Network Working Group Donald Eastlake 3rd INTERNET-DRAFT Eastlake Enterprises Intended status: Proposed Standard Radia Perlman Sun Microsystems Dinesh Dutt Cisco Expires: February 2009 August 3, 2008 RBridges: Use of IS-IS Status of This Document By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Distribution of this document is unlimited. Comments should be sent to the TRILL Working Group . 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/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract RBridges implement the TRILL protocol, which in turn makes use of an extended version of the IS-IS (Intermediate System to Intermediate System) routing protocol to determine topology and frame forwarding. RBridges provide optimal pair-wise forwarding with zero configuration, safe forwarding even during periods of temporary loops, and multipathing for both unicast and multicast traffic. Rbridges also support VLANs. This document specifies details of TRILL use of IS-IS. D. Eastlake, R. Perlman, & D. Dutt [Page 1] INTERNET-DRAFT RBridges: Use of IS-IS Table of Contents Status of This Document....................................1 Abstract...................................................1 Table of Contents..........................................2 1. Introduction............................................3 1.1 Terminology............................................3 2. Separation of IS-IS Instances...........................5 2.1 Protocol Separation of IS-IS Instances.................5 2.2 Instance Separation of TRILL IS-IS Instances...........5 3. TRILL IS-IS PDU Details.................................7 3.1 Hello PDUs.............................................7 3.2 LSP PDUs...............................................9 3.2.1 Core Instance LSP....................................9 3.2.2 ESADI LSP...........................................12 3.3 CSNP/PSNP PDUs........................................12 3.4 MGROUP PDUs...........................................13 4. Specific TLVs..........................................14 4.1 Area Address..........................................14 4.2 Protocols Supported...................................14 5. Bridged LAN Link Costs.................................15 6. IANA Considerations....................................16 7. Security Considerations................................16 8. Normative References...................................17 9. Informative References.................................17 Disclaimer................................................18 Additional IPR Provisions.................................18 Author's Address..........................................19 Expiration and File Name..................................19 D. Eastlake, R. Perlman, & D. Dutt [Page 2] INTERNET-DRAFT RBridges: Use of IS-IS 1. Introduction [RBRIDGE] specifies the TRILL base protocol which provides optimal pair-wise forwarding with zero configuration, safe forwarding even during periods of temporary loops, and multipathing for both unicast and multicast traffic. Rbridges also support VLANs. The TRILL protocol, in turn, makes use of the IS-IS [ISIS] protocol with certain extensions. [ISIS-L2] specifies the general [ISIS] facilities to provide true link state routing to any protocol running directly over Layer-2. This is a specification of details of TRILL use of IS-IS concentrating on IS-IS PDU content. It makes use of the Router Capabilities TLV [RFC4971] although perhaps some other TLV or a new TLV would be better in some cases. [RBRIDGE] specifies the TRILL enveloping of IS-IS PDUs and the flow of such PDUs, along with the determination of the Designated RBridges (DRB, equivalent to the DIS (Designated Intermediate System)) on a link and the like. {{Comments in double curly braces relate to version -03 of [ISIS- L2].}} 1.1 Terminology 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 RFC 2119. The following other special words or acronyms are used in this document: CSNP - Complete Sequence Number PDU ESADI - End Station Address Distribution Instance. LSP - Link State PDU PDU - Protocol Data Unit. PSNP - Partial Sequence Number PDU RBridge - Routing Bridge. One of the devices that implement TRILL. The second letter in Rbridge is case insensitive. Both Rbridge and RBridge are correct. TLV - Type, Length, Value. The general format of the data elements included as the content of IS-IS PDUs after their header. D. Eastlake, R. Perlman, & D. Dutt [Page 3] INTERNET-DRAFT RBridges: Use of IS-IS TRILL - TRansparent Interconnection of Lots of Link. The protocol specified partly in [RBRIDGE] and document. ** - Indicates exponentiation. 