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RBridges: Operations, Administration, and Maintenance (OAM) Support

David Bond, Vishwas ManralUNH-IOL, IP Infusion

draft-bond-trill-rbridge-oam-00

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Outline

• OAM Tools– Route Respond Traceroute– Hop Count Traceroute– RBridge Ping– Error Reporting

• OAM Option vs. OAM Frame• PDU Formats• Security

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Route Respond Traceroute

• RBridge originating the traceroute sends Route Respond Message

• Each transit RBridge and the egress RBridge send an Echo Reply Message

• Similar to the IP Option traceroute in RFC 1393

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Route Respond Traceroute

• Multi-destination traceroute's allowed– Tree discovered

• Normally end stations not involved• Possible to “tag” real traffic with traceroute

+-----+ +-------+ +-------+ +-------+ +-----+ | ESa +--+ RB0 +---+ RB1 +---+ RB2 +--+ ESb | +-----+ |ingress| |transit| |egress | +-----+ +-------+ +-------+ +-------+ Time RB0 RB1 RB2 . (1)-------> (1) -------> | . | <------- (2) | . | <------- (3) <-------(3)

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Hop Count Traceroute

• RBridge originating the traceroute sends Echo Request Message with hop count of 0

• Each transit RBridge and the egress RBridge send a Hop Count Error Message

• Based on traditional IP traceroute

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Hop Count Traceroute

• Con: more OAM traffic• Pro: no special processing needed on transit

until hop count error occurs.+-----+ +-------+ +-------+ +-------+ +-----+ | ESa +--+ RB0 +---+ RB1 +---+ RB2 +--+ ESb | +-----+ |ingress| |transit| |egress | +-----+ +-------+ +-------+ +-------+ Time RB0 RB1 RB2 . (1)-------> | | . | <------- (2) | . (3)-------> (3) -------> | . | <------- (4) <-------(4)

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RBridge Ping

• RBridge originating the ping sends Echo Request Message

• Egress RBridge sends an Echo Reply Message• Similar to ICMP Ping

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Error Reporting

• Error Message sent to ingress RBridge when error seen in a TRILL frame

• A frame format for reporting errors– MTU Error– Hop Count Error– Generic Error• Type sub-code

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OAM Option vs. OAM Frame• Draft presents OAM Option

– Problem: some data paths may slow path option tagged frames– CItE option allows ASIC to not do this, but not all RBridges may

be implement in this way– Limits size of message

• We could also use an encapsulated TRILL OAM frame– The inner ethernet header ethertype could be TRILL or a TRILL

OAM Ethertype– This does not allow tagging of real traffic

• Later drafts will specify both an OAM Option and an OAM Frame

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OAM Option vs. OAM Frame+--------------------------------+| Outer Ethernet Header |+--------------------------------+| TRILL Header |+--------------------------------+| TRILL OAM Option |+--------------------------------+| Dummy Inner Ethernet Header |+--------------------------------+| Dummy Ethernet Payload |+--------------------------------+

+--------------------------------+| Outer Ethernet Header |+--------------------------------+| TRILL Header |+--------------------------------+| Inner Ethernet Header |+--------------------------------+| TRILL or TRILL OAM Ethertype |+--------------------------------+| TRILL OAM Data |+--------------------------------+

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PDU Formats• TRILL OAM Option Common Initial Part

• These messages do not add to the base option:– Echo Request Message– Route Respond Request Message– Generic Error

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PDU Formats

• Echo Reply Message

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PDU Formats

• Hop Count Zero Error Message • MTU Error Message

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PDU Formats

• Type, Length, Value (TLV) Encodings

• Padding

• Next Hop Nickname

• Incoming Port ID

• Outgoing Port ID

• Outgoing Port MTU

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Security

• Future OAM security option will secure frames• Rate limiting important• Configuration of transmission of OAM

messages on per RBridge/port basis