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    Trill spb-comparison-extract Trill spb-comparison-extract Presentation Transcript

    • TRILL and SPBOverview & Comparison Ali Sajassi Principle Engineer NSSTG CTO Group August 14, 2009 EDCS-805350 TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 1
    • Agenda Quick Update on PBB & PBB-TE TRILL Overview SPB Overview TRILL v.s. SPB Comparison TRILL w/ MAC-in-MAC (E-TRILL) OAM for E-TRILLTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 2
    • PBB Updates draft-sajassi-l2vpn-vpls-pbb-interop.txt has been accepted as IETF WG draft about six months ago - Discusses the use of PBB over VPLS to address service instance and MAC scalability issues - Discusses different interop scenarios between PBB and VPLS including gradual migration and the following scenarios • H-VPLS with 802.1ah Access Network • H-VPLS with Mixed 802.1ad and 802.1ah Access Network • H-VPLS with MPLS Access Network and 802.1ah u-PE • H-VPLS with MPLS Access Network and 802.1ah n-PETRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 3
    • PBB Update – Cont. draft-sajassi-l2vpn-pbb-vpls-multicast.txt - use of BGP for limiting the scope of broadcast per I-SID within a single VPLS instance (e.g., multicast pruning per I-SID) - haven’t done much w/ this draft draft-sajassi-l2vpn-pbb-vpls-cmac-flush.txt -To flush C-MAC addresses in a PBB-VPLS - C-MAC flushing is needed upon AC change – e.g., switch over from primary AC to backup AC - Independent from B-MAC flushing - Cisco started project IEEE 802.1Qbe which includes this draft & MIRP registration draft-mohan-l2vpn-vpls-oam.txt - Need to updated it and get it ready for WG draft callTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 4
    • PBB-TE IEEE 802.1Qay has been completed - Went through sponsor ballot a few meetings ago It doesn’t seem like to have much traction in industry since - the major SP sponsor of this technology switched gear to MPLS - the major vendor sponsor of this technology filed bankruptcy Instead there is lot of activity and vendor participation on MPLS-TP - Lots of draft submission and discussion on IETF MPLS WG - Lots of discussions between ITU & IETF groups on OAM mechanism for MPLS-TP - Lots of vendors have committed to implementing MPLS-TP including CiscoTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 5
    • Agenda Quick Update on PBB & PBB-TE TRILL Overview SPB Overview TRILL v.s. SPB Comparison TRILL w/ MAC-in-MAC (E-TRILL) OAM for E-TRILLTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 6
    • On Collision Course Both IETF & IEEE have been working on next gen control plane for Ethernet IETF TRILL currently targets Data Center & Enterprise segments IEEE SPB targets Enterprise & Service Provider Segments Each of the above technology can extend to the missing segmentTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 7
    • Objectives for NG Ethernet Protocol Optimum multicast & unicast forwarding Fast Convergence Robust loop mitigation and/or preventions Scale for large networks Ease of maintenance & reduce number of protocols Scale to large number of MAC addresses – e.g., transparent to the core nodes ECMP !! Multi-pathing for multicast trafficTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 8
    • Classical MSTP Network Bridge Domain CE2 CE CE CE Root CE1 802.1q Bridge or HUB Cust. Eth Header Cust. Eth Header Links Disabled by Spanning Tree Cust IP Packet Cust IP PacketTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 9
    • What is TRILL? An IETF WG for Shortest Path Bridging Control Plane leverages IS-IS, but is orthogonal to L3 IS-IS Uses Routing Bridges (RBridges) using IS-IS to provide: Shortest Unicast Paths (no STP single tree constraint) Faster Convergence times Minimal or no configuration required Load-splitting among multiple paths Loop mitigation (TTL)* Support for multiple points of attachment Bonus: Relegates End Station MAC Address Learning to Edges, providing the MAC scalabilityTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 10
