Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter Guia Do Desenho
C H A P T E R
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Enterprise Mobility 4.1 Design Guide
OL-14435-01
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Cisco Unified Wireless and Mobile IP
Introduction
In IP networks, routing is based on stationary IP addresses, similar to how a postal letter is delivered to
a fixed address on an envelope. A device on a network is reachable through normal IP routing by the IP
address to which it is assigned on the network. However, when networks are in motion, problems occur
when a device roams away from its home network and is no longer reachable using normal IP routing.
This causes the active sessions of the device to terminate.
a fixed address on an envelope. A device on a network is reachable through normal IP routing by the IP
address to which it is assigned on the network. However, when networks are in motion, problems occur
when a device roams away from its home network and is no longer reachable using normal IP routing.
This causes the active sessions of the device to terminate.
Mobile IP offers a solution to these roaming problems by enabling users to keep the same IP address
while traveling to a different network (which may even be operated by a different wireless operator), thus
ensuring that a roaming individual can continue communication without sessions or connections being
dropped. Because the mobility functions of Mobile IP are performed at the network layer rather than the
physical layer, the mobile device can span different types of wireless and wireline networks while
maintaining connections and ongoing applications. Remote login, remote printing, and file transfers are
examples of applications where it is undesirable to interrupt communications while an individual roams
across network boundaries. Also, certain network services, such as software licenses and access
privileges, are based on IP addresses. Changing these IP addresses can compromise the network services.
while traveling to a different network (which may even be operated by a different wireless operator), thus
ensuring that a roaming individual can continue communication without sessions or connections being
dropped. Because the mobility functions of Mobile IP are performed at the network layer rather than the
physical layer, the mobile device can span different types of wireless and wireline networks while
maintaining connections and ongoing applications. Remote login, remote printing, and file transfers are
examples of applications where it is undesirable to interrupt communications while an individual roams
across network boundaries. Also, certain network services, such as software licenses and access
privileges, are based on IP addresses. Changing these IP addresses can compromise the network services.
This chapter describes the interaction of a mobile IP client over a Cisco Unified Wireless Network and
covers the following topics:
covers the following topics:
•
Different levels of mobility
•
Requirements for a mobility solution
•
Roaming on the Cisco Unified Wireless Network
•
Roaming on a Mobile IP-enabled network
•
Mobile IP client characteristics when roaming on a Cisco Unified Wireless Network
Different Levels of Network Mobility
There are two different levels of network mobility:
•
Layer 2 roaming across a single Layer 2 network:
–
All of the APs are on the same subnet without trunking
•
Layer 3 roaming across a single Layer 2 network:
–
Cisco Unified Wireless Network
–
Mobile IP Client