI for the relevant Data Label. This document updates RFC6325, specifically the documentation of the ESADI protocol. 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: <email@example.com>. 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. H. Zhai, et al [Page 1] INTERNET-DRAFT TRILL: ESADI 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. H. Zhai, et al [Page 2] INTERNET-DRAFT TRILL: ESADI Table of Contents 1. Introduction............................................4 1.1 Content and Precedence.................................5 1.2 Terminology............................................5 1.3 Acknowledgements.......................................5 2. ESADI Protocol Overview.................................7 2.1 ESADI Virtual Link....................................10 2.2 ESADI Neighbor Determination..........................11 2.3 ESADI Payloads........................................11 3. ESADI DRB Determination................................13 4. ESADI PDU processing...................................14 4.1 Sending of ESADI PDUs.................................15 4.2 Receipt of ESADI PDUs.................................16 5. End Station Addresses..................................17 5.1 Learning Confidence Level.............................17 5.2 Forgetting End Station Addresses......................17 5.3 Duplicate MAC Address.................................17 6. ESADI-LSP Contents.....................................20 6.1 ESADI Parameter Data..................................20 6.2 MAC Reachability TLV..................................21 6.3 Default Authentication................................22 7. IANA Considerations....................................23 7.1 ESADI Participation and Capability Flags..............23 7.2 TRILL GENINFO TLV.....................................24 8. Security Considerations................................26 Normative references......................................27 Informative References....................................28 Appendix Z: Change History................................29 Z.1 From -00 to -01.......................................29 Z.2 From -01 to -02.......................................29 Authors' Addresses........................................30 H. Zhai, et al [Page 3] INTERNET-DRAFT TRILL: ESADI 1. Introduction The IETF TRILL (Transparent Interconnection of Lots of Links) protocol [RFC6325] provides least cost pair-wise data forwarding without configuration in multi-hop networks with arbitrary topologies and link technologies, safe forwarding even during periods of temporary loops, and support for multi-pathing of both unicast and multicast traffic. TRILL accomplishes this with the IS-IS (Intermediate System to Intermediate System) [IS-IS] [RFC1195] [rfc6326bis] link state routing protocol using a header with a hop count. The design supports optimization of the distribution of multi-destination frames and two types of data labeling, VLANs (Virtual Local Area Networks) and FGLs (Fine Grained Labels, [RFCfgl]). Devices that implement TRILL are called TRILL switches or RBridges (Routing Bridges). There are five ways an RBridge can learn end station addresses, as described in Section 4.8 of [RFC6325]. The ESADI (End Station Address Distribution Information) protocol is an optional Data Label scoped way RBridges can communicate, with each other, information such as end station addresses and their RBridge of attachment. An RBridge that is announcing interest in a Data Label MAY use the ESADI protocol to announce the end station address of some or all of its attached end stations in that Data Label to other RBridges that are running ESADI for that Data Label. (In the future, ESADI may also be used for additional types of information.) By default, TRILL switches with connected end stations learn addresses from the data plane when ingressing and egressing native frames. The ESADI protocol's potential advantages over data plane learning include the following: 1. Security advantages: (1a) The ESADI protocol can be used to announce end stations with an authenticated enrollment (for example enrollment authenticated by cryptographically based EAP (Extensible Authentication Protocol [RFC3748]) methods via [802.1X]). (1b) The ESADI protocol supports cryptographic authentication of its message payloads for more secure transmission. 2. Fast update advantages: The ESADI protocol provides a fast update of end stations MAC (Media Access Control) addresses. If an end station is unplugged from one RBridge and plugged into another, frames ingressed for that MAC address can be black holed. They can be sent just to the older egress RBridge that the end station was connected to until cached address information at some remote ingress RBridge times out, possibly for tens of seconds or more [RFC6325]. H. Zhai, et al [Page 4] INTERNET-DRAFT TRILL: ESADI MAC address reachability information, some ESADI parameters, and optionally authentication information are carried in ESADI packets rather than in the TRILL IS-IS protocol. As described below, ESADI is, for each Data Label, a virtual logical topology overlay in the TRILL topology. An advantage of using ESADI over using TRILL IS-IS is that the end station attachment information is not flooded to all RBridges through TRILL IS-IS but only to RBridges advertising ESADI participation for the Data Label in which those end stations occur. 