WAN

1
Chapter 4

• WAN
• PROTOCOLS

2
WAN Switching Technologies

• Circuit Switching
• Cell Switching
• Frame Switching
• Packet Switching

3
WAN Protocol Mapping
4
Network Equipment Position

• Application N/A
• Presentation Gateways
• Session N/A
• Transport Layer 4 Switches
• Networks Routers, layer 3 switches
• Data Link Bridges, switches
• Physical Hubs, connectors, cables

5
TCP/IP Services

• TCP OSPF IGP SNMP
• UDP ARP SMTP TFTP
• IP DNS FTP NIS
• ICMP RARP Telnet BOOTP
• IGMP EGP NFS
• RIP GGP RPC

6
Components of an IP Datagram
7
IP Address Classes

8
Top-Level Domains

9
Browser Request Codes

• SYN Requests opens a connection
• ACK Acknowledges/ verifies receipt
• HTTP Request Sent to Web App
• HTTP Response Sent from Web App
• FIN Closes connection

10
Connection Steps
11
Routing Messages

• Router table
• Routing path to connect to Web server
• IP address compared to each row in table
• Router delivers according to delivery rule
  defined for the path

12
Router Forwarding Table
13
Routing Algorithms

• Distance Vector
• Uses Hop Count to calculate lowest cost source to
  destination
• Simpler and less resource intensive
• Slow in large networks
• Link State
• Each router maintains identical database
• Sends only changes about its adjacent routers
• Synchronizes as quickly as a database can be
  updated

14
Routing Example
15
Routing Protocols

• BGP ? EIGRP
• IS-IS ? IGRP
• OSPF ? RIP
• RIP2 ? RIPng for IPv6

16
Routing

• Convergence
• Dynamic routing process when a routing table is
  updated
• Describes state of agreement between routers
• Routing Domain
• Sets of routers that use same routing code
• Administrative rules and values for metrics
• Network Address Translation
• Represents all internal addresses as one to the
  Internet

17
CIDR

• Classless Inter-Domain Routing
• Allows routers to group routes together
• Reduces quantity of routing information carried
  by core routers
• New addressing scheme allows single address to
  designate several unique IP addresses
• Reduces size of router tables
• Offers more IP addresses
• Enables route aggregation

18
CIDR Aggregate
19
Policies

• Import Policies -
• Policies governing the acceptance of data
• Export Policies -
• Rules distributed across a network to other
  routers

20
IPv6

• Packet Changes
• IP addresses lengthened from 32 bits to 128 bits
• Header files reduced from 13 to 7 fields
• Priority field added for real-time traffic
• Rules for three types of addressing
• Unicast
• Anycast
• Multicast

21
IPv6
22
Extension Headers

• Extension Headers
• Replaced the optional fields defined in IPv4
• Added in between data and base header
• Allows for authentication, hop-by-hop, and
  destination options

23
Extension Headers
24
Quote of the Day

• Curiosity is one of the permanent and certain
  characteristics of a vigorous mind.
• Samuel Johnson