What does Intelligent Network has?

1. Availability - maximizes employee productivity with 24/7 reliability.
2. Scalability - traffic management for efficient use of.
3. Secure - restricts unauthorized users, grants access to right people, right time, right place.
4. Control - prioritize criticial traffic to accommodate employee.

High Availability: - Some solutions

Layer 2: Reduce STP convergence

H.323

The H.323 standard provides a foundation for audio, video, and data communications across IP-based networks, including the Internet. H.323 is an umbrella recommendation from the International Telecommunications Union (ITU) that sets standards for multimedia communications over Local Area Networks (LANs) that do not provide a guaranteed Quality of Service (QoS). These networks dominate today’s corporate desktops and include packet-switched TCP/IP and IPX over Ethernet, Fast Ethernet and Token Ring network technologies. Therefore, the H.323 standards are important building blocks for a broad new range of collaborative, LAN-based applications for multimedia communications. It includes parts of H.225.0 - RAS, Q.931, H.245 RTP/RTCP and audio/video codecs, such as the audio codecs (G.711, G.723.1, G.728, etc.) and video codecs (H.261, H.263) that compress and decompress media streams.

Media streams are transported on RTP/RTCP. RTP carries the actual media and RTCP carries status and control information. The signalling is transported reliably over TCP. The following protocols deal with signalling:

RAS manages registration, admission, status.
Q.931 manages call setup and termination.
H.245 negotiates channel usage and capabilities.
H.235 security and authentication.

How Voice over IP Processes a Telephone Call

The general flow of a two-party voice call using Voice over IP is as follows:

1. The user picks up the handset; this signals an off-hook condition to the signaling application part of Voice over IP.

2. The session application part of Voice over IP issues a dial tone and waits for the user to dial a telephone number.

3. The user dials the telephone number; those numbers are accumulated and stored by the session application.

4. After enough digits are accumulated to match a configured destination pattern, the telephone number is mapped to an IP host via the dial plan mapper. The IP host has a direct connection to either the destination telephone number or a PBX that is responsible for completing the call to the configured destination pattern.

5. The session application then runs the H.323 session protocol to establish a transmission and a reception channel for each direction over the IP network. If the call is being handled by a PBX, the PBX forwards the call to the destination telephone. If RSVP has been configured, the RSVP reservations are put into effect to achieve the desired quality of service over the IP network.

6. The CODECs are enabled for both ends of the connection and the conversation proceeds using RTP/UDP/IP as the protocol stack.

7. Any call-progress indications (or other signals that can be carried in-band) are cut through the voice path as soon as end-to-end audio channel is established. Signaling that can be detected by the voice ports (for example, in-band DTMF digits after the call setup is complete) is also trapped by the session application at either end of the connection and carried over the IP network encapsulated in RTCP using the RTCP APP extension mechanism.

8. When either end of the call hangs up, the RSVP reservations are torn down (if RSVP is used) and the session ends. Each end becomes idle, waiting for the next off-hook condition to trigger another call setup.

Table above- Cabling information

Comparsion between 4 different types of cables

1. UTP (Unshielded Twisted Pair)
- No physical shield but use balancing and filtering techniques through media filters .
- Light, thin and flexible
- Reliable and inexpensive
- Simple to install
- UTP do not have problem of grounding practice and need for properly shield connector and foil shield

2. STP (Shielded Twisted Pair )
- Effective only at preventing radiation or blocking interference as long the entire end to end link is shielded and properly grounded.
- Every component of a shielded cabling system must fully shield
- Heavier, thicker and hard to install
- Must confirm with strict shielding condition hence higher potential of degradation of emission

Note:! STP does not guarantee improve immunity to EMI. Conditions have to be met:
- Shield must be electrically continuous along the whole link
- All component in the link must be shielded. No UTP patch cord can be used.
- Shield must fully enclose the pair and the overall shield must fully enclose the core. Any gap will cause EMI leakage.
- Shield must be grounded at both ends of the link, and the building grounding system must conform to grounding standards (TIA/EIA -607)

3. FTP(Foil twisted pair )
- Also known as screened twisted pair (ScTP)
- Combination UTP and STP
- Basically is a 4 pair 100ohm UTP with a single foil surrounding all four pair
- May be used in Ethernet application same as UTP
- Strict Conditions for shielding

4. Coaxial Cable
- Use for widely for TV Industry
- Used in 10Base5 and 10 Base2
- Difficult to run and is generally more expensive then twisted pair cable.

