Frame Relay and SONET/SDH services into VPNs and Ethernet services, both wired and wireless. Service providers and enterprises will continue to grow their markets, perpetuat- ing the demand for effective options to enhance and expand long IP networks.
Table 2-3 depicts long IP services for data and voice.
Mobile IP Networks
Time, opportunity, and money remain the fundamental business requirements and primary drivers of networking technology. Today’s company networks are now strategic business assets that must be planned, leveraged, and, most of all, successful to deliver business value that is measurable in customer revenue and satisfaction. The continual quest for productivity has reached beyond network wall jacks and into the airwaves, hoping to hear IP conversa- tions on unseen networks—digital conversations invisibly streaking through the “ether.” And they are there: air links of digital information propagating through the atmosphere seeking those who would tune in to their frequency, available for whoever possesses the access key.
Table 2-3 Long IP Services
Service Categories Service Types Technology Options Design Options
Data/IP WAN business data
Network convergence Distributed computing Messaging e-mail, I-chat Application sharing Database access Client/server Intranet Internet Serial data, HDLC, PPP Frame Relay, SMDS ISDN ATM Ethernet Point to point Point to multipoint Hub and spoke Mesh
Voice/Video WAN business voice H.323 video IP telephony Unified messaging IP communications TDM voice Powered Ethernet IP telephony VoFR VoATM IETF SIP IETF MGCP/Megaco ITU H.248 ITU H.323 Point to point Point to multipoint Hub and spoke Mesh
Mobile networking allows more time in a day for professional knowledge workers to con- tribute to productivity. According to industry studies, professionals are actually at their desks just 30 percent of the time. They spend about 49 hours a month in meetings.2 That’s why we use voicemail and, to a larger extent, e-mail—attempting to achieve at least a marginal productivity gain by communicating with others asynchronously in time. Mobile networks extend user access to applications, content, and the communication tools neces- sary to make decisions and complete project tasks. Adding mobility to IP networks brings mobile computing closer to real-time applications for communicating with individuals on more time-synchronous terms.
Mobile IP networks combine wireless and IP technology to create anytime, anywhere connections to the Internet and enterprise networks. Mobile computing requires a portable computer, such as a laptop or pocket PC. Portable computing coupled with Mobile IP communications allows knowledge workers to be productive whenever and wherever it makes sense, contributing to the freshness and synchronization of information. Whether in a campus environment or distant mobile location, high-speed, secure wireless technology enables users to be constantly connected—even as they move between wireless cells or in and out of wired LAN environments.
Mobile network operators and their customers are eager for new capabilities, ranging from image transfers and text messages to web surfing and video streaming, all delivered over cell phones or other portable computing devices. These capabilities are easy to build and then extend via IP. To assist wireless service providers with the migration to IP-based networking that is truly mobile, the IETF developed a standard for taking IP into motion, publishing this capability as the Mobile IP standard IETF RFC 2002.
The Mobile IP standard allows wireless users of the technology to “roam” their IP address across multiple wireless networks, similar to the way a cellular phone number is portable across the globe. The ability to maintain the IP address when roaming across different wireless networks and coverage areas allows users to stay connected and to maintain application connectivity throughout. There are likely to be gaps in Mobile IP coverage for awhile, yet there is natural incentive for providers to deploy the standard within their networks. IP applications are high-margin services, and supporting them is a good revenue opportunity.
Mobile IP eliminates a stop-and-start approach to IP connectivity that is required with network location changes, thus enabling users to maintain the same IP address, regardless of their point of attachment to the network. This is the real power of Mobile IP: a user could be in a VoIP conversation or video streaming media conference and not lose connectivity while en route to his or her destination. Despite a user’s movement between different networks, connectivity at the different points is achieved seamlessly without user
intervention. Roaming from a wired network to a wireless or WAN is also done with ease. Mobile IP provides ubiquitous connectivity for users, whether they are within their enterprise networks or away from home.
Mobile IP Networks 71
Mobile IP has the following three components, as shown in Figure 2-10:
•
Mobile node—The mobile node is a device such as a cell phone, PDA, or laptopwhose software enables network-roaming capabilities via Mobile IP functionality.
•
Home agent—The home agent is a router on the home network serving as the anchorpoint for communication with the mobile node; it tunnels packets from a device on the Internet, called a correspondent node, to the roaming mobile node. A tunnel is established between the home agent and a reachable point for the mobile node in the foreign network.
•
Foreign agent—The foreign agent is a router that can function as the point ofattachment for the mobile node when it roams to a foreign network, delivering packets from the home agent to the mobile node.
Figure 2-10 Mobile IP Components and Relationships
Source: Cisco Systems, Inc.
When a Mobile IP node roams to a new network, that remote network’s foreign agent assigns a care-of address (CoA) as the termination point of the tunnel toward the mobile node that is visiting the foreign network. The home agent maintains an association between the home IP address of the mobile node and its CoA, which is the current location of the mobile node on the foreign network. This association is maintained for all Mobile IP nodes in a mobility binding table at the home network.
In the example that follows, a Mobile IP node in transit has been assigned a home IP address of 1.1.1.7. This node is roaming from one foreign network to another foreign network that assigns the Mobile IP node a CoA of 10.31.2.1 (the IP address of the current foreign agent).
Home Agent Internet Foreign Agent Foreign Network Home Network Foreign Network Foreign Agent Mobile Node at Home Mobile Node Visiting Foreign Network
This association is registered as a new data path via an IP tunnel to the home agent, which updates the mobility binding table for 1.1.1.7 to the current CoA point of attachment (now 10.31.2.1). Every other network transit point between the foreign agent and the home agent is transparent to the Mobile IP tunnel that is in session. This way, the Mobile IP support is only implemented in home networks and on the edges (in radio-access networks, or RANs) of wireless networks. This example of Mobile IP roaming is depicted in Figure 2-11. Figure 2-11 Roaming with Mobile IP
Source: Cisco Systems, Inc.
The mobile wireless segment of the telecom sector is one of the highest growth areas of the industry. Operators are asking Cisco innovators to assist with the transition from circuit architectures to IP-based packet systems to deliver their new mobile data services. Anywhere, anytime access is the goal. Creating mobility options for high-value knowledge workers can have a positive impact on productivity, as well as company and customer responsiveness, and can bring about a higher utilization of company core assets. Beyond the benefits of the Mobile IP standard, Mobile IP networks encompass mobile computing and mobile teleputing. Mobile IP networks consist of wireless IP LANs for data and voice—both public and private—and wireless broadband data for mobile telephony.
MN—Mobile Node FA—Foreign Agent HA—Home Agent
Mobility Binding Table:
MN CoA 1.1.1.3 1.1.1.7 1.1.1.8 1.1.1.5 10.31.1.1 10.31.2.1 10.31.2.1 10.31.3.1 HA
Old Data Path
The Movement Is Transparent to All Other Devices
No Change Is Propagated to Correspondents
New Data Path
10.31.2.1 1.1.1.7 1.1.1.7 10.31.1.1 MN MN 10.31.3.1 FA FA FA
Mobile IP Networks 73