    • TRILL Basics A TRILL Network is a collection of Routing Bridges, RBridges, or simply RBs RBs may be interconnected by islands of 802.1 bridges - RBs can be connected by multi-access links or - RBs can be connected by simple P2P links RBs use ISIS for discovery and to distribute Link State Databases Packets are bridged between RBs, but Routed RBhop- by-RBhop from Ingress to Egress Edge RBs learn End Station MAC addresses in the data plane and associate them with the edge RBs.TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 11
    • TRILL Network CE CE CE CE RBridge CE 802.1q Bridge or HUB Next Hop(1) Next Hop(2) Eth Header Eth Header TRILL Header TRILL Header Cust. Eth Header Cust. Eth Header Cust. Eth Header Cust. Eth Header Cust IP Packet Cust IP Packet Cust IP Packet Cust IP PacketTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 12
    • TRILL Basics – Multi-Access Link Support of multi-access link implies - Rbriges can replace IEEE bridges anywhere in the network - support gradual replacement of IEEE bridges by Rbridges - Existential threat to IEEE !! - mini-me IP encapsulation – e.g., outer MAC addresses have link local significance as opposed to 802.1ah which have system wide significanceTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 13
    • TRILL Basics – Multi-Access Link - II Support of multi-access link introduces some complication to IS-IS procedures -IMHO at least one-third of the TRILL spec is related to the support of multi-access link - Requires IS-IS to select a single DRB over the multi-access link - Requires that DRB to pick a designated VLAN - Requires that DRB to pick a appointed forwarder for each VLAN over the multi-access link - appointed forwarder can be same or different from the DRBTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 14
    • TRILL Routing Unicast: Packets are forwarded hop-by-hop using local Shortest path Equal Cost Multipath supported, load-balancing a local decision Multicast: Traffic is sent over Multicast Distribution Trees (MDTs) Highest priority RB (Selector) decides how many MDTs to build MDT list can be sent in LSP, but defaults to highest priority RBs If # of MDTs < # of RBs, out-of-order packet delivery may occur* Building 1 tree similar to Spanning Tree except unicast still optimal *when an unknown packet takes one path and a subsequent packet takes the known unicast pathTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 15
    • TRILL Network RBridge Domain MTD 1 1 MDT 2 MDT 3 3 2 A TRILL Network and 3 MDTs rooted at different RBsTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 16
    • Loop Mitigation There are three mechanisms for loop mitigation - Color Blocking Logic (VLAN check) - Ingress Interface Check (source check) - TTL VLAN check avoid some frames from entering a transient loop; however, there can still be scenarios where frames can enter a transient loop Ingress Interface Check prevents any frame from getting into a transient loop TLL basically kills the frames already in a transient loop gradually – e.g., traffic in the loop decays as a function of time When all the above three mechanisms are used together, then there would be no need for loop prevention mechanism – e.g., a solid loop mitigation mechanism removes the need for a loop prevention mechanism TRILL uses all the above tree mechanisms togetherTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 17
    • TRILL Frame Format Outer MAC DA Outer MAC DA Outer MAC SA NextHop Address (of next RBridge) Outer MAC SA Eth = 802.1Q Outer VLAN Eth = TRILL V/M/R, Op, TTL TRILL Address Egress RBID Ingress RBID CHbH, CItE, Reserved Optional TRILL … Extensions Inner MAC DA Inner MAC DA Inner MAC SA E2E Address Inner MAC SA Eth = 802.1Q Inner VLAN Payload ….TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 18
    • RBridge Port Model RBridge Forwarding Engine, IS-IS, Etc. Processing of Native and TRILL Frames EISS RBridge (Enhanced ISS) 802.1Q Port Vlan High Level Control Frame Processing Processing (BPDU, VRP) ISS (Internal Sublayer Service) 802.1/802.3 Low Level Control Frame Processing, Port/Link Control Logic Existing 802 stds 802.3 Phy New TRILL modulesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 19