Choosing the correct cable

• UTP
  - best choice for office environment (less EMI)
  
• STP/FTP
  - Hospital, airports and communication center.
  - Extra shield needed for EMI interference
  - External field strength exceed 3 volts/m
  
• Coaxial Cables
  - Use for widely for TV Industry

COLOUR CODE FOR UTP CABLES

T568A

W-G G W-O BL W-BL O W-BR BR
   1    2     3     4      5      6      7      8

T568B

W-O O W-G BL W-BL G W-BR BR
   1    2     3     4      5      6      7      8

Legend of colour code abbreviation

W - white colour

O - orange colour

G - green colour

BL - blue colour

BR - brown colour

STRAIGHT VS CROSSOVER VS ROLLOVER CABLES

Wireless network Standards
Wireless network standards is the key to the development of wireless technology. Based on the distance the technology covers, the standard is classified into WWAN (Wireless wide area network), WLAN (Wireless local area network), WPAN (Wireless personal area network).

1. WWAN
Data rate: <400kbps
Radio: Licensed
Standards: GSM, GPRS, UMTS

WWAN involves the cellular technology.

2. WLAN
Data rate: >10Mbps
Radio: 2.4GHz and 5GHz
Standards: 802.11

An example of application is the wireless network to connect a PC or laptop for Internet or LAN access without the used of cables. The standard is IEEE 802.11 consisting of 802.11a, 802.11b, 802.11g and other extensions. The 802.11b is the first completed standard that operates on Radio Frequency 2.4GHz unlicensed band with up to 11Mbps. The 802.11a is newly completed and operates on 5GHz. The advantage of 802.11a over 802.11b is it supports hugh bandwidth of up to 54Mbps and thus is suitable for transmitting imaging, voice and video. Its RF band is also less crowded with more usable channels. However, 802.11b has longer coverage implying with lower cost. The new 802.11g aims to bridge the gap between 802.11a and 802.11b by providing higher data rate than 802.11b and operates on the 2.4GHz band.

3. WPAN
Data rate: <800kbps
Radio: 2.4GHz
Standards: 802.15/Bluetooth

An example is a PDA communicating with a laptop. The standard used is 802.15 that includes the Bluetooth which has characteristic of low cost, lower power consumption and with much shorter range. The Bluetooth standard defines the physical and data link layer of the wireless network as well as the protocol to discover data services and other devices. Bluetooth operates on 2.4GHz with a range coverage of about 10m. The power consumption required and the cost of Bluetooth chip are much loswer than that of 802.11 thus it is suitable for lower powered consumer devices such as PDAs and mobile phones.

What To Label

Basically everything related to the structured cabling system (SCS) should be administered and thus labelled properly. This includes:

Connecting Hardwares in the work areas, telecommunications closets, equipment rooms, and entrance facilities;

• Cabling;
• Pathways containing the cabling;
• Spaces where terminations are located;
• Bonding/grouding components related to the SCS;
• Equipment related to SCS.
  

  When labelling these, make sure they are each assigned a unique identifier. The labels themselves should be legible and permanent to last the life of the component, which in some cases is as long as the life of the building.

   

  Labeling Options

  There are a number of different options. Each has its benefits and some work better in some situations than others do. It is important to understand the different options available so you can choose a few that best meet your particular needs.

  The following label options, or a combination of these options, can be used to lebal the different components of a SCS. They include:

• Directly marking the components;
• Using a pre-printed labels;
• Using labels designed and printed with labelling software;
• Using labels printed with handheld printer;
• Using colout-coded labels.

  Of course the lowest cost option is to simply mark the components directly using a permanent marker. However, for many components (i.e. cable), this is generally not the best alternative for two primary reasons. One, the handwriting might be illegible. Second, even if the handwriting is perfect, it will be prone to smearing, smudging and fading.

  Pre-printed labels are available with either text or symbols. These pre-printed labels save time and are easy to apply. Generally they are not sufficient enough for administration purposes but rather are commonly used at the work area for the users to easily identify which device each outlet is for.

  For larger quantities of label, a good solution is a software program used specially for labelling. Such software programs give you the flexibility to print standard labels or design and print your own custom labels.

  Handheld printers are useful for "on-the-job-site" label production. You willnever know when you will need a label during the installation.

  Colour-coding is an excellent method to simplify your administration system. Colour-coding can be used to differentiate services. As with pre-printed labels, colour-coding alone is not sufficient for propoer administration. But when used together with the other label options, it can dramatically simplify the cabling system administration tasks.

   

   

TCP
TCP is a connection-oriented transport protocol that sends data as an unstructured stream of bytes. By using sequence numbers and acknowledgment messages, TCP can provide a sending node with delivery information about packets transmitted to a destination node. Where data has been lost in transit from source to destination, TCP can retransmit the data until either a timeout condition is reached or until successful delivery has been achieved. TCP can also recognize duplicate messages and will discard them appropriately. If the sending computer is transmitting too fast for the receiving computer, TCP can employ flow control mechanisms to slow data transfer. TCP can also communicate delivery information to the upper-layer protocols and applications it supports.

