Metro Ethernet Forum OAM An Update Matt Squire Hatteras Networks 1

Metro Ethernet Forum OAM An Update Matt Squire Hatteras Networks 1

Scoping the Problem Bridge Bridge Bridge Bridge Provider B Bridge Bridge Bridge SONET Ethernet Bridge Provider C Bridge RPR Bridge Bridge Bridge Provider A Bridge Problem: When delivering an Ethernet service over a large, diverse network, how do you detect end-to-end connectivity problems (loss and degradation)? 2

Scoping the Problem Bridge Bridge Bridge Bridge Provider B Bridge Bridge Bridge Bridge Provider C SONET Bridge Bridge Bridge Bridge RPR Ethernet Multi-hop path Provider A Bridge MEF is looking at multi-domain service OAM mechanisms 3

Scoping the Problem Bridge Bridge Bridge Bridge Provider B Bridge Bridge Bridge Bridge Provider C Edge-to-edge Intra-Carrier OAM SONET Bridge Bridge Bridge Bridge RPR Ethernet Multi-hop path Provider A Bridge 4

Scoping the Problem Bridge Bridge Bridge Bridge Provider B Bridge Bridge Bridge Bridge Provider C Edge-to-edge Inter-Carrier OAM SONET Bridge Bridge Bridge Bridge RPR Ethernet Multi-hop path Provider A Bridge 5

Scoping the Problem Bridge Bridge Bridge Bridge Provider B Bridge Bridge Bridge Bridge Provider C End-to-end Customer OAM SONET Bridge Bridge Bridge Bridge RPR Ethernet Multi-hop path Provider A Bridge 6

Key Aspects of MEF OAM Assumes Ethernet is only common denominator – E.g. 802.3 Ethernet, Ethernet over SONET, RPR, etc. – Must use Ethernet framing for OAM communications Ethernet segments interconnected with forwarding entities (bridge, switch, etc.) – Connectionless, like IP – Segment can be real or virtual (see above) – Must deal with multicast and frame replication issues Must measure “per service” and be with data plane – Can think service VLAN for this discussion – Out-of-band OAM not possible, not accurate with data plane – OAM mixes with user data within core (only different at edges) 7

Key Aspects of MEF OAM Initial focus on “SLA” metrics – – – – Connectivity, latency, loss, jitter Includes discovery (multicast “ping”) Includes timestamped “ping” (connectivity test) Includes timestamped “hello” (connectivity verification) Other function may follow later – Traceroute (fault isolation), RDI/AIS (fault signaling), etc. – No commitment on when/how – initial focus is “Phase I” – CURRENTLY NOT DEALING WITH FAULT ISOLATION Domain oriented – Supporting hierarchical domains required – Separation of customer and carrier OAM is a big thing – Domain may be intra-provider, inter-provider, customer-customer, and other 8

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- Uses a pretty generic frame format with very few fixed fields 9

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- Destination MAC address can be Well-known Multicast – for discovery and multicast tests Unicast of peer station – for unicast tests Well-known addresses default to MEF-defined but are configurable! (important later) 10

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- OAM frames are optionally tagged OAM frames are “per-EVC” (Ethernet Virtual Connection) [That’s a VLAN to you and me] OAM frames are tagged/not as EVC is tagged/not OAM frames for measurements follow the data path! 11

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- MEF OAM uses a well-known EtherType MEF assigned default Can be configured (important later!) 12

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- Need to come back to this one (See “Security Wrinkle”) 13

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- Usual versioning capability Fixed v1 for now Ignores anything higher 14

OAM Frame 01234567 89012345 67890123 45678901 -------- -------- -------- -------- Dest MAC -------- -------- -------- -------- Dest MAC Source MAC -------- -------- -------- -------- Source MAC -------- -------- -------- -------- VLAN Ethertype VLAN Tag (Optional) -------- -------- -------- -------- OAM OAM Version EtherType Level -------- -------- -------- -------- Rsvd OpCode Data -------- -------- -------- -------- Data (OpCode specific, continued) -------- -------- -------- -------- Pretty simple op-code functions (1/2) Connectivity Test Request/Response (layer two ping ) (3) Connectivity Verification (periodic hello ) Solicited and unsolicited connectivity checking 15

A Security Wrinkle Ethernet has the unfortunate property that packets may be sent to places they don’t need to go (e.g. MAC address is not known) With OAM for a service provider environment, – OAM must not “leak” out of the provider to other providers or the customer – Customers and other providers must not be able to interfere with the carrier’s OAM To deal with this, multi-hop OAM must filter OAM at the edges of the domain 16

A Security Wrinkle Bridge Bridge Bridge Bridge Provider A OAM Barrier OAM is required to create an OAM Barrier No OAM in from the outside No OAM out from the inside Protects carrier OAM from interference and leaking An OAM domain is defined to create this barrier 17

A Security Wrinkle L 195 L 200 L 64 Level 255 Hierarchical Domains 1-octet domain level in OAM frame used to implement domains Outermost customer-customer domain 255 (0xFF) Other domains hierarchically included A inside B implies Domain A Level Domain B Level 18

A Security Wrinkle L 195 L 200 L 64 Level 255 Hierarchical Domains Requires port filtering by OAM EtherType and Domain Level At edges of domain L If (EtherType OAM EtherType) and (Domain Level L) DROP OAM PACKETS – can’t inject or leak 19

A Security Wrinkle L 195 L 200 L 64 Level 255 Hierarchical Domains Requires filter by OAM EtherType and Domain Level We realize this isn’t great, but Hard requirement for multi-level domains with hard boundaries (e.g. no leaks) Hard requirement for OAM in same path as data (e.g. no popping to CPU) Hard requirement for working over switched networks (e.g. replication) 20 Although not ideal, seems like the best way to meet requirements

Why Am I Here? MEF stuff underway, doesn’t want to wait for 802.1 OAM work for simple connectivity checking – Too many people want something now Mucho interest in MEF to be “compatible” with what .1 comes up with – Everyone hates the idea of incompatible protocols or required replacements So what can we do? 21

Why Am I Here? Easy parts – Defining MEF protocols with configurable “well-known” MAC address info and configurable “well-known” EtherType Allows migration to IEEE defined addressing via config – Other parameters also configurable Timeouts, delays, etc. – Putting “as little as possible” in fixed headers Best chance at compatibility is to require little – Version, domain level, op-code are only common fields – Everything else op-code specific If one-octet op-code ok, if one-octet version number ok, leaves only the domain level 22

Why Am I Here? Hard part – IF 802.1 accepts Same domain methods as MEF – THEN Same frame format could be used and “compatibility” provided via new op-codes for additional function – IF 802.1 accepts Same connectivity tests/verification as MEF – THEN Same op-codes for connectivity test and verification could be used for both Lots of people in MEF interested in seeing if we can work something out. 23

Summary MEF OAM Protocol work well underway – Won’t wait Defining “ping” and “hello” – Connectivity test and verification (solicited and unsolicited ping) – Not getting into fault isolation, just detection Based on hierarchical domain model – Requirement from carriers Would be great if could “quickly” get consensus on fixed header aspects so MEF work could be designed as “compatible” (subset, phase 1, version 1, whatever) of larger 801.2 project 24