    • TRILL Basics - Hellos ISIS Hellos are sent using a MAC of All-IS-IS-RBridges Hellos are used for neighbor discovery and exchange of info including: RB System ID is 48 bits (typically MAC address) All standard ISIS info Desired Designated VLAN, Designated VLAN Announcing VLAN Set, Forwarding VLAN Set The RBridge Nickname (to save space) RB Hello packets may be sent outside the RB network to discover and eliminate external loopsTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 20
    • TRILL LSP Contains: ISIS IDs of neighbors + wide link metric (#22) A 16 bit nickname (negotiated on conflicts) and nickname priority RB priority for choosing # of trees to calc Number of MDTs to calculate (if this RB is highest priority) List of nicknames for root of Trees (if this RB is highest priority) List of VLANs for which this RB is appointed forwarder (shared access links only)TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 21
    • TRILL MGROUP-LSP Brand new set of Multicast Group PDUs - MGROUP-LSP (Link State PDU) - MGROUP-CSNP (Complete Sequence Number Packet) - MGROUP-PSNP (Partial Sequence Number Packet) Same procedures and format as Level 1 PDUS (LSP, CSNP, and PSNP) GADDR TLV contains Group Address Sub-TLVS: - GMAC-ADDR - GIP-ADDR - GIPV6-ADDRTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 22
    • Agenda TRILL Overview SPB Overview (available at IEEE site) TRILL v.s. SPB Comparison TRILL w/ MAC-in-MAC (E-TRILL) OAM for E-TRILLTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 23
    • 802.1Q Data Plane Evolution Provider Backbone Bridges 802.1ah Payload Provider Bridges 802.1ad Ethernet Ethertype SA = Source MAC address VLAN C-VID DA = Destination MAC address Ethernet C-TAG Payload VID = VLAN ID S-VID C-VID = Customer VID S-TAG Payload S-VID = Service VID SA I-SID = Service ID Payload Ethertype DA B-VID = Backbone VID C-VID I-SID B-DA = Backbone DA Ethertype C-TAG I-TAG B-SA = Backbone SA C-VID S-VID B-VID Ethertype Q-TAG S-TAG B-TAG SA SA SA B-SA DA DA DA B-DA 1998 2005 2008 Standard ApprovedTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 24
    • Same Motivation as TRILL Bridge Domain CE2 CE CE CE CE CE CE CE Root CE1 CE • Traditional bridging based • Shortest path bridging on RSTP/MSTP – Optimum unicast & mcast – Non-optimal forwarding forwarding – Manual configuration – Automatic SPT management needed for disjoint trees & controlled by IS-IS mapping of VLANs to these treesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 25
    • IEEE 802.1aq variants Shortest Path Backbone Bridging (SPBM) is aimed to be deployed in PBB networks where all addresses are managed Shortest Path Bridging (SPBV) is applicable in customer, enterprise or storage area networks SPB SPBV SPBM Enterprise Network Access Network Metro Core Network • Plug & Play • Reliability • Reliability • Easy to operate • Bandwidth efficiency • Auto-discovery • Unknown addresses • Unknown or managed • Load sharing addresses • Managed addresses MAC learning MAC learning in data plane in control planeTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 26
    • Interworking with RSTP and MSTP Common Spanning Tree (CST) Internal Spanning Tree (IST) Common and Internal Spanning Tree SPT Region IST SPT Region IST CST MST Region MST Region RSTP bridgesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 27
    • IEEE 802.1aq uses IS-IS Topology discovery Each bridge is aware of the physical topology of the SPT Region Service discovery I-SID registrations are included into a new TLV Shortest Path Tree computation Maintenance of SPTs and CIST SPTs can be set according to the discovered I-SID membership information MRP is not needed VID allocation to VLANsTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 28
    • Source tree identification MAC address VLAN ID • B-SA and its Nickname incorporated into • An SPT is identified by the Group MAC DA identifies an SPT SPVID assigned to the source bridge Two VIDs only used for a whole set of Shortest Path Trees Applicable to both 802.1Q and (Base VID and another VID) 802.1ah bridges Each ECMT uses one more VID Ingress check on VID Bidirectionality of VID is preserved Consumes VLAN space Only applicable to 802.1ah bridges Unidirectional VIDs Ingress check on SA All multicast addresses take the local bit mappingTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 29
