Chapter 4:outline 4.I Overview of Network 4.4 Generalized Forward and SDN layer 。match ·data plane action ·control plane OpenFlow examples of match- 4.2 What's inside a router plus-action in action 4.3 IP:Internet Protocol ·datagram format ·fragmentation ·lPv4 addressing ·network address translation ·lPv6 Network Layer:Data Plane 4-11
4.1 Overview of Network layer • data plane • control plane 4.2 What’s inside a router 4.3 IP: Internet Protocol • datagram format • fragmentation • IPv4 addressing • network address translation • IPv6 4.4 Generalized Forward and SDN • match • action • OpenFlow examples of matchplus-action in action Chapter 4: outline Network Layer: Data Plane 4-11
Router architecture overview high-level view of generic router architecture: routing,management routing control plane(software) processor operates in millisecond time frame forwarding data plane (hardware)operttes in nanosecond timeframe high-seed switching fabric router input ports router output ports Network Layer:Data Plane 4-12
Router architecture overview high-seed switching fabric routing processor router input ports router output ports forwarding data plane (hardware) operttes in nanosecond timeframe routing, management control plane (software) operates in millisecond time frame ▪ high-level view of generic router architecture: Network Layer: Data Plane 4-12
Input port functions lookup, link forwarding line layer switch termination protocol fabric (receive) queueing physical layer: bit-level reception data link layer: decentralized switching: e.g.,Ethernet using header field values,lookup output see chapter 5 port using forwarding table in input port memory ("match plus action") goal:complete input port processing at 'line speed' queuing:if datagrams arrive faster than forwarding rate into switch fabric Network Layer:Data Plane 4-13
line termination link layer protocol (receive) lookup, forwarding queueing Input port functions decentralized switching: ▪ using header field values, lookup output port using forwarding table in input port memory (“match plus action”) ▪ goal: complete input port processing at ‘line speed’ ▪ queuing: if datagrams arrive faster than forwarding rate into switch fabric physical layer: bit-level reception data link layer: e.g., Ethernet see chapter 5 switch fabric Network Layer: Data Plane 4-13
Input port functions lookup, link forwarding line layer switch termination protocol fabric (receive) queueing physical layer: bit-level reception decentralized switching: data link layer: using header field values,lookup output e.g.,Ethernet port using forwarding table in input port see chapter 5 memory ("match plus action") destination-based forwarding:forward based only on destination IP address(traditional) generalized forwarding:forward based on any set of header field values Network Layer:Data Plane 4-14
line termination link layer protocol (receive) lookup, forwarding queueing Input port functions decentralized switching: ▪ using header field values, lookup output port using forwarding table in input port memory (“match plus action”) ▪ destination-based forwarding: forward based only on destination IP address (traditional) ▪ generalized forwarding: forward based on any set of header field values physical layer: bit-level reception data link layer: e.g., Ethernet see chapter 5 switch fabric Network Layer: Data Plane 4-14
Destination-based forwarding forwarding table Destination Address Range Link Interface 11001000000101110001000000000000 through 0 11001000000101110001011111111111 11001000000101110001100000000000 through 11001000000101110001100011111111 11001000000101110001100100000000 through 2 11001000000101110001111111111111 otherwise 3 Q:but what happens if ranges don't divide up so nicely? Network Layer:Data Plane 4-15
Destination Address Range 11001000 00010111 00010000 00000000 through 11001000 00010111 00010111 11111111 11001000 00010111 00011000 00000000 through 11001000 00010111 00011000 11111111 11001000 00010111 00011001 00000000 through 11001000 00010111 00011111 11111111 otherwise Link Interface 0 1 2 3 Q: but what happens if ranges don’t divide up so nicely? Destination-based forwarding forwarding table Network Layer: Data Plane 4-15