Frame tagging
Frame tagging is the process where packets of data are marked to aid in identification during communication. Identifiers are placed on the headers of the packets and this enables the switches on the network to correctly recognize the packet and be able to foreword it to the correct switch within the network (Flood 56). There is a situation where the packets get lost and it is in this situation that identification is needed in order to correctly identify the node.
VTP: This is a protocol that utilizes information acquired from virtual LANs in its domain and assists in the management of VLANs on a network-wide basis. The role of management includes the renaming of VLANs, addition, and deletion of VLANs. This protocol reduces and eases the task that was carried out by the network administrator. In the past, network administrators had to do this task manually and the result was a messy network that was difficult to update and manage if the network administrator was not in the office.
MPLS
Multiprotocol label switching is a technique that utilizes and employs labels in the identification of switches within a network to enable the transfer of data packets from one node to another. The similarity that this protocol has to a VLAN is that in both there is the identification of packets between the switches within the network to enable correct forwarding of packets to the correct nodes (Flood 102).
MPLS marks data packets with one or more labels that are later switched during the process of label lookup. This type of look-up is much faster than ordinary look-ups in the IP table. This enables the entry points and exit points of the data packets to be identified and hence forwarded correctly.
MPLS IS different from VLANs as it employs label lookup as opposed to A look-up of header identifiers in the IP table which is a technique employed by VLANs.
Frequency separation being used for ADSL services is between 1Mbps for uploads streams and up to 5 Mbps for download streams. ADSL uses Frequency Division multiplexing. Copper lines are used to transmit data at high speeds. This is through a digital subscriber line access multiplexer. When this multiplexing technique is employed, voice frequency signals are separated from data traffic. Traffic from the digital subscriber line is routed between the customer’s equipment and network provider. Electrical signal frequencies are multiplexed in the copper cable in order to achieve the high data rates that are experienced by subscribers. These frequencies are spaced by some specific amount in order to reduce any chances of interference (Flood, 70).
Comparisons between DSL versions (Flood, 95).
DSL Type Distance Limit
- IDSL 18000 Feet
- GLite 18000 Feet
- HDSL 12000-18000 Feet
- SDSL 12000 Feet
- VDSL 3000-4500 Feet
Two-wire and four-wire transmission is transmission techniques that involve the use of a copper pair wire as a mode of transmitting signals. It is normal to see copper pairs in places where traditional phones were used. An Analog signal is conducted from one point to another during which it is multiplexed and modulated in order for the signal to reach the other side in the same form as it was transmitted. The received signal is then amplified to restore signal strength. Several techniques of noise cancellation are implemented such as echo cancellation (Flood, 90).
DSL technology is implemented using this mode of transmission as a splitter within DSL equipment can allow the signal to utilize low frequencies that are normally underutilized.
Pair gain is a method of maximizing the number of lines being used by customers by transmitting various signals in one twisted pair. This reduces the number of lines required to add more customers to one network. This method is not good for DSL as it involves copper wire as the mode of transmission and this cannot be used by DSL as the mode of transmission line and secondly, one pair gain line usually inputs 24 voice lines and multiplexes the lines to one, T1 where the voice channels are now transmitted to the exchange. One T1 is approximately 1.5Mbps and this has to be shared across all 24 lines. The max bandwidth that a voice channel can utilize is 56 Kbps
The case of Pair gain in Australia is that after being introduced by major telecommunication companies, DSL technologies could not reach the customers despite promises from the big companies about its implementation. This has forced the customers to either look for other solutions in order to benefit from the Internet. As discussed above, telecommunication companies had first reassured the customers that it was possible to enjoy ADSL services while still using Pair gain technology. Unfortunately, this has led to many frustrated customers and this issue has even been brought to the political arena with the ministers responsible for communication being criticized.
Works Cited
Flood, Jeremy. Telecommunication networks. London: Oxford publishers, 2007. Print.