    • VLAN assignment identified by IEEE 802.1aq implements VLAN VID VID Base allocated to MSTI CIST supported by supported by SPT Set MSTI IST CST ID ID ID ID Base VID VID* SPVID Base VID Base VID Base VID B-SAGroup B-DA Learning Non- Learning Learning LearningNon-learning learning SPBB PBB-TE TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 30
    • Tree implementation • By Port Roles • By Filtering Entries Root Bridge Source Bridge Designated, Forwarding Root, Forwarding Alternate, Blocking • SPT is formed from the • Source rooted SPTs Root BridgeTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential applied in 802.1aq 31
    • MAC learning MAC learning in the data plane (Learning) IS-IS IS-IS IS-IS FDB FDB FDB Bridge Bridge Bridge A d A d e s e s d re d re s s s s d re d re s s s s Frames Frames e s e s A d A d MAC learning in the control plane (Non-learning) IS-IS Control Messages IS-IS Control Messages IS-IS Addresses Addresses Addresses FDB FDB FDB Bridge Bridge BridgeTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 32
    • SPB SPB (802.1Q compliant) Uses VID for source identification, don’t own the C-MAC Solution Attributes VID Trees, one source per bridge, distributed in IS-IS SVL learning of unicast forwarding supported Solution Requirements Must Interwork at edges with RSTP, MSTP The region may default to a single instance MSTP (associated with the “Base VID”) if the VID allocation fails or detects errors Must support loop prevention, may support ingress checkTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 33
    • SPB Concepts SPB Region Identifier!= Base VID SPT Region Payload Payload 45 45 SPVID = 22 SA SA Base VID 22 DA DA SPVID = 45 Payload SPVID = 66 22 SPVID = 44 Payload SA CST DA IST SPVID = 71 22 SA Payload DA SPVID = 41 41 Payload VID =6 SA DA Payload Payload 22 SA 41 22 DA SA SA DA DATRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 34
    • SPBB SPBB (Shortest Path Backbone Bridging) Solution Attributes Single VID for an SPT Region (may use VID Trees) Does not use learning of B-MACs Provider addresses will all be known allows for more efficient flooding (no B-MAC broadcast storms), Reduction in forwarding space Shared Forwarding, Solution Requirements Must use Multicast loop Prevention, Must use ingress check for unicastTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 35
    • SPBB Operation Shortest path between any IS-IS IS-IS two points is both the same and symmetrical for unicast and multicast BEB Backbone Edge IS-IS Bridge BEB IS-IS IS-IS IS-IS IS-IS Backbone Core Bridge BCB BCB BCB BEB BEB “A” PBBN IS-IS IS-IS BEB BEB Shortest Path Tree from “A”TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 36
    • SPBB Shortest Path Tree to/from “A” Shortest path between any IS-IS IS-IS two points is both the same and symmetrical for unicast and multicast BEB Backbone Edge IS-IS Bridge BEB IS-IS IS-IS IS-IS IS-IS Backbone Core Bridge BCB BCB BCB BEB BEB “A” PBBN IS-IS IS-IS All pairs shortest path computation performed in parallel BEB BEB Uses the full mesh networkTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 37
    • SPBB Multicast Groups I-SID 5 I-SID 5 IS-IS IS-IS MMAC for 5 from A BEB Backbone Edge IS-IS Bridge BEB IS-IS IS-IS IS-IS IS-IS Backbone Core Bridge BCB BCB BCB BEB BEB “A” PBBN IS-IS I-SID 5 IS-IS BEB BEB I-SIDs define efficient subsetsTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 38
    • Forward and Reverse path Congruency 1 Bridge3 1 1 Bridge2 1 1 Bridge1 Bridge4 Bridge5 2 1 Bridge6 Necessary if MAC learning is in the data plane Not necessary if MAC learning is in the control plane Going to be assured by both SPB and SPBBTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 39
    • Unicast and Multicast Congruency unicast 1 1 multicast Bridge3 1 Bridge2 1 1 Bridge1 Bridge4 Bridge5 2 1 Bridge6 Necessary for MAC learning in data plane Necessary for the proper operation of 802.1ag E-OAM Going to be assured by both SPBV and SPBMTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 40