1.1 Content and Precedence This document updates [RFC6325], the TRILL basic specification, essentially replacing the description of the ESADI protocol, and prevails over [RFC6325] where they conflict. Section 2 is the ESADI protocol overview. Section 3 specifies ESADI DRB state. Section 4 discusses the processing of ESADI PDUs. Section 5 discusses interaction with other modes of end station address learning. And Section 6 describes the ESADI-LSP contents. 1.2 Terminology This document uses the acronyms defined in [RFC6325] and the following phrase: Data Label - VLAN or FGL. FGL - Fine Grained Lable [RFCfgl] LSP number zero - A Link State PDU with fragment number equal to zero 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]. 1.3 Acknowledgements The authors thank the following, listed in alphabetic order, for their suggestions and contributions: H. Zhai, et al [Page 5] INTERNET-DRAFT TRILL: ESADI Somnath Chatterjee and Thomas Narten This document was produced with raw nroff. All macros used were defined in the source file. H. Zhai, et al [Page 6] INTERNET-DRAFT TRILL: ESADI 2. ESADI Protocol Overview ESADI is a Data Label scoped way for RBridges to announce and learn end station addresses rapidly and securely. An RBridge that is announcing participation in ESADI for one or more Data Labels is called an ESADI RBridge. ESADI is a separate protocol from the TRILL IS-IS implemented by all RBridges in a campus. There is a separate ESADI instance for each Data Label (VLAN or FGL). In essence, for each Data Label, there is a modified instance of the IS-IS reliable flooding mechanism in which ESADI RBridges may choose to participate. (These are not the instances being specified in [RFC6822].) It is an implementation decision how independent the multiple ESADI instances at an RBridge are. For example, the ESADI link state database could be in a single database with a field in each record indicating the Data Label to which it applies or could be a separate database per Data Label. But the ESADI update process operates separately for each ESADI instance and independently from the TRILL IS-IS update process. ESADI does no routing so there is no reason for pseudo-nodes in ESADI and none are created. This allows re-purposing one byte of the LSP ID field to expand the number of possible fragments from 2**8 to 2**16. In [IS-IS], the "LSP ID" field is 8 bytes. (Actually it is the length of System ID plus 2, but we will assume a 6-byte System ID.) The top 6 bytes of the LSP ID are the router's System ID, the next byte is non-zero for pseudo-nodes, and the bottom byte is the fragment number. In ESADI-LSPs, there is just the System ID followed by two bytes of fragment number. The same change is made to the LSP ID field of the Remaining Lifetime TLV which is used in EASDI-CSNP and ESADI-PSNP. The bottom byte of the ESADI CSNP/PSNP Header Source ID is always zero. After the TRILL header, ESADI packets have an inner Ethernet header with the Inner.MacDA of "All-Egress-RBridges" (formerly called "All- ESADI-RBridges"), an inner Data Label specifying the VLAN or FGL of interest, and the "L2-IS-IS" Ethertype followed by the ESADI payload as shown in Figure 1. H. Zhai, et al [Page 7] INTERNET-DRAFT TRILL: ESADI +--------------------------------+ | Link Header | +--------------------------------+ | TRILL Data Header | +--------------------------------+ | Inner Ethernet Addresses | +--------------------------------+ | Data Label | +--------------------------------+ | ESADI Payload | +--------------------------------+ | Link Trailer | +--------------------------------+ Figure 1. TRILL ESADI Packet Overview TRILL ESADI packets sent on an Ethernet link are structured as shown below. The outer VLAN tag will not be present if it was stripped by an Ethernet port out of which the packet was sent. H. Zhai, et al [Page 8] INTERNET-DRAFT TRILL: ESADI Outer Ethernet Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Hop Destination Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Hop Destination Addr. | Sending RBridge Port MAC Addr.| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sending RBridge Port MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethertype = C-Tag 0x8100 | Outer.VLAN Tag Information | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethertype = TRILL 0x22F3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TRILL Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | V | R |M|Op-Length| Hop Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Nickname | Ingress (Origin) Nickname | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Inner Ethernet Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | All-Egress-RBridges | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | All-Egress-RBridges cont. | Origin RBridge MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Origin RBridge MAC Address continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VLAN or FGL Data Label (4 or 8 bytes) ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethertype = L2-IS-IS 0x22F4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ESADI Payload (formatted as IS-IS): +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IS-IS Common Header, IS-IS PDU Specific Fields, IS-IS TLVs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Frame Check Sequence: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FCS (Frame Check Sequence) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: ESADI Ethernet Link Packet Format The Next Hop Destination Address or Outer.MacDA is the All-RBridges multicast address if the ESADI PDU is being multicast while, if it is being unicast, the Next Hop Destination Address is the unicast address of