1、Shortest Path Bridging 802.1AQ,Lui Simonetti & Gates Zeng,Where are we coming from ?,L2 Bridged Networks,L2 networks did not scale Why ? The MAC address L2 addressing = MAC address The MAC address is a flat address with no summarization or hierarchy possible No Scalable Control Plane With no address
2、ing hierarchy possible it was not possible to have a Link State Protocol for L2 networks which could scale No L2 OAM tools Limited Virtualization Only 802.1Q VLAN tagging,L3 IP Routed Networks,So L3 (IP) routing had to be used in the Core Why ? The IP address structure can be summarized into network
3、s using a netmask Core nodes do not need to know every single IP address on the network (they have no ARP cache) Scalable Control Plane Availability of Link State Protocols such as: IS-IS & OSPF IP OAM Tools ping, traceroute IP Virtualization possible But requires BGP & MPLS for scalability,IEEE L2
4、Ethernet evolution,Ethernet = IEEE,The balance shifts to SPB,L2 SPB Networks,Now a L2 SPB network scales MACinMAC 802.1ah brings addressing hierarchy & summarisation to Ethernet based networks Scalable Control Plane 802.1aq SPBM leverages MACinMAC and uses IS-IS for BMAC reachability L2 OAM tool 802
5、.1ag brings sophisticated OAM tools, which can complement and enhance traditional IP OAM tools Designed for Virtualization 802.1ah introduces a Service ID (I-SID) which can scale to 16 million services,L3 IP Routed Networks,Difficult to virtualize on a IP Core The IP address structure can be summari
6、zed into networks using a netmask Core nodes do not need to know every single IP address on the network (they have no ARP cache) Scalable Control Plane Availability of Link State Protocols such as: IS-IS & OSPF IP OAM Tools ping, traceroute Complex/Costly Virtualization Requires BGP & MPLS for scala
7、bility Requires VPLS for L2 virtualization over an L3 core,Virtualization Technology Comparison,MPLS versus VENA,e.g. PIM Protocol Infrastructure,e.g. RIP/OSPF Protocol Infrastructure,e.g. RFC4364 Protocol Infrastructure,e.g. Draft Rosen Protocol Infrastructure,e.g. 802.1q/D Protocol Infrastructure,
8、802.1Q(VLAN),802.1D(STP),UC IGP(IS-IS or OSPF),Layer 3 Unicast Service,Layer 3 Multicast Service,Layer 3 Virtualized Multicast Service,Top Down Vertical dependency,Layer 3 Virtualized Unicast Service,IP/SPB, SPBm/SPBm Protocol Infrastructure,Horizontally Independent,Connectivity Services independent
9、 from Infrastructure,e.g. VPLS Protocol Infrastructure,Layer 2 Virtualized Unicast Service,MPLS,Understanding Shortest Path Bridging,Mac in Mac 802.1ah encapsulation Control Plane SPB uses IS-IS Data Plane SPB Terminology: BEB, BCB, BVLAN, CVLAN. Load sharing traffic with SPBs Equal Cost Trees Loop
10、suppression using RPFC SPBs hierarchical addressing: L2VSN & L3VSN SPB uses Multicast Trees QOS & DiffServ over SPB Operations, Administration & Maintenance (OA&M) SPB leverages 802.1ag CFM & Y.1731 Performance Monitoring,SPBm 802.1ah Mac-in-Mac Encapsulation,DA,SA,Payload,VLAN ID,DA,SA,Payload,C-VI
