Switching Via An Interconnection Network overcome bus bandwidth limitations Banyan networks,other interconnection nets initially developed to connect processors in multiprocessor Advanced design:fragmenting datagram into fixed length cells,switch cells through the fabric. Cisco 12000:switches Gbps through the interconnection network Network Layer 4-26
Network Layer 4-26 Switching Via An Interconnection Network overcome bus bandwidth limitations Banyan networks, other interconnection nets initially developed to connect processors in multiprocessor Advanced design: fragmenting datagram into fixed length cells, switch cells through the fabric. Cisco 12000: switches Gbps through the interconnection network
Output Ports switch queuing: data link buffer processing fabric line management (protocol, termination decapsulation) Buffering required when datagrams arrive from fabric faster than the transmission rate Scheduling discipline chooses among queued datagrams for transmission Network Layer 4-27
Network Layer 4-27 Output Ports Buffering required when datagrams arrive from fabric faster than the transmission rate Scheduling discipline chooses among queued datagrams for transmission
Output port queueing Switch Switch Fabric Fabric Output Port Contention One Packel at Time f Time Later buffering when arrival rate via switch exceeds output line speed queueing(delay)and loss due to output port buffer overflow! Network Layer 4-28
Network Layer 4-28 Output port queueing buffering when arrival rate via switch exceeds output line speed queueing (delay) and loss due to output port buffer overflow!
Input Port Queuing Fabric slower than input ports combined -queueing may occur at input queues OHead-of-the-Line (HOL)blocking:queued datagram at front of queue prevents others in queue from moving forward queueing delay and loss due to input buffer overflow! .cc switch. switch fabric output port contention green packet at time t-only one red experiences HOL blocking packet can be transferred Network Layer 4-29
Network Layer 4-29 Input Port Queuing Fabric slower than input ports combined -> queueing may occur at input queues Head-of-the-Line (HOL) blocking: queued datagram at front of queue prevents others in queue from moving forward queueing delay and loss due to input buffer overflow!
Chapter 4:Network Layer ▣4.1 Introduction 4.5 Routing algorithms 4.2 Virtual circuit and o Link state datagram networks o Distance Vector ▣4.3What's inside a o Hierarchical routing router 4.6 Routing in the ▣4.4IP:Internet Internet Protocol o RIP o Datagram format o OSPF o IPv4 addressing o BGP o ICMP ▣4.7 Broadcast and o IPv6 multicast routing Network Layer 4-30
Network Layer 4-30 Chapter 4: Network Layer 4. 1 Introduction 4.2 Virtual circuit and datagram networks 4.3 What’s inside a router 4.4 IP: Internet Protocol Datagram format IPv4 addressing ICMP IPv6 4.5 Routing algorithms Link state Distance Vector Hierarchical routing 4.6 Routing in the Internet RIP OSPF BGP 4.7 Broadcast and multicast routing