the next hop RBridge. The VLAN for the Outer.VLAN information will always be the Designated VLAN for the link on which the packet is sent. The V and R fields will be zero while the M field will be one unless the ESADI PDU was unicast as discussed below, in which case the M field will be zero. The Data Label specified will be the VLAN or FGL to which the ESADI packet applies. The Origin RBridge MAC Address or Inner.MacSA MUST be a MAC address unique across the H. Zhai, et al [Page 9] INTERNET-DRAFT TRILL: ESADI campus owned by the RBridge originating the ESADI packet, for example, any of its port MAC addresses if it has any Ethernet ports, and each RBridge MUST use the same Inner.MacSA for all of the ESADI packets that RBridge originates. TRILL ESADI packets sent on a PPP link are structured as shown below [RFC6361]. PPP Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PPP = TNP (TRILL data) 0x005D | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TRILL Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | V | R |M|Op-Length| Hop Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress Nickname | Ingress (Origin) Nickname | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Inner Ethernet Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | All-Egress-RBridges | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | All-Egress-RBridges cont. | Origin RBridge MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Origin RBridge MAC Address continued | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VLAN or FGL Data Label (4 or 8 bytes) ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethertype = L2-IS-IS 0x22F4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ESADI Payload (formatted as IS-IS): +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IS-IS Common Header, IS-IS PDU Specific Fields, IS-IS TLVs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PPP Check Sequence: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PPP Check Sequence | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: ESADI PPP Link Packet Format 2.1 ESADI Virtual Link All transit RBridges forward ESADI packets as if they were ordinary TRILL Data packets. Because of this forwarding, it appears to an instance of the ESADI protocol at an RBridge that it is directly connected by a multi-access virtual link to all other RBridges in the campus running ESADI for that Data Label. No "routing" computation or routing decisions ever have to be performed by ESADI. An ESADI H. Zhai, et al [Page 10] INTERNET-DRAFT TRILL: ESADI RBridge merely transmits the ESADI packets it originates on this virtual link as described for TRILL Data packets in [RFC6325] and [RFCfgl]. For multicast ESADI packets it may use any distribution tree that it might use for an ordinary multi-destination TRILL Data packet. RBridges that do not implement the ESADI protocol, do not have it enabled, or are not participating for the Data Label of an ESADI packet do not decapsulate or locally process any TRILL ESADI packets they receive. Thus the ESADI packets are transparently tunneled through transit RBridges. 2.2 ESADI Neighbor Determination The ESADI instance for Data Label X at an RBridge RB1 determines who its ESADI neighbors are by logically examining the TRILL IS-IS link state database for RBridges that are data and IS-IS reachable from RB1 (see Section 2 of [ClearCorrect]) and are announcing their participation in Data Label X ESADI. When an RBridge RB2 becomes IS- IS or data unreachable from RB1 or the relevant entries for RB2 are purged from the core IS-IS link state database, it is lost as a potential neighbor and also dropped from any ESADI instances. And when RB2 is no longer announcing participation in Data Label X ESADI, it ceases to be a neighbor for the Data Label X ESADI instance, these considerations being Data Label scoped. Because of these mechanisms, there are no "Hellos" sent in ESADI. Participation announcement in a VLAN scoped ESADI instance is through setting a flag bit in the Interested VLANs sub-TLV and announcement for an FGL scoped ESADI instance is through setting a flag bit in the Interested Labels sub-TLV [rfc6326bis]. (See Section 7.1) 2.3 ESADI Payloads TRILL ESADI packet payloads are structured like IS-IS PDUs, except as indicated below, but are always TRILL encapsulated on the wire as if they were TRILL Data packets. The information distributed by the ESADI protocol includes a list of local end station MAC addresses connected to the originating RBridge and, for each such address, a one octet unsigned "confidence" rating in the range 0-254 (see Section 6.2). It is entirely up to the originating RBridge which locally connected MAC addresses it wishes to advertise via ESADI and with what confidence. It MAY advertise all, some, or none of such addresses. In addition, some ESADI parameters of the advertising RBridge (see Section 6.1) and possibly authenticaiton information (see Section 6.3) are included. Future uses of ESADI may distribute H. Zhai, et al [Page 11] INTERNET-DRAFT TRILL: ESADI other types of information. TRILL ESADI-LSPs MUST NOT contain a Data Label ID in their payload. The Data Label to which the ESADI data applies is the Data Label of the TRILL Data packet enclosing the ESADI payload. If a Data Label ID could occur within the payload, it might conflict with that TRILL Data packet Data Label and could conflict with any future Data Label mapping scheme that may be adopted [VLANmapping]. If a VLAN or FGL ID field within an ESADI-LSP PDU does include a value, that