    • Implementation of Congruency Tie-breaking extension to Dijkstra for the case of equal cost multiple paths List of node IDs comprising a path are unique {1,6,5} < {1,2,3,5} < {1,2,4,5} 1 Bridge3 1 1 Bridge2 1 1 Bridge1 Bridge4 Bridge5 2 1 Bridge6 Same algorithm is used both for unicast and multicastTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 41
    • Load sharing Two trees are calculated taking advantage of equal cost multiple paths: {1,6,5} < {1,2,3,5} < {1,2,4,5} SPT Primary Set Primary Base VID SPT Alternate Set Secondary Base VID 1 Bridge3 1 1 Bridge2 1 1 Bridge1 Bridge4 Bridge5 2 1 Bridge6TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 42
    • Loop Prevention and Mitigation Inconsistent view on network topology at different nodes may cause transient loops in case of a link-state control protocol Loop prevention Tree Agreement Protocol (TAP) Handshake mechanism between neighbors Extension to MSTP’s handshake Loop mitigation Ingress Checking (e.g. RPFC) Frames not arriving on the shortest path from the Source Bridge are discarded Makes the tree directed Good for loop prevention in most cases Transient loops may appear Severe problem for multicast traffic A chance of network melt-down remains if one does not care Ingress filtering has to be modifiedTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 43
    • Neighbor handshake mechanism Let’s make it sure that bridges having different view on network topology do not exchange frames The link between adjacent neighbors has to be blocked after a topology change until they agree that both of them have the same topology database The agreement between neighbors is implemented by a handshake mechanism A digest of the topology database is exchanged CRC Cryptographic hash function (e.g. SHA-256) Agreements at different part of the network are independent of each otherTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 44
    • Handshake: MSTP extension • Tree Agreement Protocol (TAP) • Two-way Agreement = three-way handshake Agreement Proposal Agreement • No per tree handshake • BPDUs contain – Digest of LSP database – Info on the CIST • Proposal-Agreement – Explicit on the CISTTRILL Overview – Computed for SPTs © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 45
    • Handshake: Filtering entry manipulations Wait for LSP update • SPBB networks Unicast computation • STPs are implemented by Install Unicast and Filtering Entries remove ‘unsafe’ • Do not implement the TAP Multicast FDB entries extension to MSTP Update Digest and send it to neighbors • Implement link-state database synchronization (TAP logic) Multicast computation • Loops for unicast flows are Install ‘safe’ mitigated by Ingress Checking Multicast FDB entries (RPFC) • Remove ‘unsafe’ entries if Wait for Digest synch neighbors are unsynchronized Install ‘unsafe’ Multicast FDB entriesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 46
    • Agenda TRILL Overview SPB Overview TRILL v.s. SPB Comparison TRILL w/ MAC-in-MAC (E-TRILL) OAM for E-TRILLTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 47
    • Functional Comparison TRILL 802.1aq Multipoint L2 Services: Yes Yes E-LINE, E-TREE, E-LAN C-MACs are learned Yes Yes only at the edges Optimum Unicast Fwding Yes Yes Optimum Mcast Fwding Yes Yes Multi-homing Yes Yes (using IS-IS) (using CST) ECMP Yes No Multi-pathing via multiple Yes Yes treesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 48
    • Functional Comparison – Cont. TRILL 802.1aq Ease of Provisioning Yes Yes (SPBV) No (SPBM) Enterprise/DC Applicability Yes Yes SP Applicability No Yes Congruency unicast & No Yes mcast Congruency forward & No Yes reverse (not needed) Intra-region loop Yes Yes prevention Inter-region loop No (note-1) Yes (via CIST) prevention Note-1: ©butCisco Systems, Inc. All rights of .1aq isConfidentialTRILL Overview2009 inter-region reserved. Cisco consider as intra region of TRILL 49
