OpenFlowMPLS

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OpenFlow-MPLS

• Summer Project at Ericsson
• Peyman Kazemian

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Outline

• MPLS
• Adding MPLS to OpenFlow
• Flow table changes
• Virtual ports
• Implementation
• Software Implementation
• Hardware Implementation
• Controller

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MPLS

• Stands for MultiProtocol Label Switching
• Route packets based on a fixed size label.
• Layer 2.5 protocol.
• Can Encapsulate Any layer 3 protocol
• Forwarding Equivalent Class

Ethernet
MPLS
IP
Tag
ToS (Exp)
BoS
TTL
20
3
1
8
4
MPLS
Ethernet
MPLS 1
IP
MPLS 2
MPLS n

• MPLS Can Encapsulate itself, so we can have a
  stack of labels.
• Last label has BoS 1

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MPLS Actions

• PUSH Packet entering MPLS cloud Merging MPLS
  FECs into one FEC.
• POP Packets leaving MPLS cloud FEC
  Demultiplexing
• SWAP Changing labels inside MPLS cloud.

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MPLS Actions

• Decrement MPLS TTL
• Copy TTL from/to previous label in stack or IP
• Copy ToS/Exp from/to previous label in stack or IP

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Adding MPLS to OpenFlow

• PUSH and POP are not native OpenFlow actions
• TTL/TOS operations are very specific to MPLS
• Only Swap operation can be done using OpenFlow
  actions (rewrite action)

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Flow Table Changes

• Match on up to 2 top of the stack MPLS tags.
• Rewrite Tag and Exp (in spirit of OF 0.89)
• Forward to virtual port to take care of complex
  MPLS actions

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Virtual Ports

• Can configure VPs to do Push or Pop
• Can cascade VPs to do more than one push or pop
  operation.
• VPs can be cascaded with physical ports

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Virtual Ports

• Push VPs can copy TTL or ToS from previous label
  or IP header or use a pre-configures TTL value
• Pop VPs can copy TTL or ToS to previous label or
  IP header
• VPs can decrement MPLS TTL

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Implementation

• Modified OpenFlow messages to include 12 tuples.
• Feature reply message include a bit to show
  existence of VPs
• A new feature request message for VPs
• A new configuration message for
  configuring/modifying VPs
• VP Stat messages.

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Implementation

• Port number size changed to 32 bits
• Port number gt 0xffff used for VPs

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Software Switch Implementation

• A UserSpace Switch Mart
• A KernelSpace Switch Mart I
• No Cascade Limit on VPs
• Full VPs Stats
• 4B virtual ports supported.

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Hardware Implementation

• An OpenFlow-MPLS NetFPGA implementation Done by
  Me
• Up to two cascades of VPs.
• Can just cascade VPs of the same type
• 64 Push VPs and 16 Pop VPs
• Stats are aggregated stats and not per VP stats.

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Controller and Label Distribution

• NOX is hard to modify for these changes!
• Right now, simple controller reads entries from
  an XML file and installs them.
• Google will write a controller to take care of
  label distribution protocol.

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Questions?