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TRILL OAM & BFDdraft-eastlake-trill-rbridge-bfd-00.txt
Donald E. Eastlake 3rd
155 Beaver StreetMilford, MA 01757 USA
November 2010 1TRILL OAM & BFD
Vishwas ManralIP Infusion
Vishwas.IETF @gmail.com
Contents
• TRILL OAM– Layer 3 and Layer 2 OAM don’t work for TRILL
• A TRILL OAM Channel• TRILL BFD Support
November 2010 TRILL OAM & BFD 2
Operations, Administration, & Management
• TRILL OAM operates in single and multiple hops between and through TRILL protocol stacks on RBridges. It needs to provide:– Rapid RBridge/link failure detection– TRILL error reporting (TRILL Header hop count
exhausted, egress nickname unreachable, …) and similar “ICMP-like” functions
– RBridge level traceroute– RBridge level ping
OAM
November 2010 3TRILL OAM & BFD
Layer 3 OAMDoesn’t Work for TRILL
• RBridges are not required to have IP protocol stacks or IP addresses.
• Even if all RBridges in a campus did have IP protocol stacks, those stacks would not be involved in TRILL ingress, transit, or egress processing even for IP native frames.
• Internet Protocol specific OAM does not meet the needs of TRILL.
November 2010 4TRILL OAM & BFD
OAM
Layer 2 OAMDoesn’t Work for TRILL
• Layer 2 OAM would only be applicable to the Layer 2 link between neighbor RBridges.– It could test the link and the ports but would not
test the TRILL protocol stacks– Layer 2 protocols, such as Spanning Tree or
802.1ag OAM, cannot pass through and are blocked by RBridges
November 2010 5TRILL OAM & BFD
OAM
Layer 2 OAMDoesn’t Work for TRILL
• Different links in an RBridge campus can be different technologies.– For example, all, some, or none of the links in a
campus could be PPP or 802.1 or MPLS or other…• Layer 2 specific OAM, particularly 802.1ag,
does not work for an RBridge campus.– This is one of the arguments that Shortest Path
Bridging advocates use against TRILL, that TRILL cannot use 802.1 OAM and requires new OAM facilities.
November 2010 6TRILL OAM & BFD
OAM
Operations, Administration, & Management
OAM
November 2010 7TRILL OAM & BFD
Router
Bridge
RBridge RBridge
P = Ports and Fast Path LogicET = Ethernet stack possibly with 802.1ag OAM = GreenTR = TRILL protocol stack including TRILL OAM = RedIP = IP protocol stack including Layer 3 OAM = Black
P
P
P
PET
IP
TR TRET
Router
P
ET
IP
RBridge
P
TR
ET ET ET ET ET ET
A TRILL OAM Channel
• TRILL OAM frames look like TRILL Data frames– If unicast they are routed to the egress nickname
• A special nickname Any-RBridge is available to guarantee delivery to neighbors regardless of the state of nicknames.
– If multi-destination, they are distributed over the tree identified by the egress nickname to all RBridges in the Inner.VLAN
November 2010 TRILL OAM & BFD 8
A TRILL OAM Channel
• TRILL OAM frames are detected by an OAM-aware egress RBridge based on their Inner.MacDA and/or Ethertype.– The following Special Inner.MacDAs will be
available:• Unicast: OAM-RBridge-MAC• Multicast: All-OAM-RBridges
– The following Ethertype will be available:• TRILL-OAM
November 2010 TRILL OAM & BFD 9
A TRILL OAM Channel• TRILL OAM Frames are TRILL Data Frames:
• The TRILL OAM Header and Payload are as follows:
November 2010 TRILL OAM & BFD 10
Link Header TRILL Header OAM Header OAM Data Link Trailer
SpecialInner.MacDA
InnerMacSA
TRILL-OAMEthertype
Flags, Version,OAM Protocol #
OAM Protocol Specific
A TRILL OAM Channel
• 0 = Silent• 1 = Multi-Hop• 2 - 15 available
• 1 = OAM Channel Err• 2 = BFD Control• 3 = BFD Echo• 4 – 4,094 available
November 2010 TRILL OAM & BFD 11
SpecialInner.MacDA
InnerMacSA
TRILL-OAMEthertype
Flags, Version,OAM Protocol #
OAM Protocol Specific
16 bits of OAMHeader Flags
12 bit OAMProtocol Number
4 bit OAMHeader Version
TRILL BFD Support
• BFD Control protocol provides very low overhead continuity testing messages. Because of this low overhead, they can be sent frequently and thus rapidly detect failures.
• For RBridge OAM, BFD Control is sent via the TRILL OAM Channel.
November 2010 TRILL OAM & BFD 12
TRILL BFD Support
• If support for BFD Echo is indicated through BFD Control, BFD Echo can be used to send a frame to a neighbor RBridge that is addressed back to yourself. That is, the ingress and egress nicknames in the TRILL Header are equal.
• See RFC 5880 and 5882 for general BFD information, RFC 5881 for BFD over IP.
November 2010 TRILL OAM & BFD 13
ENDDonald E. Eastlake 3rd
155 Beaver StreetMilford, MA 01757 USA
November 2010 14TRILL OAM & BFD
Vishwas ManralIP Infusion
Vishwas.IETF @gmail.com