2**12 is two to the twelfth power. D. Eastlake, R. Perlman, & D. Dutt [Page 4] INTERNET-DRAFT RBridges: Use of IS-IS 2. Separation of IS-IS Instances TRILL implements separate IS-IS instances from those used by Layer 3, that is, different from the one used by IP routers. It is important that these be distinguishable to avoid possible confusion that would occur if an IS-IS instance attempted to process IS-IS PDUs intended for a different instance. TRILL implements multiple instances of IS-IS for its own use. One, mandatory instance, includes information such as basic connectivity between routers, location of VLANs, location of IP multicast routers, and the like. RBridges also optionally implement TRILL IS-IS ESADIs (End Station Address Distribution Instances), to carry information about attached end nodes. Section 2.1 explains how TRILL encodes IS- IS frames to ensure that there is no confusion between TRILL instances of IS-IS and Layer-3 instances of IS-IS or between the mandatory core instance of TRILL IS-IS and ESADIs. 2.1 Protocol Separation of IS-IS Instances TRILL IS-IS Layer-2 frames differ from those for Layer-3 use of IS-IS and cannot be accidentally confused with them as follows: 1. TRILL IS-IS frames consist of an IS-IS frame enveloped within a frame that uses the TRILL Ethertype and has an inner multicast destination address of All-IS-IS-RBridges. 2. Native frames for Layer-3 IS-IS are sent to either the AllL1ISs (01-80-C2-00-00-14) or AllL2ISs (01-80-C2-00-00-15) multicast addresses. TRILL frames that are enveloped Layer-3 IS-IS do NOT have All-IS-IS-RBridges as their inner destination address (it will be AllL1ISs or AllL2ISs) and so are treated as ordinary TRILL data frames 3. TRILL uses a distinct, constant IS-IS Area Address that would not appear as a real Layer-3 IS-IS area address. This Area Address is the value zero. (See Section 4.1.) 2.2 Instance Separation of TRILL IS-IS Instances An RBridge campus may have up to (1 + 2**12 - 2) instances of TRILL IS-IS; that is, one mandatory core instance plus one optional ESADI per VLAN. A 12-bit field identifies a VLAN but the values 0x000 and 0xFFF are not allowed so there are (2**12 - 2) legal VLANs. The multiple instance mechanism described in [ISIS-MI] is used to D. Eastlake, R. Perlman, & D. Dutt [Page 5] INTERNET-DRAFT RBridges: Use of IS-IS distinguish these TRILL IS-IS instances for convenience in cases where they are executed in one process on an Rbridge. In particular: 1. All IS-IS PDUs for the mandatory core TRILL IS-IS instances MAY include the MI TLV with the instance number of zero, and 2. All IS-IS PDUs for optional TRILL IS-IS ESADIs, MUST include the MI TLV with the instance number equal to their VLAN ID. The instance identifier TLV is type #7. D. Eastlake, R. Perlman, & D. Dutt [Page 6] INTERNET-DRAFT RBridges: Use of IS-IS 3. TRILL IS-IS PDU Details [ISIS], as extended by [ISIS-L2], supports 7 types of PDUs: Hello, LSP, CSNP, PSNP, MGROUP, MGROUP CSNP, and MGROUP PSNP. TRILL aspects of the contents of each of the PDU types are specified in this Section. Some individual TLVs types are discussed in Section 4 below. All RBridges have a 6-octet System ID that is conveyed in the header of every TRILL IS-IS PDU they produce, just as in Layer-3 IS-IS. The Maximum Area Addresses octet in the common fixed header is set to 0x01. An RBridge campus is a single Level 1 IS-IS Area. Where some IS-IS TLVs assume a unique 32-bit Router ID, in TRILL IS- IS this field is zero All TRILL IS-IS PDUs MAY contain an Authentication TLV (TLV #10). 3.1 Hello PDUs Hellos are only used in the core instance of TRILL IS-IS. The core instance link state contains enough information that the DRB, adjacencies, and holding time for any ESADI can be determined without Hellos. (See Section 4.2.4.1 of [RBRIDGE].) All TRILL Hello PDUs contain the TRILL Area Address TLV (see Section 4.1). The Circuit Type two bit field of TRILL IS-IS Hello PDUs MUST be set to 0b01 indicating Level 1 only. An IS Neighbor TLV (TLV #6) MUST be included in a TRILL Hello if the Hello is sent on the Designated VLAN and MUST NOT be included if it is sent on any other VLAN. Core IS-IS instance Hello PDUs MUST include one or more Capability TLVs [RFC4971] (TLV #242). The D and S flags in the Capability TLV MUST be zero. Other information is included by instances of the following TRILL related subTLVs: 1. Special VLANs (subTLV #). This subTLV MUST appear once in a Capability TLV in every TRILL Hello PDU. The length of the value is four octets. The first two octets are a copy of the Outer.VLAN tag value associated with the Hello frame when it was sent. The third and forth octets give the Designated VLAN for the link. The lower 4 bits of the third octet give the upper ID bits of the Designated VLAN and the forth octet gives the lower VLAN ID bits. The upper 4 bits of the third octet are reserved and MUST be sent D. Eastlake, R. Perlman, & D. Dutt [Page 7] INTERNET-DRAFT RBridges: Use of IS-IS as zero and ignored on receipt. 