11、D,B-DA,B-SA,B-VID,802.1Q,802.1ah Provider Backbone Bridges,Legend:SA = Source MAC address DA = Dest. MAC address VID = VLAN ID C-VID = Customer VID I-SID = 24 Bit Service ID B-VID = Backbone VID B-DA = Backbone DA B-SA = Backbone SA,I-SID,Tunnel Identifiers,Service Identifiers,Customer VLANs,DA,SA,P
12、ayload,Customer with No VLAN Tags,or,Consolidated Service and Tunnel,Simplified and integrated forwarding like MPLS without the complexity,SPB Service Type encapsulations,Understanding Shortest Path Bridging,Mac in Mac 802.1ah encapsulation Control Plane SPB uses IS-IS Data Plane SPB Terminology: BE
13、B, BCB, BVLAN, CVLAN. Load sharing traffic with SPBs Equal Cost Trees Loop suppression using RPFC SPBs hierarchical addressing: L2VSN & L3VSN SPB uses Multicast Trees QOS & DiffServ over SPB Operations, Administration & Maintenance (OA&M) SPB leverages 802.1ag CFM & Y.1731 Performance Monitoring,Wha
14、t is IS-IS ?,Intermediate System to Intermediate System (IS-IS) intra-domain routing protocol Is a Link State Protocol like OSPF Is a dynamic routing protocol based on SPF routing algorithm like OSPF Capable of fast reconvergence times 100ms like OSPF (when OSPF deployed over point-point IP segments
15、) 1987: Originally developed as the routing protocol for the ISO Connectionless Network Protocol CNLP 1988: Later extended to IP Integrated IS-IS, also known as Dual IS-IS, was to provide a single routing protocol with the capabilities of routing both Connectionless Network Service (CLNS) and IP OSP
16、F v1 RFC published in 1989 Dual IS-IS RFC published in 1990 OSPF v2 RFC published in 1991,Integrated IS-IS vs. OSPF,IS-IS,Widely used by ISPs Encapsulation IS-IS runs directly over L2 (Ethernet) More difficult to spoof or attack Packet encoding IS-IS is TLV based Easier to extend (e.g. to SPB) Area
17、architecture Router is in only one area, plus perhaps the L2 backbone IS-IS area boundaries fall on links,OSPF,Widely used in the Enterprise Encapsulation OSPF runs on top of IP Subject to spoofing and DoS attacks Packet encoding OSPF uses many LSA types Tied to IPv4 (even IPv6 requires a new versio
18、n of OSPF) Area architecture OSPF area boundaries fall within a router (ABRs) Each link belongs to one area,IS-IS Adjacencies (always Point to Point),LSP : Link State PDU CSNP : Complete Sequence Numbers Protocol Data Unit PSNP : Partial Sequence Numbers Protocol Data Unit,IS-IS interfaces can be co
19、nfigured on: Discrete ethernet interfaces MLT bundles,MLT1,MLT1,Node1,Node3,Node2,2/11,2/12,2/11,2/12,L1 LSP,L1 CSNP,P2P HELLO,L1 PSNP,TLVs used with SPB,13,Pre-existing IS-IS TLVs,New SPB TLVs,SPB ISIS LSDB Detail,86-10:5# show isis lsdb lspid 0000.beb0.0020.00-00 detail =ISIS LSDB (DETAIL) =Level-
20、1 LspID: 0000.beb0.0020.00-00 SeqNum: 0x0000024b Lifetime: 589Chksum: 0x674a PDU Length: 150Host_name: 86-20Attributes: IS-Type 1 TLV:1 Area Addresses: 149.0000TLV:3 End System Neighbors:Metric: 000beb0000020 (86-20)TLV:22 Extended IS reachability:Adjacencies: 2TE Neighbors: 20000.beb0.0030.00 (86-3