field's contents is ignored. H. Zhai, et al [Page 12] INTERNET-DRAFT TRILL: ESADI 3. ESADI DRB Determination Because ESADI does no adjacency announcement or routing, the ESADI- DRB never creates a pseudonode. But a DRB is still needed for LSP synchronization by issuing ESADI-CSNP PDUs and responding to ESADI- PSNP PDUs. Generally speaking, the DRB election on the ESADI virtual link (see Section 2.1) operates similarly to a TRILL IS-IS broadcast link [RFC6327] with the following exceptions: In the Data Label X ESADI- DRB election at RB1 on an ESADI virtual link, the candidates are the local ESADI instance for Data Label X and all remote ESADI instances at RBridges that (1) are data and IS-IS reachable from RB1 [ClearCorrect], and (2) are announcing in their TRILL IS-IS LSP that they are participating in ESADI for Data Label X. The winner is the instance with the highest ESADI Parameter 7-bit priority field with ties broken by System ID, comparing fields as unsigned integers with the larger magnitude considered higher priority. "SNPA/MAC address" is not considered and there is no "Port ID". H. Zhai, et al [Page 13] INTERNET-DRAFT TRILL: ESADI 4. ESADI PDU processing Data Label X ESADI neighbors are usually not connected directly by a physical link, but are always logically connected by a virtual link (see Section 2.1). There could be hundreds or thousands of ESADI RBridges on the virtual link. There are only ESADI-LSP, ESADI-CSNP and ESADI-PSNP PDUs used in ESADI. In particular, there are no Hello or MTU PDUs because ESADI does not build a topology and does not do any routing. In IS-IS, PDU multicasting is normal on a local link and no effort is made to optimize to unicast because under the original conditions when IS-IS was designed (commonly a piece of multi-access Ethernet cable) any frame made the link busy for that frame time. But in ESADI what appears to be a simple multi-access link is generally a set of multi-hop distribution trees that may or may not be pruned. Thus, transmitting a multicast frame on such a tree can impose a substantially greater load than transmitting a unicast frame. This load may be justified if there are likely to be multiple listeners but may not be justified if there is only one recipient of interest. For this reason, under some circumstances, ESADI PDUs MAY be TRILL unicast if it is confirmed that the destination RBridge supports receiving unicast ESADI PDUs (see Section 6.1). To support unicasting of ESADI PDUs, Section 18.104.22.168 of [RFC6325] is replaced with the following: "22.214.171.124. TRILL ESADI Packets If M=1, the egress nickname designates the distribution tree. The packet is forwarded as described in Section 126.96.36.199. In addition, if the forwarding RBridge is (1) interested in the specified VLAN or Fine Grained Label, (2) implements the TRILL ESADI protocol, and (3) ESADI is enabled for that VLAN or Fine Grained Label, the inner frame is decapsulated and provided to that local ESADI protocol. If M=0 and the egress nickname is not that of the receiving RBridge, the packet is forwarded as for known unicast TRILL Data in Section 188.8.131.52. If M=0 and the egress nickname is that of the receiving RBridge and the receiving RBridge supports unicast ESADI PDUs, then the ESADI packet is decapsulated and processed if it meets the three numbered conditions in the paragraph above, otherwise it is discarded." The references to "184.108.40.206", "220.127.116.11", and "18.104.22.168" above refer to those sections in [RFC6325]. Section 4.1 describes the sending of ESADI PDUs. Section 4.2 covers the receipt of ESADI PDUs. H. Zhai, et al [Page 14] INTERNET-DRAFT TRILL: ESADI 4.1 Sending of ESADI PDUs The MTU available to ESADI payloads is at least 24 bytes less than that available to TRILL IS-IS because of the additional fields required (2(TRILL Ethertype) + 6(TRILL Header) + 6(Inner.MacDA) + 6(Inner.MacSA) + 4/8(Inner.VLAN/Inner.FGL) bytes). Thus the inner ESADI payload, starting with the Intradomain Routeing Protocol Discriminator byte, MUST NOT exceed Sz minus 24 for a VLAN ESADI instance or Sz minus 28 for an FGL ESDAI instance; however, if a larger payload is received, it is processed normally. (See [RFC6325] and [ClearCorrect] for discussions of Sz and MTU.) An ESADI instance does not transmit any ESADI PDUs if it has zero EASDI neighbors. When an ESADI instance sees that it has a new neighbor, its self-originated EASDI-LSP fragments are scheduled to be sent and MAY be unicast to that neighbor if the neighbor is announcing in its LSP that it supports unicast ESADI (see Section 6.1). If all the other ESADI instances for the same Data Label send their self-originated ESADI-LSPs immediately, there may be a surge of traffic to that new neighbor. So the other ESADI instances should wait an interval of time before sending the ESADI-LSP to a new neighbor. The interval time value is up to the device implementation and is subject to the usual IS-IS timing jitter. One suggestion is that the interval time can be assigned a random value with a range based on the ESADI instace DRB priority such ( 2 * (127 - priority) / 128) seconds. If the ESADI instance believes it is DRB, it multicasts an ESADI-CSNP periodically (thrice per CSNP Time, see Section 6.1) to keep the link state database synchronized among its neighbors on the virtual link. After receiving an ESADI-PSNP PDU, the DRB will multicast the ESADI- LSPs requested by the ESADI-PSNP on the virtual link. The multi-hop TRILL multi-destination packet distribution with Reverse Path Forwarding