2. Enabled VLANs (subTLV #). Specifies the VLANs enabled for output at the port on which the Hello was sent. The minimum size of the value is 3 octets. The third and subsequent octets provide a bit map of enabled VLANs starting at the VLAN ID indicated in the first two octets. The lower order four bits of the first octet give the upper bits of the starting VLAN ID and the second octet gives the lower bits of that VLAN ID. The upper four bits of the first octet are reserved and MUST be sent as zero and ignored on receipt. The highest order bit of the third octet indicates the VLAN equal to the starting ID while the lowest order bit of the third octet indicated that ID plus 7. For example, VLANs 1 and 14 being enabled could be encoded in 4-octets value 0x00 0x01 0x80 0x04. This subTLV may occur more than once in a TRILL Hello and a VLAN is enabled for output on the port where the Hellos was sent if this is indicated by any occurrence in the Hello. For example, a receiver could allocate a 512-octet buffer and, with appropriate shifting operations, OR in the enabled bits for each TLV of this type it finds in a Hello to derive the complete bit map of enabled VLANs. 3. Appointed Forwarders (subTLV #). This subTLV provides the mechanism by which the DRB can inform other RBridges on the link that they are the designated VLAN-x forwarder for that link for one or more ranges of VLAN IDs. The size of the value is 5*n octets where there are n appointments. Each 5 octet part of the value is formatted as follows: | octet 1 | octet 2 | octet 3 | octet 4 | octet 5 | +----------+----------+----------+-----+----+----------+ | Appointee Nickname | Start VLAN ID | End VLAN ID | +----------+----------+----------+-----+----+----------+ The VLAN range give is inclusive. To specify a single VLAN, that VLAN ID appears as both the start and end VLAN. The RBridge whose nickname is given is appointed forwarder for those VLANs for which it has end station service enabled (see item 2 above) in the inclusive range. For example, assume an RBridge with end station service enabled on VLANs 100, 101, 199, and 200 (and possibly other VLANs less than 100 or greater than 200), but not enabled for VLANS 102 through 19. It could be appointed forwarder for these four VLANs through either (1) a single 5-octet value sequence with start and end VLAN IDs of 100 and 200, or (2) a 10-octet value sequence with start and enc VLAN IDs of 100 and 101 in the first part and 199 and 200 in the second part. An RBridge's nickname may occur as appointed forwarder for D. Eastlake, R. Perlman, & D. Dutt [Page 8] INTERNET-DRAFT RBridges: Use of IS-IS multiple VLAN ranges within the same or different router capability TLVs within a DRB's Hello. In the absence of appointed forwarder subTLVs referring to a VLAN, the DRB acts as the appointed forwarder for that VLAN if it has end station service enabled for its port on that link. 3.2 LSP PDUs The TLVs to be included in TRILL LSP PDUs are very different for the mandatory core IS-IS instance of a campus, discussed in Section 3.2.1 below, and in the optional ESADIs, discussed in section 3.2.2 below. All TRILL LSP PDUs contain the TRILL Area Address TLV (see Section 4.1). In addition, in the LSP header, the P Flag and Att flags MUST be zero and the IS type two bit field MUST be set to 0b01 indicating Level 1. 3.2.1 Core Instance LSP The content of core TRILL IS-IS instance LSP PDUs includes: 1. Information on reachable RBridge neighbors and the cost of the hop via the usual IIS neighbors TLV (TLV #2). 