IPv4 and IPv6 Mobility Support Using MPLS and MP-BGP

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IPv4 and IPv6 Mobility Support Using MPLS and
MP-BGP

• draft-berzin-malis-mpls-mobility-00
• Oleg Berzin, Andy Malis
• oleg.berzin, andrew.g.malis_at_verizon.com

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Problem Statement

• Efficiently update the network on the new L3
  location of a mobile node and deliver the traffic
  to the node in an optimal manner, where
• Optimal traffic delivery is interpreted as the
  delivery of packets to the new node location
  following the best path between the mobile node
  and the correspondent node
• Packets forwarding avoids triangular routing in
  current mobile IP
• Network update process is a function of the
  network control plane
• Traffic delivery process is a function of the
  network forwarding plane

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Design Criteria

• Robust and Flexible Protocol Framework
• Mobility Management Control Plane Protocol and
  the associated functions must be placed at the
  intelligent network edges and allow to avoid the
  need to involve all nodes in the network
  (including the core nodes) in the network update
  process
• Support for mobile hosts and mobile routers
• Support for IPv4 and IPv6
• Evolutionary Architecture and Implementation
  Approach
• Mobility Management scheme should be based as
  much as possible on the existing network
  architectures and protocol framework
• Only minimal changes to the operation of mobile
  nodes should be expected
• Efficient Network Responsiveness
• The impact on the mobile application due to the
  service disruption caused by the mobile nodes
  movements and the associated network update and
  delivery processes should be reasonably minimal
• Acceptable Network Scalability and Performance
• The new requirements for Mobility Management
  functions should not result in decreased network
  scalability and performance

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Previous and Related Work

• Mobile IPv4
• Triangular routing
• Optimizations require host-to-host IP tunneling
• Foreign Agent and Home Agent Registrations
• Care-of-Address
• No support for Mobile Routers

• Mobile IPv6
• Triangular routing
• Optimizations require a return routability
  procedure, IPv6 routing header and heavy security
• Home Agent Registrations
• Micro-Mobility with HMIP
• Basic support for Mobile Routers with NEMO

• MPLS Micro-Mobility
• Triangular routing
• Extension of Mobile IPv4/v6
• Home Agent Registrations
• Multiple registrations with MPLS routers
• Heavy use of signaling during original
  registration and during the hand-off

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Proposal

• Mobility Label
• MP-BGP and MPLS-based mobility management
  solution resulting in optimal traffic delivery
  (no triangular routing)
• Evolutionary architecture based on the existing
  widely used protocol framework (MPLS and MP-BGP)
• Support for mobile host (mobile-to-fixed,
  mobile-to-mobile) and mobile router
  communications
• Support for IPv4 and IPv6
• Increased scalability due to built-in control
  plane capabilities
• Main Ideas
• Independence from Mobile IP no need for HA,
  CoA, FA and L3 tunneling
• Mobility Support Function (MSF) on the Label Edge
  Router (LER)
• Mobile Host/Router Discovery, Registration and
  Status
• Mobility Label Association/De-association,
  Mobility Bindings
• Integration with MP-BGP and Network Update
  Procedures
• Mobile Application Priority Indication and
  Recognition
• Similar to label advertisement mechanism in RFC
  4364 for L3 VPNs
• Introduce new element (Mobility Address Family)
  into MP-BGP to carry Mobility Bindings
• Introduce Mobility Labels and Mobility Bindings
  to
• De-couple IP layer topology from the user
  location in the network
• Associate the new user location with the fixed L3
  protocol address
• Use stacked MPLS labels for the identification of
  IP addresses and efficient traffic delivery

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Protocol Overview and Architecture Illustration
Mobility Support Function
Architecture
Receive Discovery from MN (Host or Router)
Reply with MSF L2/L3 Address
Receive Registration Info from MN
Mobile Router?
Yes
No
Assign Mobility Label to Host IP Address
Establish Adjacency
Logical L3 Interfaces
Assign Mobility Label(s) to IP Prefixes
Create Host Mobility Binding
L2 Grooming Network
Generate MP-BGP Update NLRI with Mobility Binding
Create Router Mobility Binding
Radio Access Network
Generate MP-BGP Update NLRI with Mobility Binding
Execute Network Update
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Network Update with Mobility Bindings

• When a Mobile Node registers with a MSF the
  serving LER updates the network with a Nodes
  Mobility Binding carrying the MPLS Label bound to
  the Nodes IP Address
• Four Update Methods are proposed
• Unsolicited Downstream Push. Updates are sent to
  all peering MSF LERs.
• Selective Downstream Push. Updates are send to a
  pre-defined set of MSF LERs (such as the
  Internet Gateways).
• Predictive Downstream Push. A targeted update is
  sent to a MSF LER node determined during the
  forwarding table lookup for a packet sent by a
  mobile node.
• Hierarchical On-Demand Distribution. The Mobility
  Binding update is first sent by a serving MSF LER
  to a set of Mobility Route Reflectors using the
  Selective Downstream Push. Once the Mobility
  Route Reflectors have been updated, all other LER
  nodes must explicitly request Mobility Labels
  from the Mobility Route Reflectors for packets
  destined to a mobile node.

Unsolicited, Selective and Predictive Network
Update Modes
Hierarchical On-Demand Distribution Network
Update Mode
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Mobility Bindings and Traffic Delivery

• Mobility Bindings associate Mobility Label, a
  Mobile Nodes IP Address or Routing Prefix and a
  Serving LERs Router ID (Origin NEXT_HOP)
• Carried as Network Layer Reachability Information
  (NLRI) using MP-BGP UPDATE messages and encoded
  as the Address Family structure in the
  MP-REACH-NLRI
• New types of MP-BGP Address Families are proposed
  IPv4 Mobility Address Family, IPv6 Mobility
  Address Family following the format in RFC 4760
  Multi-Protocol Extensions for BGP-4
• May contain additional information such as the
  Mobile Nodes priority which can be communicated
  during the registration process
• Two types of Mobility Binding Structures are
  proposed Mobile Host Mobility Binding and Mobile
  Router Mobility Binding
• Traffic delivery uses stacked MPLS labels outer
  infrastructure label (LER-to-LER) and inner label
  (Mobility Label) to identify the Mobile Node

Traffic delivery using stacked labels
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Summary and Next Step

• Key concept of this draft is the Mobility Label
  in the label stack to optimize mobile IP packet
  forwarding
• While MP-BGP is proposed for label distribution
  as in RFC 4364, were open to other label
  distribution mechanisms as well if more
  appropriate for the application
• Presented to solicit comments from the WG
• Next step is to update the draft based on
  received comments