Check will typically be less reliable than the single hop link-local LSP synchronization of TRILL IS-IS. Therefore, for LSP synchronization robustness, in addition to sending ESADI-CSNPs when it is DRB, an ESADI RBridge SHOULD also transmit an ESADI-CSNP for an ESADI instance if all of the following conditions are met: o it sees one or more ESADI neighbors for that instance, and o it does not believe it is DRB for the ESADI instance, and o it has not received or sent an ESADI-CSNP PDUs for the instance for the CSNP Time (see Section 6.1) of the DRB. In the case of receiving an ESADI-LSP with a smaller sequence number than the copy stored in the local EASDI Link State Database the local ESADI instance will also schedule to multicast the stored copy. H. Zhai, et al [Page 15] INTERNET-DRAFT TRILL: ESADI The format of a unicast ESADI packet is the format of TRILL ESADI packet, in Section 2 above, except as follows: o On an Ethernet link, in the Outer Ethernet Header the Outer.MacDA is the unicast address of the next hop RBridge. o In the TRILL header, the M bit is set to zero and the Egress Nickname is the nickname of the destination RBridge. 4.2 Receipt of ESADI PDUs Because ESADI adjacency is in terms of System ID, all IS-IS PDU acceptance tests that check that the PDU is from an adjacent system instead check that the System ID is that of an ESADI neighbor and do not check either the source Inner or Outer SNPA/MAC. Because all data reachable ESADI RBridges participating for Data Label X are adjacent, when RB1 receives an ESADI-CSNP from RB2 and detects that it has ESADI-LSPs that RB2 is missing, it sets the transmission flag only for its own ESADI-LSPs that RB2 is missing. Missing ESADI-LSPs originated by other ESADI RBridges will be detected by those other ESADI RBridges. When receiving an ESADI-PSNP PDU, if the local ESADI instance is DRB, the ESADI-LSP PDUs requested by the ESADI-PSNP will be multicast on the virtual link. H. Zhai, et al [Page 16] INTERNET-DRAFT TRILL: ESADI 5. End Station Addresses 5.1 Learning Confidence Level The confidence level mechanism allows an RBridge campus manager to cause certain address learning sources to prevail over others. MAC address information learned through a registration protocol, such as [802.1X] with a cryptographically based EAP [RFC3748] method, might be considered more reliable than information learned through the mere observation of data frames. When such authenticated learned address information is transmitted via the ESADI protocol, the use of authentication in the TRILL ESADI-LSP packets could make tampering with it in transit very difficult. As a result, it might be reasonable to announce such authenticated information via the ESADI protocol with a high confidence, so it would be used in preference to any alternative learning from data observation. 5.2 Forgetting End Station Addresses The end station addresses learned through TRILL ESADI protocol should be forgotten through changes in ESADI-LSPs. The time out of the learned end station address is up to the originating RBridge that decides when to remove such information from its ESADI-LSPs (or up to ESADI protocol timeouts if the originating RBridge becomes inaccessible). If RBridge RBn participating in the TRILL ESADI protocol for Data Label X no longer wishes to participate in ESADI, it ceases to participate in ESADI by (1) clearing the ESADI participation bit in the appropriate Interested VLANs or Interested Lables sub-TLV and (2) sending a final ESADI-LSP nulling out its ESADI-LSP information. 5.3 Duplicate MAC Address With ESADI, it is possible to persistently see two occurances of the same MAC address with the same Data Label being advertised by two or more RBridges. The specification of how to handle this situation in [RFC6325] is updated by replacing the last sentence of the last paragraph of Section 4.2 of [RFC6325] as shown below to provide better traffic spreading while avoiding possible address flip- flopping. H. Zhai, et al [Page 17] INTERNET-DRAFT TRILL: ESADI As background, assume some end station or set of end stations have two or more ports with the same MAC&VLAN with each port connected to different RBridges (RB1, RB2, ...) by separate links. With ESADI, some other RBridge, RB0, can persistently see that MAC&VLAN connected to multiple RBridges. When RB0 ingresses a frame destined that MAC&VLAN, the current [RFC6325] text permits a wide range of behavior. In particular, it would permit RB0 to use some rule such as always send to the egress with the lowest System ID, which would put all of this traffic through one of the egress RBridges and one of the end station ports. There would be no load spreading even if there were multiple different ingress RBridges and/or different MAC addresses. It also would also permit RB0 to send different traffic to different egresses by doing ECMP at a flow level, which would likely result in return traffic to RB0 from RB1, RB2, ... for the same MAC&VLAN. The resulting address flip-flopping could cause problems. This update to [RFC6325] avoids these potential difficulties by requiring RB0 to either (1) use only one egress for a particular MAC&VLAN but to select that egress pseudo-randomly based on the topology including MAC reachabilty or (2) if it will not be disturbed by the returning TRILL Data packets showing the same MAC&VLAN flip- flopping between different ingresses, it may use ECMP. Assuming multiple ingress RBridges and/or multiple MAC addresses, stragegy 1 should result in load spreading without address