    • Control Plane TRILL 802.1aq Neighbor and topology Yes Yes discovery using IS-IS VLAN pruning using IS-IS Yes Yes Multicast Pruning using IS-IS Yes Yes Dual-homing using IS-IS Yes No Node address distribution in IS- Yes Yes IS (Nickname v.s. B-MAC) P2MP MDT setup using IS-IS Yes Yes MP2MP MDT setup using IS-IS Yes No YesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 50
    • Data Plane TRILL 802.1aq Multi-Access link support Yes No Link-local outer MAC Yes No Hop-by-hop forwarding Yes Yes P2MP MDT Yes Yes MP2MP MDT Yes No (cannot do MSTP func.) TTL support Yes No RPFC support Yes YesTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 51
    • Functional Comparison TRILL 802.1aqLoad Balancing at theedge nodePer-L2 flow Yes noPer-L3 flow Yes noPer-L4 flow Yes noLoad Balancing at thecore nodePer-L2 flow Yes noPer-L3 flow Yes noPer-L4 flow Yes noTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 52
    • Scalability Comparison TRILL 802.1aq MAC scalability Yes Yes Service Instance 4K 16M Scalability Multi-pathing for unicast Yes (Note-1) No Multi-pathing for mcast Yes (Note-2) No Note-1: only a single tree per node is required Note-2: supports MP2MP MDT which means for majority of network configuration only a few MDT needs to be builtTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 53
    • Loop Mitigation & Prevention TRILL 802.1aq Loop Mitigation: VLAN Yes Yes color blocking Loop Mitigation: RPF Yes Yes check Loop Mitigation: TTL Yes No Loop Prevention: No Yes HandshakeTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 54
    • Agenda TRILL Overview SPB Overview TRILL v.s. SPB Comparison TRILL w/ MAC-in-MAC – E-TRILL OAM for E-TRILLTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 55
    • Extended TRILL Two major short comings of TRILL that makes it inadequate for SP space are: - Service Instance Scalability – need lot more than 4K - OAM support E-TRILL is intended to address these two issues and retain all the features & advantages of TRILL - Use 802.1ah encap w/ TTL added to I-tag - Use TRILL as IS-IS control plane instead of 802.1aqTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 56
    • Service Provider Use Case MetroE BEB BEB 802.1ad Network BEB BCB BCB BCB BEB BEB BCB BCB BCB BEB BEB Ext TRILL Ext TRILL Header Header 802.1ad 802.1Q 802.1Q Header Header Header Cust. Eth Cust. Eth Cust. Eth Header Header Header Cust IP Cust IP Cust IP Packet Packet PacketTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 57
    • Extended TRILL Leverage TRILL control plane and some of its forwarding techniques: – Support for ECMP is a big win-win – TTL is essential for solid loop mitigation – Support for dual-homing on the access side – If congruency is needed, then it can be supported; however, • Forward/reverse congruency is not needed because there is no MAC learning in data plane • mcast/unicast congruency is not needed if new OAM for TRILL is devised 802.1ah adds advantages of its own – BMACs allow collapsing Outer MAC header + TRILL Header – I-SIDs scale to millions of services instead of just 4KTRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 58
    • Current Frame Formats TRILL 802.1ah Outer MAC DA Outer MAC DA Outer MAC DA Outer MAC SA NextHop Outer MAC DA Outer MAC SA Address Outer MAC SA Outer MAC SA Eth = 802.1Q Outer VLAN Eth = 0x88a8 B VLAN Eth = TRILL V/M/R, TTL TRILL Eth = .1ah PCP/R, I-SID Address Egress RBID Ingress RBID I-SID C MAC DA Inner MAC DA C MAC DA Inner MAC DA Inner MAC SA E2E C MAC SA Address Inner MAC SA C MAC SA Eth = 802.1Q Eth = 802.1Q Inner VLAN C VLAN Payload Payload …. Payload ….TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 59
    • Proposed P2P frame format E-TRILL Outer MAC DA is encoded Outer MAC DA as: Outer MAC DA Outer MAC SA – Unicast: OUI + 16b eRBID Outer MAC SA – Multicast: 802.1ah format for multicast (RootRB +ISID) Eth = 0x88a8 Outer VLAN Eth = PR-TAG PCP/TTL, SID Outer MAC SA is encoded as OUI + 16b iRBID SID C MAC DA C MAC DA PR-TAG is a variant of the I-TAG with a TTL and 20- C MAC SA bit I-SID C MAC SA Eth = 802.1Q C VLAN Payload Payload ….TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 60
    • TRILL Overview © 2009 Cisco Systems, Inc. All rights reserved. Cisco Confidential 61