21、0) Metric:10SPBM Sub TLV:port id: 193 num_port 1SPB Metric: 100000.beb0.0010.00 (86-10) Metric:10SPBM Sub TLV:port id: 129 num_port 1SPB Metric: 10TLV:129 Protocol Supported: SPBM,TLV:135 TE IP Reachability: 2Metric: 1 Prefix Length: 32UP/Down Bit: FALSE IP Address: 10.0.0.20TLV:144 SUB-TLV 1 SPBM I
22、NSTANCE:Instance: 0bridge_pri: 0OUI: 00-00-20num of trees: 2vid tuple : u-bit 1 m-bit 1 ect-alg0x80c201 base vid 4001vid tuple : u-bit 1 m-bit 1 ect-alg0x80c202 base vid 4002TLV:144 SUB-TLV 3 ISID:Instance: 0Metric: 0B-MAC: 00-be-b1-00-00-10BVID:10Number of ISIDs:210(Both),11(Both) TLV:184 SPBM IPVP
23、N Reachability:Vrf ISID:31112Metric:1 Prefix Length:32IP Address: 10.1.0.20,Understanding Shortest Path Bridging,Mac in Mac 802.1ah encapsulation Control Plane SPB uses IS-IS Data Plane SPB Terminology: BEB, BCB, BVLAN, CVLAN. Load sharing traffic with SPBs Equal Cost Trees Loop suppression using RP
24、FC SPBs hierarchical addressing: L2VSN & L3VSN SPB uses Multicast Trees QOS & DiffServ over SPB Operations, Administration & Maintenance (OA&M) SPB leverages 802.1ag CFM & Y.1731 Performance Monitoring,SPB Terminology,Customer VLAN (CVLAN) A traditional VLAN with MAC learning & flooding where user d
25、evices connect to Backbone Edge Bridge (BEB) SPB node where VSN service terminates BEB node performs 802.1ah MACinMAC encapsulation/de-capsulation for the VSN BEB is involved in VSN addressing,Backbone VLAN (BVLAN or BVID) Special VLAN where MAC table populated by IS-IS shortest path calculations Pr
26、ovides reachability to EVERY BMAC in the SPB network Backbone Core Bridge (BCB) SPB node which does not terminate VSN service BCB performs forwarding only by looking at outer BMAC header BCB is unaware of service networks it transports,Shortest Path Bridging - Equal Cost Paths,IS-IS sees 2 Equal Cos
27、t paths between 2 nodes (referred as Equal Cost Trees ECT)SPB network was provisioned with 2 Backbone VLANs (BVIDs) BVID-1 BVID-2 IS-IS programs 1st Equal Cost path in Forwarding Database of BVID 1 IS-IS programs 2nd Equal Cost path in Forwarding Database of BVID 2 Service Networks (VSNs) are then h
28、ashed against one or the other or both (per flow hashing) BVIDs SPB 802.1aq defines max of 16 BVIDs,ISIS,ISIS,ISIS,ISIS,ISIS,ISIS,Cost =30,Cost =30,BVID-1,BVID-2,Reverse Path Forwarding Check (RPFC),Loop suppression SPB requires that the shortest path in each direction be the same between any two de
29、vices for both unicast and multicast pathsLogic of Reverse path Forwarding Check is to examine all frames received on a interface and make sure that the source address and ingress interface are correct. If not the frame gets dropped.,SPB Hierarchical addressing L2VSN,4/1,4/30,3/5,4/1,8600D BEB 00:bb
30、:00:00:14:00,MLT 1,MLT 1,00:00:00:00:00:02,8600G BCB 00:bb:00:00:10:00,8600C BEB 00:bb:00:00:13:00,00:00:00:00:00:01,SPB Hierarchical addressing L3VSN,4/1,4/30,3/5,4/1,8600D BEB 00:bb:00:00:14:00,MLT 1,MLT 1,8600G BCB 00:bb:00:00:10:00,8600C BEB 00:bb:00:00:13:00,L3VSN I-SID 30001,vlan 101 10.1.101.