flip-floping while stragegy 2 will produce more uniform load spreading. OLD [RFC6325] text: "... If confidences are also tied between the duplicates, for consistency it is suggested that RB2 direct all such frames (or all such frames in the same ECMP flow) toward the same egress RBridge; however, the use of other policies will not cause a network problem since transit RBridges do not examine the Inner.MacDA for known unicast frames." NEW [RFC6325] text: "... If confidences are also tied between the duplicates then RB2 MUST adopt one of the following two strategies: 1. In a pseudo-random way [RFC4086], select one of the egress RBridges that is least cost from RB2 and to which the destination MAC appears to be attached and send all traffic for the destination MAC and VLAN (or FGL) to that egress. This pseudo-random choice need only be changed when there is a change in campus topology or MAC attachment information. Such pseudo-random selection will, over a population of ingress RBridges, probabilisticly spread traffic over the possible egress RBridges. Reasonable inputs to the pseudo-random selection are the ingress RBridge System ID and/or nickname, the VLAN or FGL, the destination MAC address, and a vector of H. Zhai, et al [Page 18] INTERNET-DRAFT TRILL: ESADI the RBridges with connectivity to that MAC and VLAN. There is no need for different RBridges to use the same pseudo-random function. 2. If RB2 supports ECMP and will not be disturbed by return traffic from the same MAC and VLAN (or FGL) coming from different ingress RBridges, then it MAY send traffic over ECMP at the flow level to the egress RBridges that are least cost from RB2 and to which the destination MAC appears to be attached." H. Zhai, et al [Page 19] INTERNET-DRAFT TRILL: ESADI 6. ESADI-LSP Contents The only PDUs used in ESADI are the Level 1 ESADI-LSP, ESADI-CSNP, and ESADI-PSNP PDUs. Currently, the contents of an ESADI-LSP consists of zero or more MAC Reachability TLVs, optionally an Authentication TLV, and exactly one ESADI parameter APPsub-TLV. Other data may be included in the future and, as in IS-IS, an ESADI instances ignores any TLVs or sub-TLVs it does not understand. This section specifies the format for the ESADI parameter data APPsub-TLV, gives the reference for the ESADI MAC Reachability TLV, and discusses default authentication configuration. For robustness, the payload for an ESADI-LSP number zero MUST NOT exceed 1470 minus 24 bytes in length (1446 bytes) if it has an Inner.VLAN or 1470 minus 28 bytes (1442 bytes) if it has an Inner.FGL. But if an ESADI-LSP number zero is received longer, it is still processed normally. 6.1 ESADI Parameter Data The figure below presents the format of the ESADI parameter data. This APPsub-TLV MUST be included in a TRILL GENINFO TLV in ESADI-LSP number zero. If it is missing from ESADI-LSP number zero or if ESADI- LSP number zero is not known, priority for the sending RBridge defaults to 0x40 and CSNP Time defaults to 30. If there is more than one occurrence in ESADI-LSP number zero, the first occurrence will be used. Occurrences of the ESADI parameter data APPsub-TLV in non-zero ESADI-LSP fragments are ignored. +-+-+-+-+-+-+-+-+ | Type | (1 byte) +-+-+-+-+-+-+-+-+ | Length | (1 byte) +-+-+-+-+-+-+-+-+ |R| Priority | (1 byte) +-+-+-+-+-+-+-+-+ | CSNP Time | (1 byte) +-+-+-+-+-+-+-+-+ | Flags | (1 byte) +---------------+ | Reserved for expansion (variable) +-+-+-+-... Figure 4. ESADI Parameter APPsub-TLV Type: set to ESADI-PARAM subTLV (TRILL APPsub-TLV type 1). H. Zhai, et al [Page 20] INTERNET-DRAFT TRILL: ESADI Length: Set to 2 to 255. R: A reserved bit that MUST be sent as zero and ignored on receipt. Priority: The Priority field gives the originating RBridge's priority for being DRB on the ESADI instance virtual link (see Section 2.1) for the Data Label in which the PDU containing the parameter data was sent. It is an unsigned seven-bit integer with larger magnitude indication higher priority. It defaults to 0x40 for an RBridge participating in ESADI for which it has not been configured. CSNP Time: An unsigned byte that gives the amount of time in seconds during which the originating RBridge, if it is DRB on the ESADI virtual link, will send at least three EASDI-CSNP PDUs. It defaults to 30 seconds for an RBridge participating in ESADI for which it has not been configured. Flags: A byte of flags associated with the originating ESADI instance as follows: 0 1 2 3 4 5 6 7 +---+---+---+---+---+---+---+---+ | UN| Reserved | +---+---+---+---+---+---+---+---+ The UN flag indicates that the RBridge originating the ESADI- LSP including this ESADI Parameter Data will accept and properly process ESADI PDUs sent by TRILL unicast. The remaining bits are reserved for future use and MUST be sent as zero and ignored on receipt. Reserved for future expansion: Future versions of the ESADI Parameters APPsub-TLV may have additional information. A receiving ESADI RBridge ignores any additional data here unless it implements such future expansion(s). 6.2 MAC Reachability TLV The primary information in TRILL ESADI-LSP PDUs consists of MAC Reachability (MAC-RI) TLVs as specified in [RFC6165]. These TLVs contain one or more unicast MAC addresses of end stations that are both on a port and in a VLAN for which the originating RBridge is appointed forwarder, along with the one octet unsigned Confidence in this information with a value in the range 0-254. If such a TLV is received with a confidence of 255, it is treated as if the confidence was 254. (This is to assure that any received address information can H. Zhai, et al [Page 21] INTERNET-DRAFT TRILL: ESADI be overridden by local address information statically configured with a Confidence of 255.) The TLVs in TRILL ESADI PDUs, including the MAC-RI TLV, MUST NOT contain the Data Label ID. If a Data Label ID is present in the MAC- RI TLV, it is ignored. In the encapsulated TRILL ESADI packet, only the Inner.VLAN or Inner.FGL tag indicates the Data Label to which the ESADI-LSP applies. 