2. The RBridge flags, nickname, VLANs, and other information via one or more Capability TLVs [RFC4971] (TLV #242). The D and S flags in the Capability TLV MUST be zero. Other information is included by instances of the following TRILL related subTLVs: 2.a TRILL Flags (subTLV #). Exactly one TRILL Flags subTLV must occur in the link state of every RBridge. The length of the value of this subTLV is variable with a minimum size of 1 octet. The top four bits of the first octet are defined as below. Additional bits may be specified in the future and those bits may extend into subsequence octets. The value of all bits in any octets not present is assumed by a receiver to be zero. first octet 0 1 2 3 4 - 7 +----+----+----+----+-----------+--- | V0 | V1 | V2 | V3 | reserved | +----+----+----+----+-----------+--- V0 through V4 indicate support of TRILL Header Versions 0 through 4. The remaining bits of the first octet (and all bits D. Eastlake, R. Perlman, & D. Dutt [Page 9] INTERNET-DRAFT RBridges: Use of IS-IS of subsequent octets if present) are reserved and MUST be zero when sent and ignored on receipt. 2.b Nickname and Tree Root (subTLV #). If an RBridge is to be able to act as an ingress, egress, or tree root, it must have a nickname. The value is either 3, 5, or 7 octets in length. The first octet is the RBridge's nickname priority and the second and third octets are its nickname. If octets 4 and 5 are present, they are the RBridge's priority to be a tree root as an unsigned 16-bit integer that defaults to 0x8000 if absent. If octets 6 and 7 are present, they are an unsigned 16-bit integer that gives the number of additional trees every RBridge in the campus is to compute if the RBridge in whose link state this occurs is the highest priority tree root. If octets 6 and 7 are absent, this number of additional trees defaults to 1. (See [RBRIDGE] Section 4.3.) {{While the Device ID subTLV in [ISIS-L2] could be used for Nickname, putting the Nickname priority in 8 of the Options bits, the Root Priority subTLV and Root Identity subTLV in [ISIS-L2] does not correspond with how RBridges determine distribution tree roots or multi-path multi-destination frames.}} 2.c Distribution Tree Roots (subTLV #). The value is a variable length array of the nicknames of the RBridges which the originating RBridge might pick as the root of the distribution tree for multi-destination traffic for which it is the ingress RBridge. If the list is empty or this subTLV is not provided, the originating RBridge can only select the highest priority tree root (see [RBRIDGE] Section 4.3). 2.d VLANs (subTLV #). The value of this subTLV consists of a VLAN range, flags, and a variable length list of spanning tree root bridge IDs. This subTLV may appear zero, one, or many times. The union of the VLAN ranges in all occurrences MUST be precisely the set of VLANs for which the originating RBridge is appointed forwarder on at least one port and the VLAN ranges in multiple VLANs subTLVs for an RBridge MUST NOT overlap. That is, the intersection of the VLAN ranges for any pair of these subTLVs originated by an RBridge must be null. The value length is 4 + 6*n where n is the number of root bridge IDs. The initial 4 octets of value are as follows: 0 1 2 3 4 - 15 16 - 19 20 - 31 +----+----+----+----+------------+----------+------------+-- | M4 | M6 | OM | R | VLAN start | Reserved | VLAN end | +----+----+----+----+------------+----------+------------+-- The M4 bit indicates that there is an IPv4 multicast router on D. Eastlake, R. Perlman, & D. Dutt [Page 10] INTERNET-DRAFT RBridges: Use of IS-IS a link for which the originating RBridge is appointed forwarder for every VLAN in the indicated range. The M6 bit indicates the same for an IPv6 multicast router. The OM bit indicates that this RBridge requests that all non-IP derived multicast traffic in the indicated VLAN range be sent to it. The R and Reserved bits MUST be sent as zero and are ignored on receipt. The VLAN start and end IDs are inclusive. A range of one VLAN ID is indicated by setting them both to that VLAN ID value. The list of zero or more spanning tree root bridge IDs is the set of root bridge IDs seen for all ports for the VLANs in the range and for which the RBridge is appointed forwarder. This information is learned from BPDUs heard by the RBridge. If MSTP is in use on a link, the root bridge referred to is the CIST (common and internal spanning tree) root bridge. While, of course, only one spanning tree root should be seen on any particular port, there may be multiple ports in the same VLAN connected to differed bridged LANs with different spanning tree roots. If no spanning tree roots can be seen on any of the links in any of the VLANs in the range indicated for which the RBridge is appointed forwarder (for example all such links are point-to-point links to other RBridges or to