IP
IP is the primary layer 3 protocol in the Internet suite. In addition to internetwork routing, IP provides error reporting and fragmentation and reassembly of information units called datagrams for transmission over networks with different maximum data unit sizes. IP represents the heart of the Internet protocol suite.

IP addresses are globally unique, 32-bit numbers assigned by the Network Information Center. Globally unique addresses permit IP networks anywhere in the world to communicate with each other.

An IP address is divided into three parts. The first part designates the network address, the second part designates the subnet address, and the third part designates the host address.

IP addressing supports three different network classes. Class A networks are intended mainly for use with a few very large networks, because they provide only 8 bits for the network address field. Class B networks allocate 16 bits, and Class C networks allocate 24 bits for the network address field. Class C networks only provide 8 bits for the host field, however, so the number of hosts per network may be a limiting factor. In all three cases, the leftmost bit(s) indicate the network class. IP addresses are written in dotted decimal format; for example, 34.0.0.1. Figure 2 shows the address formats for Class A, B, and C IP networks.

IP networks also can be divided into smaller units called subnetworks or "subnets." Subnets provide extra flexibility for the network administrator. For example, assume that a network has been assigned a Class A address and all the nodes on the network use a Class A address. Further assume that the dotted decimal representation of this network's address is 34.0.0.0. (All zeros in the host field of an address specify the entire network.) The administrator can subdivide the network using subnetting. This is done by "borrowing" bits from the host portion of the address and using them as a subnet field.

Traditionally, all subnets of the same network number used the same subnet mask. In other words, a network manager would choose an eight-bit mask for all subnets in the network. This strategy is easy to manage for both network administrators and routing protocols. However, this practice wastes address space in some networks. Some subnets have many hosts and some have only a few, but each consumes an entire subnet number. Serial lines are the most extreme example, because each has only two hosts that can be connected via a serial line subnet.

As IP subnets have grown, administrators have looked for ways to use their address space more efficiently. One of the techniques that has resulted is called Variable Length Subnet Masks (VLSM). With VLSM, a network administrator can use a long mask on networks with few hosts and a short mask on subnets with many hosts. However, this technique is more complex than making them all one size, and addresses must be assigned carefully.

On some media, such as IEEE 802 LANs, IP addresses are dynamically discovered through the use of two other members of the Internet protocol suite: Address Resolution Protocol (ARP) and Reverse Address Resolution Protocol (RARP). ARP uses broadcast messages to determine the hardware (MAC layer) address corresponding to a particular network-layer address. ARP is sufficiently generic to allow use of IP with virtually any type of underlying media access mechanism. RARP uses broadcast messages to determine the network-layer address associated with a particular hardware address. RARP is especially important to diskless nodes, for which network-layer addresses usually are unknown at boot time.

Routing in IP Environments
An "internet" is a group of interconnected networks. The Internet, on the other hand, is the collection of networks that permits communication between most research institutions, universities, and many other organizations around the world. Routers within the Internet are organized hierarchically. Some routers are used to move information through one particular group of networks under the same administrative authority and control. (Such an entity is called an autonomous system.) Routers used for information exchange within autonomous systems are called interior routers, and they use a variety of interior gateway protocols (IGPs) to accomplish this end. Routers that move information between autonomous systems are called exterior routers; they use the Exterior Gateway Protocol (EGP) or Border Gateway Protocol (BGP).

Routing protocols used with IP are dynamic in nature. Dynamic routing requires the software in the routing devices to calculate routes. Dynamic routing algorithms adapt to changes in the network and automatically select the best routes. In contrast with dynamic routing, static routing calls for routes to be established by the network administrator. Static routes do not change until the network administrator changes them.

IP routing specifies that IP datagrams travel through an internetwork one router hop at a time. The entire route is not known at the outset of the journey. Instead, at each stop, the next router hop is determined by matching the destination address within the datagram with an entry in the current node's routing table. Each node's involvement in the routing process consists only of forwarding packets based on internal information. IP does not provide for error reporting back to the source when routing anomalies occur. This task is left to another Internet protocol: the Internet Control Message Protocol (ICMP.)

ICMP performs a number of tasks within an IP internetwork. In addition to the principal reason for which it was created (reporting routing failures back to the source), ICMP provides a method for testing node reachability across an internet (the ICMP Echo and Reply messages), a method for increasing routing efficiency (the ICMP Redirect message), a method for informing sources that a datagram has exceeded its allocated time to exist within an internet (the ICMP Time Exceeded message), and other helpful messages. All in all, ICMP is an integral part of any IP implementation, particularly those that run in routers.