6.3 Default Authentication The Authentication TLV may be included in ESADI PDUs. The default for ESADI PDU Authentication is based on the state of TRILL IS-IS shared secret authentication for LSP PDUs. If TRILL IS-IS authentication and ESADI are implemented at a TRILL switch, then ESADI MUST be able to use the authentication algorithms implemented for TRILL IS-IS and implement the keying material derivation function given below. If ESADI authentication has been configured, that configuration is not restricted by the configuration of TRILL IS-IS security. If TRILL IS-IS authentication is not in effect for LSP PDUs originated by a TRILL switch then, by default, ESADI PDUs originated by that TRILL switch are also unsecured. If such IS-IS LSP PDU authentication is in effect at a TRILL switch then, unless configured otherwise, ESADI PDUs sent by that switch MUST use the same algorithm in their Authentication TLVs. The ESADI authentication keying material used is derived from the IS-IS LSP shared secret keying material as detailed below. However, such authentication MAY be configured to use some other keying material. HMAC-SHA256 ( "TRILL ESADI", IS-IS-LSP-shared-key ) In the above HMAC-SHA256 is as described in [FIPS180] [RFC6234] and "TRILL ESADI" is the eleven byte US ASCII [ASCII] string indicated. IS-IS-LSP-shared-key is secret keying material being used by the originating TRILL switch for IS-IS LSP authentication. H. Zhai, et al [Page 22] INTERNET-DRAFT TRILL: ESADI 7. IANA Considerations IANA allocation and registry considerations are given below. 7.1 ESADI Participation and Capability Flags IANA is requested to allocate bit TBD [3 recommended] as the "ESADI Participation" bit in the Interested VLANs sub-TLV and the Interested Labels sub-TLVs [rfc6326bis]. If The ESADI Participation bit is a one, it indicates that the originating RBridge is participating in ESADI for the indicated VLAN(s) or FGL(s). In addition, IANA is requested to create two sub-registries in the TRILL Parameters Registry for such bits1 as follows: Sub-Registry: Interested VLANs Flag Bits Registration Procedures: IETF Review Note: These bits appear in the Interested VLANs record within the Interested VLANs and Spanning Tree Roots Sub-TLV (INT-VLAN). References: [rfc6326bis], This document Bit Mnemonic Description Reference --- -------- ----------- --------- 0 M4 IPv4 Multicast Router Attached [rfc6326bis] 1 M6 IPv6 Multicast Router Attached [rfc6326bis] 2 - available for allocation 3 ES ESADI Participation This document 4-15 - (used for a VLAN ID) [rfc6326bis] 16-19 - available for allocation 20-31 - (used for a VLAN ID) [rfc6326bis] H. Zhai, et al [Page 23] INTERNET-DRAFT TRILL: ESADI Sub-Registry: Interested Labels Flag Bits Registration Procedures: IETF Review Note: These bits appear in the Interested Labels record within the Interested Labels and Spanning Tree Roots Sub-TLV (INT-LABEL). References: [rfc6326bis], This document Bit Mnemonic Description Reference --- -------- ----------- --------- 0 M4 IPv4 Multicast Router Attached [rfc6326bis] 1 M6 IPv6 Multicast Router Attached [rfc6326bis] 2 BM Bit Map [rfc6326bis] 3 ES ESADI Participation This document 4-7 - available for allocation 7.2 TRILL GENINFO TLV IANA is requested to allocate an IS-IS Application Identifier under the Generic Information TLV (#251) for TRILL [RFC6823] and to create a subregistry in the TRILL Parameters Registry for "TRILL APPsub-TLVs under IS-IS TLV #251 Application Identifier #TBD". The initial contents of this subregistry are as follows: Type Name Reference ------ -------- ----------- 0 Reserved <this RFC> 1 ESADI-PARAM <this RFC> 2-254 Available <this RFC> 255 Reserved <this RFC> TRILL APPsub-TLV Types 2 through 254 are available for allocation by IETF Review. The RFC causing such an allocation will also include a discussion of security issues and of the rate of change of the information being advertised. TRILL APPsub-TLVs MUST NOT alter basic IS-IS protocol operation including the establishment of TRILL IS-IS adjacencies, the IS-IS update process, and the decision process for TRILL IS-IS [IS-IS] [RFC1195] [RFC6327]. The TRILL Generic Information TLV MUST NOT be used in an IS-IS instance zero [RFC6822]. The V, I, D, and S flags in the initial flags byte of a TRILL Generic Information TLV have the meanings specified in [RFC6823] but are not currently used as TRILL operates as a Level 1 IS-IS area and no semantics is hereby assigned to the inclusion of an IPv4 and/or IPv6 address via the I and V flags. Thus these flags MUST be zero; however, use of multi-level IS-IS is an obvious extension for TRILL H. Zhai, et al [Page 24] INTERNET-DRAFT TRILL: ESADI [MultiLevel] and future IETF Standards Actions may update or obsolete this specification to provide for the use of any or all of these flags in the TRILL GENINFO TLV. The ESADI Parameters information, for which TRILL APPsub-TLV 1 is hereby assigned, is compact and slow changing (see Section 6.1). For Security Considerations related to ESADI and the ESADI parameters APPsub-TLV, see Section 8. H. Zhai, et al [Page 