FACT protocol

1
Forwarding and Control Element Protocol (FACT)
by Ram Gopal, Alex Audu, Chaoping Wu, Hormuzd
Khosravi
ltdraft-gopal-forces-fact-04.txtgt
2
FACT Protocol Updates

• Protocol draft updated to be compliant with
  latest Requirements draft v-09
• Added Separate Control and Data Channels
• Updated Reliability section
• Updated Security section
• Updated CE Failover section
• Cleanup of text in PE State Maintenance section
• Other updates to clarify text, meet all
  requirements

3
Separate Control Data Channels

• PE Traffic Maintenance messages will be sent over
  data channel
• All other FACT messages will use the control
  channel
• Provide robustness against Denial of Service
  (DoS) attacks
• Data channel will use same reliable transport as
  control channel
• Priority bits in header can be used to prioritize
  different traffic on data channel
• Used with rate limiting mechanisms on FE to
  protect against DoS attacks

CE
Control
Data
FE
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Reliability

• FACT uses reliable transport for control channel
  to meet requirements
• For IP networks, TCP/SCTP is recommended
• Simplifies protocol design
• Makes protocol easily deployable in single and
  multi-hop scenarios
• Allows use of TLS for security

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Security

• Security associations are established before FACT
  association establishment
• 3 modes of security
• No security option for closed box scenario
• FACT usage model for IPSec
• FACT usage model for TLS
• IPSec, TLS are configurable by network admin
• TLS is recommended

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CE Failover (Strong Consistency)

• FE sends protocol packets to both CEs
• No CE to CE protocol needed for synchronization

FE
Primary CE
Standby CE
Asso Estab (Caps, Topo)
1
Asso Estab (Caps, Topo)
2
Data Control
3
Data Control (HBeats only)
4
5
FAILURE
PRI-CE-DOWN
6
Data Control
7
7
CE Failover (Weak Consistency)

• FE sends protocol packets only to primary CE

FE
Primary CE
Standby CE
Asso Estab (Caps, Topo)
1
Asso Estab (Caps, Topo)
2
Data Control
3
Control (HBeats only)
4
5
FAILURE
PRI-CE-DOWN
6
Data Control
7
8
Questions
9
Compared to Requirements v-09

• Meets All Requirements
• Configuration/Control/Capability discovery
• Security
• Scalability
• Multi-hop
• Message Priority
• Reliability
• Interconnect independence
• CE Failover
• Packet Redirection
• Topology Exchange
• Dynamic Association
• Command bundling
• Asynchronous event notification
• Query Statistics
• Protection against DoS attacks

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Back up
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Protocol Overview

• Protocol to support communication between CE and
  FE in a distributed fault-tolerant architecture.
• Master/Slave relationship between CE-FE.
• Logical separation by means of providing base
  protocol and service functions.
• Service specific functions can be encoded using
  TLV, OID or XML.
• Transport/Interconnect independence
• Supports latest ForCES Requirements draft.

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FACT NE model
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Message Structure
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Message Class and Messages (1)

• Association Establishment
• To establish logical connection between CE and FE
• Join, Leave message etc
• Capabilities Exchange Configuration
• To exchange FEs capabilities and to configure
  FEs functions.
• Capability request, Configure FE Blocks, Topology
  request etc
• State Maintenance
• To track element states and report state changes.
• Heart-beat, PE UP, PE Down, PE Active and
  Inactive etc

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Message Class and Messages (2)

• Traffic Maintenance
• To control data and control traffic between CE
  and FE.
• Packet Redirection, Control packet forwarding
  etc.
• Event Notification
• Asynchronous status change notification by FE to
  CE.
• Event Register, Deregister, Notification
  message,etc..
• Vendor Specific
• To extend the protocol beyond its current
  capabilities.

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Association Phase
FE
CE
Join Request
1
Validation of FE endpoint
Join Response
2
Capability Request
3
FE Block addressing, handles and relationship
Capability Response
4
Topology Request
5
Topology Response
6
PE UP
7
PE UP ack
8
State Maintenance (Element State)
PE (FE) ACTIVE
9
PE ACTIVE ack
10
Data Channel Estab
11
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Normal Operation
FE
CE
Heart beat request
1
Heart beat response
2
Query Request
3
Query Response
4
Port Event Notification
5
Configure Logical Comps Req
6
Configure Logical Comps Ack
7
Control packet redirect
8
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Element State
ACTIVE
Alternate CE/FE active
CE/FE active
CE/FE inactive
INACTIVE
CE/FE down CE-FE communication failure
CE/FE down CE-FE communication failure
CE/FE UP
DOWN