Interior Routing Protocols
Interior Routing Protocols or IGPs operate within autonomous systems. The following sections provide brief descriptions of several IGPs that are currently popular in TCP/IP networks.

RIP
A discussion of routing protocols within an IP environment must begin with the Routing Information Protocol (RIP). RIP was developed by Xerox Corporation in the early 1980s for use in Xerox Network Systems (XNS) networks. Today, many PC networks use routing protocols based on RIP.

RIP works well in small environments but has serious limitations when used in larger internetworks. For example, RIP limits the number of router hops between any two hosts in an internet to 16. RIP is also slow to converge, meaning that it takes a relatively long time for network changes to become known to all routers. Finally, RIP determines the best path through an internet by looking only at the number of hops between the two end nodes. This technique ignores differences in line speed, line utilization, and all other metrics, many of which can be important factors in choosing the best path between two nodes. For this reason, many companies with large internets are migrating away from RIP to more sophisticated routing protocols.

IGRP
With the creation of the Interior Gateway Routing Protocol (IGRP) in the early 1980s, Cisco Systems was the first company to solve the problems associated with using RIP to route datagrams between interior routers. IGRP determines the best path through an internet by examining the bandwidth and delay of the networks between routers. IGRP converges faster than RIP, thereby avoiding the routing loops caused by disagreement over the next routing hop to be taken. Further, IGRP does not share RIP's hop count limitation. As a result of these and other improvements over RIP, IGRP enabled many large, complex, topologically diverse internetworks to be deployed.

Cisco has recently enhanced IGRP to handle the increasingly large, mission-critical networks being designed today. This new version of IGRP is called Enhanced IGRP. Enhanced IGRP combines the ease of use of traditional distance vector routing protocols with the fast rerouting capabilities of the newer link state routing protocols.

Enhanced IGRP consumes significantly less bandwidth than IGRP because it is able to limit the exchange of routing information to include only the changed information. In addition, Enhanced IGRP is capable of handling AppleTalk and Novell IPX routing information, as well as IP routing information.

OSPF
OSPF was developed by the Internet Engineering Task Force (IETF) as a replacement for RIP. OSPF is based on work started by John McQuillan in the late 1970s and continued by Radia Perlman and Digital Equipment Corporation (DEC) in the mid-1980s. Every major IP routing vendor supports OSPF.

OSPF is an intradomain, link state, hierarchical routing protocol. OSPF supports hierarchical routing within an autonomous system. Autonomous systems can be divided into routing areas. A routing area is typically a collection of one or more subnets that are closely related. All areas must connect to the backbone area.

OSPF provides fast rerouting and supports variable length subnet masks.

Integrated IS-IS
ISO 10589 (IS-IS) is an intradomain, link state, hierarchical routing protocol used as the DECnet Phase V routing algorithm. It is similar in many ways to OSPF. IS-IS can operate over a variety of subnetworks, including broadcast LANs, WANs, and point-to-point links.

Integrated IS-IS is an implementation of IS-IS for more than just OSI protocols. Today, Integrated IS-IS supports both OSI and IP protocols.

Like all integrated routing protocols, Integrated IS-IS calls for all routers to run a single routing algorithm. Link state advertisements sent by routers running Integrated IS-IS include all destinations running either IP or OSI network-layer protocols. Protocols such as ARP and ICMP for IP and End System-to-Intermediate System (ES-IS) for OSI must still be supported by routers running Integrated IS-IS.

Exterior Routing Protocols
EGPs provide routing between autonomous systems. The two most popular EGPs in the TCP/IP community are discussed in this section.

EGP
The first widespread exterior routing protocol was the Exterior Gateway Protocol. EGP provides dynamic connectivity but assumes that all autonomous systems are connected in a tree topology. This was true in the early Internet but is no longer true.

Although EGP is a dynamic routing protocol, it uses a very simple design. It does not use metrics and therefore cannot make true intelligent routing decisions. EGP routing updates contain network reachability information. In other words, they specify that certain networks are reachable through certain routers. Because of its limitations with regard to today's complex internetworks, EGP is being phased out in favor of routing protocols such as BGP.

BGP
BGP represents an attempt to address the most serious of EGP's problems. Like EGP, BGP is an interdomain routing protocol created for use in the Internet core routers. Unlike EGP, BGP was designed to prevent routing loops in arbitrary topologies and to allow policy-based route selection.

BGP was co-authored by a Cisco founder, and Cisco continues to be very involved in BGP development. The latest revision of BGP, BGP4, was designed to handle the scaling problems of the growing Internet.