end stations so no BPDUs are received) then the listed set of spanning tree root IDs will be null. If there are any two VLANs in the range indicated for which the value of the M4, M6, or OM bits are different, the subTLV is incorrect and must be split into multiple subTLVs each indicating only VLANs with the same M4, M6, and OM values. If there are any two VLANs in the range indicated for which the set of root bridge IDs see on all links for which the RBridge is appointed forwarder for the VLAN are not the same, the subTLV is incorrect and must be split into multiple subTLVs each indicating only VLANs with the same set of DRB seen root bridge IDs. It is always safe to use subTLVs with a "range" of one VLAN ID but this may be too verbose. 2.e ESADI Participation (subTLV #). The value of this optional subTLV is 6*N octets where N is the number of VLAN ranges given. The presence of this subTLV in the LSP for an RBridge constitutes the ESADI participation flag for the VLANs in the range or ranges given. Each 6 octets of value is structured as follows: 0 1-7 | 8-15 | 16-19 20-23 | 24-31 | 32-39 | +-+----------+------+-------+-------+-------+--------------+ |R| Priority | VLAN start | VLAN end | Holding Time | +-+----------+------+-------+-------+-------+--------------+ D. Eastlake, R. Perlman, & D. Dutt [Page 11] INTERNET-DRAFT RBridges: Use of IS-IS The R bit is reserved and MUST be sent as zero and ignored on receipt. The Priority field gives the RBridge's priority for being DRB on the EASDI virtual links for the VLAN or VLANs indicated while the Holding Time field gives its holding time if it is DRB. The VLAN start and end values give the inclusive range of VLAN IDs for which the RBridge wishes to participate in an ESADI. A range of one VLAN is specified by making the start and end IDs equal. 2.f VLAN Groups (subTLV #). The value of this optional subTLV consists of two or more 16-bit fields each of which has a VLAN ID in the low order 12 bits and the top 4 bits zero. The first such VLAN ID is the primary, or may be zero if there is no primary. Address learning is shared between the listed VLANs at the originating RBridges as described in Section 4.6.3 of [RBRIDGE]. This subTLV may appear zero, one, or many times. Note: See Section 3.4 below for multicast groups. 3.2.2 ESADI LSP The TRILL information in ESADI LSP PDUs consists of one or more MAC Reachability (MAC-RI) TLVs [ISIS-L2] (TLV #139). Each MAC-RI TLV contains the VLAN ID and one or more unicast MAC addresses of end stations which 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. {{There is no place in the current MAC-Reachability TLV for the confidence level. It could go where the VLAN-ID currently is as the VLAN ID is not needed for the TRILL use. Alternatively, some option bits and the confidence could be inserted before or after the VLAN- ID. Or the confidence could be changed to 4 bits and packed in with the VLAN-ID...}} 3.3 CSNP/PSNP PDUs CSNP stands for Complete Sequence Number Packet and PSNP for Partial Sequence Number Packet. These relate to the IS-IS link state flooding algorithm and link state sequence numbers. There is no change from typical Layer-3 sequence number IS-IS PDUs except for the inclusion of instance separation TLVs as indicated in Section 2 above and the addition of MGROUP CSNP and PSNP PDUs. TRILL IS-IS uses only Level 1 sequence number packets. D. Eastlake, R. Perlman, & D. Dutt [Page 12] INTERNET-DRAFT RBridges: Use of IS-IS 3.4 MGROUP PDUs MGROUP PDUs [ISIS-L2] are only sent as part of the core IS-IS instance. They contain one or more Group Address (GADDR) TLVs each of which, in turn, contains one or more Group MAC Address (GMAC-ADDR) sub-TLVs. Those GMAC-ADDR sub-TLVs specify the VLAN involved and list the IP-derived multicast addresses for which there are listeners on links for which the originating RBridge is appointed forwarder. (MGROUP PDUs must be in the core instance of TRILL IS-IS, even if an ESADI is in use for the relevant VLAN, so that transit RBridges can properly prune the distribution of multicast frames.) All TRILL MGROUP PDUs contain the TRILL Area Address TLV (see Section 4.1). D. Eastlake, R. Perlman, & D. Dutt [Page 13] INTERNET-DRAFT RBridges: Use of IS-IS 4. Specific TLVs This section describes particular TLVs included or not included in TRILL IS-IS PDUs. 4.1 Area Address The TRILL zero Area Address TLV is encoded as follows: +--------------------------+--------------------------+ | 0x01 (Area Address TLV) | 0x02 (Length of