{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

NetworkRoutingI

NetworkRoutingI - Switching and Forwarding Switching and...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Csci 232: Computer Networks Forwarding and Routing Network Layer Part I 1 Switching and Forwarding Network Layer Part I Switching and Forwarding Generic Router Architecture Forwarding Tables: Bridges/Layer 2 Switches; VLAN Routers and Layer 3 Switches Forwarding in Layer 3 (Network Layer) Network Layer Functions Network Service Models: VC vs. Datagram ATM and IP Datagram Forwarding IP Addressing Network vs. host: address blocks, longest prefix matching Address allocation and DHCP IP Datagram Forwarding Model and ARP Protocol IP and ICMP Protocols, IP Fragmentation and Re-assembly Readings: Textbook: Chapter 4: Section 4.1; Csci 232: Computer Networks Forwarding and Routing Network Layer Part I 2 Routing & Forwarding: Logical View of a Router A E D C B F 2 2 1 3 1 1 2 5 3 5 Csci 232: Computer Networks Forwarding and Routing Network Layer Part I 3 IP Addressing: Basics Globally unique (for “public” IP addresses) IP address: 32-bit identifier for host, router interface Interface: connection between host/router and physical link router’s typically have multiple interfaces host may have multiple interfaces IP addresses associated with each interface Dot notation (for ease of human reading) 223.1.1.1 = 11011111 00000001 00000001 00000001 223 1 1 1 Csci 232: Computer Networks Forwarding and Routing Network Layer Part I 4 IP Addressing: Network vs. Host Two-level hierarchy network part (high order bits) host part (low order bits) What’s a network ? ( from IP address perspective) device interfaces with same network part of IP address can physically reach each other without intervening router 223.1.1.1 223.1.1.3 223.1.1.4 223.1.2.2 223.1.2.1 223.1.2.6 223.1.3.2 223.1.3.1 223.1.3.27 223.1.1.2 223.1.7.0 223.1.7.1 223.1.8.0 223.1.8.1 223.1.9.1 223.1.9.2 multi-access LAN point-to-point link Csci 232: Computer Networks Forwarding and Routing Network Layer Part I 5 “Classful” IP Addressing 32 bits 0network host 10 network host 110 network host 1110 multicast address A B C D class 1.0.0.0 to 127.255.255.255 128.0.0.0 to 191.255.255.255 192.0.0.0 to 223.255.255.255 224.0.0.0 to 239.255.255.255 7 7 15 23 31 Disadvantage: inefficient use of address space; address space exhaustion e.g., class B net allocated enough addresses for 65K hosts, even if only 2K hosts in that network Csci 232: Computer Networks Forwarding and Routing Network Layer Part I 6 Classless Addressing: CIDR CIDR: C lassless I nter D omain R outing Network portion of address is of arbitrary length Addresses allocated in contiguous blocks Number of addresses assigned always power of 2 Address format: a.b.c.d/x x is number of bits in network portion of address 11001000 00010111 0001000 0 00000000 network part host part 200.23.16.0/23
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon