Segment Routing in Trellis

Transcript

1. Segment Routing in Trellis Yi-Sung Chiu
2. Agenda • Background • Multi-Protocol Label Switching (MPLS) • Software-Defined Network (SDN) • Segment Routing (SR) • SR in ONOS • Trellis Usecase • 2x2 Leaf Spine Fabric 2
3. Background Multi-Protocol Label Switching (MPLS) Software-Defined Network (SDN) 3
4. Background • In legacy network, MPLS with 1RSVP-TE is used to provide • Traffic engineering (TE) • Fast rerouting (FRR) • Software-defined network (SDN) was proposed for centralized network intelligence Segment routing was introduced based on the two network technologies 4 1 Resource Reservation Protocol - Traffic Engineering
5. Multi-Protocol Label Switching (MPLS) • Source Routing • Label Switching • Between layer 2 and layer 3 Layer 2 Header MPLS Header Layer 3 Header Layer 3 Payload Label Exp S TTL 0 19 22 23 31 Label: Label Value Exp: Experimental Use for QoS S: Bottom of Stack TTL: Time to Live 5
6. Terminology • Label Edge Router (LER) • Label Switching Router (LSR) • Label Switching Path (LSP) • Label Distribution Protocol (LDP) 6
7. How MPLS works? ℎ1 ℎ2 7 Add labels 1 MPLS lookup 2 MPLS lookup 3 MPLS & IP lookup 4
8. Penultimate Hop Popping • Egress LSR double lookup problem • MPLS table lookup • IP table lookup Pop labels at penultimate nodes • Only IP table Lookup at egress nodes 8
9. Software-Defined Network (SDN) 9 Underlying infrastructure is abstracted for applications and network services * Cited from https://www.opennetworking.org/sdn-definition/ Network control become directly programmable Network intelligence is (logically) centralized with a global view of network
10. Segment Routing (SR) 10
11. What problems are we trying to solve? • Two main control protocols for MPLS • LDP for scaling and simplicity • RSVP-TE for traffic engineering (TE) and fast rerouting (FRR) • RSVP-TE is hard to deploy, manage and scale 11
12. Segment Routing (SR) • A source routing mechanism support traffic engineering • Without requiring mid-point state • Addressed by IETF SPRING (Source Packet Routing In NetworkinG) • 1RFC 8402 12 1 Ref. [1]
13. More Precise… A source-routing architecture that seeks the right balance between distributed intelligence and centralized optimization. The application steers its packets through an ordered list of instructions and realizes end-to-end policy without creating any per-flow state in the network. 13 * Cited from http://www.segment-routing.net/
14. Implementation • Two implementations on data plane • MPLS (SR-MPLS) • IPv6 (SRv6) • Two types of 1IGP segment • Prefix/Node • Adjacency 14 1 Interior Gateway Protocol
15. IGP Prefix/Node Segment • Global unique within a SR domain • Typically multi-hop • ECMP-aware shortest-path first (SPF) route to designated node 15
16. IGP Adjacency Segment • Locally unique within a SR router • Typically single-hop 16
17. Combining IGP Segments 17 A F C B E D 24134 14006 14003 ℎ1 ℎ2 Packet 14006 24134 14003 Packet 14006 Packet 14006 24134 14003 Packet 14006 Packet POP [14003, 24134] POP [14006] Packet Prefix/Node Segment Adjacency Segment
18. Comparison – MPLS 18 • Each node on the new path should update MPLS table • Per-flow state
19. • Only the edge switch has to be updated • Update added labels Comparison – SR 19
20. SR in ONOS 20
21. 1Network Programming API in ONOS 21 1 Ref. [4] Topology Independent Abstraction Pipeline Independent Abstraction Control Protocol Independent Abstraction