Value) | +--------------------------+--------------------------+ | 0x01 (Length of Address) | 0x00 (zero Area Address) | +--------------------------+--------------------------+ 4.2 Protocols Supported Since no NLPID (Network Layer Protocol Identifier) has been allocated by the ISO/IEC TR 9577 Registry for the Ethernet protocol or MAC-48 address type or TRILL, there is no way to indicate support of IS-IS routing for these in a Protocols Supported TLV (TLV #129). D. Eastlake, R. Perlman, & D. Dutt [Page 14] INTERNET-DRAFT RBridges: Use of IS-IS 5. Bridged LAN Link Costs RBridges use IS-IS to support TRILL and may be interconnected by direct links such as 802.3, or by bridged LANs. If there an intervening bridge or bridges, the link is really multiple bridged physical links. RBridges can automatically detect this condition under some circumstances. For loop avoidance purposes RBridges listen for BPDUs and keep track of the most recent announced root bridge on a link [RBRIDGE], if any. This bridge, or the fact that no BPDUs have been received, is reported in the link state database as described in Section 3.2.1 above. It is still possible for RBridges to be connected by a bridged LAN where the bridge ports to which they are connected have been configured not to emit BPDUs. On the other hand, if any RBridge connected to a link is seeing BPDUs, it is likely that there are one or more intervening bridges between it and any RBridge on the link to which it appears to be adjacent. When a link is a bridged LAN, transit traffic will experience at least two bridged physical links and possibly many more. To account for this, RBridges SHOULD assume, for IS-IS routing purpose, that the default metric for traversing such a link is 2*C + 1, where C is the Layer-3 IS-IS default metric (usually auto-configured from port speed). More precise link cost can be asserted by management configuration. D. Eastlake, R. Perlman, & D. Dutt [Page 15] INTERNET-DRAFT RBridges: Use of IS-IS 6. IANA Considerations IANA needs to add nine subTLV values under the IS-IS Capabilities TLV (#242). They are all specified in Section 3.1 and 3.2.1 above and are as follows: Name Value ---- ----- Special VLANs Enabled VLANs Appointed Forwarders TRILL Flags Nickname and Tree Root Distribution Tree Roots VLANs ESADI Participation VLAN Groups 7. Security Considerations This document raises no new security issues for IS-IS. IS-IS security may be used to secure the IS-IS messages discussed here. See [RFC3567]. See [RBRIDGE] for TRILL Security Considerations. D. Eastlake, R. Perlman, & D. Dutt [Page 16] INTERNET-DRAFT RBridges: Use of IS-IS 8. Normative References [ISIS] - "Intermediate system to Intermediate system routeing information exchange protocol for use in conjunction with the Protocol for providing the Connectionless-mode Network Service (ISO 8473)", ISO, ISO/IEC 10589:1992. [ISIS-L2] - D. Ward et. al, "Carrying Attached Addresses in IS-IS", draft-ward-l2isis-03.txt, work in progress, May 2008. [ISIS-MI] - S. Previd et. al., "IS-IS Multi-instance", draft-ietf- isis-mi-00.txt, work in progress, February 2008. [RBRIDGE] - "Rbridges: Base Protocol Specification", draft-ietf- trill-rbridge-protocol-08.txt, work in progress, July 2008. [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4971] - Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., "Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information", RFC 4971, July 2007. 9. Informative References [RFC3567] Li, T. and R. Atkinson, "Intermediate System to Intermediate System (IS-IS) Cryptographic Authentication", RFC 3567, July 2003. D. Eastlake, R. Perlman, & D. Dutt [Page 17] INTERNET-DRAFT RBridges: Use of IS-IS Disclaimer This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Additional IPR Provisions The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. Copyright (C) The IETF Trust 2008. This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. D. Eastlake, R. Perlman, & D. Dutt [Page 18] INTERNET-DRAFT RBridges: Use of IS-IS Author's Address Donald E. Eastlake 3rd Eastlake Enterprises 155 Beaver Street Milford, MA 01757 USA Phone: +1-508-634-2066 email: d3e3e3@gmail.com Radia Perlman Sun Microsystems 16 Network Circle Menlo Park, CA 94025 Phone: +1-650-960-1300 Email: Radia.Perlman@sun.com Dinesh G. Dutt Cisco Systems 170 Tasman Drive San Jose, CA 95134-1706 USA Phone: +1-408-527-0955 email: ddutt@cisco.com Expiration and File Name This draft expires in February 2009. Its file name is . D. Eastlake, R. Perlman, & D. Dutt [Page 19]