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Routing

Extra Protocols: Routing

Routing as slideshow

MPLS Review

• DTR - Delay, Throughput, Reliability (IPp in ToS byte)
• EOS - End of Stack of labels
• MPLS' TTL

MPLS Review

• Label-Switched Paths
• Label Distribution Protocol
• the "MPLS cloud" looks like a single hop, a black box, to the outside network

MPLS

• separate forwarding and routing
  • MPLS-TE, traffic engineering
• virtual circuits (VRF, virtual routing and forwarding)
  • MPLS VPN

OSPF

• interior routing protocol
  • path determination, metrics, convergence, and load balancing
• shortest path tree
• link state database

OSPF

• Wikipedia entry
  • IP protocol 89 (Layer 4), packet header
  • 224.0.0.5 and 224.0.0.6
  • backbone area
  • designated router, backup designated router

OSPF

• OSPF Tutorial
  • link state vs distance vector
    • link state works better when link cost and bandwidth are unequal

OSPF

• OSPF supports CIDR and VLSM (variable length subnet masks)
• OSPF supports authentication and converges quickly
• all routers need a unique 32-bit ID (IPv4 address?)
• neighbors are determined by a HELLO packet, multicast with TTL of 1 sent every 10 seconds
• once neighbors are known, designated and backup routers elected, and then
• and then adjacencies formed
  • adjacency states: down (initial, no HELLO), init, 2-way (all neighbors except DR and BDR), exchange (of DBD database descriptor packets), loading, full ...
• LSA, link state advertisements
  • router, network, summary, external ...