25] INTERNET-DRAFT TRILL: ESADI 8. Security Considerations For general TRILL Security Considerations, see [RFC6325]. More TBD H. Zhai, et al [Page 26] INTERNET-DRAFT TRILL: ESADI Normative references [ASCII] - American National Standards Institute (formerly United States of America Standards Institute), "USA Code for Information Interchange", ANSI X3.4-1968, 1968. ANSI X3.4-1968 has been replaced by newer versions with slight modifications, but the 1968 version remains definitive for the Internet. [FIPS180] - "Secure Hash Standard (SHS)", United States of American, National Institute of Science and Technology, Federal Information Processing Standard (FIPS) 180-4, March 2012, http://csrc.nist.gov/publications/fips/fips180-4/fips-180-4.pdf [IS-IS] - International Organization for Standardization, "Intermediate system to Intermediate system intra-domain routeing information exchange protocol for use in conjunction with the protocol for providing the connectionless-mode Network Service (ISO 8473)", ISO/IEC 10589:2002, Second Edition, Nov 2002. [RFC1195] - Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC1195, December 1990. [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC2119, March 1997. [RFC4086] - Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC4086, June 2005. [RFC6165] - Banerjee, A. and D. Ward, "Extensions to IS-IS for Layer-2 Systems", RFC6165, April 2011. [RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A. Ghanwani, "Routing Bridges (RBridges): Base Protocol Specification", RFC6325, July 2011. [RFC6327] - Eastlake 3rd, D., Perlman, R., Ghanwani, A., Dutt, D., and V. Manral, "Routing Bridges (RBridges): Adjacency", RFC 6327, July 2011. [RFC6361] - Carlson, J. and D. Eastlake 3rd, "PPP Transparent Interconnection of Lots of Links (TRILL) Protocol Control Protocol", RFC6361, August 2011. [RFC6823] - Ginsberg, L., Previdi, S., and M. Shand, "Advertising Generic Information in IS-IS", RFC6823, December 2012. [ClearCorrect] - Eastlake, D., Zhang, M., Ghanwani, A., Manral, V., A. Benerjee, "TRILL: Clarifications, Corrections, and Updates", H. Zhai, et al [Page 27] INTERNET-DRAFT TRILL: ESADI draft-ietf-trill-clear-correct, in RFC Editor's queue. [rfc6326bis] - Eastlake, D., Senevirathne, T., Ghanwani, A., Dutt, D., and A. Banerjee, "Transparent Interconnection of Lots of Links (TRILL) Use of IS-IS", draft-ietf-isis-rfc6326bis, work in progress. [RFCfgl] - Eastlake, D., M. Zhang, P. Agarwal, R. Perlman, D. Dutt, "TRILL (Transparent Interconnection of Lots of Links): Fine- Grained Labeling", draft-ietf-trill-fine-labeling, work in progress. Informative References [802.1X] - IEEE 802.1, "IEEE Standard for Local and metropolitan area networks / Port-Based Network Access Control", IEEE Std 802.1X-2010, 5 February 2010. [RFC6822] - Previdi, S., Ed., Ginsberg, L., Shand, M., Roy, A., and D. Ward, "IS-IS Multi-Instance", RFC6822, December 2012. [MultiLevel] - Perlman, R., D. Eastlake, A. Ghanwani, H. Zhai, "Multilevel TRILL (Transparent Interconnection of Lots of Links)", draft-perlman-trill-rbridge-multilevel, work in progress. [RFC3748] - Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. Levkowetz, Ed., "Extensible Authentication Protocol (EAP)", RFC 3748, June 2004. [RFC6234] - Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)", RFC6234, May 2011. [VLANmapping] - Perlman, R., D. Dutt, A. Banerjee, A. Rijhsinghani, and D. Eastlake, "RBridges: Campus VLAN and Priority Regions", draft-ietf-trill-rbridge-vlan-mapping, work in progress. H. Zhai, et al [Page 28] INTERNET-DRAFT TRILL: ESADI Appendix Z: Change History RFC Editor: Please delete this section before publication. Z.1 From -00 to -01 1. Add Section 6.3 "Default Authentication". 2. Add "Acknowledgements" Section. 3. Change requirement from "MAY" to "SHOULD" for an ESADI RBridge that is not DRB to send an ESADI-CSNP if it does not receive an ESADI-CSNP in long enough. 4. Default CSNP Time was listed as 30 in one place and 40 in another. Change to uniformly specify 30. 5. Update references to RFC 6326 to reference the 6326bis draft. 6. Relax allocation criteria for TRILL APPsub-TLV type code points from Standard Action to IETF Review. 7. Numerous Editorial changes. Z.2 From -01 to -02 1. Extend to cover FGL and well as VLAN and introduce the term "Data Label" to cover both. 2. Expand number of LSP fragments to 2**16. 3. Simplify neighbor detection to no longer require possesion of ESADO LSP zero. 4. Add update to last sentence of Section 4.2 of [RFC6325]. 5. Update references for publication of RFCs 6822 and 6823. 6. Additional minor changes. H. Zhai, et al [Page 29] INTERNET-DRAFT TRILL: ESADI Authors' Addresses Hongjun Zhai ZTE Corporation 68 Zijinghua Road Nanjing 200012 China Phone: +86-25-52877345 Email: firstname.lastname@example.org Fangwei Hu ZTE Corporation 889 Bibo Road Shanghai 201203 China Phone: +86-21-68896273 Email: email@example.com Radia Perlman Intel Labs 2200 Mission College Blvd. Santa Clara, CA 95054-1549 USA Phone: +1-408-765-8080 Email: Radia@alum.mit.edu Donald Eastlake Huawei R&D USA 155 Beaver Street Milford, MA 01757 USA Phone: +1-508-333-2270 Email: firstname.lastname@example.org Olen Stokes Extreme Networks Pamlico Building One, Suite 100 3306 East NC Hwy 54 RTP, NC 27709 USA Email: email@example.com H. Zhai, et al [Page 30] INTERNET-DRAFT TRILL: ESADI Copyright and IPR Provisions Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. 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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. H. Zhai, et al [Page 31]