22. 1SR in ONOS Architecture 22 OpenFlow Netconf P4Runtime ...more OVS Arista Barefoot Cavium Mellanox Ciena Cisco Corsa Fujitsu HP Huawei Juniper Lumentum Microsemi Polatis ... FlowRule API Topology API FlowObjective API Intent API Packet API ... Distributed core State management, notifications, high-availability & scale-out Northbound API Device/protocol-agnostic Java, REST, CLI, gRPC Device driver Allow device-specific variants of standard protocols Shared protocol libraries Apps Apps Apps Control and configure the network using a global topology view and independently of the device-specific details Segment Routing Take OpenFlow and OvS for example 1 Ref. [4]
23. Trellis Usecase 2x2 Leaf Spine Fabric 23
24. Trellis Usecase (I) • 2x2 leaf spine fabric 24 Spine Switch Leaf Switch 1 Node segment ID (SID) 1
25. Trellis Usecase (II) 25 Dst B
26. 1OF-DPA Pipeline (Simplified View) 1 Ref. [5] 26
27. L3 Unicast at Source Leaf 27
28. OF-DPA Pipeline – Source Leaf (I) 28 MPLS Interface Group
29. Ingress Port Table Table ID Selector Treatment 0 (No traffic selector criteria for this flow) Transition: TABLE: 10 (VLAN Table) 29
30. OF-DPA Pipeline – Source Leaf (II) 30 MPLS Interface Group
31. VLAN Table Table ID Selector Treatment 10 IN_PORT: 3 (Edge port) VLAN_VID: None VLAN_PUSH: vlan VLAN_ID: 20 (vlan-untagged configuration from users) Transition: TABLE: 20 (Termination MAC Table) 31
32. OF-DPA Pipeline – Source Leaf (III) 32 MPLS Interface Group
33. Termination MAC Table Table ID Selector Treatment 20 IN_PORT: 3 ETH_DST: 00:00:00:00:01:80 (Current node MAC) ETH_TYPE: ipv4 VLAN_VID: 20 Transition: TABLE: 30 (Unicast Routing Table) 33
34. OF-DPA Pipeline – Source Leaf (IV) 34 MPLS Interface Group
35. Unicast Routing Table Table ID Selector Treatment 30 ETH_TYPE: ipv4 IPV4_DST: 10.6.2.0/24 (Destination IP subnet) Def[GROUP:0x70000021] (Deferred) Transition: TABLE: 60 (ACL Policy Table) 35
36. OF-DPA Pipeline – Source Leaf (V) 36 MPLS Interface Group
37. ACL Policy Table Table ID Selector Treatment 60 (No traffic selector criteria for this flow) NOACTION 37
38. OF-DPA Pipeline – Source Leaf (VI) 38 MPLS Interface Group
39. L3 ECMP Group Group ID Type Bucket Action 0x70000021 Select GROUP: 0x92000020 (MPLS Label Group) GROUP: 0x9200002d (MPLS Label Group) 39
40. OF-DPA Pipeline – Source Leaf (VII) 40 MPLS Interface Group
41. MPLS Label Group Group ID Type Bucket Action 0x92000020 Indirect VLAN_POP MPLS_PUSH: mpls_unicast MPLS_LABEL: 202 (Destination node SID configuration from user) GROUP: 0x9000001f (MPLS Interface Group) VLAN_PUSH: vlan VLAN_ID: 4095 41
42. OF-DPA Pipeline – Source Leaf (VIII) 42 MPLS Interface Group
43. MPLS Interface Group Group ID Type Bucket Action 0x9000001f Indirect ETH_DST: 00:00:00:00:03:80 (Next hop spine node MAC) ETH_SRC: 00:00:00:00:01:80 (Current leaf node MAC) VLAN_ID: 4094 GROUP: 0xffe0001 (L2 Interface Group) VLAN_ID 4094 is served as internal default VLAN tag 43
44. OF-DPA Pipeline – Source Leaf (IX) 44 MPLS Interface Group
45. L2 Interface Group Group ID Type Bucket Action 0xffe0001 Indirect VLAN_POP OUTPUT: 1 (Next hop output port) 45
46. L3 Unicast at Spine 46
47. OF-DPA Pipeline – Spine (I) 47 MPLS Interface Group
48. Ingress Port Table Table ID Selector Treatment 0 (No traffic selector criteria for this flow) Transition: TABLE: 10 (VLAN Table) 48
49. OF-DPA Pipeline – Spine (II) 49 MPLS Interface Group
50. VLAN Table Table ID Selector Treatment 10 IN_PORT: 1 (Leaf node connected port) VLAN_VID: None VLAN_PUSH: vlan VLAN_ID: 4094 Transition: TABLE: 20 (Termination MAC Table) 50
51. OF-DPA Pipeline – Spine (III) 51 MPLS Interface Group
52. Termination MAC Table Table ID Selector Treatment 20 IN_PORT: 1 ETH_DST: 00:00:00:00:03:80 (Current node MAC) ETH_TYPE: mpls_unicast VLAN_VID: 4094 Transition: TABLE: 23 (MPLS Table) 52
53. OF-DPA Pipeline – Spine (IV) 53 MPLS Interface Group