31、0/24,vlan 102 10.1.102.0/24,10.1.102.10/24,10.1.101.10/24,L2VSN SPB Multicast trees,1 L2VSN Terminated at 4 BEBs = 4 multicast trees / BVLAN = 8 multicast trees in 2 BVLANs Each multicast tree unique to I-SID + BEB to which it is rooted unique multicast BMAC allocated:consumes forwarding records in
32、SPB nodes only on SPB nodes which are on the multicast tree path,L2 VSN I-SID 1000,Only 1 (of 4) multicast tree shown,Shortest Path Bridging L2 Service VSN,Congruent unicast & multicast paths Congruent forward & reverse path,Important Properties All traffic types (known, unknown traffic, broadcast)
33、use the same path no out of order packets possible Traffic A B will follow the same path as B A Multicast trees are ROOT-ed at source node within every service instance and only flood packets to I-SID service node members No MAC learning & flooding in the Core Fully QoS aware infrastructure,Vlan 20,
34、Vlan 20,Vlan 20,组播地址通过动态I-SID 映射到专用VSN上,a. 当节点上有Receive时，组播数据才会传给该节点； b. IS-IS 协议维护组播拓扑.，整个网络恢复时间小于1秒,Multicast Sender Grp 239.0.0.10,Join 239.0.0.10,IGMP,IGMP,Join 239.0.0.10,IGMP,Join 239.0.0.10,I-SID 300,IPMC,Receiver,Receiver,Receiver,重要特性： 边缘节点启用IGMP VENA架构为核心 不再需要PIM或者 DVMRP等复杂的协议,VENA IP组播服务V
35、SN,SPB QOS model & DiffServ,In the SPB model, all QOS within the SPB Fabric is based on the Backbone-VLAN p-bits Therefore it is essential that the desired QOS markings (IP DSCP or Customer-VLAN p-bits) or QOS policies at the edge BEBs are translated into correct B-VID p-bits so that inner BCB nodes
36、 can preserve the desired DiffServ PHB (Per Hop Behaviour),8600G,MLT 1,MLT 1,SPB Fabric QOS based on BVLAN p-bits,IP DSCP = EF,IP DSCP = EF,BVID p-bit = 6,BVID p-bit = 6,BCB,BEB,BEB,Summary of SPB Unicast Services,Summary of SPBM Services,Mcast over L2VSN,I-SID 13990001,vlan 101 10.18.101.0/24,vlan
37、102 10.16.102.0/24,Mcast overVRFs,Mcast Receiver,Mcast Sender,Mcast Receiver,Mcast Sender,GRT (over native IS-IS),vlan 20 10.18.20.0/24,vlan 20 10.16.20.0/24,Mcast Over GRT,Mcast Receiver,Mcast Sender,Understanding Shortest Path Bridging,Mac in Mac 802.1ah encapsulation Control Plane SPB uses IS-IS
38、Data Plane SPB Terminology: BEB, BCB, BVLAN, CVLAN. Load sharing traffic with SPBs Equal Cost Trees Loop suppression using RPFC SPBs hierarchical addressing: L2VSN & L3VSN SPB uses Multicast Trees QOS & DiffServ over SPB Operations, Administration & Maintenance (OA&M) SPB leverages 802.1ag CFM & Y.1
39、731 Performance Monitoring,IEEE 802.1ag CFM Connectivity Fault Management and ITU Y.1731 Performance Management,802.1ag CFM Maintenance hierarchies Layer 2 Ping Layer 2 Traceroute Layer 2 Tracetree CFM Level Hierarchies Service (e.g., all BEBs supporting common service instance) CMAC CFM (use level
40、6 or 7) Network (e.g. all devices common to a domain) SPBM CFM (use level 4 or 5) Y.1731 Performance Monitoring Frame Delay Frame Delay Variation Frame Loss,Trunk,802.1ag,802.1ag,Service,802.1ag Maintenance levels/hierarchy,Conceptually: monitor the trunk or the service or both,Built-in and on-switc
41、h,IEEE 802.1ag / Y.1731 Message Types,Loopback Message (LBM) & Loopback Reply (LBR) L2 ping (like IP ping at L2) Linktrace Message (LTM) & Linktrace Reply (LTR) L2 traceroute (like IP traceroute at L2) L2 tracetree (no IP equivalent) Continuity Check Message (CCM) Delay Measurement (DM) Y.1731 Perfo
42、rmance Monitoring: latency, jitter, frame loss * Future software release,LBM,LBR,MEP,MEP,LTM,MEP,MEP,MIP,MIP,LTR,LTR,LTR,CCM,CCM,MEP,MEP,Further resources,Network Virtualization using Shortest Path Bridging and IP/SPB White Paper http:/ Shortest Path Bridging MAC (SPBM) Avaya ERS8800/8600 Configuration Manual http:/ Shortest Path Bridging (802.1aq) for ERS 8600 / 8800 Technical Configuration Guide http:/ Basic SPBM Configuration http:/ Migrating to a Virtual Services Fabric using Shortest Path Bridging Technical Configuration Guide http:/