54. MPLS 0 Flow Table Table ID Selector Treatment 23 (No traffic selector criteria for this flow) Transition: TABLE: 24 (MPLS 1 Flow Table) 54
55. OF-DPA Pipeline – Spine (V) 55 MPLS Interface Group
56. MPLS 1 Flow Table Table ID Selector Treatment 24 ETH_TYPE: mpls_unicast MPLS_LABEL: 202 (Destination node SID configuration from user) MPLS_BOS: true Def[MPLS_POP:ipv4, DEC_TTL, GROUP:0x7000001e] (Deferred) Transition: TABLE: 60 (ACL Policy Table) 56
57. OF-DPA Pipeline – Spine (VI) 57 MPLS Interface Group
58. ACL Policy Table Table ID Selector Treatment 60 (No traffic selector criteria for this flow) NOACTION 58
59. OF-DPA Pipeline – Spine (VII) 59 MPLS Interface Group
60. L3 ECMP Group Group ID Type Bucket Action 0x7000001e Select GROUP: 0x2000001c (MPLS Label Group) 60
61. OF-DPA Pipeline – Spine (VIII) 61 MPLS Interface Group
62. L3 Unicast Group Group ID Type Bucket Action 0x2000001c Indirect ETH_DST: 00:00:00:00:02:80 (Next hop leaf switch MAC) ETH_SRC: 00:00:00:00:03:80 (Current spine switch MAC) VLAN_ID: 4094 GROUP: 0xffe0002 (L2 Interface Group) 62
63. OF-DPA Pipeline – Spine (IX) 63 MPLS Interface Group
64. L2 Interface Group Group ID Type Bucket Action 0xffe0002 Indirect VLAN_POP OUTPUT: 2 (Next hop output port) 64
65. L3 Unicast at Destination Leaf 65
66. OF-DPA Pipeline – Destination Leaf (I) 66 MPLS Interface Group
67. Ingress Port Table Table ID Selector Treatment 0 (No traffic selector criteria for this flow) Transition: TABLE: 10 (VLAN Table) 67
68. OF-DPA Pipeline – Destination Leaf (II) 68 MPLS Interface Group
69. VLAN Table Table ID Selector Treatment 10 IN_PORT: 1 (Spine node connected port) VLAN_VID: None VLAN_PUSH: vlan VLAN_ID: 4094 Transition: TABLE: 20 (Termination MAC Table) 69
70. OF-DPA Pipeline – Destination Leaf (III) 70 MPLS Interface Group
71. Termination MAC Table Table ID Selector Treatment 20 IN_PORT: 1 ETH_DST: 00:00:00:00:02:80 (Current node MAC) ETH_TYPE: ipv4 VLAN_VID: 4094 Transition: TABLE: 30 (Unicast Routing Table) 71
72. OF-DPA Pipeline – Destination Leaf (IV) 72 MPLS Interface Group
73. Unicast Routing Table Table ID Selector Treatment 30 ETH_TYPE: ipv4 IPV4_DST: 10.6.2.1/32 (Destination IP) Def[GROUP: 0x20000031] (Deferred) Transition: TABLE: 60 (ACL Policy Table) 73
74. OF-DPA Pipeline – Destination Leaf (V) 74 MPLS Interface Group
75. ACL Policy Table Table ID Selector Treatment 60 (No traffic selector criteria for this flow) NOACTION 75
76. OF-DPA Pipeline – Destination Leaf (VI) 76 MPLS Interface Group
77. L3 Unicast Group Group ID Type Bucket Action 0x20000031 Indirect ETH_DST: 00:00:00:00:00:03 (Destination MAC) ETH_SRC: 00:00:00:00:02:80 (Current leaf switch MAC) VLAN_ID: 40 GROUP: 0x280003 (L2 Interface Group) 77
78. OF-DPA Pipeline – Destination Leaf (VII) 78 MPLS Interface Group
79. L2 Interface Group Group ID Type Bucket Action 0x280003 Indirect VLAN_POP OUTPUT: 3 (Destination output port) 79
80. Thank You 80
81. Reference [1] “Segment Routing Architecture.” IETF. [Online]. Available: rfc8402 [2] “Segment Routing: A Tutorial.” APNIC, 22 Feb. 2016. [Online]. Available: https://www.slideshare.net/apnic/segment-routing-a-tutorial [3] “Segment Routing with MPLS data plane.” IETF. [Online]. Available: draft-ietf- spring-segment-routing-mpls-14 [4] “ONOS+P4 tutorial (master).” ONF. [Online]. Available: http://bit.ly/onos-p4- tutorial-slides [5] “Fabric Design Note.” OpenCORD Wiki. [Online]. Available: https://wiki.opencord.org/display/CORD/Fabric+Design+Note [6] “OpenFlow™ Data Plane Abstraction (OF-DPA): Abstract Switch Specification.” Broadcom. [Online]. Available: https://docs.broadcom.com/docs/12378911 81